LilyPond program-reference

# GNU LilyPond – Internals Reference

This document is also available as a PDF and as a HTML indexed multiple pages.

This is the Internals Reference (IR) for version 2.12.3 of LilyPond, the GNU music typesetter.

# 1. Music definitions

## 1.1 Music expressions

### 1.1.1 AbsoluteDynamicEvent

Create a dynamic mark.

Syntax: note`\x`, where `\x` is a dynamic mark like `\ppp` or `\sfz`. A complete list is in file ‘`ly/dynamic-scripts-init.ly`’.

Event classes: absolute-dynamic-event, dynamic-event, music-event and StreamEvent.

Accepted by: Dynamic_engraver, Dynamic_performer and New_dynamic_engraver.

Properties:

> `name` (symbol):

>   `'AbsoluteDynamicEvent`

>   Name of this music object.

> `types` (list):

>   `'(general-music event dynamic-event absolute-dynamic-event)`

>   The types of this music object; determines by what engraver this music expression is processed.

### 1.1.2 AnnotateOutputEvent

Print an annotation of an output element.

Event classes: annotate-output-event, music-event and StreamEvent.

Accepted by: Balloon_engraver.

Properties:

> `name` (symbol):

>   `'AnnotateOutputEvent`

>   Name of this music object.

> `types` (list):

>   `'(general-music event annotate-output-event)`

>   The types of this music object; determines by what engraver this music expression is processed.

### 1.1.3 ApplyContext

Call the argument with the current context during interpreting phase.

Properties:

> `name` (symbol):

>   `'ApplyContext`

>   Name of this music object.

> `types` (list):

>   `'(general-music apply-context)`

>   The types of this music object; determines by what engraver this music expression is processed.

> `iterator-ctor` (procedure):

>   `ly:apply-context-iterator::constructor`

>   Function to construct a `music-event-iterator` object for this music.

### 1.1.4 ApplyOutputEvent

Call the argument with all current grobs during interpreting phase.

Syntax: `\applyOutput #'context func`

Arguments to func are 1. the grob, 2. the originating context, and 3. the context where func is called.

Event classes: apply-output-event, layout-instruction-event, music-event and StreamEvent.

Accepted by: Output_property_engraver.

Properties:

> `name` (symbol):

>   `'ApplyOutputEvent`

>   Name of this music object.

> `types` (list):

>   `'(general-music event apply-output-event)`

>   The types of this music object; determines by what engraver this music expression is processed.

### 1.1.5 ArpeggioEvent

Make an arpeggio on this note.

Syntax: note`-\arpeggio`

Event classes: arpeggio-event, music-event and StreamEvent.

Accepted by: Arpeggio_engraver.

Properties:

> `name` (symbol):

>   `'ArpeggioEvent`

>   Name of this music object.

> `types` (list):

>   `'(general-music arpeggio-event event)`

>   The types of this music object; determines by what engraver this music expression is processed.

### 1.1.6 ArticulationEvent

Add an articulation marking to a note.

Syntax: note`x` `y`, where `x` is a direction (`^` for up or `_` for down), or LilyPond’s choice (no direction specified)), and where `y` is an articulation (such as `-.`, `->`, `\tenuto`, `\downbow`). See the Notation Reference for details.

Event classes: articulation-event, script-event, music-event and StreamEvent.

Accepted by: Script_engraver.

Properties:

> `name` (symbol):

>   `'ArticulationEvent`

>   Name of this music object.

> `types` (list):

>   `'(general-music event articulation-event script-event)`

>   The types of this music object; determines by what engraver this music expression is processed.

### 1.1.7 AutoChangeMusic

Used for making voices that switch between piano staves automatically.

Properties:

> `name` (symbol):

>   `'AutoChangeMusic`

>   Name of this music object.

> `iterator-ctor` (procedure):

>   `ly:auto-change-iterator::constructor`

>   Function to construct a `music-event-iterator` object for this music.

> `start-callback` (procedure):

>   `ly:music-wrapper::start-callback`

>   Function to compute the negative length of starting grace notes. This property can only be defined as initializer in ‘`scm/define-music-types.scm`’.

> `length-callback` (procedure):

>   `ly:music-wrapper::length-callback`

>   How to compute the duration of this music. This property can only be defined as initializer in ‘`scm/define-music-types.scm`’.

> `types` (list):

>   `'(general-music music-wrapper-music auto-change-instruction)`

>   The types of this music object; determines by what engraver this music expression is processed.

### 1.1.8 BarCheck

Check whether this music coincides with the start of the measure.

Properties:

> `name` (symbol):

>   `'BarCheck`

>   Name of this music object.

> `types` (list):

>   `'(general-music bar-check)`

>   The types of this music object; determines by what engraver this music expression is processed.

> `iterator-ctor` (procedure):

>   `ly:bar-check-iterator::constructor`

>   Function to construct a `music-event-iterator` object for this music.

### 1.1.9 BassFigureEvent

Print a bass-figure text.

Event classes: bass-figure-event, rhythmic-event, music-event and StreamEvent.

Accepted by: Figured_bass_engraver.

Properties:

> `name` (symbol):

>   `'BassFigureEvent`

>   Name of this music object.

> `types` (list):

>   `'(general-music event rhythmic-event bass-figure-event)`

>   The types of this music object; determines by what engraver this music expression is processed.

### 1.1.10 BeamEvent

Start or stop a beam.

Syntax for manual control: `c8-[ c c-] c8`

Event classes: beam-event, span-event, music-event and StreamEvent.

Accepted by: Beam_engraver, Beam_performer and Grace_beam_engraver.

Properties:

> `name` (symbol):

>   `'BeamEvent`

>   Name of this music object.

> `types` (list):

>   `'(general-music event beam-event span-event)`

>   The types of this music object; determines by what engraver this music expression is processed.

### 1.1.11 BeamForbidEvent

Specify that a note may not auto-beamed.

Event classes: beam-forbid-event, music-event and StreamEvent.

Accepted by: Auto_beam_engraver.

Properties:

> `name` (symbol):

>   `'BeamForbidEvent`

>   Name of this music object.

> `types` (list):

>   `'(general-music event beam-forbid-event)`

>   The types of this music object; determines by what engraver this music expression is processed.

### 1.1.12 BendAfterEvent

A drop/fall/doit jazz articulation.

Event classes: bend-after-event, music-event and StreamEvent.

Accepted by: Bend_engraver.

Properties:

> `name` (symbol):

>   `'BendAfterEvent`

>   Name of this music object.

> `types` (list):

>   `'(general-music bend-after-event event)`

>   The types of this music object; determines by what engraver this music expression is processed.

### 1.1.13 BreathingEvent

Create a ‘breath mark’ or ‘comma’.

Syntax: note`\breathe`

Event classes: breathing-event, music-event and StreamEvent.

Accepted by: Breathing_sign_engraver.

Properties:

> `name` (symbol):

>   `'BreathingEvent`

>   Name of this music object.

> `types` (list):

>   `'(general-music event breathing-event)`

>   The types of this music object; determines by what engraver this music expression is processed.

### 1.1.14 ClusterNoteEvent

A note that is part of a cluster.

Event classes: cluster-note-event, melodic-event, rhythmic-event, music-event and StreamEvent.

Accepted by: Cluster_spanner_engraver.

Properties:

> `name` (symbol):

>   `'ClusterNoteEvent`

>   Name of this music object.

> `types` (list):

>   `'(general-music cluster-note-event melodic-event rhythmic-event event)`

>   The types of this music object; determines by what engraver this music expression is processed.

### 1.1.15 ContextChange

Change staves in Piano staff.

Syntax: `\change Staff = new-id`

Properties:

> `name` (symbol):

>   `'ContextChange`

>   Name of this music object.

> `iterator-ctor` (procedure):

>   `ly:change-iterator::constructor`

>   Function to construct a `music-event-iterator` object for this music.

> `types` (list):

>   `'(general-music translator-change-instruction)`

>   The types of this music object; determines by what engraver this music expression is processed.

### 1.1.16 ContextSpeccedMusic

Interpret the argument music within a specific context.

Properties:

> `name` (symbol):

>   `'ContextSpeccedMusic`

>   Name of this music object.

> `iterator-ctor` (procedure):

>   `ly:context-specced-music-iterator::constructor`

>   Function to construct a `music-event-iterator` object for this music.

> `length-callback` (procedure):

>   `ly:music-wrapper::length-callback`

>   How to compute the duration of this music. This property can only be defined as initializer in ‘`scm/define-music-types.scm`’.

> `start-callback` (procedure):

>   `ly:music-wrapper::start-callback`

>   Function to compute the negative length of starting grace notes. This property can only be defined as initializer in ‘`scm/define-music-types.scm`’.

> `types` (list):

>   `'(context-specification general-music music-wrapper-music)`

>   The types of this music object; determines by what engraver this music expression is processed.

### 1.1.17 CrescendoEvent

Begin or end a crescendo.

Syntax: note`\cr` … note`\rc`

You can also use `\<`, `\!`, `\cresc`, and `\endcresc`. See the Notation Reference for details.

Event classes: crescendo-event, span-dynamic-event, span-event, music-event and StreamEvent.

Accepted by: Dynamic_engraver, Dynamic_performer and New_dynamic_engraver.

Properties:

> `name` (symbol):

>   `'CrescendoEvent`

>   Name of this music object.

> `types` (list):

>   `'(general-music span-event span-dynamic-event crescendo-event event)`

>   The types of this music object; determines by what engraver this music expression is processed.

### 1.1.18 DecrescendoEvent

See CrescendoEvent.

Event classes: decrescendo-event, span-dynamic-event, span-event, music-event and StreamEvent.

Accepted by: Dynamic_engraver, Dynamic_performer and New_dynamic_engraver.

Properties:

> `name` (symbol):

>   `'DecrescendoEvent`

>   Name of this music object.

> `types` (list):

>   `'(general-music span-event span-dynamic-event decrescendo-event event)`

>   The types of this music object; determines by what engraver this music expression is processed.

### 1.1.19 Event

Atomic music event.

Properties:

> `name` (symbol):

>   `'Event`

>   Name of this music object.

> `types` (list):

>   `'(general-music event)`

>   The types of this music object; determines by what engraver this music expression is processed.

### 1.1.20 EventChord

Internally used to group a set of events.

Properties:

> `name` (symbol):

>   `'EventChord`

>   Name of this music object.

> `iterator-ctor` (procedure):

>   `ly:event-chord-iterator::constructor`

>   Function to construct a `music-event-iterator` object for this music.

> `length-callback` (procedure):

>   `ly:music-sequence::maximum-length-callback`

>   How to compute the duration of this music. This property can only be defined as initializer in ‘`scm/define-music-types.scm`’.

> `to-relative-callback` (procedure):

>   `ly:music-sequence::event-chord-relative-callback`

>   How to transform a piece of music to relative pitches.

> `types` (list):

>   `'(general-music event-chord simultaneous-music)`

>   The types of this music object; determines by what engraver this music expression is processed.

### 1.1.21 ExtenderEvent

Extend lyrics.

Event classes: extender-event, music-event and StreamEvent.

Accepted by: Extender_engraver.

Properties:

> `name` (symbol):

>   `'ExtenderEvent`

>   Name of this music object.

> `types` (list):

>   `'(general-music extender-event event)`

>   The types of this music object; determines by what engraver this music expression is processed.

### 1.1.22 FingeringEvent

Specify what finger to use for this note.

Event classes: fingering-event, music-event and StreamEvent.

Accepted by: Fingering_engraver.

Properties:

> `name` (symbol):

>   `'FingeringEvent`

>   Name of this music object.

> `types` (list):

>   `'(general-music fingering-event event)`

>   The types of this music object; determines by what engraver this music expression is processed.

### 1.1.23 GlissandoEvent

Start a glissando on this note.

Event classes: glissando-event, music-event and StreamEvent.

Accepted by: Glissando_engraver.

Properties:

> `name` (symbol):

>   `'GlissandoEvent`

>   Name of this music object.

> `types` (list):

>   `'(general-music glissando-event event)`

>   The types of this music object; determines by what engraver this music expression is processed.

### 1.1.24 GraceMusic

Interpret the argument as grace notes.

Properties:

> `name` (symbol):

>   `'GraceMusic`

>   Name of this music object.

> `start-callback` (procedure):

>   `ly:grace-music::start-callback`

>   Function to compute the negative length of starting grace notes. This property can only be defined as initializer in ‘`scm/define-music-types.scm`’.

> `length` (moment):

>   `#<Mom 0>`

>   The duration of this music.

> `iterator-ctor` (procedure):

>   `ly:grace-iterator::constructor`

>   Function to construct a `music-event-iterator` object for this music.

> `types` (list):

>   `'(grace-music music-wrapper-music general-music)`

>   The types of this music object; determines by what engraver this music expression is processed.

### 1.1.25 HarmonicEvent

Mark a note as harmonic.

Event classes: harmonic-event, music-event and StreamEvent.

Not accepted by any engraver or performer.

Properties:

> `name` (symbol):

>   `'HarmonicEvent`

>   Name of this music object.

> `types` (list):

>   `'(general-music event harmonic-event)`

>   The types of this music object; determines by what engraver this music expression is processed.

### 1.1.26 HyphenEvent

A hyphen between lyric syllables.

Event classes: hyphen-event, music-event and StreamEvent.

Accepted by: Hyphen_engraver.

Properties:

> `name` (symbol):

>   `'HyphenEvent`

>   Name of this music object.

> `types` (list):

>   `'(general-music hyphen-event event)`

>   The types of this music object; determines by what engraver this music expression is processed.

### 1.1.27 KeyChangeEvent

Change the key signature.

Syntax: `\key` name scale

Event classes: key-change-event, music-event and StreamEvent.

Accepted by: Key_engraver and Key_performer.

Properties:

> `name` (symbol):

>   `'KeyChangeEvent`

>   Name of this music object.

> `to-relative-callback` (procedure):

>   `#<procedure #f (x p)>`

>   How to transform a piece of music to relative pitches.

> `types` (list):

>   `'(general-music key-change-event event)`

>   The types of this music object; determines by what engraver this music expression is processed.

### 1.1.28 LabelEvent

Place a bookmarking label.

Event classes: label-event, music-event and StreamEvent.

Accepted by: Paper_column_engraver.

Properties:

> `name` (symbol):

>   `'LabelEvent`

>   Name of this music object.

> `types` (list):

>   `'(general-music label-event event)`

>   The types of this music object; determines by what engraver this music expression is processed.

### 1.1.29 LaissezVibrerEvent

Don’t damp this chord.

Syntax: note`\laissezVibrer`

Event classes: laissez-vibrer-event, music-event and StreamEvent.

Accepted by: Laissez_vibrer_engraver.

Properties:

> `name` (symbol):

>   `'LaissezVibrerEvent`

>   Name of this music object.

> `types` (list):

>   `'(general-music event laissez-vibrer-event)`

>   The types of this music object; determines by what engraver this music expression is processed.

### 1.1.30 LigatureEvent

Start or end a ligature.

Event classes: ligature-event, span-event, music-event and StreamEvent.

Accepted by: Ligature_bracket_engraver, Mensural_ligature_engraver and Vaticana_ligature_engraver.

Properties:

> `name` (symbol):

>   `'LigatureEvent`

>   Name of this music object.

> `span-type` (string):

>   `'ligature`

>   What kind of spanner should be created?

>   TODO: Consider making type into symbol.

> `types` (list):

>   `'(general-music span-event ligature-event event)`

>   The types of this music object; determines by what engraver this music expression is processed.

### 1.1.31 LineBreakEvent

Allow, forbid or force a line break.

Event classes: line-break-event, break-event, music-event and StreamEvent.

Accepted by: Page_turn_engraver and Paper_column_engraver.

Properties:

> `name` (symbol):

>   `'LineBreakEvent`

>   Name of this music object.

> `types` (list):

>   `'(general-music line-break-event break-event event)`

>   The types of this music object; determines by what engraver this music expression is processed.

### 1.1.32 LyricCombineMusic

Align lyrics to the start of notes.

Syntax: `\lyricsto` voicename lyrics

Properties:

> `name` (symbol):

>   `'LyricCombineMusic`

>   Name of this music object.

> `length` (moment):

>   `#<Mom 0>`

>   The duration of this music.

> `types` (list):

>   `'(general-music lyric-combine-music)`

>   The types of this music object; determines by what engraver this music expression is processed.

> `iterator-ctor` (procedure):

>   `ly:lyric-combine-music-iterator::constructor`

>   Function to construct a `music-event-iterator` object for this music.

### 1.1.33 LyricEvent

A lyric syllable. Must be entered in lyrics mode, i.e., `\lyrics { twinkle4 twinkle4 }` .

Event classes: lyric-event, rhythmic-event, music-event and StreamEvent.

Accepted by: Lyric_engraver and Lyric_performer.

Properties:

> `name` (symbol):

>   `'LyricEvent`

>   Name of this music object.

> `types` (list):

>   `'(general-music rhythmic-event lyric-event event)`

>   The types of this music object; determines by what engraver this music expression is processed.

### 1.1.34 MarkEvent

Insert a rehearsal mark.

Syntax: `\mark` marker

Example: `\mark "A"`

Event classes: mark-event, music-event and StreamEvent.

Accepted by: Mark_engraver.

Properties:

> `name` (symbol):

>   `'MarkEvent`

>   Name of this music object.

> `types` (list):

>   `'(general-music mark-event event)`

>   The types of this music object; determines by what engraver this music expression is processed.

### 1.1.35 MultiMeasureRestEvent

Used internally by `MultiMeasureRestMusic` to signal rests.

Event classes: multi-measure-rest-event, rhythmic-event, music-event and StreamEvent.

Accepted by: Multi_measure_rest_engraver.

Properties:

> `name` (symbol):

>   `'MultiMeasureRestEvent`

>   Name of this music object.

> `types` (list):

>   `'(general-music event rhythmic-event multi-measure-rest-event)`

>   The types of this music object; determines by what engraver this music expression is processed.

### 1.1.36 MultiMeasureRestMusic

Rests that may be compressed into Multi rests.

Syntax: `R2.*4` for 4 measures in 3/4 time.

Properties:

> `name` (symbol):

>   `'MultiMeasureRestMusic`

>   Name of this music object.

> `iterator-ctor` (procedure):

>   `ly:sequential-iterator::constructor`

>   Function to construct a `music-event-iterator` object for this music.

> `elements-callback` (procedure):

>   `mm-rest-child-list`

>   Return a list of children, for use by a sequential iterator. Takes a single music parameter.

> `types` (list):

>   `'(general-music multi-measure-rest)`

>   The types of this music object; determines by what engraver this music expression is processed.

### 1.1.37 MultiMeasureTextEvent

Texts on multi measure rests.

Syntax: `R-\markup { \roman "bla" }`

Note the explicit font switch.

Event classes: multi-measure-text-event, music-event and StreamEvent.

Accepted by: Multi_measure_rest_engraver.

Properties:

> `name` (symbol):

>   `'MultiMeasureTextEvent`

>   Name of this music object.

> `types` (list):

>   `'(general-music event multi-measure-text-event)`

>   The types of this music object; determines by what engraver this music expression is processed.

### 1.1.38 Music

Generic type for music expressions.

Properties:

> `name` (symbol):

>   `'Music`

>   Name of this music object.

> `types` (list):

>   `'(general-music)`

>   The types of this music object; determines by what engraver this music expression is processed.

### 1.1.39 NoteEvent

A note.

Event classes: note-event, melodic-event, rhythmic-event, music-event and StreamEvent.

Accepted by: Chord_name_engraver, Completion_heads_engraver, Drum_note_performer, Drum_notes_engraver, Fretboard_engraver, Note_heads_engraver, Note_name_engraver, Note_performer and Tab_note_heads_engraver.

Properties:

> `name` (symbol):

>   `'NoteEvent`

>   Name of this music object.

> `types` (list):

>   `'(general-music event note-event rhythmic-event melodic-event)`

>   The types of this music object; determines by what engraver this music expression is processed.

### 1.1.40 NoteGroupingEvent

Start or stop grouping brackets.

Event classes: note-grouping-event, music-event and StreamEvent.

Accepted by: Horizontal_bracket_engraver.

Properties:

> `name` (symbol):

>   `'NoteGroupingEvent`

>   Name of this music object.

> `types` (list):

>   `'(general-music event note-grouping-event)`

>   The types of this music object; determines by what engraver this music expression is processed.

### 1.1.41 OverrideProperty

Extend the definition of a graphical object.

Syntax: `\override` [ context `.` ] object property `=` value

Properties:

> `name` (symbol):

>   `'OverrideProperty`

>   Name of this music object.

> `types` (list):

>   `'(general-music layout-instruction-event override-property-event)`

>   The types of this music object; determines by what engraver this music expression is processed.

> `iterator-ctor` (procedure):

>   `ly:push-property-iterator::constructor`

>   Function to construct a `music-event-iterator` object for this music.

### 1.1.42 PageBreakEvent

Allow, forbid or force a page break.

Event classes: page-break-event, break-event, music-event and StreamEvent.

Accepted by: Page_turn_engraver and Paper_column_engraver.

Properties:

> `name` (symbol):

>   `'PageBreakEvent`

>   Name of this music object.

> `types` (list):

>   `'(general-music break-event page-break-event event)`

>   The types of this music object; determines by what engraver this music expression is processed.

### 1.1.43 PageTurnEvent

Allow, forbid or force a page turn.

Event classes: page-turn-event, break-event, music-event and StreamEvent.

Accepted by: Page_turn_engraver and Paper_column_engraver.

Properties:

> `name` (symbol):

>   `'PageTurnEvent`

>   Name of this music object.

> `types` (list):

>   `'(general-music break-event page-turn-event event)`

>   The types of this music object; determines by what engraver this music expression is processed.

### 1.1.44 PartCombineMusic

Combine two parts on a staff, either merged or as separate voices.

Properties:

> `name` (symbol):

>   `'PartCombineMusic`

>   Name of this music object.

> `length-callback` (procedure):

>   `ly:music-sequence::maximum-length-callback`

>   How to compute the duration of this music. This property can only be defined as initializer in ‘`scm/define-music-types.scm`’.

> `start-callback` (procedure):

>   `ly:music-sequence::minimum-start-callback`

>   Function to compute the negative length of starting grace notes. This property can only be defined as initializer in ‘`scm/define-music-types.scm`’.

> `types` (list):

>   `'(general-music part-combine-music)`

>   The types of this music object; determines by what engraver this music expression is processed.

> `iterator-ctor` (procedure):

>   `ly:part-combine-iterator::constructor`

>   Function to construct a `music-event-iterator` object for this music.

### 1.1.45 PercentEvent

Used internally to signal percent repeats.

Event classes: percent-event, rhythmic-event, music-event and StreamEvent.

Accepted by: Percent_repeat_engraver and Slash_repeat_engraver.

Properties:

> `name` (symbol):

>   `'PercentEvent`

>   Name of this music object.

> `types` (list):

>   `'(general-music event percent-event rhythmic-event)`

>   The types of this music object; determines by what engraver this music expression is processed.

### 1.1.46 PercentRepeatedMusic

Repeats encoded by percents.

Properties:

> `name` (symbol):

>   `'PercentRepeatedMusic`

>   Name of this music object.

> `iterator-ctor` (procedure):

>   `ly:percent-repeat-iterator::constructor`

>   Function to construct a `music-event-iterator` object for this music.

> `start-callback` (procedure):

>   `ly:repeated-music::first-start`

>   Function to compute the negative length of starting grace notes. This property can only be defined as initializer in ‘`scm/define-music-types.scm`’.

> `length-callback` (procedure):

>   `ly:repeated-music::unfolded-music-length`

>   How to compute the duration of this music. This property can only be defined as initializer in ‘`scm/define-music-types.scm`’.

> `types` (list):

>   `'(general-music repeated-music percent-repeated-music)`

>   The types of this music object; determines by what engraver this music expression is processed.

### 1.1.47 PesOrFlexaEvent

Within a ligature, mark the previous and the following note to form a pes (if melody goes up) or a flexa (if melody goes down).

Event classes: pes-or-flexa-event, music-event and StreamEvent.

Accepted by: Vaticana_ligature_engraver.

Properties:

> `name` (symbol):

>   `'PesOrFlexaEvent`

>   Name of this music object.

> `types` (list):

>   `'(general-music pes-or-flexa-event event)`

>   The types of this music object; determines by what engraver this music expression is processed.

### 1.1.48 PhrasingSlurEvent

Start or end phrasing slur.

Syntax: note`\(` and note`\)`

Event classes: phrasing-slur-event, span-event, music-event and StreamEvent.

Accepted by: Phrasing_slur_engraver.

Properties:

> `name` (symbol):

>   `'PhrasingSlurEvent`

>   Name of this music object.

> `types` (list):

>   `'(general-music span-event event phrasing-slur-event)`

>   The types of this music object; determines by what engraver this music expression is processed.

### 1.1.49 PropertySet

Set a context property.

Syntax: `\property context.prop = scheme-val`

Properties:

> `name` (symbol):

>   `'PropertySet`

>   Name of this music object.

> `types` (list):

>   `'(layout-instruction-event general-music)`

>   The types of this music object; determines by what engraver this music expression is processed.

> `iterator-ctor` (procedure):

>   `ly:property-iterator::constructor`

>   Function to construct a `music-event-iterator` object for this music.

### 1.1.50 PropertyUnset

Remove the definition of a context `\property`.

Properties:

> `name` (symbol):

>   `'PropertyUnset`

>   Name of this music object.

> `types` (list):

>   `'(layout-instruction-event general-music)`

>   The types of this music object; determines by what engraver this music expression is processed.

> `iterator-ctor` (procedure):

>   `ly:property-unset-iterator::constructor`

>   Function to construct a `music-event-iterator` object for this music.

### 1.1.51 QuoteMusic

Quote preprocessed snippets of music.

Properties:

> `name` (symbol):

>   `'QuoteMusic`

>   Name of this music object.

> `iterator-ctor` (procedure):

>   `ly:music-wrapper-iterator::constructor`

>   Function to construct a `music-event-iterator` object for this music.

> `length-callback` (procedure):

>   `ly:music-wrapper::length-callback`

>   How to compute the duration of this music. This property can only be defined as initializer in ‘`scm/define-music-types.scm`’.

> `start-callback` (procedure):

>   `ly:music-wrapper::start-callback`

>   Function to compute the negative length of starting grace notes. This property can only be defined as initializer in ‘`scm/define-music-types.scm`’.

> `types` (list):

>   `'(general-music music-wrapper-music)`

>   The types of this music object; determines by what engraver this music expression is processed.

### 1.1.52 RelativeOctaveCheck

Check if a pitch is in the correct octave.

Properties:

> `name` (symbol):

>   `'RelativeOctaveCheck`

>   Name of this music object.

> `to-relative-callback` (procedure):

>   `ly:relative-octave-check::relative-callback`

>   How to transform a piece of music to relative pitches.

> `types` (list):

>   `'(general-music relative-octave-check)`

>   The types of this music object; determines by what engraver this music expression is processed.

### 1.1.53 RelativeOctaveMusic

Music that was entered in relative octave notation.

Properties:

> `name` (symbol):

>   `'RelativeOctaveMusic`

>   Name of this music object.

> `to-relative-callback` (procedure):

>   `ly:relative-octave-music::relative-callback`

>   How to transform a piece of music to relative pitches.

> `iterator-ctor` (procedure):

>   `ly:music-wrapper-iterator::constructor`

>   Function to construct a `music-event-iterator` object for this music.

> `length-callback` (procedure):

>   `ly:music-wrapper::length-callback`

>   How to compute the duration of this music. This property can only be defined as initializer in ‘`scm/define-music-types.scm`’.

> `start-callback` (procedure):

>   `ly:music-wrapper::start-callback`

>   Function to compute the negative length of starting grace notes. This property can only be defined as initializer in ‘`scm/define-music-types.scm`’.

> `types` (list):

>   `'(music-wrapper-music general-music relative-octave-music)`

>   The types of this music object; determines by what engraver this music expression is processed.

### 1.1.54 RepeatTieEvent

Ties for starting a second volta bracket.

Event classes: repeat-tie-event, music-event and StreamEvent.

Accepted by: Repeat_tie_engraver.

Properties:

> `name` (symbol):

>   `'RepeatTieEvent`

>   Name of this music object.

> `types` (list):

>   `'(general-music event repeat-tie-event)`

>   The types of this music object; determines by what engraver this music expression is processed.

### 1.1.55 RepeatedMusic

Repeat music in different ways.

Properties:

> `name` (symbol):

>   `'RepeatedMusic`

>   Name of this music object.

> `types` (list):

>   `'(general-music repeated-music)`

>   The types of this music object; determines by what engraver this music expression is processed.

### 1.1.56 RestEvent

A Rest.

Syntax: `r4` for a quarter rest.

Event classes: rest-event, rhythmic-event, music-event and StreamEvent.

Accepted by: Figured_bass_engraver and Rest_engraver.

Properties:

> `name` (symbol):

>   `'RestEvent`

>   Name of this music object.

> `types` (list):

>   `'(general-music event rhythmic-event rest-event)`

>   The types of this music object; determines by what engraver this music expression is processed.

### 1.1.57 RevertProperty

The opposite of OverrideProperty: remove a previously added property from a graphical object definition.

Properties:

> `name` (symbol):

>   `'RevertProperty`

>   Name of this music object.

> `types` (list):

>   `'(general-music layout-instruction-event)`

>   The types of this music object; determines by what engraver this music expression is processed.

> `iterator-ctor` (procedure):

>   `ly:pop-property-iterator::constructor`

>   Function to construct a `music-event-iterator` object for this music.

### 1.1.58 ScriptEvent

Add an articulation mark to a note.

Event classes: script-event, music-event and StreamEvent.

Not accepted by any engraver or performer.

Properties:

> `name` (symbol):

>   `'ScriptEvent`

>   Name of this music object.

> `types` (list):

>   `'(general-music event)`

>   The types of this music object; determines by what engraver this music expression is processed.

### 1.1.59 SequentialMusic

Music expressions concatenated.

Syntax: `\sequential { … }` or simply `{ … }`

Properties:

> `name` (symbol):

>   `'SequentialMusic`

>   Name of this music object.

> `length-callback` (procedure):

>   `ly:music-sequence::cumulative-length-callback`

>   How to compute the duration of this music. This property can only be defined as initializer in ‘`scm/define-music-types.scm`’.

> `start-callback` (procedure):

>   `ly:music-sequence::first-start-callback`

>   Function to compute the negative length of starting grace notes. This property can only be defined as initializer in ‘`scm/define-music-types.scm`’.

> `elements-callback` (procedure):

>   `#<procedure #f (m)>`

>   Return a list of children, for use by a sequential iterator. Takes a single music parameter.

> `iterator-ctor` (procedure):

>   `ly:sequential-iterator::constructor`

>   Function to construct a `music-event-iterator` object for this music.

> `types` (list):

>   `'(general-music sequential-music)`

>   The types of this music object; determines by what engraver this music expression is processed.

### 1.1.60 SimultaneousMusic

Music playing together.

Syntax: `\simultaneous { … }` or `<< … >>`

Properties:

> `name` (symbol):

>   `'SimultaneousMusic`

>   Name of this music object.

> `iterator-ctor` (procedure):

>   `ly:simultaneous-music-iterator::constructor`

>   Function to construct a `music-event-iterator` object for this music.

> `start-callback` (procedure):

>   `ly:music-sequence::minimum-start-callback`

>   Function to compute the negative length of starting grace notes. This property can only be defined as initializer in ‘`scm/define-music-types.scm`’.

> `length-callback` (procedure):

>   `ly:music-sequence::maximum-length-callback`

>   How to compute the duration of this music. This property can only be defined as initializer in ‘`scm/define-music-types.scm`’.

> `to-relative-callback` (procedure):

>   `ly:music-sequence::simultaneous-relative-callback`

>   How to transform a piece of music to relative pitches.

> `types` (list):

>   `'(general-music simultaneous-music)`

>   The types of this music object; determines by what engraver this music expression is processed.

### 1.1.61 SkipEvent

Filler that takes up duration, but does not print anything.

Syntax: `s4` for a skip equivalent to a quarter rest.

Event classes: skip-event, rhythmic-event, music-event and StreamEvent.

Not accepted by any engraver or performer.

Properties:

> `name` (symbol):

>   `'SkipEvent`

>   Name of this music object.

> `types` (list):

>   `'(general-music event rhythmic-event skip-event)`

>   The types of this music object; determines by what engraver this music expression is processed.

### 1.1.62 SkipMusic

Filler that takes up duration, does not print anything, and also does not create staves or voices implicitly.

Syntax: `\skip` duration

Properties:

> `name` (symbol):

>   `'SkipMusic`

>   Name of this music object.

> `length-callback` (procedure):

>   `ly:music-duration-length`

>   How to compute the duration of this music. This property can only be defined as initializer in ‘`scm/define-music-types.scm`’.

> `iterator-ctor` (procedure):

>   `ly:simple-music-iterator::constructor`

>   Function to construct a `music-event-iterator` object for this music.

> `types` (list):

>   `'(general-music event rhythmic-event skip-event)`

>   The types of this music object; determines by what engraver this music expression is processed.

### 1.1.63 SlurEvent

Start or end slur.

Syntax: note`(` and note`)`

Event classes: slur-event, span-event, music-event and StreamEvent.

Accepted by: Slur_engraver and Slur_performer.

Properties:

> `name` (symbol):

>   `'SlurEvent`

>   Name of this music object.

> `types` (list):

>   `'(general-music span-event event slur-event)`

>   The types of this music object; determines by what engraver this music expression is processed.

### 1.1.64 SoloOneEvent

Print ‘Solo 1’.

Event classes: solo-one-event, part-combine-event, music-event and StreamEvent.

Accepted by: Part_combine_engraver.

Properties:

> `name` (symbol):

>   `'SoloOneEvent`

>   Name of this music object.

> `part-combine-status` (symbol):

>   `'solo1`

>   Change to what kind of state? Options are `solo1`, `solo2` and `unisono`.

> `types` (list):

>   `'(general-music event part-combine-event solo-one-event)`

>   The types of this music object; determines by what engraver this music expression is processed.

### 1.1.65 SoloTwoEvent

Print ‘Solo 2’.

Event classes: solo-two-event, part-combine-event, music-event and StreamEvent.

Accepted by: Part_combine_engraver.

Properties:

> `name` (symbol):

>   `'SoloTwoEvent`

>   Name of this music object.

> `part-combine-status` (symbol):

>   `'solo2`

>   Change to what kind of state? Options are `solo1`, `solo2` and `unisono`.

> `types` (list):

>   `'(general-music event part-combine-event solo-two-event)`

>   The types of this music object; determines by what engraver this music expression is processed.

### 1.1.66 SostenutoEvent

Depress or release sostenuto pedal.

Event classes: sostenuto-event, pedal-event, span-event, music-event and StreamEvent.

Accepted by: Piano_pedal_engraver and Piano_pedal_performer.

Properties:

> `name` (symbol):

>   `'SostenutoEvent`

>   Name of this music object.

> `types` (list):

>   `'(general-music event pedal-event sostenuto-event)`

>   The types of this music object; determines by what engraver this music expression is processed.

### 1.1.67 SpacingSectionEvent

Start a new spacing section.

Event classes: spacing-section-event, music-event and StreamEvent.

Accepted by: Spacing_engraver.

Properties:

> `name` (symbol):

>   `'SpacingSectionEvent`

>   Name of this music object.

> `types` (list):

>   `'(general-music event spacing-section-event)`

>   The types of this music object; determines by what engraver this music expression is processed.

### 1.1.68 SpanEvent

Event for anything that is started at a different time than stopped.

Event classes: span-event, music-event and StreamEvent.

Not accepted by any engraver or performer.

Properties:

> `name` (symbol):

>   `'SpanEvent`

>   Name of this music object.

> `types` (list):

>   `'(general-music event)`

>   The types of this music object; determines by what engraver this music expression is processed.

### 1.1.69 StaffSpanEvent

Start or stop a staff symbol.

Event classes: staff-span-event, span-event, music-event and StreamEvent.

Accepted by: Staff_symbol_engraver.

Properties:

> `name` (symbol):

>   `'StaffSpanEvent`

>   Name of this music object.

> `types` (list):

>   `'(general-music event span-event staff-span-event)`

>   The types of this music object; determines by what engraver this music expression is processed.

### 1.1.70 StringNumberEvent

Specify on which string to play this note.

Syntax: `\number`

Event classes: string-number-event, music-event and StreamEvent.

Accepted by: Fretboard_engraver and Tab_note_heads_engraver.

Properties:

> `name` (symbol):

>   `'StringNumberEvent`

>   Name of this music object.

> `types` (list):

>   `'(general-music string-number-event event)`

>   The types of this music object; determines by what engraver this music expression is processed.

### 1.1.71 StrokeFingerEvent

Specify with which finger to pluck a string.

Syntax: `\rightHandFinger text`

Event classes: stroke-finger-event, music-event and StreamEvent.

Accepted by: Fingering_engraver.

Properties:

> `name` (symbol):

>   `'StrokeFingerEvent`

>   Name of this music object.

> `types` (list):

>   `'(general-music stroke-finger-event event)`

>   The types of this music object; determines by what engraver this music expression is processed.

### 1.1.72 SustainEvent

Depress or release sustain pedal.

Event classes: sustain-event, pedal-event, span-event, music-event and StreamEvent.

Accepted by: Piano_pedal_engraver and Piano_pedal_performer.

Properties:

> `name` (symbol):

>   `'SustainEvent`

>   Name of this music object.

> `types` (list):

>   `'(general-music event pedal-event sustain-event)`

>   The types of this music object; determines by what engraver this music expression is processed.

### 1.1.73 TextScriptEvent

Print text.

Event classes: text-script-event, script-event, music-event and StreamEvent.

Accepted by: Text_engraver.

Properties:

> `name` (symbol):

>   `'TextScriptEvent`

>   Name of this music object.

> `types` (list):

>   `'(general-music script-event text-script-event event)`

>   The types of this music object; determines by what engraver this music expression is processed.

### 1.1.74 TextSpanEvent

Start a text spanner, e.g., 8va.....|

Event classes: text-span-event, span-event, music-event and StreamEvent.

Accepted by: Text_spanner_engraver.

Properties:

> `name` (symbol):

>   `'TextSpanEvent`

>   Name of this music object.

> `types` (list):

>   `'(general-music span-event event text-span-event)`

>   The types of this music object; determines by what engraver this music expression is processed.

### 1.1.75 TieEvent

A tie.

Syntax: note`-~`

Event classes: tie-event, music-event and StreamEvent.

Accepted by: Completion_heads_engraver, Tie_engraver and Tie_performer.

Properties:

> `name` (symbol):

>   `'TieEvent`

>   Name of this music object.

> `types` (list):

>   `'(general-music tie-event event)`

>   The types of this music object; determines by what engraver this music expression is processed.

### 1.1.76 TimeScaledMusic

Multiply durations, as in tuplets.

Syntax: `\times fraction music`, e.g. `\times 2/3 { … }` for triplets.

Properties:

> `name` (symbol):

>   `'TimeScaledMusic`

>   Name of this music object.

> `length-callback` (procedure):

>   `ly:music-wrapper::length-callback`

>   How to compute the duration of this music. This property can only be defined as initializer in ‘`scm/define-music-types.scm`’.

> `start-callback` (procedure):

>   `ly:music-wrapper::start-callback`

>   Function to compute the negative length of starting grace notes. This property can only be defined as initializer in ‘`scm/define-music-types.scm`’.

> `iterator-ctor` (procedure):

>   `ly:time-scaled-music-iterator::constructor`

>   Function to construct a `music-event-iterator` object for this music.

> `types` (list):

>   `'(time-scaled-music music-wrapper-music general-music)`

>   The types of this music object; determines by what engraver this music expression is processed.

### 1.1.77 TransposedMusic

Music that has been transposed.

Properties:

> `name` (symbol):

>   `'TransposedMusic`

>   Name of this music object.

> `iterator-ctor` (procedure):

>   `ly:music-wrapper-iterator::constructor`

>   Function to construct a `music-event-iterator` object for this music.

> `start-callback` (procedure):

>   `ly:music-wrapper::start-callback`

>   Function to compute the negative length of starting grace notes. This property can only be defined as initializer in ‘`scm/define-music-types.scm`’.

> `length-callback` (procedure):

>   `ly:music-wrapper::length-callback`

>   How to compute the duration of this music. This property can only be defined as initializer in ‘`scm/define-music-types.scm`’.

> `to-relative-callback` (procedure):

>   `ly:relative-octave-music::no-relative-callback`

>   How to transform a piece of music to relative pitches.

> `types` (list):

>   `'(music-wrapper-music general-music transposed-music)`

>   The types of this music object; determines by what engraver this music expression is processed.

### 1.1.78 TremoloEvent

Unmeasured tremolo.

Event classes: tremolo-event, music-event and StreamEvent.

Accepted by: Stem_engraver.

Properties:

> `name` (symbol):

>   `'TremoloEvent`

>   Name of this music object.

> `types` (list):

>   `'(general-music event tremolo-event)`

>   The types of this music object; determines by what engraver this music expression is processed.

### 1.1.79 TremoloRepeatedMusic

Repeated notes denoted by tremolo beams.

Properties:

> `name` (symbol):

>   `'TremoloRepeatedMusic`

>   Name of this music object.

> `iterator-ctor` (procedure):

>   `ly:chord-tremolo-iterator::constructor`

>   Function to construct a `music-event-iterator` object for this music.

> `start-callback` (procedure):

>   `ly:repeated-music::first-start`

>   Function to compute the negative length of starting grace notes. This property can only be defined as initializer in ‘`scm/define-music-types.scm`’.

> `length-callback` (procedure):

>   `ly:repeated-music::folded-music-length`

>   How to compute the duration of this music. This property can only be defined as initializer in ‘`scm/define-music-types.scm`’.

> `types` (list):

>   `'(general-music repeated-music tremolo-repeated-music)`

>   The types of this music object; determines by what engraver this music expression is processed.

### 1.1.80 TremoloSpanEvent

Tremolo over two stems

Event classes: tremolo-span-event, span-event, music-event and StreamEvent.

Accepted by: Chord_tremolo_engraver.

Properties:

> `name` (symbol):

>   `'TremoloSpanEvent`

>   Name of this music object.

> `types` (list):

>   `'(general-music event span-event tremolo-span-event)`

>   The types of this music object; determines by what engraver this music expression is processed.

### 1.1.81 TrillSpanEvent

Start a trill spanner tr~~~

Event classes: trill-span-event, span-event, music-event and StreamEvent.

Accepted by: Trill_spanner_engraver.

Properties:

> `name` (symbol):

>   `'TrillSpanEvent`

>   Name of this music object.

> `types` (list):

>   `'(general-music span-event event trill-span-event)`

>   The types of this music object; determines by what engraver this music expression is processed.

### 1.1.82 TupletSpanEvent

Used internally to signal where tuplet brackets start and stop.

Event classes: tuplet-span-event, span-event, music-event and StreamEvent.

Accepted by: Tuplet_engraver.

Properties:

> `name` (symbol):

>   `'TupletSpanEvent`

>   Name of this music object.

> `types` (list):

>   `'(tuplet-span-event span-event event general-music)`

>   The types of this music object; determines by what engraver this music expression is processed.

### 1.1.83 UnaCordaEvent

Depress or release una-corda pedal.

Event classes: una-corda-event, pedal-event, span-event, music-event and StreamEvent.

Accepted by: Piano_pedal_engraver and Piano_pedal_performer.

Properties:

> `name` (symbol):

>   `'UnaCordaEvent`

>   Name of this music object.

> `types` (list):

>   `'(general-music event pedal-event una-corda-event)`

>   The types of this music object; determines by what engraver this music expression is processed.

### 1.1.84 UnfoldedRepeatedMusic

Repeated music which is fully written (and played) out.

Properties:

> `name` (symbol):

>   `'UnfoldedRepeatedMusic`

>   Name of this music object.

> `iterator-ctor` (procedure):

>   `ly:unfolded-repeat-iterator::constructor`

>   Function to construct a `music-event-iterator` object for this music.

> `start-callback` (procedure):

>   `ly:repeated-music::first-start`

>   Function to compute the negative length of starting grace notes. This property can only be defined as initializer in ‘`scm/define-music-types.scm`’.

> `types` (list):

>   `'(general-music repeated-music unfolded-repeated-music)`

>   The types of this music object; determines by what engraver this music expression is processed.

> `length-callback` (procedure):

>   `ly:repeated-music::unfolded-music-length`

>   How to compute the duration of this music. This property can only be defined as initializer in ‘`scm/define-music-types.scm`’.

### 1.1.85 UnisonoEvent

Print ‘a 2’.

Event classes: unisono-event, part-combine-event, music-event and StreamEvent.

Accepted by: Part_combine_engraver.

Properties:

> `name` (symbol):

>   `'UnisonoEvent`

>   Name of this music object.

> `part-combine-status` (symbol):

>   `'unisono`

>   Change to what kind of state? Options are `solo1`, `solo2` and `unisono`.

> `types` (list):

>   `'(general-music event part-combine-event unisono-event)`

>   The types of this music object; determines by what engraver this music expression is processed.

### 1.1.86 UnrelativableMusic

Music that cannot be converted from relative to absolute notation. For example, transposed music.

Properties:

> `name` (symbol):

>   `'UnrelativableMusic`

>   Name of this music object.

> `to-relative-callback` (procedure):

>   `ly:relative-octave-music::no-relative-callback`

>   How to transform a piece of music to relative pitches.

> `iterator-ctor` (procedure):

>   `ly:music-wrapper-iterator::constructor`

>   Function to construct a `music-event-iterator` object for this music.

> `length-callback` (procedure):

>   `ly:music-wrapper::length-callback`

>   How to compute the duration of this music. This property can only be defined as initializer in ‘`scm/define-music-types.scm`’.

> `types` (list):

>   `'(music-wrapper-music general-music unrelativable-music)`

>   The types of this music object; determines by what engraver this music expression is processed.

### 1.1.87 VoiceSeparator

Separate polyphonic voices in simultaneous music.

Syntax: `\\`

Properties:

> `name` (symbol):

>   `'VoiceSeparator`

>   Name of this music object.

> `types` (list):

>   `'(separator general-music)`

>   The types of this music object; determines by what engraver this music expression is processed.

### 1.1.88 VoltaRepeatedMusic

Repeats with alternatives placed sequentially.

Properties:

> `name` (symbol):

>   `'VoltaRepeatedMusic`

>   Name of this music object.

> `iterator-ctor` (procedure):

>   `ly:volta-repeat-iterator::constructor`

>   Function to construct a `music-event-iterator` object for this music.

> `start-callback` (procedure):

>   `ly:repeated-music::first-start`

>   Function to compute the negative length of starting grace notes. This property can only be defined as initializer in ‘`scm/define-music-types.scm`’.

> `length-callback` (procedure):

>   `ly:repeated-music::volta-music-length`

>   How to compute the duration of this music. This property can only be defined as initializer in ‘`scm/define-music-types.scm`’.

> `types` (list):

>   `'(general-music repeated-music volta-repeated-music)`

>   The types of this music object; determines by what engraver this music expression is processed.

## 1.2 Music classes

### 1.2.1 StreamEvent

Music event type `StreamEvent` is in music objects of type AbsoluteDynamicEvent, AnnotateOutputEvent, ApplyOutputEvent, ArpeggioEvent, ArticulationEvent, BassFigureEvent, BeamEvent, BeamForbidEvent, BendAfterEvent, BreathingEvent, ClusterNoteEvent, CrescendoEvent, DecrescendoEvent, ExtenderEvent, FingeringEvent, GlissandoEvent, HarmonicEvent, HyphenEvent, KeyChangeEvent, LabelEvent, LaissezVibrerEvent, LigatureEvent, LineBreakEvent, LyricEvent, MarkEvent, MultiMeasureRestEvent, MultiMeasureTextEvent, NoteEvent, NoteGroupingEvent, PageBreakEvent, PageTurnEvent, PercentEvent, PesOrFlexaEvent, PhrasingSlurEvent, RepeatTieEvent, RestEvent, ScriptEvent, SkipEvent, SlurEvent, SoloOneEvent, SoloTwoEvent, SostenutoEvent, SpacingSectionEvent, SpanEvent, StaffSpanEvent, StringNumberEvent, StrokeFingerEvent, SustainEvent, TextScriptEvent, TextSpanEvent, TieEvent, TremoloEvent, TremoloSpanEvent, TrillSpanEvent, TupletSpanEvent, UnaCordaEvent and UnisonoEvent.

Not accepted by any engraver or performer.

### 1.2.2 absolute-dynamic-event

Music event type `absolute-dynamic-event` is in music objects of type AbsoluteDynamicEvent.

Accepted by: Dynamic_engraver, Dynamic_performer and New_dynamic_engraver.

### 1.2.3 annotate-output-event

Music event type `annotate-output-event` is in music objects of type AnnotateOutputEvent.

Accepted by: Balloon_engraver.

### 1.2.4 apply-output-event

Music event type `apply-output-event` is in music objects of type ApplyOutputEvent.

Accepted by: Output_property_engraver.

### 1.2.5 arpeggio-event

Music event type `arpeggio-event` is in music objects of type ArpeggioEvent.

Accepted by: Arpeggio_engraver.

### 1.2.6 articulation-event

Music event type `articulation-event` is in music objects of type ArticulationEvent.

Accepted by: Script_engraver.

### 1.2.7 bass-figure-event

Music event type `bass-figure-event` is in music objects of type BassFigureEvent.

Accepted by: Figured_bass_engraver.

### 1.2.8 beam-event

Music event type `beam-event` is in music objects of type BeamEvent.

Accepted by: Beam_engraver, Beam_performer and Grace_beam_engraver.

### 1.2.9 beam-forbid-event

Music event type `beam-forbid-event` is in music objects of type BeamForbidEvent.

Accepted by: Auto_beam_engraver.

### 1.2.10 bend-after-event

Music event type `bend-after-event` is in music objects of type BendAfterEvent.

Accepted by: Bend_engraver.

### 1.2.11 break-event

Music event type `break-event` is in music objects of type LineBreakEvent, PageBreakEvent and PageTurnEvent.

Accepted by: Page_turn_engraver and Paper_column_engraver.

### 1.2.12 breathing-event

Music event type `breathing-event` is in music objects of type BreathingEvent.

Accepted by: Breathing_sign_engraver.

### 1.2.13 cluster-note-event

Music event type `cluster-note-event` is in music objects of type ClusterNoteEvent.

Accepted by: Cluster_spanner_engraver.

### 1.2.14 crescendo-event

Music event type `crescendo-event` is in music objects of type CrescendoEvent.

Accepted by: Dynamic_performer.

### 1.2.15 decrescendo-event

Music event type `decrescendo-event` is in music objects of type DecrescendoEvent.

Accepted by: Dynamic_performer.

### 1.2.16 dynamic-event

Music event type `dynamic-event` is in music objects of type AbsoluteDynamicEvent.

Not accepted by any engraver or performer.

### 1.2.17 extender-event

Music event type `extender-event` is in music objects of type ExtenderEvent.

Accepted by: Extender_engraver.

### 1.2.18 fingering-event

Music event type `fingering-event` is in music objects of type FingeringEvent.

Accepted by: Fingering_engraver.

### 1.2.19 glissando-event

Music event type `glissando-event` is in music objects of type GlissandoEvent.

Accepted by: Glissando_engraver.

### 1.2.20 harmonic-event

Music event type `harmonic-event` is in music objects of type HarmonicEvent.

Not accepted by any engraver or performer.

### 1.2.21 hyphen-event

Music event type `hyphen-event` is in music objects of type HyphenEvent.

Accepted by: Hyphen_engraver.

### 1.2.22 key-change-event

Music event type `key-change-event` is in music objects of type KeyChangeEvent.

Accepted by: Key_engraver and Key_performer.

### 1.2.23 label-event

Music event type `label-event` is in music objects of type LabelEvent.

Accepted by: Paper_column_engraver.

### 1.2.24 laissez-vibrer-event

Music event type `laissez-vibrer-event` is in music objects of type LaissezVibrerEvent.

Accepted by: Laissez_vibrer_engraver.

### 1.2.25 layout-instruction-event

Music event type `layout-instruction-event` is in music objects of type ApplyOutputEvent.

Not accepted by any engraver or performer.

### 1.2.26 ligature-event

Music event type `ligature-event` is in music objects of type LigatureEvent.

Accepted by: Ligature_bracket_engraver, Mensural_ligature_engraver and Vaticana_ligature_engraver.

### 1.2.27 line-break-event

Music event type `line-break-event` is in music objects of type LineBreakEvent.

Not accepted by any engraver or performer.

### 1.2.28 lyric-event

Music event type `lyric-event` is in music objects of type LyricEvent.

Accepted by: Lyric_engraver and Lyric_performer.

### 1.2.29 mark-event

Music event type `mark-event` is in music objects of type MarkEvent.

Accepted by: Mark_engraver.

### 1.2.30 melodic-event

Music event type `melodic-event` is in music objects of type ClusterNoteEvent and NoteEvent.

Not accepted by any engraver or performer.

### 1.2.31 multi-measure-rest-event

Music event type `multi-measure-rest-event` is in music objects of type MultiMeasureRestEvent.

Accepted by: Multi_measure_rest_engraver.

### 1.2.32 multi-measure-text-event

Music event type `multi-measure-text-event` is in music objects of type MultiMeasureTextEvent.

Accepted by: Multi_measure_rest_engraver.

### 1.2.33 music-event

Music event type `music-event` is in music objects of type AbsoluteDynamicEvent, AnnotateOutputEvent, ApplyOutputEvent, ArpeggioEvent, ArticulationEvent, BassFigureEvent, BeamEvent, BeamForbidEvent, BendAfterEvent, BreathingEvent, ClusterNoteEvent, CrescendoEvent, DecrescendoEvent, ExtenderEvent, FingeringEvent, GlissandoEvent, HarmonicEvent, HyphenEvent, KeyChangeEvent, LabelEvent, LaissezVibrerEvent, LigatureEvent, LineBreakEvent, LyricEvent, MarkEvent, MultiMeasureRestEvent, MultiMeasureTextEvent, NoteEvent, NoteGroupingEvent, PageBreakEvent, PageTurnEvent, PercentEvent, PesOrFlexaEvent, PhrasingSlurEvent, RepeatTieEvent, RestEvent, ScriptEvent, SkipEvent, SlurEvent, SoloOneEvent, SoloTwoEvent, SostenutoEvent, SpacingSectionEvent, SpanEvent, StaffSpanEvent, StringNumberEvent, StrokeFingerEvent, SustainEvent, TextScriptEvent, TextSpanEvent, TieEvent, TremoloEvent, TremoloSpanEvent, TrillSpanEvent, TupletSpanEvent, UnaCordaEvent and UnisonoEvent.

Not accepted by any engraver or performer.

### 1.2.34 note-event

Music event type `note-event` is in music objects of type NoteEvent.

Accepted by: Chord_name_engraver, Completion_heads_engraver, Drum_note_performer, Drum_notes_engraver, Fretboard_engraver, Note_heads_engraver, Note_name_engraver, Note_performer and Tab_note_heads_engraver.

### 1.2.35 note-grouping-event

Music event type `note-grouping-event` is in music objects of type NoteGroupingEvent.

Accepted by: Horizontal_bracket_engraver.

### 1.2.36 page-break-event

Music event type `page-break-event` is in music objects of type PageBreakEvent.

Not accepted by any engraver or performer.

### 1.2.37 page-turn-event

Music event type `page-turn-event` is in music objects of type PageTurnEvent.

Not accepted by any engraver or performer.

### 1.2.38 part-combine-event

Music event type `part-combine-event` is in music objects of type SoloOneEvent, SoloTwoEvent and UnisonoEvent.

Accepted by: Part_combine_engraver.

### 1.2.39 pedal-event

Music event type `pedal-event` is in music objects of type SostenutoEvent, SustainEvent and UnaCordaEvent.

Not accepted by any engraver or performer.

### 1.2.40 percent-event

Music event type `percent-event` is in music objects of type PercentEvent.

Accepted by: Percent_repeat_engraver and Slash_repeat_engraver.

### 1.2.41 pes-or-flexa-event

Music event type `pes-or-flexa-event` is in music objects of type PesOrFlexaEvent.

Accepted by: Vaticana_ligature_engraver.

### 1.2.42 phrasing-slur-event

Music event type `phrasing-slur-event` is in music objects of type PhrasingSlurEvent.

Accepted by: Phrasing_slur_engraver.

### 1.2.43 repeat-tie-event

Music event type `repeat-tie-event` is in music objects of type RepeatTieEvent.

Accepted by: Repeat_tie_engraver.

### 1.2.44 rest-event

Music event type `rest-event` is in music objects of type RestEvent.

Accepted by: Figured_bass_engraver and Rest_engraver.

### 1.2.45 rhythmic-event

Music event type `rhythmic-event` is in music objects of type BassFigureEvent, ClusterNoteEvent, LyricEvent, MultiMeasureRestEvent, NoteEvent, PercentEvent, RestEvent and SkipEvent.

Not accepted by any engraver or performer.

### 1.2.46 script-event

Music event type `script-event` is in music objects of type ArticulationEvent, ScriptEvent and TextScriptEvent.

Not accepted by any engraver or performer.

### 1.2.47 skip-event

Music event type `skip-event` is in music objects of type SkipEvent.

Not accepted by any engraver or performer.

### 1.2.48 slur-event

Music event type `slur-event` is in music objects of type SlurEvent.

Accepted by: Slur_engraver and Slur_performer.

### 1.2.49 solo-one-event

Music event type `solo-one-event` is in music objects of type SoloOneEvent.

Not accepted by any engraver or performer.

### 1.2.50 solo-two-event

Music event type `solo-two-event` is in music objects of type SoloTwoEvent.

Not accepted by any engraver or performer.

### 1.2.51 sostenuto-event

Music event type `sostenuto-event` is in music objects of type SostenutoEvent.

Accepted by: Piano_pedal_engraver and Piano_pedal_performer.

### 1.2.52 spacing-section-event

Music event type `spacing-section-event` is in music objects of type SpacingSectionEvent.

Accepted by: Spacing_engraver.

### 1.2.53 span-dynamic-event

Music event type `span-dynamic-event` is in music objects of type CrescendoEvent and DecrescendoEvent.

Accepted by: Dynamic_engraver and New_dynamic_engraver.

### 1.2.54 span-event

Music event type `span-event` is in music objects of type BeamEvent, CrescendoEvent, DecrescendoEvent, LigatureEvent, PhrasingSlurEvent, SlurEvent, SostenutoEvent, SpanEvent, StaffSpanEvent, SustainEvent, TextSpanEvent, TremoloSpanEvent, TrillSpanEvent, TupletSpanEvent and UnaCordaEvent.

Not accepted by any engraver or performer.

### 1.2.55 staff-span-event

Music event type `staff-span-event` is in music objects of type StaffSpanEvent.

Accepted by: Staff_symbol_engraver.

### 1.2.56 string-number-event

Music event type `string-number-event` is in music objects of type StringNumberEvent.

Accepted by: Fretboard_engraver and Tab_note_heads_engraver.

### 1.2.57 stroke-finger-event

Music event type `stroke-finger-event` is in music objects of type StrokeFingerEvent.

Accepted by: Fingering_engraver.

### 1.2.58 sustain-event

Music event type `sustain-event` is in music objects of type SustainEvent.

Accepted by: Piano_pedal_engraver and Piano_pedal_performer.

### 1.2.59 text-script-event

Music event type `text-script-event` is in music objects of type TextScriptEvent.

Accepted by: Text_engraver.

### 1.2.60 text-span-event

Music event type `text-span-event` is in music objects of type TextSpanEvent.

Accepted by: Text_spanner_engraver.

### 1.2.61 tie-event

Music event type `tie-event` is in music objects of type TieEvent.

Accepted by: Completion_heads_engraver, Tie_engraver and Tie_performer.

### 1.2.62 tremolo-event

Music event type `tremolo-event` is in music objects of type TremoloEvent.

Accepted by: Stem_engraver.

### 1.2.63 tremolo-span-event

Music event type `tremolo-span-event` is in music objects of type TremoloSpanEvent.

Accepted by: Chord_tremolo_engraver.

### 1.2.64 trill-span-event

Music event type `trill-span-event` is in music objects of type TrillSpanEvent.

Accepted by: Trill_spanner_engraver.

### 1.2.65 tuplet-span-event

Music event type `tuplet-span-event` is in music objects of type TupletSpanEvent.

Accepted by: Tuplet_engraver.

### 1.2.66 una-corda-event

Music event type `una-corda-event` is in music objects of type UnaCordaEvent.

Accepted by: Piano_pedal_engraver and Piano_pedal_performer.

### 1.2.67 unisono-event

Music event type `unisono-event` is in music objects of type UnisonoEvent.

Not accepted by any engraver or performer.

## 1.3 Music properties

`X-offset` (number)

  Offset of resulting grob; only used for balloon texts.

`Y-offset` (number)

  Offset of resulting grob; only used for balloon texts.

`absolute-octave` (integer)

  The absolute octave for a octave check note.

`alteration` (number)

  Alteration for figured bass.

`articulation-type` (string)

  Key for script definitions alist.

  TODO: Consider making type into symbol.

`articulations` (list of music)

  Articulation events specifically for this note.

`associated-context` (string)

  Name of the Voice context associated with this `\newaddlyrics` section.

`augmented` (boolean)

  This figure is for an augmented figured bass (with `+` sign).

`augmented-slash` (boolean)

  This figure is for an augmented figured bass (back-slashed number).

`bass` (boolean)

  Set if this note is a bass note in a chord.

`bracket-start` (boolean)

  Start a bracket here.

  TODO: Use SpanEvents?

`bracket-stop` (boolean)

  Stop a bracket here.

`break-penalty` (number)

  Penalty for line break hint.

`break-permission` (symbol)

  Whether to allow, forbid or force a line break.

`cautionary` (boolean)

  If set, this alteration needs a cautionary accidental.

`change-to-id` (string)

  Name of the context to change to.

`change-to-type` (symbol)

  Type of the context to change to.

`compress-procedure` (procedure)

  Compress this music expression. Arg 1: the music, arg 2: factor.

`context-id` (string)

  Name of context.

`context-type` (symbol)

  Type of context.

`create-new` (boolean)

  Create a fresh context.

`delta-step` (number)

  How much should a fall change pitch?

`denominator` (integer)

  Denominator in a time signature.

`descend-only` (boolean)

  If set, this `\context` only descends in the context tree.

`digit` (integer)

  Digit for fingering.

`diminished` (boolean)

  This bass figure should be slashed.

`direction` (direction)

  Print this up or down?

`drum-type` (symbol)

  Which percussion instrument to play this note on.

`duration` (duration)

  Duration of this note or lyric.

`element` (music)

  The single child of a Music_wrapper music object, or the body of a repeat.

`elements` (list of music)

  A list of elements for sequential of simultaneous music, or the alternatives of repeated music.

`elements-callback` (procedure)

  Return a list of children, for use by a sequential iterator. Takes a single music parameter.

`error-found` (boolean)

  If true, a parsing error was found in this expression.

`figure` (integer)

  A bass figure.

`force-accidental` (boolean)

  If set, a cautionary accidental should always be printed on this note.

`grob-property` (symbol)

  The symbol of the grob property to set.

`grob-property-path` (list)

  A list of symbols, locating a nested grob property, e.g., `(beamed-lengths details)`.

`grob-value` (any type)

  The value of the grob property to set.

`input-tag` (any type)

  Arbitrary marker to relate input and output.

`inversion` (boolean)

  If set, this chord note is inverted.

`iterator-ctor` (procedure)

  Function to construct a `music-event-iterator` object for this music.

`label` (markup)

  Label of a mark.

`last-pitch` (pitch)

  The last pitch after relativization.

`length` (moment)

  The duration of this music.

`length-callback` (procedure)

  How to compute the duration of this music. This property can only be defined as initializer in ‘`scm/define-music-types.scm`’.

`line-break-permission` (symbol)

  When the music is at top-level, whether to allow, forbid or force a line break.

`metronome-count` (number)

  How many beats in a minute?

`name` (symbol)

  Name of this music object.

`no-continuation` (boolean)

  If set, disallow continuation lines.

`numerator` (integer)

  Numerator of a time signature.

`octavation` (integer)

  This pitch was octavated by how many octaves? For chord inversions, this is negative.

`once` (boolean)

  Apply this operation only during one time step?

`origin` (input location)

  Where was this piece of music defined?

`page-break-permission` (symbol)

  When the music is at top-level, whether to allow, forbid or force a page break.

`page-label` (symbol)

  The label of a page marker.

`page-marker` (boolean)

  If true, and the music expression is found at top-level, a page marker object is instanciated instead of a score.

`page-turn-permission` (symbol)

  When the music is at top-level, whether to allow, forbid or force a page turn.

`parenthesize` (boolean)

  Enclose resulting objects in parentheses?

`part-combine-status` (symbol)

  Change to what kind of state? Options are `solo1`, `solo2` and `unisono`.

`pitch` (pitch)

  The pitch of this note.

`pitch-alist` (list)

  A list of pitches jointly forming the scale of a key signature.

`pop-first` (boolean)

  Do a revert before we try to do a override on some grob property.

`prob-property` (symbol)

  The symbol of the prob property to set.

`procedure` (procedure)

  The function to run with `\applycontext`. It must take a single argument, being the context.

`property-operations` (list)

  Do these operations for instantiating the context.

`quoted-context-id` (string)

  The ID of the context to direct quotes to, e.g., `cue`.

`quoted-context-type` (symbol)

  The name of the context to direct quotes to, e.g., `Voice`.

`quoted-events` (vector)

  A vector of with `moment` and `event-list` entries.

`quoted-music-name` (string)

  The name of the voice to quote.

`quoted-transposition` (pitch)

  The pitch used for the quote, overriding `\transposition`.

`quoted-voice-direction` (direction)

  Should the quoted voice be up-stem or down-stem?

`repeat-count` (integer)

  Do a `\repeat` how often?

`span-direction` (direction)

  Does this start or stop a spanner?

`span-type` (string)

  What kind of spanner should be created?

  TODO: Consider making type into symbol.

`split-list` (list)

  Splitting moments for part combiner.

`start-callback` (procedure)

  Function to compute the negative length of starting grace notes. This property can only be defined as initializer in ‘`scm/define-music-types.scm`’.

`string-number` (integer)

  The number of the string in a `StringNumberEvent.`

`symbol` (symbol)

  Grob name to perform an override or revert on.

`tags` (list)

  List of symbols that for denoting extra details, e.g., `\tag #'part …` could tag a piece of music as only being active in a part.

`tempo-unit` (duration)

  The unit for the metronome count.

`text` (markup)

  Markup expression to be printed.

`text-type` (symbol)

  Particular type of text script (e.g., finger, dynamic).

`to-relative-callback` (procedure)

  How to transform a piece of music to relative pitches.

`tonic` (pitch)

  Base of the scale.

`tremolo-type` (integer)

  Speed of tremolo, e.g., 16 for `c4:16`.

`trill-pitch` (pitch)

  Pitch of other note of the trill.

`tweaks` (list)

  An alist of properties to override in the backend for the grob made of this event.

`type` (symbol)

  The type of this music object. Determines iteration in some cases.

`types` (list)

  The types of this music object; determines by what engraver this music expression is processed.

`untransposable` (boolean)

  If set, this music is not transposed.

`value` (any type)

  Assignment value for a translation property.

`void` (boolean)

  If this property is `#t`, then the music expression is to be discarded by the toplevel music handler.

`what` (symbol)

  What to change for auto-change.

  FIXME: Naming.

# 2. Translation

## 2.1 Contexts

### 2.1.1 ChoirStaff

Identical to `StaffGroup` except that the contained staves are not connected vertically.

This context creates the following layout object(s):

SystemStartBar, SystemStartBrace, SystemStartBracket and SystemStartSquare.

This context sets the following properties:

- Set translator property `shortVocalName` to `'()`.
- Set translator property `vocalName` to `'()`.
- Set translator property `systemStartDelimiter` to `'SystemStartBracket`.

Context ChoirStaff can contain Staff, StaffGroup, ChoirStaff, ChordNames, Lyrics, PianoStaff, GrandStaff, RhythmicStaff and DrumStaff.

This context is built from the following engraver(s):

> `System_start_delimiter_engraver`

>   Create a system start delimiter (i.e., a `SystemStartBar`, `SystemStartBrace`, `SystemStartBracket` or `SystemStartSquare` spanner).

>   Properties (read)

>   > `systemStartDelimiter` (symbol)

>   >   Which grob to make for the start of the system/staff? Set to `SystemStartBrace`, `SystemStartBracket` or `SystemStartBar`.

>   > `systemStartDelimiterHierarchy` (pair)

>   >   A nested list, indicating the nesting of a start delimiters.

>   > `currentCommandColumn` (layout object)

>   >   Grob that is X-parent to all current breakable (clef, key signature, etc.) items.

>   This engraver creates the following layout object(s):

>   SystemStartBar, SystemStartBrace, SystemStartBracket and SystemStartSquare.

### 2.1.2 ChordNames

Typesets chord names.

This context creates the following layout object(s):

ChordName, StaffSpacing and VerticalAxisGroup.

This context sets the following properties:

- Set grob-property `remove-empty` in VerticalAxisGroup to `#t`.
- Set grob-property `remove-first` in VerticalAxisGroup to `#t`.
- Set grob-property `minimum-Y-extent` in VerticalAxisGroup to `'(0 . 2)`.

This context is a ‘bottom’ context; it cannot contain other contexts.

This context is built from the following engraver(s):

> `Hara_kiri_engraver`

>   Like `Axis_group_engraver`, but make a hara-kiri spanner, and add interesting items (i.e., note heads, lyric syllables, and normal rests).

>   Properties (read)

>   > `keepAliveInterfaces` (list)

>   >   A list of symbols, signifying grob interfaces that are worth keeping a staff with `remove-empty` set around for.

>   This engraver creates the following layout object(s):

>   VerticalAxisGroup.

> `Skip_event_swallow_translator`

>   Swallow `\skip`.

> `Chord_name_engraver`

>   Catch note events and generate the appropriate chordname.

>   Music types accepted:

>   note-event

>   Properties (read)

>   > `chordChanges` (boolean)

>   >   Only show changes in chords scheme?

>   > `chordNameExceptions` (list)

>   >   An alist of chord exceptions. Contains `(chord . markup)` entries.

>   > `chordNameFunction` (procedure)

>   >   The function that converts lists of pitches to chord names.

>   > `chordNoteNamer` (procedure)

>   >   A function that converts from a pitch object to a text markup. Used for single pitches.

>   > `chordRootNamer` (procedure)

>   >   A function that converts from a pitch object to a text markup. Used for chords.

>   > `chordNameExceptions` (list)

>   >   An alist of chord exceptions. Contains `(chord . markup)` entries.

>   > `majorSevenSymbol` (markup)

>   >   How should the major 7th be formatted in a chord name?

>   This engraver creates the following layout object(s):

>   ChordName.

> `Separating_line_group_engraver`

>   Generate objects for computing spacing parameters.

>   Properties (read)

>   > `createSpacing` (boolean)

>   >   Create `StaffSpacing` objects? Should be set for staves.

>   Properties (write)

>   > `hasStaffSpacing` (boolean)

>   >   True if the current `CommandColumn` contains items that will affect spacing.

>   This engraver creates the following layout object(s):

>   StaffSpacing.

> `Output_property_engraver`

>   Apply a procedure to any grob acknowledged.

>   Music types accepted:

>   apply-output-event

> `Rest_swallow_translator`

>   Swallow rest.

### 2.1.3 CueVoice

Corresponds to a voice on a staff. This context handles the conversion of dynamic signs, stems, beams, super- and subscripts, slurs, ties, and rests.

You have to instantiate this explicitly if you want to have multiple voices on the same staff.

This context also accepts commands for the following context(s):

Voice.

This context creates the following layout object(s):

Arpeggio, Beam, BendAfter, BreathingSign, ClusterSpannerBeacon, ClusterSpanner, CombineTextScript, Dots, DoublePercentRepeatCounter, DoublePercentRepeat, DynamicLineSpanner, DynamicTextSpanner, DynamicText, Fingering, Glissando, Hairpin, InstrumentSwitch, LaissezVibrerTieColumn, LaissezVibrerTie, LigatureBracket, MultiMeasureRestNumber, MultiMeasureRestText, MultiMeasureRest, NoteColumn, NoteHead, NoteSpacing, PercentRepeatCounter, PercentRepeat, PhrasingSlur, RepeatSlash, RepeatTieColumn, RepeatTie, Rest, ScriptColumn, Script, Slur, StemTremolo, Stem, StringNumber, StrokeFinger, TextScript, TextSpanner, TieColumn, Tie, TrillPitchAccidental, TrillPitchGroup, TrillPitchHead, TrillSpanner, TupletBracket, TupletNumber and VoiceFollower.

This context sets the following properties:

- Set grob-property `thickness` in Beam to `0.35`.
- Set grob-property `length-fraction` in Beam to `0.629960524947437`.
- Set grob-property `length-fraction` in Stem to `0.629960524947437`.
- Set translator property `fontSize` to `-4`.
- Set translator property `localKeySignature` to `'()`.

This context is a ‘bottom’ context; it cannot contain other contexts.

This context is built from the following engraver(s):

> `Skip_event_swallow_translator`

>   Swallow `\skip`.

> `Instrument_switch_engraver`

>   Create a cue text for taking instrument.

>   Properties (read)

>   > `instrumentCueName` (markup)

>   >   The name to print if another instrument is to be taken.

>   This engraver creates the following layout object(s):

>   InstrumentSwitch.

> `Grace_engraver`

>   Set font size and other properties for grace notes.

>   Properties (read)

>   > `graceSettings` (list)

>   >   Overrides for grace notes. This property should be manipulated through the `add-grace-property` function.

> `Tuplet_engraver`

>   Catch tuplet events and generate appropriate bracket.

>   Music types accepted:

>   tuplet-span-event

>   Properties (read)

>   > `tupletFullLength` (boolean)

>   >   If set, the tuplet is printed up to the start of the next note.

>   > `tupletFullLengthNote` (boolean)

>   >   If set, end at the next note, otherwise end on the matter (time signatures, etc.) before the note.

>   This engraver creates the following layout object(s):

>   TupletBracket and TupletNumber.

> `Tie_engraver`

>   Generate ties between note heads of equal pitch.

>   Music types accepted:

>   tie-event

>   Properties (read)

>   > `tieWaitForNote` (boolean)

>   >   If true, tied notes do not have to follow each other directly. This can be used for writing out arpeggios.

>   Properties (write)

>   > `tieMelismaBusy` (boolean)

>   >   Signal whether a tie is present.

>   This engraver creates the following layout object(s):

>   Tie and TieColumn.

> `Slur_engraver`

>   Build slur grobs from slur events.

>   Music types accepted:

>   slur-event

>   Properties (read)

>   > `slurMelismaBusy` (boolean)

>   >   Signal if a slur is present.

>   > `doubleSlurs` (boolean)

>   >   If set, two slurs are created for every slurred note, one above and one below the chord.

>   This engraver creates the following layout object(s):

>   Slur.

> `Cluster_spanner_engraver`

>   Engrave a cluster using `Spanner` notation.

>   Music types accepted:

>   cluster-note-event

>   This engraver creates the following layout object(s):

>   ClusterSpanner and ClusterSpannerBeacon.

> `Phrasing_slur_engraver`

>   Print phrasing slurs. Similar to Slur_engraver.

>   Music types accepted:

>   phrasing-slur-event

>   This engraver creates the following layout object(s):

>   PhrasingSlur.

> `Spanner_break_forbid_engraver`

>   Forbid breaks in certain spanners.

> `Note_spacing_engraver`

>   Generate `NoteSpacing`, an object linking horizontal lines for use in spacing.

>   This engraver creates the following layout object(s):

>   NoteSpacing.

> `Rhythmic_column_engraver`

>   Generate `NoteColumn`, an object that groups stems, note heads, and rests.

>   This engraver creates the following layout object(s):

>   NoteColumn.

> `Script_column_engraver`

>   Find potentially colliding scripts and put them into a `ScriptColumn` object; that will fix the collisions.

>   This engraver creates the following layout object(s):

>   ScriptColumn.

> `Script_engraver`

>   Handle note scripted articulations.

>   Music types accepted:

>   articulation-event

>   Properties (read)

>   > `scriptDefinitions` (list)

>   >   The description of scripts. This is used by the `Script_engraver` for typesetting note-superscripts and subscripts. See ‘`scm/script.scm`’ for more information.

>   This engraver creates the following layout object(s):

>   Script.

> `Bend_engraver`

>   Create fall spanners.

>   Music types accepted:

>   bend-after-event

>   This engraver creates the following layout object(s):

>   BendAfter.

> `Fingering_engraver`

>   Create fingering scripts.

>   Music types accepted:

>   stroke-finger-event and fingering-event

>   This engraver creates the following layout object(s):

>   Fingering.

> `Dynamic_align_engraver`

>   Align hairpins and dynamic texts on a horizontal line

>   Properties (read)

>   > `currentMusicalColumn` (layout object)

>   >   Grob that is X-parent to all non-breakable items (note heads, lyrics, etc.).

>   This engraver creates the following layout object(s):

>   DynamicLineSpanner.

> `New_dynamic_engraver`

>   Create hairpins, dynamic texts, and their vertical alignments. The symbols are collected onto a `DynamicLineSpanner` grob which takes care of vertical positioning.

>   Music types accepted:

>   span-dynamic-event and absolute-dynamic-event

>   Properties (read)

>   > `crescendoSpanner` (symbol)

>   >   The type of spanner to be used for crescendi. Available values are ‘`hairpin`’ and ‘`text`’. If unset, a hairpin crescendo is used.

>   > `crescendoText` (markup)

>   >   The text to print at start of non-hairpin crescendo, i.e., ‘`cresc.`’.

>   > `currentMusicalColumn` (layout object)

>   >   Grob that is X-parent to all non-breakable items (note heads, lyrics, etc.).

>   > `decrescendoSpanner` (symbol)

>   >   The type of spanner to be used for decrescendi. Available values are ‘`hairpin`’ and ‘`text`’. If unset, a hairpin decrescendo is used.

>   > `decrescendoText` (markup)

>   >   The text to print at start of non-hairpin decrescendo, i.e., ‘`dim.`’.

>   This engraver creates the following layout object(s):

>   DynamicText, DynamicTextSpanner and Hairpin.

> `Text_engraver`

>   Create text scripts.

>   Music types accepted:

>   text-script-event

>   This engraver creates the following layout object(s):

>   TextScript.

> `Part_combine_engraver`

>   Part combine engraver for orchestral scores: Print markings ‘a2’, ‘Solo’, ‘Solo II’, and ‘unisono’.

>   Music types accepted:

>   part-combine-event

>   Properties (read)

>   > `printPartCombineTexts` (boolean)

>   >   Set ‘Solo’ and ‘A due’ texts in the part combiner?

>   > `soloText` (markup)

>   >   The text for the start of a solo when part-combining.

>   > `soloIIText` (markup)

>   >   The text for the start of a solo for voice ‘two’ when part-combining.

>   > `aDueText` (markup)

>   >   Text to print at a unisono passage.

>   This engraver creates the following layout object(s):

>   CombineTextScript.

> `Slash_repeat_engraver`

>   Make beat repeats.

>   Music types accepted:

>   percent-event

>   Properties (read)

>   > `measureLength` (moment)

>   >   Length of one measure in the current time signature.

>   This engraver creates the following layout object(s):

>   RepeatSlash.

> `Percent_repeat_engraver`

>   Make whole bar and double bar repeats.

>   Music types accepted:

>   percent-event

>   Properties (read)

>   > `countPercentRepeats` (boolean)

>   >   If set, produce counters for percent repeats.

>   > `currentCommandColumn` (layout object)

>   >   Grob that is X-parent to all current breakable (clef, key signature, etc.) items.

>   > `measureLength` (moment)

>   >   Length of one measure in the current time signature.

>   > `repeatCountVisibility` (procedure)

>   >   A procedure taking as arguments an integer and context, returning whether the corresponding percent repeat number should be printed when `countPercentRepeats` is set.

>   Properties (write)

>   > `forbidBreak` (boolean)

>   >   If set to `##t`, prevent a line break at this point.

>   This engraver creates the following layout object(s):

>   DoublePercentRepeat, DoublePercentRepeatCounter, PercentRepeat and PercentRepeatCounter.

> `Chord_tremolo_engraver`

>   Generate beams for tremolo repeats.

>   Music types accepted:

>   tremolo-span-event

>   This engraver creates the following layout object(s):

>   Beam.

> `New_fingering_engraver`

>   Create fingering scripts for notes in a new chord. This engraver is ill-named, since it also takes care of articulations and harmonic note heads.

>   Properties (read)

>   > `fingeringOrientations` (list)

>   >   A list of symbols, containing ‘`left`’, ‘`right`’, ‘`up`’ and/or ‘`down`’. This list determines where fingerings are put relative to the chord being fingered.

>   > `harmonicDots` (boolean)

>   >   If set, harmonic notes in dotted chords get dots.

>   > `strokeFingerOrientations` (list)

>   >   See `fingeringOrientations`.

>   > `stringNumberOrientations` (list)

>   >   See `fingeringOrientations`.

>   This engraver creates the following layout object(s):

>   Fingering, Script, StringNumber and StrokeFinger.

> `Auto_beam_engraver`

>   Generate beams based on measure characteristics and observed Stems. Uses `beatLength`, `measureLength`, and `measurePosition` to decide when to start and stop a beam. Overriding beaming is done through Stem_engraver properties `stemLeftBeamCount` and `stemRightBeamCount`.

>   Music types accepted:

>   beam-forbid-event

>   Properties (read)

>   > `autoBeaming` (boolean)

>   >   If set to true then beams are generated automatically.

>   > `autoBeamSettings` (list)

>   >   Specifies when automatically generated beams should begin and end. See behavior Setting automatic beam behavior for more information.

>   > `beatLength` (moment)

>   >   The length of one beat in this time signature.

>   > `subdivideBeams` (boolean)

>   >   If set, multiple beams will be subdivided at beat positions by only drawing one beam over the beat.

>   This engraver creates the following layout object(s):

>   Beam.

> `Grace_beam_engraver`

>   Handle `Beam` events by engraving beams. If omitted, then notes are printed with flags instead of beams. Only engraves beams when we are at grace points in time.

>   Music types accepted:

>   beam-event

>   Properties (read)

>   > `beamMelismaBusy` (boolean)

>   >   Signal if a beam is present.

>   > `beatLength` (moment)

>   >   The length of one beat in this time signature.

>   > `subdivideBeams` (boolean)

>   >   If set, multiple beams will be subdivided at beat positions by only drawing one beam over the beat.

>   This engraver creates the following layout object(s):

>   Beam.

> `Beam_engraver`

>   Handle `Beam` events by engraving beams. If omitted, then notes are printed with flags instead of beams.

>   Music types accepted:

>   beam-event

>   Properties (read)

>   > `beamMelismaBusy` (boolean)

>   >   Signal if a beam is present.

>   > `beatLength` (moment)

>   >   The length of one beat in this time signature.

>   > `subdivideBeams` (boolean)

>   >   If set, multiple beams will be subdivided at beat positions by only drawing one beam over the beat.

>   Properties (write)

>   > `forbidBreak` (boolean)

>   >   If set to `##t`, prevent a line break at this point.

>   This engraver creates the following layout object(s):

>   Beam.

> `Stem_engraver`

>   Create stems and single-stem tremolos. It also works together with the beam engraver for overriding beaming.

>   Music types accepted:

>   tremolo-event

>   Properties (read)

>   > `tremoloFlags` (integer)

>   >   The number of tremolo flags to add if no number is specified.

>   > `stemLeftBeamCount` (integer)

>   >   Specify the number of beams to draw on the left side of the next note. Overrides automatic beaming. The value is only used once, and then it is erased.

>   > `stemRightBeamCount` (integer)

>   >   See `stemLeftBeamCount`.

>   This engraver creates the following layout object(s):

>   Stem and StemTremolo.

> `Tweak_engraver`

>   Read the `tweaks` property from the originating event, and set properties.

> `Rest_engraver`

>   Engrave rests.

>   Music types accepted:

>   rest-event

>   Properties (read)

>   > `middleCPosition` (number)

>   >   The place of the middle C, measured in half staff-spaces. Usually determined by looking at `middleCClefPosition` and `middleCOffset`.

>   This engraver creates the following layout object(s):

>   Rest.

> `Dots_engraver`

>   Create Dots objects for rhythmic-head-interfaces.

>   This engraver creates the following layout object(s):

>   Dots.

> `Note_heads_engraver`

>   Generate note heads.

>   Music types accepted:

>   note-event

>   Properties (read)

>   > `middleCPosition` (number)

>   >   The place of the middle C, measured in half staff-spaces. Usually determined by looking at `middleCClefPosition` and `middleCOffset`.

>   > `staffLineLayoutFunction` (procedure)

>   >   Layout of staff lines, `traditional`, or `semitone`.

>   This engraver creates the following layout object(s):

>   NoteHead.

> `Breathing_sign_engraver`

>   Create a breathing sign.

>   Music types accepted:

>   breathing-event

>   This engraver creates the following layout object(s):

>   BreathingSign.

> `Ligature_bracket_engraver`

>   Handle `Ligature_events` by engraving `Ligature` brackets.

>   Music types accepted:

>   ligature-event

>   This engraver creates the following layout object(s):

>   LigatureBracket.

> `Glissando_engraver`

>   Engrave glissandi.

>   Music types accepted:

>   glissando-event

>   This engraver creates the following layout object(s):

>   Glissando.

> `Note_head_line_engraver`

>   Engrave a line between two note heads, for example a glissando. If `followVoice` is set, staff switches also generate a line.

>   Properties (read)

>   > `followVoice` (boolean)

>   >   If set, note heads are tracked across staff switches by a thin line.

>   This engraver creates the following layout object(s):

>   Glissando and VoiceFollower.

> `Repeat_tie_engraver`

>   Create repeat ties.

>   Music types accepted:

>   repeat-tie-event

>   This engraver creates the following layout object(s):

>   RepeatTie and RepeatTieColumn.

> `Laissez_vibrer_engraver`

>   Create laissez vibrer items.

>   Music types accepted:

>   laissez-vibrer-event

>   This engraver creates the following layout object(s):

>   LaissezVibrerTie and LaissezVibrerTieColumn.

> `Forbid_line_break_engraver`

>   Forbid line breaks when note heads are still playing at some point.

>   Properties (read)

>   > `busyGrobs` (list)

>   >   A queue of `(end-moment . GROB)` cons cells. This is for internal (C++) use only. This property contains the grobs which are still busy (e.g. note heads, spanners, etc.).

>   Properties (write)

>   > `forbidBreak` (boolean)

>   >   If set to `##t`, prevent a line break at this point.

> `Grob_pq_engraver`

>   Administrate when certain grobs (e.g., note heads) stop playing.

>   Properties (read)

>   > `busyGrobs` (list)

>   >   A queue of `(end-moment . GROB)` cons cells. This is for internal (C++) use only. This property contains the grobs which are still busy (e.g. note heads, spanners, etc.).

>   Properties (write)

>   > `busyGrobs` (list)

>   >   A queue of `(end-moment . GROB)` cons cells. This is for internal (C++) use only. This property contains the grobs which are still busy (e.g. note heads, spanners, etc.).

> `Trill_spanner_engraver`

>   Create trill spanner from an event.

>   Music types accepted:

>   trill-span-event

>   Properties (read)

>   > `currentCommandColumn` (layout object)

>   >   Grob that is X-parent to all current breakable (clef, key signature, etc.) items.

>   > `currentMusicalColumn` (layout object)

>   >   Grob that is X-parent to all non-breakable items (note heads, lyrics, etc.).

>   This engraver creates the following layout object(s):

>   TrillSpanner.

> `Text_spanner_engraver`

>   Create text spanner from an event.

>   Music types accepted:

>   text-span-event

>   This engraver creates the following layout object(s):

>   TextSpanner.

> `Multi_measure_rest_engraver`

>   Engrave multi-measure rests that are produced with ‘`R`’. It reads `measurePosition` and `internalBarNumber` to determine what number to print over the MultiMeasureRest. Reads `measureLength` to determine whether it should use a whole rest or a breve rest to represent one measure.

>   Music types accepted:

>   multi-measure-text-event and multi-measure-rest-event

>   Properties (read)

>   > `internalBarNumber` (integer)

>   >   Contains the current barnumber. This property is used for internal timekeeping, among others by the `Accidental_engraver`.

>   > `restNumberThreshold` (number)

>   >   If a multimeasure rest has more measures than this, a number is printed.

>   > `breakableSeparationItem` (layout object)

>   >   The breakable items in this time step, for this staff.

>   > `currentCommandColumn` (layout object)

>   >   Grob that is X-parent to all current breakable (clef, key signature, etc.) items.

>   > `measurePosition` (moment)

>   >   How much of the current measure have we had. This can be set manually to create incomplete measures.

>   > `measureLength` (moment)

>   >   Length of one measure in the current time signature.

>   This engraver creates the following layout object(s):

>   MultiMeasureRest, MultiMeasureRestNumber and MultiMeasureRestText.

> `Arpeggio_engraver`

>   Generate an Arpeggio symbol.

>   Music types accepted:

>   arpeggio-event

>   This engraver creates the following layout object(s):

>   Arpeggio.

> `Output_property_engraver`

>   Apply a procedure to any grob acknowledged.

>   Music types accepted:

>   apply-output-event

> `Pitched_trill_engraver`

>   Print the bracketed note head after a note head with trill.

>   This engraver creates the following layout object(s):

>   TrillPitchAccidental, TrillPitchGroup and TrillPitchHead.

> `Font_size_engraver`

>   Put `fontSize` into `font-size` grob property.

>   Properties (read)

>   > `fontSize` (number)

>   >   The relative size of all grobs in a context.

### 2.1.4 Devnull

Silently discards all musical information given to this context.

This context also accepts commands for the following context(s):

Voice and Staff.

This context creates the following layout object(s):

none.

This context is a ‘bottom’ context; it cannot contain other contexts.

This context is built from the following engraver(s):

> `Swallow_engraver`

>   This engraver swallows everything given to it silently. The purpose of this is to prevent spurious ‘event junked’ warnings.

### 2.1.5 DrumStaff

Handles typesetting for percussion.

This context also accepts commands for the following context(s):

Staff.

This context creates the following layout object(s):

BarLine, BassFigureAlignmentPositioning, BassFigureAlignment, BassFigureBracket, BassFigureContinuation, BassFigureLine, BassFigure, Clef, DotColumn, InstrumentName, LedgerLineSpanner, NoteCollision, OctavateEight, RestCollision, ScriptRow, SostenutoPedalLineSpanner, StaffSpacing, StaffSymbol, SustainPedalLineSpanner, TimeSignature, UnaCordaPedalLineSpanner and VerticalAxisGroup.

This context sets the following properties:

- Set grob-property `staff-padding` in Script to `0.75`.
- Set translator property `clefPosition` to `0`.
- Set translator property `clefGlyph` to `"clefs.percussion"`.
- Set translator property `shortInstrumentName` to `'()`.
- Set translator property `instrumentName` to `'()`.
- Set grob-property `minimum-Y-extent` in VerticalAxisGroup to `'(-4 . 4)`.
- Set translator property `ignoreFiguredBassRest` to `#t`.
- Set translator property `createSpacing` to `#t`.
- Set translator property `localKeySignature` to `'()`.

Context DrumStaff can contain DrumVoice and CueVoice.

This context is built from the following engraver(s):

> `Script_row_engraver`

>   Determine order in horizontal side position elements.

>   This engraver creates the following layout object(s):

>   ScriptRow.

> `Figured_bass_position_engraver`

>   Position figured bass alignments over notes.

>   This engraver creates the following layout object(s):

>   BassFigureAlignmentPositioning.

> `Figured_bass_engraver`

>   Make figured bass numbers.

>   Music types accepted:

>   bass-figure-event and rest-event

>   Properties (read)

>   > `figuredBassAlterationDirection` (direction)

>   >   Where to put alterations relative to the main figure.

>   > `figuredBassCenterContinuations` (boolean)

>   >   Whether to vertically center pairs of extender lines. This does not work with three or more lines.

>   > `figuredBassFormatter` (procedure)

>   >   A routine generating a markup for a bass figure.

>   > `implicitBassFigures` (list)

>   >   A list of bass figures that are not printed as numbers, but only as extender lines.

>   > `useBassFigureExtenders` (boolean)

>   >   Whether to use extender lines for repeated bass figures.

>   > `ignoreFiguredBassRest` (boolean)

>   >   Don’t swallow rest events.

>   This engraver creates the following layout object(s):

>   BassFigure, BassFigureAlignment, BassFigureBracket, BassFigureContinuation and BassFigureLine.

> `Axis_group_engraver`

>   Group all objects created in this context in a `VerticalAxisGroup` spanner.

>   Properties (read)

>   > `currentCommandColumn` (layout object)

>   >   Grob that is X-parent to all current breakable (clef, key signature, etc.) items.

>   This engraver creates the following layout object(s):

>   VerticalAxisGroup.

> `Instrument_name_engraver`

>   Create a system start text for instrument or vocal names.

>   Properties (read)

>   > `currentCommandColumn` (layout object)

>   >   Grob that is X-parent to all current breakable (clef, key signature, etc.) items.

>   > `shortInstrumentName` (markup)

>   >   See `instrument`.

>   > `instrumentName` (markup)

>   >   The name to print left of a staff. The `instrument` property labels the staff in the first system, and the `instr` property labels following lines.

>   > `shortVocalName` (markup)

>   >   Name of a vocal line, short version.

>   > `vocalName` (markup)

>   >   Name of a vocal line.

>   This engraver creates the following layout object(s):

>   InstrumentName.

> `Piano_pedal_align_engraver`

>   Align piano pedal symbols and brackets.

>   Properties (read)

>   > `currentCommandColumn` (layout object)

>   >   Grob that is X-parent to all current breakable (clef, key signature, etc.) items.

>   This engraver creates the following layout object(s):

>   SostenutoPedalLineSpanner, SustainPedalLineSpanner and UnaCordaPedalLineSpanner.

> `Rest_collision_engraver`

>   Handle collisions of rests.

>   Properties (read)

>   > `busyGrobs` (list)

>   >   A queue of `(end-moment . GROB)` cons cells. This is for internal (C++) use only. This property contains the grobs which are still busy (e.g. note heads, spanners, etc.).

>   This engraver creates the following layout object(s):

>   RestCollision.

> `Grob_pq_engraver`

>   Administrate when certain grobs (e.g., note heads) stop playing.

>   Properties (read)

>   > `busyGrobs` (list)

>   >   A queue of `(end-moment . GROB)` cons cells. This is for internal (C++) use only. This property contains the grobs which are still busy (e.g. note heads, spanners, etc.).

>   Properties (write)

>   > `busyGrobs` (list)

>   >   A queue of `(end-moment . GROB)` cons cells. This is for internal (C++) use only. This property contains the grobs which are still busy (e.g. note heads, spanners, etc.).

> `Collision_engraver`

>   Collect `NoteColumns`, and as soon as there are two or more, put them in a `NoteCollision` object.

>   This engraver creates the following layout object(s):

>   NoteCollision.

> `Staff_symbol_engraver`

>   Create the constellation of five (default) staff lines.

>   Music types accepted:

>   staff-span-event

>   This engraver creates the following layout object(s):

>   StaffSymbol.

> `Ledger_line_engraver`

>   Create the spanner to draw ledger lines, and notices objects that need ledger lines.

>   This engraver creates the following layout object(s):

>   LedgerLineSpanner.

> `Time_signature_engraver`

>   Create a TimeSignature whenever `timeSignatureFraction` changes.

>   Properties (read)

>   > `implicitTimeSignatureVisibility` (vector)

>   >   break visibility for the default time signature.

>   > `timeSignatureFraction` (pair of numbers)

>   >   A pair of numbers, signifying the time signature. For example, `#'(4 . 4)` is a 4/4 time signature.

>   This engraver creates the following layout object(s):

>   TimeSignature.

> `Clef_engraver`

>   Determine and set reference point for pitches.

>   Properties (read)

>   > `clefGlyph` (string)

>   >   Name of the symbol within the music font.

>   > `clefOctavation` (integer)

>   >   Add this much extra octavation. Values of 7 and -7 are common.

>   > `clefPosition` (number)

>   >   Where should the center of the clef symbol go, measured in half staff spaces from the center of the staff.

>   > `explicitClefVisibility` (vector)

>   >   ‘`break-visibility`’ function for clef changes.

>   > `forceClef` (boolean)

>   >   Show clef symbol, even if it has not changed. Only active for the first clef after the property is set, not for the full staff.

>   This engraver creates the following layout object(s):

>   Clef and OctavateEight.

> `Staff_collecting_engraver`

>   Maintain the `stavesFound` variable.

>   Properties (read)

>   > `stavesFound` (list of grobs)

>   >   A list of all staff-symbols found.

>   Properties (write)

>   > `stavesFound` (list of grobs)

>   >   A list of all staff-symbols found.

> `Dot_column_engraver`

>   Engrave dots on dotted notes shifted to the right of the note. If omitted, then dots appear on top of the notes.

>   This engraver creates the following layout object(s):

>   DotColumn.

> `Separating_line_group_engraver`

>   Generate objects for computing spacing parameters.

>   Properties (read)

>   > `createSpacing` (boolean)

>   >   Create `StaffSpacing` objects? Should be set for staves.

>   Properties (write)

>   > `hasStaffSpacing` (boolean)

>   >   True if the current `CommandColumn` contains items that will affect spacing.

>   This engraver creates the following layout object(s):

>   StaffSpacing.

> `Font_size_engraver`

>   Put `fontSize` into `font-size` grob property.

>   Properties (read)

>   > `fontSize` (number)

>   >   The relative size of all grobs in a context.

> `Bar_engraver`

>   Create barlines. This engraver is controlled through the `whichBar` property. If it has no bar line to create, it will forbid a linebreak at this point.

>   Properties (read)

>   > `whichBar` (string)

>   >   This property is read to determine what type of bar line to create.

>   >   Example:

>   >   >     \set Staff.whichBar = "|:"

>   >   This will create a start-repeat bar in this staff only. Valid values are described in bar-line-interface.

>   Properties (write)

>   > `forbidBreak` (boolean)

>   >   If set to `##t`, prevent a line break at this point.

>   This engraver creates the following layout object(s):

>   BarLine.

> `Output_property_engraver`

>   Apply a procedure to any grob acknowledged.

>   Music types accepted:

>   apply-output-event

### 2.1.6 DrumVoice

A voice on a percussion staff.

This context also accepts commands for the following context(s):

Voice.

This context creates the following layout object(s):

Beam, BendAfter, BreathingSign, CombineTextScript, Dots, DoublePercentRepeatCounter, DoublePercentRepeat, DynamicLineSpanner, DynamicTextSpanner, DynamicText, Hairpin, InstrumentSwitch, LaissezVibrerTieColumn, LaissezVibrerTie, MultiMeasureRestNumber, MultiMeasureRestText, MultiMeasureRest, NoteColumn, NoteHead, NoteSpacing, PercentRepeatCounter, PercentRepeat, PhrasingSlur, RepeatSlash, RepeatTieColumn, RepeatTie, Rest, ScriptColumn, Script, Slur, StemTremolo, Stem, TextScript, TextSpanner, TieColumn, Tie, TrillPitchAccidental, TrillPitchGroup, TrillPitchHead, TrillSpanner, TupletBracket and TupletNumber.

This context sets the following properties:

- Set translator property `localKeySignature` to `'()`.

This context is a ‘bottom’ context; it cannot contain other contexts.

This context is built from the following engraver(s):

> `Skip_event_swallow_translator`

>   Swallow `\skip`.

> `Drum_notes_engraver`

>   Generate drum note heads.

>   Music types accepted:

>   note-event

>   Properties (read)

>   > `drumStyleTable` (hash table)

>   >   A hash table which maps drums to layout settings. Predefined values: ‘`drums-style`’, ‘`timbales-style`’, ‘`congas-style`’, ‘`bongos-style`’, and ‘`percussion-style`’.

>   >   The layout style is a hash table, containing the drum-pitches (e.g., the symbol ‘`hihat`’) as keys, and a list `(notehead-style script vertical-position)` as values.

>   This engraver creates the following layout object(s):

>   NoteHead and Script.

> `Grob_pq_engraver`

>   Administrate when certain grobs (e.g., note heads) stop playing.

>   Properties (read)

>   > `busyGrobs` (list)

>   >   A queue of `(end-moment . GROB)` cons cells. This is for internal (C++) use only. This property contains the grobs which are still busy (e.g. note heads, spanners, etc.).

>   Properties (write)

>   > `busyGrobs` (list)

>   >   A queue of `(end-moment . GROB)` cons cells. This is for internal (C++) use only. This property contains the grobs which are still busy (e.g. note heads, spanners, etc.).

> `Skip_event_swallow_translator`

>   Swallow `\skip`.

> `Instrument_switch_engraver`

>   Create a cue text for taking instrument.

>   Properties (read)

>   > `instrumentCueName` (markup)

>   >   The name to print if another instrument is to be taken.

>   This engraver creates the following layout object(s):

>   InstrumentSwitch.

> `Grace_engraver`

>   Set font size and other properties for grace notes.

>   Properties (read)

>   > `graceSettings` (list)

>   >   Overrides for grace notes. This property should be manipulated through the `add-grace-property` function.

> `Tuplet_engraver`

>   Catch tuplet events and generate appropriate bracket.

>   Music types accepted:

>   tuplet-span-event

>   Properties (read)

>   > `tupletFullLength` (boolean)

>   >   If set, the tuplet is printed up to the start of the next note.

>   > `tupletFullLengthNote` (boolean)

>   >   If set, end at the next note, otherwise end on the matter (time signatures, etc.) before the note.

>   This engraver creates the following layout object(s):

>   TupletBracket and TupletNumber.

> `Tie_engraver`

>   Generate ties between note heads of equal pitch.

>   Music types accepted:

>   tie-event

>   Properties (read)

>   > `tieWaitForNote` (boolean)

>   >   If true, tied notes do not have to follow each other directly. This can be used for writing out arpeggios.

>   Properties (write)

>   > `tieMelismaBusy` (boolean)

>   >   Signal whether a tie is present.

>   This engraver creates the following layout object(s):

>   Tie and TieColumn.

> `Slur_engraver`

>   Build slur grobs from slur events.

>   Music types accepted:

>   slur-event

>   Properties (read)

>   > `slurMelismaBusy` (boolean)

>   >   Signal if a slur is present.

>   > `doubleSlurs` (boolean)

>   >   If set, two slurs are created for every slurred note, one above and one below the chord.

>   This engraver creates the following layout object(s):

>   Slur.

> `Phrasing_slur_engraver`

>   Print phrasing slurs. Similar to Slur_engraver.

>   Music types accepted:

>   phrasing-slur-event

>   This engraver creates the following layout object(s):

>   PhrasingSlur.

> `Spanner_break_forbid_engraver`

>   Forbid breaks in certain spanners.

> `Note_spacing_engraver`

>   Generate `NoteSpacing`, an object linking horizontal lines for use in spacing.

>   This engraver creates the following layout object(s):

>   NoteSpacing.

> `Rhythmic_column_engraver`

>   Generate `NoteColumn`, an object that groups stems, note heads, and rests.

>   This engraver creates the following layout object(s):

>   NoteColumn.

> `Script_column_engraver`

>   Find potentially colliding scripts and put them into a `ScriptColumn` object; that will fix the collisions.

>   This engraver creates the following layout object(s):

>   ScriptColumn.

> `Script_engraver`

>   Handle note scripted articulations.

>   Music types accepted:

>   articulation-event

>   Properties (read)

>   > `scriptDefinitions` (list)

>   >   The description of scripts. This is used by the `Script_engraver` for typesetting note-superscripts and subscripts. See ‘`scm/script.scm`’ for more information.

>   This engraver creates the following layout object(s):

>   Script.

> `Bend_engraver`

>   Create fall spanners.

>   Music types accepted:

>   bend-after-event

>   This engraver creates the following layout object(s):

>   BendAfter.

> `Dynamic_align_engraver`

>   Align hairpins and dynamic texts on a horizontal line

>   Properties (read)

>   > `currentMusicalColumn` (layout object)

>   >   Grob that is X-parent to all non-breakable items (note heads, lyrics, etc.).

>   This engraver creates the following layout object(s):

>   DynamicLineSpanner.

> `New_dynamic_engraver`

>   Create hairpins, dynamic texts, and their vertical alignments. The symbols are collected onto a `DynamicLineSpanner` grob which takes care of vertical positioning.

>   Music types accepted:

>   span-dynamic-event and absolute-dynamic-event

>   Properties (read)

>   > `crescendoSpanner` (symbol)

>   >   The type of spanner to be used for crescendi. Available values are ‘`hairpin`’ and ‘`text`’. If unset, a hairpin crescendo is used.

>   > `crescendoText` (markup)

>   >   The text to print at start of non-hairpin crescendo, i.e., ‘`cresc.`’.

>   > `currentMusicalColumn` (layout object)

>   >   Grob that is X-parent to all non-breakable items (note heads, lyrics, etc.).

>   > `decrescendoSpanner` (symbol)

>   >   The type of spanner to be used for decrescendi. Available values are ‘`hairpin`’ and ‘`text`’. If unset, a hairpin decrescendo is used.

>   > `decrescendoText` (markup)

>   >   The text to print at start of non-hairpin decrescendo, i.e., ‘`dim.`’.

>   This engraver creates the following layout object(s):

>   DynamicText, DynamicTextSpanner and Hairpin.

> `Text_engraver`

>   Create text scripts.

>   Music types accepted:

>   text-script-event

>   This engraver creates the following layout object(s):

>   TextScript.

> `Part_combine_engraver`

>   Part combine engraver for orchestral scores: Print markings ‘a2’, ‘Solo’, ‘Solo II’, and ‘unisono’.

>   Music types accepted:

>   part-combine-event

>   Properties (read)

>   > `printPartCombineTexts` (boolean)

>   >   Set ‘Solo’ and ‘A due’ texts in the part combiner?

>   > `soloText` (markup)

>   >   The text for the start of a solo when part-combining.

>   > `soloIIText` (markup)

>   >   The text for the start of a solo for voice ‘two’ when part-combining.

>   > `aDueText` (markup)

>   >   Text to print at a unisono passage.

>   This engraver creates the following layout object(s):

>   CombineTextScript.

> `Slash_repeat_engraver`

>   Make beat repeats.

>   Music types accepted:

>   percent-event

>   Properties (read)

>   > `measureLength` (moment)

>   >   Length of one measure in the current time signature.

>   This engraver creates the following layout object(s):

>   RepeatSlash.

> `Percent_repeat_engraver`

>   Make whole bar and double bar repeats.

>   Music types accepted:

>   percent-event

>   Properties (read)

>   > `countPercentRepeats` (boolean)

>   >   If set, produce counters for percent repeats.

>   > `currentCommandColumn` (layout object)

>   >   Grob that is X-parent to all current breakable (clef, key signature, etc.) items.

>   > `measureLength` (moment)

>   >   Length of one measure in the current time signature.

>   > `repeatCountVisibility` (procedure)

>   >   A procedure taking as arguments an integer and context, returning whether the corresponding percent repeat number should be printed when `countPercentRepeats` is set.

>   Properties (write)

>   > `forbidBreak` (boolean)

>   >   If set to `##t`, prevent a line break at this point.

>   This engraver creates the following layout object(s):

>   DoublePercentRepeat, DoublePercentRepeatCounter, PercentRepeat and PercentRepeatCounter.

> `Chord_tremolo_engraver`

>   Generate beams for tremolo repeats.

>   Music types accepted:

>   tremolo-span-event

>   This engraver creates the following layout object(s):

>   Beam.

> `Auto_beam_engraver`

>   Generate beams based on measure characteristics and observed Stems. Uses `beatLength`, `measureLength`, and `measurePosition` to decide when to start and stop a beam. Overriding beaming is done through Stem_engraver properties `stemLeftBeamCount` and `stemRightBeamCount`.

>   Music types accepted:

>   beam-forbid-event

>   Properties (read)

>   > `autoBeaming` (boolean)

>   >   If set to true then beams are generated automatically.

>   > `autoBeamSettings` (list)

>   >   Specifies when automatically generated beams should begin and end. See behavior Setting automatic beam behavior for more information.

>   > `beatLength` (moment)

>   >   The length of one beat in this time signature.

>   > `subdivideBeams` (boolean)

>   >   If set, multiple beams will be subdivided at beat positions by only drawing one beam over the beat.

>   This engraver creates the following layout object(s):

>   Beam.

> `Grace_beam_engraver`

>   Handle `Beam` events by engraving beams. If omitted, then notes are printed with flags instead of beams. Only engraves beams when we are at grace points in time.

>   Music types accepted:

>   beam-event

>   Properties (read)

>   > `beamMelismaBusy` (boolean)

>   >   Signal if a beam is present.

>   > `beatLength` (moment)

>   >   The length of one beat in this time signature.

>   > `subdivideBeams` (boolean)

>   >   If set, multiple beams will be subdivided at beat positions by only drawing one beam over the beat.

>   This engraver creates the following layout object(s):

>   Beam.

> `Beam_engraver`

>   Handle `Beam` events by engraving beams. If omitted, then notes are printed with flags instead of beams.

>   Music types accepted:

>   beam-event

>   Properties (read)

>   > `beamMelismaBusy` (boolean)

>   >   Signal if a beam is present.

>   > `beatLength` (moment)

>   >   The length of one beat in this time signature.

>   > `subdivideBeams` (boolean)

>   >   If set, multiple beams will be subdivided at beat positions by only drawing one beam over the beat.

>   Properties (write)

>   > `forbidBreak` (boolean)

>   >   If set to `##t`, prevent a line break at this point.

>   This engraver creates the following layout object(s):

>   Beam.

> `Stem_engraver`

>   Create stems and single-stem tremolos. It also works together with the beam engraver for overriding beaming.

>   Music types accepted:

>   tremolo-event

>   Properties (read)

>   > `tremoloFlags` (integer)

>   >   The number of tremolo flags to add if no number is specified.

>   > `stemLeftBeamCount` (integer)

>   >   Specify the number of beams to draw on the left side of the next note. Overrides automatic beaming. The value is only used once, and then it is erased.

>   > `stemRightBeamCount` (integer)

>   >   See `stemLeftBeamCount`.

>   This engraver creates the following layout object(s):

>   Stem and StemTremolo.

> `Tweak_engraver`

>   Read the `tweaks` property from the originating event, and set properties.

> `Rest_engraver`

>   Engrave rests.

>   Music types accepted:

>   rest-event

>   Properties (read)

>   > `middleCPosition` (number)

>   >   The place of the middle C, measured in half staff-spaces. Usually determined by looking at `middleCClefPosition` and `middleCOffset`.

>   This engraver creates the following layout object(s):

>   Rest.

> `Dots_engraver`

>   Create Dots objects for rhythmic-head-interfaces.

>   This engraver creates the following layout object(s):

>   Dots.

> `Breathing_sign_engraver`

>   Create a breathing sign.

>   Music types accepted:

>   breathing-event

>   This engraver creates the following layout object(s):

>   BreathingSign.

> `Repeat_tie_engraver`

>   Create repeat ties.

>   Music types accepted:

>   repeat-tie-event

>   This engraver creates the following layout object(s):

>   RepeatTie and RepeatTieColumn.

> `Laissez_vibrer_engraver`

>   Create laissez vibrer items.

>   Music types accepted:

>   laissez-vibrer-event

>   This engraver creates the following layout object(s):

>   LaissezVibrerTie and LaissezVibrerTieColumn.

> `Forbid_line_break_engraver`

>   Forbid line breaks when note heads are still playing at some point.

>   Properties (read)

>   > `busyGrobs` (list)

>   >   A queue of `(end-moment . GROB)` cons cells. This is for internal (C++) use only. This property contains the grobs which are still busy (e.g. note heads, spanners, etc.).

>   Properties (write)

>   > `forbidBreak` (boolean)

>   >   If set to `##t`, prevent a line break at this point.

> `Grob_pq_engraver`

>   Administrate when certain grobs (e.g., note heads) stop playing.

>   Properties (read)

>   > `busyGrobs` (list)

>   >   A queue of `(end-moment . GROB)` cons cells. This is for internal (C++) use only. This property contains the grobs which are still busy (e.g. note heads, spanners, etc.).

>   Properties (write)

>   > `busyGrobs` (list)

>   >   A queue of `(end-moment . GROB)` cons cells. This is for internal (C++) use only. This property contains the grobs which are still busy (e.g. note heads, spanners, etc.).

> `Trill_spanner_engraver`

>   Create trill spanner from an event.

>   Music types accepted:

>   trill-span-event

>   Properties (read)

>   > `currentCommandColumn` (layout object)

>   >   Grob that is X-parent to all current breakable (clef, key signature, etc.) items.

>   > `currentMusicalColumn` (layout object)

>   >   Grob that is X-parent to all non-breakable items (note heads, lyrics, etc.).

>   This engraver creates the following layout object(s):

>   TrillSpanner.

> `Text_spanner_engraver`

>   Create text spanner from an event.

>   Music types accepted:

>   text-span-event

>   This engraver creates the following layout object(s):

>   TextSpanner.

> `Multi_measure_rest_engraver`

>   Engrave multi-measure rests that are produced with ‘`R`’. It reads `measurePosition` and `internalBarNumber` to determine what number to print over the MultiMeasureRest. Reads `measureLength` to determine whether it should use a whole rest or a breve rest to represent one measure.

>   Music types accepted:

>   multi-measure-text-event and multi-measure-rest-event

>   Properties (read)

>   > `internalBarNumber` (integer)

>   >   Contains the current barnumber. This property is used for internal timekeeping, among others by the `Accidental_engraver`.

>   > `restNumberThreshold` (number)

>   >   If a multimeasure rest has more measures than this, a number is printed.

>   > `breakableSeparationItem` (layout object)

>   >   The breakable items in this time step, for this staff.

>   > `currentCommandColumn` (layout object)

>   >   Grob that is X-parent to all current breakable (clef, key signature, etc.) items.

>   > `measurePosition` (moment)

>   >   How much of the current measure have we had. This can be set manually to create incomplete measures.

>   > `measureLength` (moment)

>   >   Length of one measure in the current time signature.

>   This engraver creates the following layout object(s):

>   MultiMeasureRest, MultiMeasureRestNumber and MultiMeasureRestText.

> `Output_property_engraver`

>   Apply a procedure to any grob acknowledged.

>   Music types accepted:

>   apply-output-event

> `Pitched_trill_engraver`

>   Print the bracketed note head after a note head with trill.

>   This engraver creates the following layout object(s):

>   TrillPitchAccidental, TrillPitchGroup and TrillPitchHead.

> `Font_size_engraver`

>   Put `fontSize` into `font-size` grob property.

>   Properties (read)

>   > `fontSize` (number)

>   >   The relative size of all grobs in a context.

### 2.1.7 FiguredBass

(not documented)

This context creates the following layout object(s):

BassFigureAlignment, BassFigureBracket, BassFigureContinuation, BassFigureLine, BassFigure, StaffSpacing and VerticalAxisGroup.

This context sets the following properties:

- Set grob-property `minimum-Y-extent` in VerticalAxisGroup to `'(0 . 2)`.
- Set grob-property `remove-first` in VerticalAxisGroup to `#t`.
- Set grob-property `remove-empty` in VerticalAxisGroup to `#t`.

This context is a ‘bottom’ context; it cannot contain other contexts.

This context is built from the following engraver(s):

> `Hara_kiri_engraver`

>   Like `Axis_group_engraver`, but make a hara-kiri spanner, and add interesting items (i.e., note heads, lyric syllables, and normal rests).

>   Properties (read)

>   > `keepAliveInterfaces` (list)

>   >   A list of symbols, signifying grob interfaces that are worth keeping a staff with `remove-empty` set around for.

>   This engraver creates the following layout object(s):

>   VerticalAxisGroup.

> `Separating_line_group_engraver`

>   Generate objects for computing spacing parameters.

>   Properties (read)

>   > `createSpacing` (boolean)

>   >   Create `StaffSpacing` objects? Should be set for staves.

>   Properties (write)

>   > `hasStaffSpacing` (boolean)

>   >   True if the current `CommandColumn` contains items that will affect spacing.

>   This engraver creates the following layout object(s):

>   StaffSpacing.

> `Skip_event_swallow_translator`

>   Swallow `\skip`.

> `Note_swallow_translator`

>   Swallow notes.

> `Figured_bass_engraver`

>   Make figured bass numbers.

>   Music types accepted:

>   bass-figure-event and rest-event

>   Properties (read)

>   > `figuredBassAlterationDirection` (direction)

>   >   Where to put alterations relative to the main figure.

>   > `figuredBassCenterContinuations` (boolean)

>   >   Whether to vertically center pairs of extender lines. This does not work with three or more lines.

>   > `figuredBassFormatter` (procedure)

>   >   A routine generating a markup for a bass figure.

>   > `implicitBassFigures` (list)

>   >   A list of bass figures that are not printed as numbers, but only as extender lines.

>   > `useBassFigureExtenders` (boolean)

>   >   Whether to use extender lines for repeated bass figures.

>   > `ignoreFiguredBassRest` (boolean)

>   >   Don’t swallow rest events.

>   This engraver creates the following layout object(s):

>   BassFigure, BassFigureAlignment, BassFigureBracket, BassFigureContinuation and BassFigureLine.

### 2.1.8 FretBoards

(not documented)

This context creates the following layout object(s):

FretBoard, InstrumentName, StaffSpacing and VerticalAxisGroup.

This context sets the following properties:

- Set translator property `predefinedDiagramTable` to `#<hash-table 0/113>`.

This context is a ‘bottom’ context; it cannot contain other contexts.

This context is built from the following engraver(s):

> `Instrument_name_engraver`

>   Create a system start text for instrument or vocal names.

>   Properties (read)

>   > `currentCommandColumn` (layout object)

>   >   Grob that is X-parent to all current breakable (clef, key signature, etc.) items.

>   > `shortInstrumentName` (markup)

>   >   See `instrument`.

>   > `instrumentName` (markup)

>   >   The name to print left of a staff. The `instrument` property labels the staff in the first system, and the `instr` property labels following lines.

>   > `shortVocalName` (markup)

>   >   Name of a vocal line, short version.

>   > `vocalName` (markup)

>   >   Name of a vocal line.

>   This engraver creates the following layout object(s):

>   InstrumentName.

> `Font_size_engraver`

>   Put `fontSize` into `font-size` grob property.

>   Properties (read)

>   > `fontSize` (number)

>   >   The relative size of all grobs in a context.

> `Separating_line_group_engraver`

>   Generate objects for computing spacing parameters.

>   Properties (read)

>   > `createSpacing` (boolean)

>   >   Create `StaffSpacing` objects? Should be set for staves.

>   Properties (write)

>   > `hasStaffSpacing` (boolean)

>   >   True if the current `CommandColumn` contains items that will affect spacing.

>   This engraver creates the following layout object(s):

>   StaffSpacing.

> `Fretboard_engraver`

>   Generate one or more tablature noteheads from event of type `NoteEvent`.

>   Music types accepted:

>   string-number-event and note-event

>   Properties (read)

>   > `stringTunings` (list)

>   >   The tablature strings tuning. It is a list of the pitch (in semitones) of each string (starting with the lower one).

>   > `minimumFret` (number)

>   >   The tablature auto string-selecting mechanism selects the highest string with a fret at least `minimumFret`.

>   > `maximumFretStretch` (number)

>   >   Don’t allocate frets further than this from specified frets.

>   > `tablatureFormat` (procedure)

>   >   A function formatting a tablature note head. Called with three arguments: string number, context and event. It returns the text as a string.

>   > `highStringOne` (boolean)

>   >   Whether the first string is the string with highest pitch on the instrument. This used by the automatic string selector for tablature notation.

>   > `predefinedDiagramTable` (hash table)

>   >   The hash table of predefined fret diagrams to use in FretBoards.

>   This engraver creates the following layout object(s):

>   FretBoard.

> `Axis_group_engraver`

>   Group all objects created in this context in a `VerticalAxisGroup` spanner.

>   Properties (read)

>   > `currentCommandColumn` (layout object)

>   >   Grob that is X-parent to all current breakable (clef, key signature, etc.) items.

>   This engraver creates the following layout object(s):

>   VerticalAxisGroup.

> `Output_property_engraver`

>   Apply a procedure to any grob acknowledged.

>   Music types accepted:

>   apply-output-event

### 2.1.9 Global

Hard coded entry point for LilyPond. Cannot be tuned.

This context creates the following layout object(s):

none.

Context Global can contain Score.

### 2.1.10 GrandStaff

A group of staves, with a brace on the left side, grouping the staves together. The bar lines of the contained staves are connected vertically.

This context creates the following layout object(s):

Arpeggio, SpanBar, SystemStartBar, SystemStartBrace, SystemStartBracket and SystemStartSquare.

This context sets the following properties:

- Set translator property `systemStartDelimiter` to `'SystemStartBrace`.
- Set translator property `localKeySignature` to `'()`.

Context GrandStaff can contain Staff and FiguredBass.

This context is built from the following engraver(s):

> `System_start_delimiter_engraver`

>   Create a system start delimiter (i.e., a `SystemStartBar`, `SystemStartBrace`, `SystemStartBracket` or `SystemStartSquare` spanner).

>   Properties (read)

>   > `systemStartDelimiter` (symbol)

>   >   Which grob to make for the start of the system/staff? Set to `SystemStartBrace`, `SystemStartBracket` or `SystemStartBar`.

>   > `systemStartDelimiterHierarchy` (pair)

>   >   A nested list, indicating the nesting of a start delimiters.

>   > `currentCommandColumn` (layout object)

>   >   Grob that is X-parent to all current breakable (clef, key signature, etc.) items.

>   This engraver creates the following layout object(s):

>   SystemStartBar, SystemStartBrace, SystemStartBracket and SystemStartSquare.

> `Span_arpeggio_engraver`

>   Make arpeggios that span multiple staves.

>   Properties (read)

>   > `connectArpeggios` (boolean)

>   >   If set, connect arpeggios across piano staff.

>   This engraver creates the following layout object(s):

>   Arpeggio.

> `Span_bar_engraver`

>   Make cross-staff bar lines: It catches all normal bar lines and draws a single span bar across them.

>   This engraver creates the following layout object(s):

>   SpanBar.

### 2.1.11 GregorianTranscriptionStaff

Handles clefs, bar lines, keys, accidentals. It can contain `Voice` contexts.

This context also accepts commands for the following context(s):

Staff.

This context creates the following layout object(s):

AccidentalCautionary, AccidentalPlacement, AccidentalSuggestion, Accidental, BarLine, BassFigureAlignmentPositioning, BassFigureAlignment, BassFigureBracket, BassFigureContinuation, BassFigureLine, BassFigure, Clef, DotColumn, InstrumentName, KeyCancellation, KeySignature, LedgerLineSpanner, NoteCollision, OctavateEight, OttavaBracket, PianoPedalBracket, RestCollision, ScriptRow, SostenutoPedalLineSpanner, SostenutoPedal, StaffSpacing, StaffSymbol, SustainPedalLineSpanner, SustainPedal, TimeSignature, UnaCordaPedalLineSpanner, UnaCordaPedal and VerticalAxisGroup.

This context sets the following properties:

- Set grob-property `transparent` in BarLine to `#t`.
- Set translator property `shortInstrumentName` to `'()`.
- Set translator property `instrumentName` to `'()`.
- Set grob-property `minimum-Y-extent` in VerticalAxisGroup to `'(-4 . 4)`.
- Set translator property `ignoreFiguredBassRest` to `#t`.
- Set translator property `createSpacing` to `#t`.
- Set translator property `localKeySignature` to `'()`.

Context GregorianTranscriptionStaff can contain GregorianTranscriptionVoice and CueVoice.

This context is built from the following engraver(s):

> `Script_row_engraver`

>   Determine order in horizontal side position elements.

>   This engraver creates the following layout object(s):

>   ScriptRow.

> `Figured_bass_position_engraver`

>   Position figured bass alignments over notes.

>   This engraver creates the following layout object(s):

>   BassFigureAlignmentPositioning.

> `Figured_bass_engraver`

>   Make figured bass numbers.

>   Music types accepted:

>   bass-figure-event and rest-event

>   Properties (read)

>   > `figuredBassAlterationDirection` (direction)

>   >   Where to put alterations relative to the main figure.

>   > `figuredBassCenterContinuations` (boolean)

>   >   Whether to vertically center pairs of extender lines. This does not work with three or more lines.

>   > `figuredBassFormatter` (procedure)

>   >   A routine generating a markup for a bass figure.

>   > `implicitBassFigures` (list)

>   >   A list of bass figures that are not printed as numbers, but only as extender lines.

>   > `useBassFigureExtenders` (boolean)

>   >   Whether to use extender lines for repeated bass figures.

>   > `ignoreFiguredBassRest` (boolean)

>   >   Don’t swallow rest events.

>   This engraver creates the following layout object(s):

>   BassFigure, BassFigureAlignment, BassFigureBracket, BassFigureContinuation and BassFigureLine.

> `Axis_group_engraver`

>   Group all objects created in this context in a `VerticalAxisGroup` spanner.

>   Properties (read)

>   > `currentCommandColumn` (layout object)

>   >   Grob that is X-parent to all current breakable (clef, key signature, etc.) items.

>   This engraver creates the following layout object(s):

>   VerticalAxisGroup.

> `String_number_engraver`

>   Swallow string number events. The purpose of this engraver is to process tablatures for normal notation. To provent warnings for unprocessed string number events to obscure real error messages, this engraver swallows them all.

> `Instrument_name_engraver`

>   Create a system start text for instrument or vocal names.

>   Properties (read)

>   > `currentCommandColumn` (layout object)

>   >   Grob that is X-parent to all current breakable (clef, key signature, etc.) items.

>   > `shortInstrumentName` (markup)

>   >   See `instrument`.

>   > `instrumentName` (markup)

>   >   The name to print left of a staff. The `instrument` property labels the staff in the first system, and the `instr` property labels following lines.

>   > `shortVocalName` (markup)

>   >   Name of a vocal line, short version.

>   > `vocalName` (markup)

>   >   Name of a vocal line.

>   This engraver creates the following layout object(s):

>   InstrumentName.

> `Piano_pedal_align_engraver`

>   Align piano pedal symbols and brackets.

>   Properties (read)

>   > `currentCommandColumn` (layout object)

>   >   Grob that is X-parent to all current breakable (clef, key signature, etc.) items.

>   This engraver creates the following layout object(s):

>   SostenutoPedalLineSpanner, SustainPedalLineSpanner and UnaCordaPedalLineSpanner.

> `Piano_pedal_engraver`

>   Engrave piano pedal symbols and brackets.

>   Music types accepted:

>   una-corda-event, sustain-event and sostenuto-event

>   Properties (read)

>   > `currentCommandColumn` (layout object)

>   >   Grob that is X-parent to all current breakable (clef, key signature, etc.) items.

>   > `pedalSostenutoStrings` (list)

>   >   See `pedalSustainStrings`.

>   > `pedalSostenutoStyle` (symbol)

>   >   See `pedalSustainStyle`.

>   > `pedalSustainStrings` (list)

>   >   A list of strings to print for sustain-pedal. Format is `(up updown down)`, where each of the three is the string to print when this is done with the pedal.

>   > `pedalSustainStyle` (symbol)

>   >   A symbol that indicates how to print sustain pedals: `text`, `bracket` or `mixed` (both).

>   > `pedalUnaCordaStrings` (list)

>   >   See `pedalSustainStrings`.

>   > `pedalUnaCordaStyle` (symbol)

>   >   See `pedalSustainStyle`.

>   This engraver creates the following layout object(s):

>   PianoPedalBracket, SostenutoPedal, SustainPedal and UnaCordaPedal.

> `Accidental_engraver`

>   Make accidentals. Catch note heads, ties and notices key-change events. This engraver usually lives at Staff level, but reads the settings for Accidental at `Voice` level, so you can `\override` them at `Voice`.

>   Properties (read)

>   > `autoAccidentals` (list)

>   >   List of different ways to typeset an accidental.

>   >   For determining when to print an accidental, several different rules are tried. The rule that gives the highest number of accidentals is used.

>   >   Each entry in the list is either a symbol or a procedure.

>   >   symbol

>   >     The symbol is the name of the context in which the following rules are to be applied. For example, if context is Score then all staves share accidentals, and if context is Staff then all voices in the same staff share accidentals, but staves do not.

>   >   procedure

>   >     The procedure represents an accidental rule to be applied to the previously specified context.

>   >     The procedure takes the following arguments:

>   >     `context`

>   >       The current context to which the rule should be applied.

>   >     `pitch`

>   >       The pitch of the note to be evaluated.

>   >     `barnum`

>   >       The current bar number.

>   >     `measurepos`

>   >       The current measure position.

>   >     The procedure returns a pair of booleans. The first states whether an extra natural should be added. The second states whether an accidental should be printed. `(#t . #f)` does not make sense.

>   > `autoCautionaries` (list)

>   >   List similar to `autoAccidentals`, but it controls cautionary accidentals rather than normal ones. Both lists are tried, and the one giving the most accidentals wins. In case of draw, a normal accidental is typeset.

>   > `internalBarNumber` (integer)

>   >   Contains the current barnumber. This property is used for internal timekeeping, among others by the `Accidental_engraver`.

>   > `extraNatural` (boolean)

>   >   Whether to typeset an extra natural sign before accidentals changing from a non-natural to another non-natural.

>   > `harmonicAccidentals` (boolean)

>   >   If set, harmonic notes in chords get accidentals.

>   > `keySignature` (list)

>   >   The current key signature. This is an alist containing `(step . alter)` or `((octave . step) . alter)`, where step is a number in the range 0 to 6 and alter a fraction, denoting alteration. For alterations, use symbols, e.g. `keySignature = #`((6 . ,FLAT))`.

>   > `localKeySignature` (list)

>   >   The key signature at this point in the measure. The format is the same as for `keySignature`, but can also contain `((octave . name) . (alter barnumber . measureposition))` pairs.

>   Properties (write)

>   > `localKeySignature` (list)

>   >   The key signature at this point in the measure. The format is the same as for `keySignature`, but can also contain `((octave . name) . (alter barnumber . measureposition))` pairs.

>   This engraver creates the following layout object(s):

>   Accidental, AccidentalCautionary, AccidentalPlacement and AccidentalSuggestion.

> `Rest_collision_engraver`

>   Handle collisions of rests.

>   Properties (read)

>   > `busyGrobs` (list)

>   >   A queue of `(end-moment . GROB)` cons cells. This is for internal (C++) use only. This property contains the grobs which are still busy (e.g. note heads, spanners, etc.).

>   This engraver creates the following layout object(s):

>   RestCollision.

> `Grob_pq_engraver`

>   Administrate when certain grobs (e.g., note heads) stop playing.

>   Properties (read)

>   > `busyGrobs` (list)

>   >   A queue of `(end-moment . GROB)` cons cells. This is for internal (C++) use only. This property contains the grobs which are still busy (e.g. note heads, spanners, etc.).

>   Properties (write)

>   > `busyGrobs` (list)

>   >   A queue of `(end-moment . GROB)` cons cells. This is for internal (C++) use only. This property contains the grobs which are still busy (e.g. note heads, spanners, etc.).

> `Collision_engraver`

>   Collect `NoteColumns`, and as soon as there are two or more, put them in a `NoteCollision` object.

>   This engraver creates the following layout object(s):

>   NoteCollision.

> `Staff_symbol_engraver`

>   Create the constellation of five (default) staff lines.

>   Music types accepted:

>   staff-span-event

>   This engraver creates the following layout object(s):

>   StaffSymbol.

> `Ledger_line_engraver`

>   Create the spanner to draw ledger lines, and notices objects that need ledger lines.

>   This engraver creates the following layout object(s):

>   LedgerLineSpanner.

> `Time_signature_engraver`

>   Create a TimeSignature whenever `timeSignatureFraction` changes.

>   Properties (read)

>   > `implicitTimeSignatureVisibility` (vector)

>   >   break visibility for the default time signature.

>   > `timeSignatureFraction` (pair of numbers)

>   >   A pair of numbers, signifying the time signature. For example, `#'(4 . 4)` is a 4/4 time signature.

>   This engraver creates the following layout object(s):

>   TimeSignature.

> `Key_engraver`

>   Engrave a key signature.

>   Music types accepted:

>   key-change-event

>   Properties (read)

>   > `createKeyOnClefChange` (boolean)

>   >   Print a key signature whenever the clef is changed.

>   > `explicitKeySignatureVisibility` (vector)

>   >   ‘`break-visibility`’ function for explicit key changes. ‘`\override`’ of the `break-visibility` property will set the visibility for normal (i.e., at the start of the line) key signatures.

>   > `extraNatural` (boolean)

>   >   Whether to typeset an extra natural sign before accidentals changing from a non-natural to another non-natural.

>   > `keyAlterationOrder` (list)

>   >   An alist that defines in what order alterations should be printed. The format is `(step . alter)`, where step is a number from 0 to 6 and alter from -2 (sharp) to 2 (flat).

>   > `keySignature` (list)

>   >   The current key signature. This is an alist containing `(step . alter)` or `((octave . step) . alter)`, where step is a number in the range 0 to 6 and alter a fraction, denoting alteration. For alterations, use symbols, e.g. `keySignature = #`((6 . ,FLAT))`.

>   > `lastKeySignature` (list)

>   >   Last key signature before a key signature change.

>   > `printKeyCancellation` (boolean)

>   >   Print restoration alterations before a key signature change.

>   Properties (write)

>   > `keySignature` (list)

>   >   The current key signature. This is an alist containing `(step . alter)` or `((octave . step) . alter)`, where step is a number in the range 0 to 6 and alter a fraction, denoting alteration. For alterations, use symbols, e.g. `keySignature = #`((6 . ,FLAT))`.

>   > `lastKeySignature` (list)

>   >   Last key signature before a key signature change.

>   > `tonic` (pitch)

>   >   The tonic of the current scale.

>   This engraver creates the following layout object(s):

>   KeyCancellation and KeySignature.

> `Clef_engraver`

>   Determine and set reference point for pitches.

>   Properties (read)

>   > `clefGlyph` (string)

>   >   Name of the symbol within the music font.

>   > `clefOctavation` (integer)

>   >   Add this much extra octavation. Values of 7 and -7 are common.

>   > `clefPosition` (number)

>   >   Where should the center of the clef symbol go, measured in half staff spaces from the center of the staff.

>   > `explicitClefVisibility` (vector)

>   >   ‘`break-visibility`’ function for clef changes.

>   > `forceClef` (boolean)

>   >   Show clef symbol, even if it has not changed. Only active for the first clef after the property is set, not for the full staff.

>   This engraver creates the following layout object(s):

>   Clef and OctavateEight.

> `Ottava_spanner_engraver`

>   Create a text spanner when the ottavation property changes.

>   Properties (read)

>   > `ottavation` (markup)

>   >   If set, the text for an ottava spanner. Changing this creates a new text spanner.

>   > `originalMiddleCPosition` (integer)

>   >   Used for temporary overriding middle C in octavation brackets.

>   > `currentMusicalColumn` (layout object)

>   >   Grob that is X-parent to all non-breakable items (note heads, lyrics, etc.).

>   This engraver creates the following layout object(s):

>   OttavaBracket.

> `Staff_collecting_engraver`

>   Maintain the `stavesFound` variable.

>   Properties (read)

>   > `stavesFound` (list of grobs)

>   >   A list of all staff-symbols found.

>   Properties (write)

>   > `stavesFound` (list of grobs)

>   >   A list of all staff-symbols found.

> `Dot_column_engraver`

>   Engrave dots on dotted notes shifted to the right of the note. If omitted, then dots appear on top of the notes.

>   This engraver creates the following layout object(s):

>   DotColumn.

> `Separating_line_group_engraver`

>   Generate objects for computing spacing parameters.

>   Properties (read)

>   > `createSpacing` (boolean)

>   >   Create `StaffSpacing` objects? Should be set for staves.

>   Properties (write)

>   > `hasStaffSpacing` (boolean)

>   >   True if the current `CommandColumn` contains items that will affect spacing.

>   This engraver creates the following layout object(s):

>   StaffSpacing.

> `Font_size_engraver`

>   Put `fontSize` into `font-size` grob property.

>   Properties (read)

>   > `fontSize` (number)

>   >   The relative size of all grobs in a context.

> `Bar_engraver`

>   Create barlines. This engraver is controlled through the `whichBar` property. If it has no bar line to create, it will forbid a linebreak at this point.

>   Properties (read)

>   > `whichBar` (string)

>   >   This property is read to determine what type of bar line to create.

>   >   Example:

>   >   >     \set Staff.whichBar = "|:"

>   >   This will create a start-repeat bar in this staff only. Valid values are described in bar-line-interface.

>   Properties (write)

>   > `forbidBreak` (boolean)

>   >   If set to `##t`, prevent a line break at this point.

>   This engraver creates the following layout object(s):

>   BarLine.

> `Output_property_engraver`

>   Apply a procedure to any grob acknowledged.

>   Music types accepted:

>   apply-output-event

### 2.1.12 GregorianTranscriptionVoice

Corresponds to a voice on a staff. This context handles the conversion of dynamic signs, stems, beams, super- and subscripts, slurs, ties, and rests.

You have to instantiate this explicitly if you want to have multiple voices on the same staff.

This context also accepts commands for the following context(s):

Voice.

This context creates the following layout object(s):

Arpeggio, Beam, BendAfter, BreathingSign, ClusterSpannerBeacon, ClusterSpanner, CombineTextScript, Dots, DoublePercentRepeatCounter, DoublePercentRepeat, DynamicLineSpanner, DynamicTextSpanner, DynamicText, Fingering, Glissando, Hairpin, InstrumentSwitch, LaissezVibrerTieColumn, LaissezVibrerTie, LigatureBracket, MultiMeasureRestNumber, MultiMeasureRestText, MultiMeasureRest, NoteColumn, NoteHead, NoteSpacing, PercentRepeatCounter, PercentRepeat, PhrasingSlur, RepeatSlash, RepeatTieColumn, RepeatTie, Rest, ScriptColumn, Script, Slur, StemTremolo, Stem, StringNumber, StrokeFinger, TextScript, TextSpanner, TieColumn, Tie, TrillPitchAccidental, TrillPitchGroup, TrillPitchHead, TrillSpanner, TupletBracket, TupletNumber and VoiceFollower.

This context sets the following properties:

- Set grob-property `padding` in TextSpanner to `-0.1`.
- Set grob-property `style` in TextSpanner to `'line`.
- Set grob-property `dash-fraction` in TextSpanner to `'()`.
- Set translator property `autoBeaming` to `#f`.
- Set grob-property `padding` in Script to `0.5`.
- Set grob-property `transparent` in LigatureBracket to `#t`.
- Set translator property `localKeySignature` to `'()`.

This context is a ‘bottom’ context; it cannot contain other contexts.

This context is built from the following engraver(s):

> `Skip_event_swallow_translator`

>   Swallow `\skip`.

> `Instrument_switch_engraver`

>   Create a cue text for taking instrument.

>   Properties (read)

>   > `instrumentCueName` (markup)

>   >   The name to print if another instrument is to be taken.

>   This engraver creates the following layout object(s):

>   InstrumentSwitch.

> `Grace_engraver`

>   Set font size and other properties for grace notes.

>   Properties (read)

>   > `graceSettings` (list)

>   >   Overrides for grace notes. This property should be manipulated through the `add-grace-property` function.

> `Tuplet_engraver`

>   Catch tuplet events and generate appropriate bracket.

>   Music types accepted:

>   tuplet-span-event

>   Properties (read)

>   > `tupletFullLength` (boolean)

>   >   If set, the tuplet is printed up to the start of the next note.

>   > `tupletFullLengthNote` (boolean)

>   >   If set, end at the next note, otherwise end on the matter (time signatures, etc.) before the note.

>   This engraver creates the following layout object(s):

>   TupletBracket and TupletNumber.

> `Tie_engraver`

>   Generate ties between note heads of equal pitch.

>   Music types accepted:

>   tie-event

>   Properties (read)

>   > `tieWaitForNote` (boolean)

>   >   If true, tied notes do not have to follow each other directly. This can be used for writing out arpeggios.

>   Properties (write)

>   > `tieMelismaBusy` (boolean)

>   >   Signal whether a tie is present.

>   This engraver creates the following layout object(s):

>   Tie and TieColumn.

> `Slur_engraver`

>   Build slur grobs from slur events.

>   Music types accepted:

>   slur-event

>   Properties (read)

>   > `slurMelismaBusy` (boolean)

>   >   Signal if a slur is present.

>   > `doubleSlurs` (boolean)

>   >   If set, two slurs are created for every slurred note, one above and one below the chord.

>   This engraver creates the following layout object(s):

>   Slur.

> `Cluster_spanner_engraver`

>   Engrave a cluster using `Spanner` notation.

>   Music types accepted:

>   cluster-note-event

>   This engraver creates the following layout object(s):

>   ClusterSpanner and ClusterSpannerBeacon.

> `Phrasing_slur_engraver`

>   Print phrasing slurs. Similar to Slur_engraver.

>   Music types accepted:

>   phrasing-slur-event

>   This engraver creates the following layout object(s):

>   PhrasingSlur.

> `Spanner_break_forbid_engraver`

>   Forbid breaks in certain spanners.

> `Note_spacing_engraver`

>   Generate `NoteSpacing`, an object linking horizontal lines for use in spacing.

>   This engraver creates the following layout object(s):

>   NoteSpacing.

> `Rhythmic_column_engraver`

>   Generate `NoteColumn`, an object that groups stems, note heads, and rests.

>   This engraver creates the following layout object(s):

>   NoteColumn.

> `Script_column_engraver`

>   Find potentially colliding scripts and put them into a `ScriptColumn` object; that will fix the collisions.

>   This engraver creates the following layout object(s):

>   ScriptColumn.

> `Script_engraver`

>   Handle note scripted articulations.

>   Music types accepted:

>   articulation-event

>   Properties (read)

>   > `scriptDefinitions` (list)

>   >   The description of scripts. This is used by the `Script_engraver` for typesetting note-superscripts and subscripts. See ‘`scm/script.scm`’ for more information.

>   This engraver creates the following layout object(s):

>   Script.

> `Bend_engraver`

>   Create fall spanners.

>   Music types accepted:

>   bend-after-event

>   This engraver creates the following layout object(s):

>   BendAfter.

> `Fingering_engraver`

>   Create fingering scripts.

>   Music types accepted:

>   stroke-finger-event and fingering-event

>   This engraver creates the following layout object(s):

>   Fingering.

> `Dynamic_align_engraver`

>   Align hairpins and dynamic texts on a horizontal line

>   Properties (read)

>   > `currentMusicalColumn` (layout object)

>   >   Grob that is X-parent to all non-breakable items (note heads, lyrics, etc.).

>   This engraver creates the following layout object(s):

>   DynamicLineSpanner.

> `New_dynamic_engraver`

>   Create hairpins, dynamic texts, and their vertical alignments. The symbols are collected onto a `DynamicLineSpanner` grob which takes care of vertical positioning.

>   Music types accepted:

>   span-dynamic-event and absolute-dynamic-event

>   Properties (read)

>   > `crescendoSpanner` (symbol)

>   >   The type of spanner to be used for crescendi. Available values are ‘`hairpin`’ and ‘`text`’. If unset, a hairpin crescendo is used.

>   > `crescendoText` (markup)

>   >   The text to print at start of non-hairpin crescendo, i.e., ‘`cresc.`’.

>   > `currentMusicalColumn` (layout object)

>   >   Grob that is X-parent to all non-breakable items (note heads, lyrics, etc.).

>   > `decrescendoSpanner` (symbol)

>   >   The type of spanner to be used for decrescendi. Available values are ‘`hairpin`’ and ‘`text`’. If unset, a hairpin decrescendo is used.

>   > `decrescendoText` (markup)

>   >   The text to print at start of non-hairpin decrescendo, i.e., ‘`dim.`’.

>   This engraver creates the following layout object(s):

>   DynamicText, DynamicTextSpanner and Hairpin.

> `Text_engraver`

>   Create text scripts.

>   Music types accepted:

>   text-script-event

>   This engraver creates the following layout object(s):

>   TextScript.

> `Part_combine_engraver`

>   Part combine engraver for orchestral scores: Print markings ‘a2’, ‘Solo’, ‘Solo II’, and ‘unisono’.

>   Music types accepted:

>   part-combine-event

>   Properties (read)

>   > `printPartCombineTexts` (boolean)

>   >   Set ‘Solo’ and ‘A due’ texts in the part combiner?

>   > `soloText` (markup)

>   >   The text for the start of a solo when part-combining.

>   > `soloIIText` (markup)

>   >   The text for the start of a solo for voice ‘two’ when part-combining.

>   > `aDueText` (markup)

>   >   Text to print at a unisono passage.

>   This engraver creates the following layout object(s):

>   CombineTextScript.

> `Slash_repeat_engraver`

>   Make beat repeats.

>   Music types accepted:

>   percent-event

>   Properties (read)

>   > `measureLength` (moment)

>   >   Length of one measure in the current time signature.

>   This engraver creates the following layout object(s):

>   RepeatSlash.

> `Percent_repeat_engraver`

>   Make whole bar and double bar repeats.

>   Music types accepted:

>   percent-event

>   Properties (read)

>   > `countPercentRepeats` (boolean)

>   >   If set, produce counters for percent repeats.

>   > `currentCommandColumn` (layout object)

>   >   Grob that is X-parent to all current breakable (clef, key signature, etc.) items.

>   > `measureLength` (moment)

>   >   Length of one measure in the current time signature.

>   > `repeatCountVisibility` (procedure)

>   >   A procedure taking as arguments an integer and context, returning whether the corresponding percent repeat number should be printed when `countPercentRepeats` is set.

>   Properties (write)

>   > `forbidBreak` (boolean)

>   >   If set to `##t`, prevent a line break at this point.

>   This engraver creates the following layout object(s):

>   DoublePercentRepeat, DoublePercentRepeatCounter, PercentRepeat and PercentRepeatCounter.

> `Chord_tremolo_engraver`

>   Generate beams for tremolo repeats.

>   Music types accepted:

>   tremolo-span-event

>   This engraver creates the following layout object(s):

>   Beam.

> `New_fingering_engraver`

>   Create fingering scripts for notes in a new chord. This engraver is ill-named, since it also takes care of articulations and harmonic note heads.

>   Properties (read)

>   > `fingeringOrientations` (list)

>   >   A list of symbols, containing ‘`left`’, ‘`right`’, ‘`up`’ and/or ‘`down`’. This list determines where fingerings are put relative to the chord being fingered.

>   > `harmonicDots` (boolean)

>   >   If set, harmonic notes in dotted chords get dots.

>   > `strokeFingerOrientations` (list)

>   >   See `fingeringOrientations`.

>   > `stringNumberOrientations` (list)

>   >   See `fingeringOrientations`.

>   This engraver creates the following layout object(s):

>   Fingering, Script, StringNumber and StrokeFinger.

> `Auto_beam_engraver`

>   Generate beams based on measure characteristics and observed Stems. Uses `beatLength`, `measureLength`, and `measurePosition` to decide when to start and stop a beam. Overriding beaming is done through Stem_engraver properties `stemLeftBeamCount` and `stemRightBeamCount`.

>   Music types accepted:

>   beam-forbid-event

>   Properties (read)

>   > `autoBeaming` (boolean)

>   >   If set to true then beams are generated automatically.

>   > `autoBeamSettings` (list)

>   >   Specifies when automatically generated beams should begin and end. See behavior Setting automatic beam behavior for more information.

>   > `beatLength` (moment)

>   >   The length of one beat in this time signature.

>   > `subdivideBeams` (boolean)

>   >   If set, multiple beams will be subdivided at beat positions by only drawing one beam over the beat.

>   This engraver creates the following layout object(s):

>   Beam.

> `Grace_beam_engraver`

>   Handle `Beam` events by engraving beams. If omitted, then notes are printed with flags instead of beams. Only engraves beams when we are at grace points in time.

>   Music types accepted:

>   beam-event

>   Properties (read)

>   > `beamMelismaBusy` (boolean)

>   >   Signal if a beam is present.

>   > `beatLength` (moment)

>   >   The length of one beat in this time signature.

>   > `subdivideBeams` (boolean)

>   >   If set, multiple beams will be subdivided at beat positions by only drawing one beam over the beat.

>   This engraver creates the following layout object(s):

>   Beam.

> `Beam_engraver`

>   Handle `Beam` events by engraving beams. If omitted, then notes are printed with flags instead of beams.

>   Music types accepted:

>   beam-event

>   Properties (read)

>   > `beamMelismaBusy` (boolean)

>   >   Signal if a beam is present.

>   > `beatLength` (moment)

>   >   The length of one beat in this time signature.

>   > `subdivideBeams` (boolean)

>   >   If set, multiple beams will be subdivided at beat positions by only drawing one beam over the beat.

>   Properties (write)

>   > `forbidBreak` (boolean)

>   >   If set to `##t`, prevent a line break at this point.

>   This engraver creates the following layout object(s):

>   Beam.

> `Stem_engraver`

>   Create stems and single-stem tremolos. It also works together with the beam engraver for overriding beaming.

>   Music types accepted:

>   tremolo-event

>   Properties (read)

>   > `tremoloFlags` (integer)

>   >   The number of tremolo flags to add if no number is specified.

>   > `stemLeftBeamCount` (integer)

>   >   Specify the number of beams to draw on the left side of the next note. Overrides automatic beaming. The value is only used once, and then it is erased.

>   > `stemRightBeamCount` (integer)

>   >   See `stemLeftBeamCount`.

>   This engraver creates the following layout object(s):

>   Stem and StemTremolo.

> `Tweak_engraver`

>   Read the `tweaks` property from the originating event, and set properties.

> `Rest_engraver`

>   Engrave rests.

>   Music types accepted:

>   rest-event

>   Properties (read)

>   > `middleCPosition` (number)

>   >   The place of the middle C, measured in half staff-spaces. Usually determined by looking at `middleCClefPosition` and `middleCOffset`.

>   This engraver creates the following layout object(s):

>   Rest.

> `Dots_engraver`

>   Create Dots objects for rhythmic-head-interfaces.

>   This engraver creates the following layout object(s):

>   Dots.

> `Note_heads_engraver`

>   Generate note heads.

>   Music types accepted:

>   note-event

>   Properties (read)

>   > `middleCPosition` (number)

>   >   The place of the middle C, measured in half staff-spaces. Usually determined by looking at `middleCClefPosition` and `middleCOffset`.

>   > `staffLineLayoutFunction` (procedure)

>   >   Layout of staff lines, `traditional`, or `semitone`.

>   This engraver creates the following layout object(s):

>   NoteHead.

> `Breathing_sign_engraver`

>   Create a breathing sign.

>   Music types accepted:

>   breathing-event

>   This engraver creates the following layout object(s):

>   BreathingSign.

> `Ligature_bracket_engraver`

>   Handle `Ligature_events` by engraving `Ligature` brackets.

>   Music types accepted:

>   ligature-event

>   This engraver creates the following layout object(s):

>   LigatureBracket.

> `Glissando_engraver`

>   Engrave glissandi.

>   Music types accepted:

>   glissando-event

>   This engraver creates the following layout object(s):

>   Glissando.

> `Note_head_line_engraver`

>   Engrave a line between two note heads, for example a glissando. If `followVoice` is set, staff switches also generate a line.

>   Properties (read)

>   > `followVoice` (boolean)

>   >   If set, note heads are tracked across staff switches by a thin line.

>   This engraver creates the following layout object(s):

>   Glissando and VoiceFollower.

> `Repeat_tie_engraver`

>   Create repeat ties.

>   Music types accepted:

>   repeat-tie-event

>   This engraver creates the following layout object(s):

>   RepeatTie and RepeatTieColumn.

> `Laissez_vibrer_engraver`

>   Create laissez vibrer items.

>   Music types accepted:

>   laissez-vibrer-event

>   This engraver creates the following layout object(s):

>   LaissezVibrerTie and LaissezVibrerTieColumn.

> `Forbid_line_break_engraver`

>   Forbid line breaks when note heads are still playing at some point.

>   Properties (read)

>   > `busyGrobs` (list)

>   >   A queue of `(end-moment . GROB)` cons cells. This is for internal (C++) use only. This property contains the grobs which are still busy (e.g. note heads, spanners, etc.).

>   Properties (write)

>   > `forbidBreak` (boolean)

>   >   If set to `##t`, prevent a line break at this point.

> `Grob_pq_engraver`

>   Administrate when certain grobs (e.g., note heads) stop playing.

>   Properties (read)

>   > `busyGrobs` (list)

>   >   A queue of `(end-moment . GROB)` cons cells. This is for internal (C++) use only. This property contains the grobs which are still busy (e.g. note heads, spanners, etc.).

>   Properties (write)

>   > `busyGrobs` (list)

>   >   A queue of `(end-moment . GROB)` cons cells. This is for internal (C++) use only. This property contains the grobs which are still busy (e.g. note heads, spanners, etc.).

> `Trill_spanner_engraver`

>   Create trill spanner from an event.

>   Music types accepted:

>   trill-span-event

>   Properties (read)

>   > `currentCommandColumn` (layout object)

>   >   Grob that is X-parent to all current breakable (clef, key signature, etc.) items.

>   > `currentMusicalColumn` (layout object)

>   >   Grob that is X-parent to all non-breakable items (note heads, lyrics, etc.).

>   This engraver creates the following layout object(s):

>   TrillSpanner.

> `Text_spanner_engraver`

>   Create text spanner from an event.

>   Music types accepted:

>   text-span-event

>   This engraver creates the following layout object(s):

>   TextSpanner.

> `Multi_measure_rest_engraver`

>   Engrave multi-measure rests that are produced with ‘`R`’. It reads `measurePosition` and `internalBarNumber` to determine what number to print over the MultiMeasureRest. Reads `measureLength` to determine whether it should use a whole rest or a breve rest to represent one measure.

>   Music types accepted:

>   multi-measure-text-event and multi-measure-rest-event

>   Properties (read)

>   > `internalBarNumber` (integer)

>   >   Contains the current barnumber. This property is used for internal timekeeping, among others by the `Accidental_engraver`.

>   > `restNumberThreshold` (number)

>   >   If a multimeasure rest has more measures than this, a number is printed.

>   > `breakableSeparationItem` (layout object)

>   >   The breakable items in this time step, for this staff.

>   > `currentCommandColumn` (layout object)

>   >   Grob that is X-parent to all current breakable (clef, key signature, etc.) items.

>   > `measurePosition` (moment)

>   >   How much of the current measure have we had. This can be set manually to create incomplete measures.

>   > `measureLength` (moment)

>   >   Length of one measure in the current time signature.

>   This engraver creates the following layout object(s):

>   MultiMeasureRest, MultiMeasureRestNumber and MultiMeasureRestText.

> `Arpeggio_engraver`

>   Generate an Arpeggio symbol.

>   Music types accepted:

>   arpeggio-event

>   This engraver creates the following layout object(s):

>   Arpeggio.

> `Output_property_engraver`

>   Apply a procedure to any grob acknowledged.

>   Music types accepted:

>   apply-output-event

> `Pitched_trill_engraver`

>   Print the bracketed note head after a note head with trill.

>   This engraver creates the following layout object(s):

>   TrillPitchAccidental, TrillPitchGroup and TrillPitchHead.

> `Font_size_engraver`

>   Put `fontSize` into `font-size` grob property.

>   Properties (read)

>   > `fontSize` (number)

>   >   The relative size of all grobs in a context.

### 2.1.13 Lyrics

Corresponds to a voice with lyrics. Handles the printing of a single line of lyrics.

This context creates the following layout object(s):

InstrumentName, LyricExtender, LyricHyphen, LyricSpace, LyricText, StanzaNumber and VerticalAxisGroup.

This context sets the following properties:

- Set grob-property `bar-size` in BarLine to `0.1`.
- Set grob-property `font-size` in InstrumentName to `1.0`.
- Set grob-property `self-alignment-Y` in InstrumentName to `#f`.
- Set grob-property `padding` in SeparationItem to `0.2`.
- Set grob-property `keep-fixed-while-stretching` in VerticalAxisGroup to `#t`.
- Set grob-property `remove-empty` in VerticalAxisGroup to `#t`.
- Set grob-property `remove-first` in VerticalAxisGroup to `#t`.
- Set translator property `shortInstrumentName` to `'()`.
- Set translator property `instrumentName` to `'()`.
- Set grob-property `minimum-Y-extent` in VerticalAxisGroup to `'(-0.75 . 2.0)`.

This context is a ‘bottom’ context; it cannot contain other contexts.

This context is built from the following engraver(s):

> `Hara_kiri_engraver`

>   Like `Axis_group_engraver`, but make a hara-kiri spanner, and add interesting items (i.e., note heads, lyric syllables, and normal rests).

>   Properties (read)

>   > `keepAliveInterfaces` (list)

>   >   A list of symbols, signifying grob interfaces that are worth keeping a staff with `remove-empty` set around for.

>   This engraver creates the following layout object(s):

>   VerticalAxisGroup.

> `Font_size_engraver`

>   Put `fontSize` into `font-size` grob property.

>   Properties (read)

>   > `fontSize` (number)

>   >   The relative size of all grobs in a context.

> `Skip_event_swallow_translator`

>   Swallow `\skip`.

> `Instrument_name_engraver`

>   Create a system start text for instrument or vocal names.

>   Properties (read)

>   > `currentCommandColumn` (layout object)

>   >   Grob that is X-parent to all current breakable (clef, key signature, etc.) items.

>   > `shortInstrumentName` (markup)

>   >   See `instrument`.

>   > `instrumentName` (markup)

>   >   The name to print left of a staff. The `instrument` property labels the staff in the first system, and the `instr` property labels following lines.

>   > `shortVocalName` (markup)

>   >   Name of a vocal line, short version.

>   > `vocalName` (markup)

>   >   Name of a vocal line.

>   This engraver creates the following layout object(s):

>   InstrumentName.

> `Stanza_number_engraver`

>   Engrave stanza numbers.

>   Properties (read)

>   > `stanza` (markup)

>   >   Stanza ‘number’ to print before the start of a verse. Use in `Lyrics` context.

>   This engraver creates the following layout object(s):

>   StanzaNumber.

> `Hyphen_engraver`

>   Create lyric hyphens and distance constraints between words.

>   Music types accepted:

>   hyphen-event

>   This engraver creates the following layout object(s):

>   LyricHyphen and LyricSpace.

> `Extender_engraver`

>   Create lyric extenders.

>   Music types accepted:

>   extender-event

>   Properties (read)

>   > `extendersOverRests` (boolean)

>   >   Whether to continue extenders as they cross a rest.

>   This engraver creates the following layout object(s):

>   LyricExtender.

> `Lyric_engraver`

>   Engrave text for lyrics.

>   Music types accepted:

>   lyric-event

>   Properties (read)

>   > `ignoreMelismata` (boolean)

>   >   Ignore melismata for this Lyrics line.

>   > `lyricMelismaAlignment` (direction)

>   >   Alignment to use for a melisma syllable.

>   This engraver creates the following layout object(s):

>   LyricText.

### 2.1.14 MensuralStaff

Same as `Staff` context, except that it is accommodated for typesetting a piece in mensural style.

This context also accepts commands for the following context(s):

Staff.

This context creates the following layout object(s):

AccidentalCautionary, AccidentalPlacement, AccidentalSuggestion, Accidental, BarLine, BassFigureAlignmentPositioning, BassFigureAlignment, BassFigureBracket, BassFigureContinuation, BassFigureLine, BassFigure, Clef, Custos, DotColumn, InstrumentName, KeyCancellation, KeySignature, LedgerLineSpanner, NoteCollision, OctavateEight, OttavaBracket, PianoPedalBracket, RestCollision, ScriptRow, SostenutoPedalLineSpanner, SostenutoPedal, StaffSpacing, StaffSymbol, SustainPedalLineSpanner, SustainPedal, TimeSignature, UnaCordaPedalLineSpanner, UnaCordaPedal and VerticalAxisGroup.

This context sets the following properties:

- Set translator property `printKeyCancellation` to `#f`.
- Set translator property `autoCautionaries` to `'()`.
- Set translator property `autoAccidentals` to `'(Staff #<procedure #f (context pitch barnum measurepos)>)`.
- Set translator property `extraNatural` to `#f`.
- Set grob-property `neutral-direction` in Custos to `-1`.
- Set grob-property `neutral-position` in Custos to `3`.
- Set grob-property `style` in Custos to `'mensural`.
- Set grob-property `glyph-name-alist` in Accidental to `'((-1/2 . accidentals.mensuralM1) (0 . accidentals.vaticana0) (1/2 . accidentals.mensural1))`.
- Set grob-property `glyph-name-alist` in KeySignature to `'((-1/2 . accidentals.mensuralM1) (0 . accidentals.vaticana0) (1/2 . accidentals.mensural1))`.
- Set grob-property `style` in TimeSignature to `'mensural`.
- Set translator property `clefOctavation` to `0`.
- Set translator property `clefPosition` to `-2`.
- Set translator property `middleCPosition` to `-6`.
- Set translator property `middleCClefPosition` to `-6`.
- Set translator property `clefGlyph` to `"clefs.mensural.g"`.
- Set grob-property `thickness` in StaffSymbol to `0.6`.
- Set grob-property `transparent` in BarLine to `#t`.
- Set translator property `shortInstrumentName` to `'()`.
- Set translator property `instrumentName` to `'()`.
- Set grob-property `minimum-Y-extent` in VerticalAxisGroup to `'(-4 . 4)`.
- Set translator property `ignoreFiguredBassRest` to `#t`.
- Set translator property `createSpacing` to `#t`.
- Set translator property `localKeySignature` to `'()`.

Context MensuralStaff can contain MensuralVoice and CueVoice.

This context is built from the following engraver(s):

> `Custos_engraver`

>   Engrave custodes.

>   This engraver creates the following layout object(s):

>   Custos.

> `Script_row_engraver`

>   Determine order in horizontal side position elements.

>   This engraver creates the following layout object(s):

>   ScriptRow.

> `Figured_bass_position_engraver`

>   Position figured bass alignments over notes.

>   This engraver creates the following layout object(s):

>   BassFigureAlignmentPositioning.

> `Figured_bass_engraver`

>   Make figured bass numbers.

>   Music types accepted:

>   bass-figure-event and rest-event

>   Properties (read)

>   > `figuredBassAlterationDirection` (direction)

>   >   Where to put alterations relative to the main figure.

>   > `figuredBassCenterContinuations` (boolean)

>   >   Whether to vertically center pairs of extender lines. This does not work with three or more lines.

>   > `figuredBassFormatter` (procedure)

>   >   A routine generating a markup for a bass figure.

>   > `implicitBassFigures` (list)

>   >   A list of bass figures that are not printed as numbers, but only as extender lines.

>   > `useBassFigureExtenders` (boolean)

>   >   Whether to use extender lines for repeated bass figures.

>   > `ignoreFiguredBassRest` (boolean)

>   >   Don’t swallow rest events.

>   This engraver creates the following layout object(s):

>   BassFigure, BassFigureAlignment, BassFigureBracket, BassFigureContinuation and BassFigureLine.

> `Axis_group_engraver`

>   Group all objects created in this context in a `VerticalAxisGroup` spanner.

>   Properties (read)

>   > `currentCommandColumn` (layout object)

>   >   Grob that is X-parent to all current breakable (clef, key signature, etc.) items.

>   This engraver creates the following layout object(s):

>   VerticalAxisGroup.

> `String_number_engraver`

>   Swallow string number events. The purpose of this engraver is to process tablatures for normal notation. To provent warnings for unprocessed string number events to obscure real error messages, this engraver swallows them all.

> `Instrument_name_engraver`

>   Create a system start text for instrument or vocal names.

>   Properties (read)

>   > `currentCommandColumn` (layout object)

>   >   Grob that is X-parent to all current breakable (clef, key signature, etc.) items.

>   > `shortInstrumentName` (markup)

>   >   See `instrument`.

>   > `instrumentName` (markup)

>   >   The name to print left of a staff. The `instrument` property labels the staff in the first system, and the `instr` property labels following lines.

>   > `shortVocalName` (markup)

>   >   Name of a vocal line, short version.

>   > `vocalName` (markup)

>   >   Name of a vocal line.

>   This engraver creates the following layout object(s):

>   InstrumentName.

> `Piano_pedal_align_engraver`

>   Align piano pedal symbols and brackets.

>   Properties (read)

>   > `currentCommandColumn` (layout object)

>   >   Grob that is X-parent to all current breakable (clef, key signature, etc.) items.

>   This engraver creates the following layout object(s):

>   SostenutoPedalLineSpanner, SustainPedalLineSpanner and UnaCordaPedalLineSpanner.

> `Piano_pedal_engraver`

>   Engrave piano pedal symbols and brackets.

>   Music types accepted:

>   una-corda-event, sustain-event and sostenuto-event

>   Properties (read)

>   > `currentCommandColumn` (layout object)

>   >   Grob that is X-parent to all current breakable (clef, key signature, etc.) items.

>   > `pedalSostenutoStrings` (list)

>   >   See `pedalSustainStrings`.

>   > `pedalSostenutoStyle` (symbol)

>   >   See `pedalSustainStyle`.

>   > `pedalSustainStrings` (list)

>   >   A list of strings to print for sustain-pedal. Format is `(up updown down)`, where each of the three is the string to print when this is done with the pedal.

>   > `pedalSustainStyle` (symbol)

>   >   A symbol that indicates how to print sustain pedals: `text`, `bracket` or `mixed` (both).

>   > `pedalUnaCordaStrings` (list)

>   >   See `pedalSustainStrings`.

>   > `pedalUnaCordaStyle` (symbol)

>   >   See `pedalSustainStyle`.

>   This engraver creates the following layout object(s):

>   PianoPedalBracket, SostenutoPedal, SustainPedal and UnaCordaPedal.

> `Accidental_engraver`

>   Make accidentals. Catch note heads, ties and notices key-change events. This engraver usually lives at Staff level, but reads the settings for Accidental at `Voice` level, so you can `\override` them at `Voice`.

>   Properties (read)

>   > `autoAccidentals` (list)

>   >   List of different ways to typeset an accidental.

>   >   For determining when to print an accidental, several different rules are tried. The rule that gives the highest number of accidentals is used.

>   >   Each entry in the list is either a symbol or a procedure.

>   >   symbol

>   >     The symbol is the name of the context in which the following rules are to be applied. For example, if context is Score then all staves share accidentals, and if context is Staff then all voices in the same staff share accidentals, but staves do not.

>   >   procedure

>   >     The procedure represents an accidental rule to be applied to the previously specified context.

>   >     The procedure takes the following arguments:

>   >     `context`

>   >       The current context to which the rule should be applied.

>   >     `pitch`

>   >       The pitch of the note to be evaluated.

>   >     `barnum`

>   >       The current bar number.

>   >     `measurepos`

>   >       The current measure position.

>   >     The procedure returns a pair of booleans. The first states whether an extra natural should be added. The second states whether an accidental should be printed. `(#t . #f)` does not make sense.

>   > `autoCautionaries` (list)

>   >   List similar to `autoAccidentals`, but it controls cautionary accidentals rather than normal ones. Both lists are tried, and the one giving the most accidentals wins. In case of draw, a normal accidental is typeset.

>   > `internalBarNumber` (integer)

>   >   Contains the current barnumber. This property is used for internal timekeeping, among others by the `Accidental_engraver`.

>   > `extraNatural` (boolean)

>   >   Whether to typeset an extra natural sign before accidentals changing from a non-natural to another non-natural.

>   > `harmonicAccidentals` (boolean)

>   >   If set, harmonic notes in chords get accidentals.

>   > `keySignature` (list)

>   >   The current key signature. This is an alist containing `(step . alter)` or `((octave . step) . alter)`, where step is a number in the range 0 to 6 and alter a fraction, denoting alteration. For alterations, use symbols, e.g. `keySignature = #`((6 . ,FLAT))`.

>   > `localKeySignature` (list)

>   >   The key signature at this point in the measure. The format is the same as for `keySignature`, but can also contain `((octave . name) . (alter barnumber . measureposition))` pairs.

>   Properties (write)

>   > `localKeySignature` (list)

>   >   The key signature at this point in the measure. The format is the same as for `keySignature`, but can also contain `((octave . name) . (alter barnumber . measureposition))` pairs.

>   This engraver creates the following layout object(s):

>   Accidental, AccidentalCautionary, AccidentalPlacement and AccidentalSuggestion.

> `Rest_collision_engraver`

>   Handle collisions of rests.

>   Properties (read)

>   > `busyGrobs` (list)

>   >   A queue of `(end-moment . GROB)` cons cells. This is for internal (C++) use only. This property contains the grobs which are still busy (e.g. note heads, spanners, etc.).

>   This engraver creates the following layout object(s):

>   RestCollision.

> `Grob_pq_engraver`

>   Administrate when certain grobs (e.g., note heads) stop playing.

>   Properties (read)

>   > `busyGrobs` (list)

>   >   A queue of `(end-moment . GROB)` cons cells. This is for internal (C++) use only. This property contains the grobs which are still busy (e.g. note heads, spanners, etc.).

>   Properties (write)

>   > `busyGrobs` (list)

>   >   A queue of `(end-moment . GROB)` cons cells. This is for internal (C++) use only. This property contains the grobs which are still busy (e.g. note heads, spanners, etc.).

> `Collision_engraver`

>   Collect `NoteColumns`, and as soon as there are two or more, put them in a `NoteCollision` object.

>   This engraver creates the following layout object(s):

>   NoteCollision.

> `Staff_symbol_engraver`

>   Create the constellation of five (default) staff lines.

>   Music types accepted:

>   staff-span-event

>   This engraver creates the following layout object(s):

>   StaffSymbol.

> `Ledger_line_engraver`

>   Create the spanner to draw ledger lines, and notices objects that need ledger lines.

>   This engraver creates the following layout object(s):

>   LedgerLineSpanner.

> `Time_signature_engraver`

>   Create a TimeSignature whenever `timeSignatureFraction` changes.

>   Properties (read)

>   > `implicitTimeSignatureVisibility` (vector)

>   >   break visibility for the default time signature.

>   > `timeSignatureFraction` (pair of numbers)

>   >   A pair of numbers, signifying the time signature. For example, `#'(4 . 4)` is a 4/4 time signature.

>   This engraver creates the following layout object(s):

>   TimeSignature.

> `Key_engraver`

>   Engrave a key signature.

>   Music types accepted:

>   key-change-event

>   Properties (read)

>   > `createKeyOnClefChange` (boolean)

>   >   Print a key signature whenever the clef is changed.

>   > `explicitKeySignatureVisibility` (vector)

>   >   ‘`break-visibility`’ function for explicit key changes. ‘`\override`’ of the `break-visibility` property will set the visibility for normal (i.e., at the start of the line) key signatures.

>   > `extraNatural` (boolean)

>   >   Whether to typeset an extra natural sign before accidentals changing from a non-natural to another non-natural.

>   > `keyAlterationOrder` (list)

>   >   An alist that defines in what order alterations should be printed. The format is `(step . alter)`, where step is a number from 0 to 6 and alter from -2 (sharp) to 2 (flat).

>   > `keySignature` (list)

>   >   The current key signature. This is an alist containing `(step . alter)` or `((octave . step) . alter)`, where step is a number in the range 0 to 6 and alter a fraction, denoting alteration. For alterations, use symbols, e.g. `keySignature = #`((6 . ,FLAT))`.

>   > `lastKeySignature` (list)

>   >   Last key signature before a key signature change.

>   > `printKeyCancellation` (boolean)

>   >   Print restoration alterations before a key signature change.

>   Properties (write)

>   > `keySignature` (list)

>   >   The current key signature. This is an alist containing `(step . alter)` or `((octave . step) . alter)`, where step is a number in the range 0 to 6 and alter a fraction, denoting alteration. For alterations, use symbols, e.g. `keySignature = #`((6 . ,FLAT))`.

>   > `lastKeySignature` (list)

>   >   Last key signature before a key signature change.

>   > `tonic` (pitch)

>   >   The tonic of the current scale.

>   This engraver creates the following layout object(s):

>   KeyCancellation and KeySignature.

> `Clef_engraver`

>   Determine and set reference point for pitches.

>   Properties (read)

>   > `clefGlyph` (string)

>   >   Name of the symbol within the music font.

>   > `clefOctavation` (integer)

>   >   Add this much extra octavation. Values of 7 and -7 are common.

>   > `clefPosition` (number)

>   >   Where should the center of the clef symbol go, measured in half staff spaces from the center of the staff.

>   > `explicitClefVisibility` (vector)

>   >   ‘`break-visibility`’ function for clef changes.

>   > `forceClef` (boolean)

>   >   Show clef symbol, even if it has not changed. Only active for the first clef after the property is set, not for the full staff.

>   This engraver creates the following layout object(s):

>   Clef and OctavateEight.

> `Ottava_spanner_engraver`

>   Create a text spanner when the ottavation property changes.

>   Properties (read)

>   > `ottavation` (markup)

>   >   If set, the text for an ottava spanner. Changing this creates a new text spanner.

>   > `originalMiddleCPosition` (integer)

>   >   Used for temporary overriding middle C in octavation brackets.

>   > `currentMusicalColumn` (layout object)

>   >   Grob that is X-parent to all non-breakable items (note heads, lyrics, etc.).

>   This engraver creates the following layout object(s):

>   OttavaBracket.

> `Staff_collecting_engraver`

>   Maintain the `stavesFound` variable.

>   Properties (read)

>   > `stavesFound` (list of grobs)

>   >   A list of all staff-symbols found.

>   Properties (write)

>   > `stavesFound` (list of grobs)

>   >   A list of all staff-symbols found.

> `Dot_column_engraver`

>   Engrave dots on dotted notes shifted to the right of the note. If omitted, then dots appear on top of the notes.

>   This engraver creates the following layout object(s):

>   DotColumn.

> `Separating_line_group_engraver`

>   Generate objects for computing spacing parameters.

>   Properties (read)

>   > `createSpacing` (boolean)

>   >   Create `StaffSpacing` objects? Should be set for staves.

>   Properties (write)

>   > `hasStaffSpacing` (boolean)

>   >   True if the current `CommandColumn` contains items that will affect spacing.

>   This engraver creates the following layout object(s):

>   StaffSpacing.

> `Font_size_engraver`

>   Put `fontSize` into `font-size` grob property.

>   Properties (read)

>   > `fontSize` (number)

>   >   The relative size of all grobs in a context.

> `Bar_engraver`

>   Create barlines. This engraver is controlled through the `whichBar` property. If it has no bar line to create, it will forbid a linebreak at this point.

>   Properties (read)

>   > `whichBar` (string)

>   >   This property is read to determine what type of bar line to create.

>   >   Example:

>   >   >     \set Staff.whichBar = "|:"

>   >   This will create a start-repeat bar in this staff only. Valid values are described in bar-line-interface.

>   Properties (write)

>   > `forbidBreak` (boolean)

>   >   If set to `##t`, prevent a line break at this point.

>   This engraver creates the following layout object(s):

>   BarLine.

> `Output_property_engraver`

>   Apply a procedure to any grob acknowledged.

>   Music types accepted:

>   apply-output-event

### 2.1.15 MensuralVoice

Same as `Voice` context, except that it is accommodated for typesetting a piece in mensural style.

This context also accepts commands for the following context(s):

Voice.

This context creates the following layout object(s):

Arpeggio, Beam, BendAfter, BreathingSign, ClusterSpannerBeacon, ClusterSpanner, CombineTextScript, Dots, DoublePercentRepeatCounter, DoublePercentRepeat, DynamicLineSpanner, DynamicTextSpanner, DynamicText, Fingering, Glissando, Hairpin, InstrumentSwitch, LaissezVibrerTieColumn, LaissezVibrerTie, MensuralLigature, MultiMeasureRestNumber, MultiMeasureRestText, MultiMeasureRest, NoteColumn, NoteHead, NoteSpacing, PercentRepeatCounter, PercentRepeat, PhrasingSlur, RepeatSlash, RepeatTieColumn, RepeatTie, Rest, ScriptColumn, Script, StemTremolo, Stem, StringNumber, StrokeFinger, TextScript, TextSpanner, TieColumn, Tie, TrillPitchAccidental, TrillPitchGroup, TrillPitchHead, TrillSpanner, TupletBracket, TupletNumber and VoiceFollower.

This context sets the following properties:

- Set translator property `autoBeaming` to `#f`.
- Set grob-property `style` in Rest to `'mensural`.
- Set grob-property `style` in NoteHead to `'mensural`.
- Set translator property `localKeySignature` to `'()`.

This context is a ‘bottom’ context; it cannot contain other contexts.

This context is built from the following engraver(s):

> `Mensural_ligature_engraver`

>   Handle `Mensural_ligature_events` by glueing special ligature heads together.

>   Music types accepted:

>   ligature-event

>   This engraver creates the following layout object(s):

>   MensuralLigature.

> `Skip_event_swallow_translator`

>   Swallow `\skip`.

> `Instrument_switch_engraver`

>   Create a cue text for taking instrument.

>   Properties (read)

>   > `instrumentCueName` (markup)

>   >   The name to print if another instrument is to be taken.

>   This engraver creates the following layout object(s):

>   InstrumentSwitch.

> `Grace_engraver`

>   Set font size and other properties for grace notes.

>   Properties (read)

>   > `graceSettings` (list)

>   >   Overrides for grace notes. This property should be manipulated through the `add-grace-property` function.

> `Tuplet_engraver`

>   Catch tuplet events and generate appropriate bracket.

>   Music types accepted:

>   tuplet-span-event

>   Properties (read)

>   > `tupletFullLength` (boolean)

>   >   If set, the tuplet is printed up to the start of the next note.

>   > `tupletFullLengthNote` (boolean)

>   >   If set, end at the next note, otherwise end on the matter (time signatures, etc.) before the note.

>   This engraver creates the following layout object(s):

>   TupletBracket and TupletNumber.

> `Tie_engraver`

>   Generate ties between note heads of equal pitch.

>   Music types accepted:

>   tie-event

>   Properties (read)

>   > `tieWaitForNote` (boolean)

>   >   If true, tied notes do not have to follow each other directly. This can be used for writing out arpeggios.

>   Properties (write)

>   > `tieMelismaBusy` (boolean)

>   >   Signal whether a tie is present.

>   This engraver creates the following layout object(s):

>   Tie and TieColumn.

> `Cluster_spanner_engraver`

>   Engrave a cluster using `Spanner` notation.

>   Music types accepted:

>   cluster-note-event

>   This engraver creates the following layout object(s):

>   ClusterSpanner and ClusterSpannerBeacon.

> `Phrasing_slur_engraver`

>   Print phrasing slurs. Similar to Slur_engraver.

>   Music types accepted:

>   phrasing-slur-event

>   This engraver creates the following layout object(s):

>   PhrasingSlur.

> `Spanner_break_forbid_engraver`

>   Forbid breaks in certain spanners.

> `Note_spacing_engraver`

>   Generate `NoteSpacing`, an object linking horizontal lines for use in spacing.

>   This engraver creates the following layout object(s):

>   NoteSpacing.

> `Rhythmic_column_engraver`

>   Generate `NoteColumn`, an object that groups stems, note heads, and rests.

>   This engraver creates the following layout object(s):

>   NoteColumn.

> `Script_column_engraver`

>   Find potentially colliding scripts and put them into a `ScriptColumn` object; that will fix the collisions.

>   This engraver creates the following layout object(s):

>   ScriptColumn.

> `Script_engraver`

>   Handle note scripted articulations.

>   Music types accepted:

>   articulation-event

>   Properties (read)

>   > `scriptDefinitions` (list)

>   >   The description of scripts. This is used by the `Script_engraver` for typesetting note-superscripts and subscripts. See ‘`scm/script.scm`’ for more information.

>   This engraver creates the following layout object(s):

>   Script.

> `Bend_engraver`

>   Create fall spanners.

>   Music types accepted:

>   bend-after-event

>   This engraver creates the following layout object(s):

>   BendAfter.

> `Fingering_engraver`

>   Create fingering scripts.

>   Music types accepted:

>   stroke-finger-event and fingering-event

>   This engraver creates the following layout object(s):

>   Fingering.

> `Dynamic_align_engraver`

>   Align hairpins and dynamic texts on a horizontal line

>   Properties (read)

>   > `currentMusicalColumn` (layout object)

>   >   Grob that is X-parent to all non-breakable items (note heads, lyrics, etc.).

>   This engraver creates the following layout object(s):

>   DynamicLineSpanner.

> `New_dynamic_engraver`

>   Create hairpins, dynamic texts, and their vertical alignments. The symbols are collected onto a `DynamicLineSpanner` grob which takes care of vertical positioning.

>   Music types accepted:

>   span-dynamic-event and absolute-dynamic-event

>   Properties (read)

>   > `crescendoSpanner` (symbol)

>   >   The type of spanner to be used for crescendi. Available values are ‘`hairpin`’ and ‘`text`’. If unset, a hairpin crescendo is used.

>   > `crescendoText` (markup)

>   >   The text to print at start of non-hairpin crescendo, i.e., ‘`cresc.`’.

>   > `currentMusicalColumn` (layout object)

>   >   Grob that is X-parent to all non-breakable items (note heads, lyrics, etc.).

>   > `decrescendoSpanner` (symbol)

>   >   The type of spanner to be used for decrescendi. Available values are ‘`hairpin`’ and ‘`text`’. If unset, a hairpin decrescendo is used.

>   > `decrescendoText` (markup)

>   >   The text to print at start of non-hairpin decrescendo, i.e., ‘`dim.`’.

>   This engraver creates the following layout object(s):

>   DynamicText, DynamicTextSpanner and Hairpin.

> `Text_engraver`

>   Create text scripts.

>   Music types accepted:

>   text-script-event

>   This engraver creates the following layout object(s):

>   TextScript.

> `Part_combine_engraver`

>   Part combine engraver for orchestral scores: Print markings ‘a2’, ‘Solo’, ‘Solo II’, and ‘unisono’.

>   Music types accepted:

>   part-combine-event

>   Properties (read)

>   > `printPartCombineTexts` (boolean)

>   >   Set ‘Solo’ and ‘A due’ texts in the part combiner?

>   > `soloText` (markup)

>   >   The text for the start of a solo when part-combining.

>   > `soloIIText` (markup)

>   >   The text for the start of a solo for voice ‘two’ when part-combining.

>   > `aDueText` (markup)

>   >   Text to print at a unisono passage.

>   This engraver creates the following layout object(s):

>   CombineTextScript.

> `Slash_repeat_engraver`

>   Make beat repeats.

>   Music types accepted:

>   percent-event

>   Properties (read)

>   > `measureLength` (moment)

>   >   Length of one measure in the current time signature.

>   This engraver creates the following layout object(s):

>   RepeatSlash.

> `Percent_repeat_engraver`

>   Make whole bar and double bar repeats.

>   Music types accepted:

>   percent-event

>   Properties (read)

>   > `countPercentRepeats` (boolean)

>   >   If set, produce counters for percent repeats.

>   > `currentCommandColumn` (layout object)

>   >   Grob that is X-parent to all current breakable (clef, key signature, etc.) items.

>   > `measureLength` (moment)

>   >   Length of one measure in the current time signature.

>   > `repeatCountVisibility` (procedure)

>   >   A procedure taking as arguments an integer and context, returning whether the corresponding percent repeat number should be printed when `countPercentRepeats` is set.

>   Properties (write)

>   > `forbidBreak` (boolean)

>   >   If set to `##t`, prevent a line break at this point.

>   This engraver creates the following layout object(s):

>   DoublePercentRepeat, DoublePercentRepeatCounter, PercentRepeat and PercentRepeatCounter.

> `Chord_tremolo_engraver`

>   Generate beams for tremolo repeats.

>   Music types accepted:

>   tremolo-span-event

>   This engraver creates the following layout object(s):

>   Beam.

> `New_fingering_engraver`

>   Create fingering scripts for notes in a new chord. This engraver is ill-named, since it also takes care of articulations and harmonic note heads.

>   Properties (read)

>   > `fingeringOrientations` (list)

>   >   A list of symbols, containing ‘`left`’, ‘`right`’, ‘`up`’ and/or ‘`down`’. This list determines where fingerings are put relative to the chord being fingered.

>   > `harmonicDots` (boolean)

>   >   If set, harmonic notes in dotted chords get dots.

>   > `strokeFingerOrientations` (list)

>   >   See `fingeringOrientations`.

>   > `stringNumberOrientations` (list)

>   >   See `fingeringOrientations`.

>   This engraver creates the following layout object(s):

>   Fingering, Script, StringNumber and StrokeFinger.

> `Auto_beam_engraver`

>   Generate beams based on measure characteristics and observed Stems. Uses `beatLength`, `measureLength`, and `measurePosition` to decide when to start and stop a beam. Overriding beaming is done through Stem_engraver properties `stemLeftBeamCount` and `stemRightBeamCount`.

>   Music types accepted:

>   beam-forbid-event

>   Properties (read)

>   > `autoBeaming` (boolean)

>   >   If set to true then beams are generated automatically.

>   > `autoBeamSettings` (list)

>   >   Specifies when automatically generated beams should begin and end. See behavior Setting automatic beam behavior for more information.

>   > `beatLength` (moment)

>   >   The length of one beat in this time signature.

>   > `subdivideBeams` (boolean)

>   >   If set, multiple beams will be subdivided at beat positions by only drawing one beam over the beat.

>   This engraver creates the following layout object(s):

>   Beam.

> `Grace_beam_engraver`

>   Handle `Beam` events by engraving beams. If omitted, then notes are printed with flags instead of beams. Only engraves beams when we are at grace points in time.

>   Music types accepted:

>   beam-event

>   Properties (read)

>   > `beamMelismaBusy` (boolean)

>   >   Signal if a beam is present.

>   > `beatLength` (moment)

>   >   The length of one beat in this time signature.

>   > `subdivideBeams` (boolean)

>   >   If set, multiple beams will be subdivided at beat positions by only drawing one beam over the beat.

>   This engraver creates the following layout object(s):

>   Beam.

> `Beam_engraver`

>   Handle `Beam` events by engraving beams. If omitted, then notes are printed with flags instead of beams.

>   Music types accepted:

>   beam-event

>   Properties (read)

>   > `beamMelismaBusy` (boolean)

>   >   Signal if a beam is present.

>   > `beatLength` (moment)

>   >   The length of one beat in this time signature.

>   > `subdivideBeams` (boolean)

>   >   If set, multiple beams will be subdivided at beat positions by only drawing one beam over the beat.

>   Properties (write)

>   > `forbidBreak` (boolean)

>   >   If set to `##t`, prevent a line break at this point.

>   This engraver creates the following layout object(s):

>   Beam.

> `Stem_engraver`

>   Create stems and single-stem tremolos. It also works together with the beam engraver for overriding beaming.

>   Music types accepted:

>   tremolo-event

>   Properties (read)

>   > `tremoloFlags` (integer)

>   >   The number of tremolo flags to add if no number is specified.

>   > `stemLeftBeamCount` (integer)

>   >   Specify the number of beams to draw on the left side of the next note. Overrides automatic beaming. The value is only used once, and then it is erased.

>   > `stemRightBeamCount` (integer)

>   >   See `stemLeftBeamCount`.

>   This engraver creates the following layout object(s):

>   Stem and StemTremolo.

> `Tweak_engraver`

>   Read the `tweaks` property from the originating event, and set properties.

> `Rest_engraver`

>   Engrave rests.

>   Music types accepted:

>   rest-event

>   Properties (read)

>   > `middleCPosition` (number)

>   >   The place of the middle C, measured in half staff-spaces. Usually determined by looking at `middleCClefPosition` and `middleCOffset`.

>   This engraver creates the following layout object(s):

>   Rest.

> `Dots_engraver`

>   Create Dots objects for rhythmic-head-interfaces.

>   This engraver creates the following layout object(s):

>   Dots.

> `Note_heads_engraver`

>   Generate note heads.

>   Music types accepted:

>   note-event

>   Properties (read)

>   > `middleCPosition` (number)

>   >   The place of the middle C, measured in half staff-spaces. Usually determined by looking at `middleCClefPosition` and `middleCOffset`.

>   > `staffLineLayoutFunction` (procedure)

>   >   Layout of staff lines, `traditional`, or `semitone`.

>   This engraver creates the following layout object(s):

>   NoteHead.

> `Breathing_sign_engraver`

>   Create a breathing sign.

>   Music types accepted:

>   breathing-event

>   This engraver creates the following layout object(s):

>   BreathingSign.

> `Glissando_engraver`

>   Engrave glissandi.

>   Music types accepted:

>   glissando-event

>   This engraver creates the following layout object(s):

>   Glissando.

> `Note_head_line_engraver`

>   Engrave a line between two note heads, for example a glissando. If `followVoice` is set, staff switches also generate a line.

>   Properties (read)

>   > `followVoice` (boolean)

>   >   If set, note heads are tracked across staff switches by a thin line.

>   This engraver creates the following layout object(s):

>   Glissando and VoiceFollower.

> `Repeat_tie_engraver`

>   Create repeat ties.

>   Music types accepted:

>   repeat-tie-event

>   This engraver creates the following layout object(s):

>   RepeatTie and RepeatTieColumn.

> `Laissez_vibrer_engraver`

>   Create laissez vibrer items.

>   Music types accepted:

>   laissez-vibrer-event

>   This engraver creates the following layout object(s):

>   LaissezVibrerTie and LaissezVibrerTieColumn.

> `Forbid_line_break_engraver`

>   Forbid line breaks when note heads are still playing at some point.

>   Properties (read)

>   > `busyGrobs` (list)

>   >   A queue of `(end-moment . GROB)` cons cells. This is for internal (C++) use only. This property contains the grobs which are still busy (e.g. note heads, spanners, etc.).

>   Properties (write)

>   > `forbidBreak` (boolean)

>   >   If set to `##t`, prevent a line break at this point.

> `Grob_pq_engraver`

>   Administrate when certain grobs (e.g., note heads) stop playing.

>   Properties (read)

>   > `busyGrobs` (list)

>   >   A queue of `(end-moment . GROB)` cons cells. This is for internal (C++) use only. This property contains the grobs which are still busy (e.g. note heads, spanners, etc.).

>   Properties (write)

>   > `busyGrobs` (list)

>   >   A queue of `(end-moment . GROB)` cons cells. This is for internal (C++) use only. This property contains the grobs which are still busy (e.g. note heads, spanners, etc.).

> `Trill_spanner_engraver`

>   Create trill spanner from an event.

>   Music types accepted:

>   trill-span-event

>   Properties (read)

>   > `currentCommandColumn` (layout object)

>   >   Grob that is X-parent to all current breakable (clef, key signature, etc.) items.

>   > `currentMusicalColumn` (layout object)

>   >   Grob that is X-parent to all non-breakable items (note heads, lyrics, etc.).

>   This engraver creates the following layout object(s):

>   TrillSpanner.

> `Text_spanner_engraver`

>   Create text spanner from an event.

>   Music types accepted:

>   text-span-event

>   This engraver creates the following layout object(s):

>   TextSpanner.

> `Multi_measure_rest_engraver`

>   Engrave multi-measure rests that are produced with ‘`R`’. It reads `measurePosition` and `internalBarNumber` to determine what number to print over the MultiMeasureRest. Reads `measureLength` to determine whether it should use a whole rest or a breve rest to represent one measure.

>   Music types accepted:

>   multi-measure-text-event and multi-measure-rest-event

>   Properties (read)

>   > `internalBarNumber` (integer)

>   >   Contains the current barnumber. This property is used for internal timekeeping, among others by the `Accidental_engraver`.

>   > `restNumberThreshold` (number)

>   >   If a multimeasure rest has more measures than this, a number is printed.

>   > `breakableSeparationItem` (layout object)

>   >   The breakable items in this time step, for this staff.

>   > `currentCommandColumn` (layout object)

>   >   Grob that is X-parent to all current breakable (clef, key signature, etc.) items.

>   > `measurePosition` (moment)

>   >   How much of the current measure have we had. This can be set manually to create incomplete measures.

>   > `measureLength` (moment)

>   >   Length of one measure in the current time signature.

>   This engraver creates the following layout object(s):

>   MultiMeasureRest, MultiMeasureRestNumber and MultiMeasureRestText.

> `Arpeggio_engraver`

>   Generate an Arpeggio symbol.

>   Music types accepted:

>   arpeggio-event

>   This engraver creates the following layout object(s):

>   Arpeggio.

> `Output_property_engraver`

>   Apply a procedure to any grob acknowledged.

>   Music types accepted:

>   apply-output-event

> `Pitched_trill_engraver`

>   Print the bracketed note head after a note head with trill.

>   This engraver creates the following layout object(s):

>   TrillPitchAccidental, TrillPitchGroup and TrillPitchHead.

> `Font_size_engraver`

>   Put `fontSize` into `font-size` grob property.

>   Properties (read)

>   > `fontSize` (number)

>   >   The relative size of all grobs in a context.

### 2.1.16 NoteNames

(not documented)

This context creates the following layout object(s):

NoteName, StaffSpacing, TieColumn, Tie and VerticalAxisGroup.

This context sets the following properties:

- Set grob-property `minimum-Y-extent` in VerticalAxisGroup to `#f`.

This context is a ‘bottom’ context; it cannot contain other contexts.

This context is built from the following engraver(s):

> `Separating_line_group_engraver`

>   Generate objects for computing spacing parameters.

>   Properties (read)

>   > `createSpacing` (boolean)

>   >   Create `StaffSpacing` objects? Should be set for staves.

>   Properties (write)

>   > `hasStaffSpacing` (boolean)

>   >   True if the current `CommandColumn` contains items that will affect spacing.

>   This engraver creates the following layout object(s):

>   StaffSpacing.

> `Note_name_engraver`

>   Print pitches as words.

>   Music types accepted:

>   note-event

>   Properties (read)

>   > `printOctaveNames` (boolean)

>   >   Print octave marks for the `NoteNames` context.

>   This engraver creates the following layout object(s):

>   NoteName.

> `Tie_engraver`

>   Generate ties between note heads of equal pitch.

>   Music types accepted:

>   tie-event

>   Properties (read)

>   > `tieWaitForNote` (boolean)

>   >   If true, tied notes do not have to follow each other directly. This can be used for writing out arpeggios.

>   Properties (write)

>   > `tieMelismaBusy` (boolean)

>   >   Signal whether a tie is present.

>   This engraver creates the following layout object(s):

>   Tie and TieColumn.

> `Skip_event_swallow_translator`

>   Swallow `\skip`.

> `Rest_swallow_translator`

>   Swallow rest.

> `Axis_group_engraver`

>   Group all objects created in this context in a `VerticalAxisGroup` spanner.

>   Properties (read)

>   > `currentCommandColumn` (layout object)

>   >   Grob that is X-parent to all current breakable (clef, key signature, etc.) items.

>   This engraver creates the following layout object(s):

>   VerticalAxisGroup.

### 2.1.17 PianoStaff

Just like `GrandStaff` but with support for instrument names at the start of each system.

This context also accepts commands for the following context(s):

GrandStaff.

This context creates the following layout object(s):

Arpeggio, InstrumentName, SpanBar, SystemStartBar, SystemStartBrace, SystemStartBracket and SystemStartSquare.

This context sets the following properties:

- Set translator property `shortInstrumentName` to `'()`.
- Set translator property `instrumentName` to `'()`.
- Set translator property `systemStartDelimiter` to `'SystemStartBrace`.
- Set translator property `localKeySignature` to `'()`.

Context PianoStaff can contain Staff and FiguredBass.

This context is built from the following engraver(s):

> `Instrument_name_engraver`

>   Create a system start text for instrument or vocal names.

>   Properties (read)

>   > `currentCommandColumn` (layout object)

>   >   Grob that is X-parent to all current breakable (clef, key signature, etc.) items.

>   > `shortInstrumentName` (markup)

>   >   See `instrument`.

>   > `instrumentName` (markup)

>   >   The name to print left of a staff. The `instrument` property labels the staff in the first system, and the `instr` property labels following lines.

>   > `shortVocalName` (markup)

>   >   Name of a vocal line, short version.

>   > `vocalName` (markup)

>   >   Name of a vocal line.

>   This engraver creates the following layout object(s):

>   InstrumentName.

> `System_start_delimiter_engraver`

>   Create a system start delimiter (i.e., a `SystemStartBar`, `SystemStartBrace`, `SystemStartBracket` or `SystemStartSquare` spanner).

>   Properties (read)

>   > `systemStartDelimiter` (symbol)

>   >   Which grob to make for the start of the system/staff? Set to `SystemStartBrace`, `SystemStartBracket` or `SystemStartBar`.

>   > `systemStartDelimiterHierarchy` (pair)

>   >   A nested list, indicating the nesting of a start delimiters.

>   > `currentCommandColumn` (layout object)

>   >   Grob that is X-parent to all current breakable (clef, key signature, etc.) items.

>   This engraver creates the following layout object(s):

>   SystemStartBar, SystemStartBrace, SystemStartBracket and SystemStartSquare.

> `Span_arpeggio_engraver`

>   Make arpeggios that span multiple staves.

>   Properties (read)

>   > `connectArpeggios` (boolean)

>   >   If set, connect arpeggios across piano staff.

>   This engraver creates the following layout object(s):

>   Arpeggio.

> `Span_bar_engraver`

>   Make cross-staff bar lines: It catches all normal bar lines and draws a single span bar across them.

>   This engraver creates the following layout object(s):

>   SpanBar.

### 2.1.18 RhythmicStaff

A context like `Staff` but for printing rhythms. Pitches are ignored; the notes are printed on one line.

This context also accepts commands for the following context(s):

Staff.

This context creates the following layout object(s):

BarLine, DotColumn, InstrumentName, LedgerLineSpanner, StaffSpacing, StaffSymbol, TimeSignature and VerticalAxisGroup.

This context sets the following properties:

- Set grob-property `neutral-direction` in Beam to `1`.
- Set grob-property `neutral-direction` in Stem to `1`.
- Set grob-property `line-count` in StaffSymbol to `1`.
- Set grob-property `staff-padding` in VoltaBracket to `3`.
- Set grob-property `bar-size` in BarLine to `4`.
- Set translator property `squashedPosition` to `0`.
- Set translator property `createSpacing` to `#t`.
- Set translator property `localKeySignature` to `'()`.
- Set grob-property `minimum-Y-extent` in VerticalAxisGroup to `#f`.

Context RhythmicStaff can contain Voice and CueVoice.

This context is built from the following engraver(s):

> `Ledger_line_engraver`

>   Create the spanner to draw ledger lines, and notices objects that need ledger lines.

>   This engraver creates the following layout object(s):

>   LedgerLineSpanner.

> `Axis_group_engraver`

>   Group all objects created in this context in a `VerticalAxisGroup` spanner.

>   Properties (read)

>   > `currentCommandColumn` (layout object)

>   >   Grob that is X-parent to all current breakable (clef, key signature, etc.) items.

>   This engraver creates the following layout object(s):

>   VerticalAxisGroup.

> `Instrument_name_engraver`

>   Create a system start text for instrument or vocal names.

>   Properties (read)

>   > `currentCommandColumn` (layout object)

>   >   Grob that is X-parent to all current breakable (clef, key signature, etc.) items.

>   > `shortInstrumentName` (markup)

>   >   See `instrument`.

>   > `instrumentName` (markup)

>   >   The name to print left of a staff. The `instrument` property labels the staff in the first system, and the `instr` property labels following lines.

>   > `shortVocalName` (markup)

>   >   Name of a vocal line, short version.

>   > `vocalName` (markup)

>   >   Name of a vocal line.

>   This engraver creates the following layout object(s):

>   InstrumentName.

> `Time_signature_engraver`

>   Create a TimeSignature whenever `timeSignatureFraction` changes.

>   Properties (read)

>   > `implicitTimeSignatureVisibility` (vector)

>   >   break visibility for the default time signature.

>   > `timeSignatureFraction` (pair of numbers)

>   >   A pair of numbers, signifying the time signature. For example, `#'(4 . 4)` is a 4/4 time signature.

>   This engraver creates the following layout object(s):

>   TimeSignature.

> `Pitch_squash_engraver`

>   Set the vertical position of note heads to `squashedPosition`, if that property is set. This can be used to make a single-line staff demonstrating the rhythm of a melody.

>   Properties (read)

>   > `squashedPosition` (integer)

>   >   Vertical position of squashing for Pitch_squash_engraver.

> `Staff_symbol_engraver`

>   Create the constellation of five (default) staff lines.

>   Music types accepted:

>   staff-span-event

>   This engraver creates the following layout object(s):

>   StaffSymbol.

> `Bar_engraver`

>   Create barlines. This engraver is controlled through the `whichBar` property. If it has no bar line to create, it will forbid a linebreak at this point.

>   Properties (read)

>   > `whichBar` (string)

>   >   This property is read to determine what type of bar line to create.

>   >   Example:

>   >   >     \set Staff.whichBar = "|:"

>   >   This will create a start-repeat bar in this staff only. Valid values are described in bar-line-interface.

>   Properties (write)

>   > `forbidBreak` (boolean)

>   >   If set to `##t`, prevent a line break at this point.

>   This engraver creates the following layout object(s):

>   BarLine.

> `Dot_column_engraver`

>   Engrave dots on dotted notes shifted to the right of the note. If omitted, then dots appear on top of the notes.

>   This engraver creates the following layout object(s):

>   DotColumn.

> `Separating_line_group_engraver`

>   Generate objects for computing spacing parameters.

>   Properties (read)

>   > `createSpacing` (boolean)

>   >   Create `StaffSpacing` objects? Should be set for staves.

>   Properties (write)

>   > `hasStaffSpacing` (boolean)

>   >   True if the current `CommandColumn` contains items that will affect spacing.

>   This engraver creates the following layout object(s):

>   StaffSpacing.

> `Font_size_engraver`

>   Put `fontSize` into `font-size` grob property.

>   Properties (read)

>   > `fontSize` (number)

>   >   The relative size of all grobs in a context.

> `Output_property_engraver`

>   Apply a procedure to any grob acknowledged.

>   Music types accepted:

>   apply-output-event

### 2.1.19 Score

This is the top level notation context. No other context can contain a `Score` context. This context handles the administration of time signatures. It also makes sure that items such as clefs, time signatures, and key-signatures are aligned across staves.

You cannot explicitly instantiate a `Score` context (since it is not contained in any other context). It is instantiated automatically when an output definition (a `\score` or `\layout` block) is processed.

This context creates the following layout object(s):

BarNumber, BreakAlignGroup, BreakAlignment, GraceSpacing, LeftEdge, MetronomeMark, NonMusicalPaperColumn, PaperColumn, ParenthesesItem, RehearsalMark, SpacingSpanner, SystemStartBar, SystemStartBrace, SystemStartBracket, SystemStartSquare, VerticalAlignment, VoltaBracketSpanner and VoltaBracket.

This context sets the following properties:

- Set translator property `timing` to `#t`.
- Set translator property `verticallySpacedContexts` to `'(Staff)`.
- Set translator property `instrumentTransposition` to `#<Pitch c' >`.
- Set translator property `quotedEventTypes` to `'(note-event rest-event tie-event beam-event tuplet-span-event)`.
- Set translator property `keepAliveInterfaces` to `'(rhythmic-grob-interface lyric-interface percent-repeat-item-interface percent-repeat-interface stanza-number-interface)`.
- Set translator property `graceSettings` to `'((Voice Stem direction 1) (Voice Stem font-size -3) (Voice NoteHead font-size -3) (Voice Dots font-size -3) (Voice Stem length-fraction 0.8) (Voice Stem no-stem-extend #t) (Voice Beam thickness 0.384) (Voice Beam length-fraction 0.8) (Voice Accidental font-size -4) (Voice AccidentalCautionary font-size -4) (Voice Slur direction -1) (Voice Script font-size -3))`.
- Set translator property `metronomeMarkFormatter` to `format-metronome-markup`.
- Set translator property `figuredBassFormatter` to `format-bass-figure`.
- Set translator property `tablatureFormat` to `fret-number-tablature-format`.
- Set translator property `stringTunings` to `'(4 -1 -5 -10 -15 -20)`.
- Set translator property `highStringOne` to `#t`.
- Set translator property `stringOneTopmost` to `#t`.
- Set translator property `bassStaffProperties` to `'((assign clefGlyph clefs.F) (assign clefPosition 2) (assign middleCPosition 6) (assign middleCClefPosition 6))`.
- Set translator property `chordNameExceptionsPartial` to `'(((#<Pitch c' > #<Pitch d' >) (#<procedure line-markup (layout props args)> ((#<procedure normal-size-super-markup (layout props arg)> 2)))) ((#<Pitch c' > #<Pitch ees' >) (#<procedure line-markup (layout props args)> (m))) ((#<Pitch c' > #<Pitch f' >) (#<procedure line-markup (layout props args)> ((#<procedure normal-size-super-markup (layout props arg)> sus4)))) ((#<Pitch c' > #<Pitch g' >) (#<procedure line-markup (layout props args)> ((#<procedure normal-size-super-markup (layout props arg)> 5)))) ((#<Pitch c' > #<Pitch ees' > #<Pitch f' >) (#<procedure line-markup (layout props args)> (m)) (#<procedure line-markup (layout props args)> ((#<procedure normal-size-super-markup (layout props arg)> sus4)))) ((#<Pitch c' > #<Pitch d' > #<Pitch ees' >) (#<procedure line-markup (layout props args)> (m)) (#<procedure line-markup (layout props args)> ((#<procedure normal-size-super-markup (layout props arg)> sus2)))))`.
- Set translator property `chordNameExceptionsFull` to `'(((#<Pitch c' > #<Pitch e' > #<Pitch gis' >) (#<procedure line-markup (layout props args)> (+))) ((#<Pitch c' > #<Pitch ees' > #<Pitch ges' >) (#<procedure line-markup (layout props args)> ((#<procedure super-markup (layout props arg)> o)))) ((#<Pitch c' > #<Pitch ees' > #<Pitch ges' > #<Pitch bes' >) (#<procedure line-markup (layout props args)> ((#<procedure super-markup (layout props arg)> ø)))) ((#<Pitch c' > #<Pitch ees' > #<Pitch ges' > #<Pitch beses' >) (#<procedure line-markup (layout props args)> ((#<procedure super-markup (layout props arg)> o7)))))`.
- Set translator property `chordPrefixSpacer` to `0`.
- Set translator property `chordRootNamer` to `note-name->markup`.
- Set translator property `chordNoteNamer` to `'()`.
- Set translator property `chordNameExceptions` to `'(((#<Pitch e' > #<Pitch gis' >) #<procedure line-markup (layout props args)> (+)) ((#<Pitch ees' > #<Pitch ges' >) #<procedure line-markup (layout props args)> ((#<procedure super-markup (layout props arg)> o))) ((#<Pitch ees' > #<Pitch ges' > #<Pitch bes' >) #<procedure line-markup (layout props args)> ((#<procedure super-markup (layout props arg)> ø))) ((#<Pitch ees' > #<Pitch ges' > #<Pitch beses' >) #<procedure line-markup (layout props args)> ((#<procedure super-markup (layout props arg)> o7))))`.
- Set translator property `chordNameSeparator` to `'(#<procedure simple-markup (layout props str)> /)`.
- Set translator property `majorSevenSymbol` to `'(#<procedure line-markup (layout props args)> ((#<procedure triangle-markup (layout props filled)> #f)))`.
- Set translator property `chordNameFunction` to `ignatzek-chord-names`.
- Set translator property `barCheckSynchronize` to `#f`.
- Set translator property `keyAlterationOrder` to `'((6 . -1/2) (2 . -1/2) (5 . -1/2) (1 . -1/2) (4 . -1/2) (0 . -1/2) (3 . -1/2) (3 . 1/2) (0 . 1/2) (4 . 1/2) (1 . 1/2) (5 . 1/2) (2 . 1/2) (6 . 1/2) (6 . -1) (2 . -1) (5 . -1) (1 . -1) (4 . -1) (0 . -1) (3 . -1) (3 . 1) (0 . 1) (4 . 1) (2 . 1) (5 . 1) (2 . 1) (6 . 1))`.
- Set translator property `printKeyCancellation` to `#t`.
- Set translator property `autoCautionaries` to `'()`.
- Set translator property `autoAccidentals` to `'(Staff #<procedure #f (context pitch barnum measurepos)>)`.
- Set translator property `extraNatural` to `#t`.
- Set translator property `subdivideBeams` to `#f`.
- Set translator property `rehearsalMark` to `1`.
- Set translator property `markFormatter` to `format-mark-letters`.
- Set translator property `lyricMelismaAlignment` to `-1`.
- Set translator property `strokeFingerOrientations` to `'(right)`.
- Set translator property `stringNumberOrientations` to `'(up down)`.
- Set translator property `fingeringOrientations` to `'(up down)`.
- Set translator property `harmonicAccidentals` to `#t`.
- Set translator property `pedalSostenutoStyle` to `'mixed`.
- Set translator property `pedalSostenutoStrings` to `'(Sost. Ped. *Sost. Ped. *)`.
- Set translator property `pedalUnaCordaStyle` to `'text`.
- Set translator property `pedalUnaCordaStrings` to `'(una corda tre corde)`.
- Set translator property `pedalSustainStyle` to `'text`.
- Set translator property `pedalSustainStrings` to `'(Ped. *Ped. *)`.
- Set translator property `scriptDefinitions` to `'((thumb (script-stencil feta thumb . thumb) (avoid-slur . inside) (padding . 0.2) (direction . 1)) (accent (avoid-slur . around) (padding . 0.2) (quantize-position . #t) (script-stencil feta sforzato . sforzato) (side-relative-direction . -1)) (espressivo (avoid-slur . around) (padding . 0.2) (quantize-position . #t) (script-stencil feta espr . espr) (side-relative-direction . -1)) (marcato (script-stencil feta dmarcato . umarcato) (padding . 0.2) (avoid-slur . inside) (quantize-position . #t) (side-relative-direction . -1)) (staccatissimo (avoid-slur . inside) (script-stencil feta dstaccatissimo . ustaccatissimo) (padding . 0.2) (side-relative-direction . -1)) (portato (script-stencil feta uportato . dportato) (avoid-slur . around) (slur-padding . 0.3) (padding . 0.45) (side-relative-direction . -1)) (accentus (script-stencil feta uaccentus . uaccentus) (side-relative-direction . -1) (avoid-slur . #f) (padding . 0.2) (quantize-position . #t) (script-priority . -100) (direction . 1)) (ictus (script-stencil feta ictus . ictus) (side-relative-direction . -1) (quantize-position . #t) (avoid-slur . #f) (padding . 0.2) (script-priority . -100) (direction . -1)) (semicirculus (script-stencil feta dsemicirculus . dsemicirculus) (side-relative-direction . -1) (quantize-position . #t) (avoid-slur . #f) (padding . 0.2) (script-priority . -100) (direction . 1)) (circulus (script-stencil feta circulus . circulus) (side-relative-direction . -1) (avoid-slur . #f) (padding . 0.2) (quantize-position . #t) (script-priority . -100) (direction . 1)) (signumcongruentiae (script-stencil feta dsignumcongruentiae . usignumcongruentiae) (padding . 0.2) (avoid-slur . outside) (direction . 1)) (fermata (script-stencil feta dfermata . ufermata) (padding . 0.2) (avoid-slur . around) (script-priority . 4000) (direction . 1)) (shortfermata (script-stencil feta dshortfermata . ushortfermata) (padding . 0.2) (avoid-slur . around) (direction . 1)) (longfermata (script-stencil feta dlongfermata . ulongfermata) (padding . 0.2) (avoid-slur . around) (direction . 1)) (verylongfermata (script-stencil feta dverylongfermata . uverylongfermata) (padding . 0.2) (avoid-slur . around) (direction . 1)) (stopped (script-stencil feta stopped . stopped) (avoid-slur . inside) (padding . 0.2) (direction . 1)) (staccato (script-stencil feta staccato . staccato) (side-relative-direction . -1) (quantize-position . #t) (avoid-slur . inside) (toward-stem-shift . 0.5) (padding . 0.2) (script-priority . -100)) (tenuto (script-stencil feta tenuto . tenuto) (quantize-position . #t) (avoid-slur . inside) (padding . 0.2) (side-relative-direction . -1)) (comma (script-stencil feta lcomma . rcomma) (quantize-position . #t) (padding . 0.2) (avoid-slur . #f) (direction . 1)) (varcomma (script-stencil feta lvarcomma . rvarcomma) (quantize-position . #t) (padding . 0.2) (avoid-slur . #f) (direction . 1)) (upbow (script-stencil feta upbow . upbow) (avoid-slur . around) (padding . 0.2) (direction . 1)) (downbow (script-stencil feta downbow . downbow) (padding . 0.2) (avoid-slur . around) (direction . 1)) (lheel (script-stencil feta upedalheel . upedalheel) (padding . 0.2) (avoid-slur . around) (direction . -1)) (rheel (script-stencil feta dpedalheel . dpedalheel) (padding . 0.2) (avoid-slur . around) (direction . 1)) (ltoe (script-stencil feta upedaltoe . upedaltoe) (padding . 0.2) (avoid-slur . around) (direction . -1)) (rtoe (script-stencil feta dpedaltoe . dpedaltoe) (padding . 0.2) (avoid-slur . around) (direction . 1)) (turn (script-stencil feta turn . turn) (avoid-slur . inside) (padding . 0.2) (direction . 1)) (open (avoid-slur . outside) (padding . 0.2) (script-stencil feta open . open) (direction . 1)) (flageolet (script-stencil feta flageolet . flageolet) (padding . 0.2) (avoid-slur . around) (direction . 1)) (reverseturn (script-stencil feta reverseturn . reverseturn) (padding . 0.2) (avoid-slur . inside) (direction . 1)) (trill (script-stencil feta trill . trill) (direction . 1) (padding . 0.2) (avoid-slur . outside) (script-priority . 2000)) (prall (script-stencil feta prall . prall) (padding . 0.2) (avoid-slur . around) (direction . 1)) (mordent (script-stencil feta mordent . mordent) (padding . 0.2) (avoid-slur . around) (direction . 1)) (prallprall (script-stencil feta prallprall . prallprall) (padding . 0.2) (avoid-slur . around) (direction . 1)) (prallmordent (script-stencil feta prallmordent . prallmordent) (padding . 0.2) (avoid-slur . around) (direction . 1)) (upprall (script-stencil feta upprall . upprall) (padding . 0.2) (avoid-slur . around) (direction . 1)) (downprall (script-stencil feta downprall . downprall) (padding . 0.2) (avoid-slur . around) (direction . 1)) (upmordent (script-stencil feta upmordent . upmordent) (padding . 0.2) (avoid-slur . around) (direction . 1)) (downmordent (script-stencil feta downmordent . downmordent) (padding . 0.2) (avoid-slur . around) (direction . 1)) (lineprall (script-stencil feta lineprall . lineprall) (padding . 0.2) (avoid-slur . around) (direction . 1)) (pralldown (script-stencil feta pralldown . pralldown) (padding . 0.2) (avoid-slur . around) (direction . 1)) (prallup (script-stencil feta prallup . prallup) (padding . 0.2) (avoid-slur . around) (direction . 1)) (segno (script-stencil feta segno . segno) (padding . 0.2) (avoid-slur . outside) (direction . 1)) (coda (script-stencil feta coda . coda) (padding . 0.2) (avoid-slur . outside) (direction . 1)) (varcoda (script-stencil feta varcoda . varcoda) (padding . 0.2) (avoid-slur . outside) (direction . 1)))`.
- Set translator property `autoBeamCheck` to `default-auto-beam-check`.
- Set translator property `autoBeaming` to `#t`.
- Set translator property `autoBeamSettings` to `'(((end 1 32 2 2) . #<Mom 1/4>) ((end 1 32 2 2) . #<Mom 1/2>) ((end 1 32 2 2) . #<Mom 3/4>) ((end 1 16 3 2) . #<Mom 1/4>) ((end 1 16 3 2) . #<Mom 1/2>) ((end 1 16 3 2) . #<Mom 3/4>) ((end 1 16 3 2) . #<Mom 1>) ((end 1 16 3 2) . #<Mom 5/4>) ((end 1 32 3 2) . #<Mom 1/8>) ((end 1 32 3 2) . #<Mom 1/4>) ((end 1 32 3 2) . #<Mom 3/8>) ((end 1 32 3 2) . #<Mom 1/2>) ((end 1 32 3 2) . #<Mom 5/8>) ((end 1 32 3 2) . #<Mom 3/4>) ((end 1 32 3 2) . #<Mom 7/8>) ((end 1 32 3 2) . #<Mom 1>) ((end 1 32 3 2) . #<Mom 9/8>) ((end 1 32 3 2) . #<Mom 5/4>) ((end 1 32 3 2) . #<Mom 11/8>) ((end 1 32 2 4) . #<Mom 1/8>) ((end 1 32 2 4) . #<Mom 1/4>) ((end 1 32 2 4) . #<Mom 3/8>) ((end * * 3 4) . #<Mom 3/4>) ((end 1 16 3 4) . #<Mom 1/4>) ((end 1 16 3 4) . #<Mom 1/2>) ((end 1 32 3 4) . #<Mom 1/8>) ((end 1 32 3 4) . #<Mom 1/4>) ((end 1 32 3 4) . #<Mom 3/8>) ((end 1 32 3 4) . #<Mom 1/2>) ((end 1 32 3 4) . #<Mom 5/8>) ((end * * 4 4) . #<Mom 1/2>) ((end 1 12 4 4) . #<Mom 1/4>) ((end 1 12 4 4) . #<Mom 3/4>) ((end 1 16 4 4) . #<Mom 1/4>) ((end 1 16 4 4) . #<Mom 3/4>) ((end 1 32 4 4) . #<Mom 1/8>) ((end 1 32 4 4) . #<Mom 1/4>) ((end 1 32 4 4) . #<Mom 3/8>) ((end 1 32 4 4) . #<Mom 5/8>) ((end 1 32 4 4) . #<Mom 3/4>) ((end 1 32 4 4) . #<Mom 7/8>) ((end * * 3 8) . #<Mom 3/8>) ((end * * 4 8) . #<Mom 1/4>) ((end 1 32 4 8) . #<Mom 1/8>) ((end 1 32 4 8) . #<Mom 3/8>) ((end 1 32 6 8) . #<Mom 1/8>) ((end 1 32 6 8) . #<Mom 1/4>) ((end 1 32 6 8) . #<Mom 3/8>) ((end 1 32 6 8) . #<Mom 1/2>) ((end 1 32 6 8) . #<Mom 5/8>) ((end 1 32 9 8) . #<Mom 1/8>) ((end 1 32 9 8) . #<Mom 1/4>) ((end 1 32 9 8) . #<Mom 3/8>) ((end 1 32 9 8) . #<Mom 1/2>) ((end 1 32 9 8) . #<Mom 5/8>) ((end 1 32 9 8) . #<Mom 3/4>) ((end 1 32 9 8) . #<Mom 7/8>) ((end 1 32 9 8) . #<Mom 1>) ((end 1 32 12 8) . #<Mom 1/8>) ((end 1 32 12 8) . #<Mom 1/4>) ((end 1 32 12 8) . #<Mom 3/8>) ((end 1 32 12 8) . #<Mom 1/2>) ((end 1 32 12 8) . #<Mom 5/8>) ((end 1 32 12 8) . #<Mom 3/4>) ((end 1 32 12 8) . #<Mom 7/8>) ((end 1 32 12 8) . #<Mom 1>) ((end 1 32 12 8) . #<Mom 9/8>) ((end 1 32 12 8) . #<Mom 5/4>) ((end 1 32 12 8) . #<Mom 11/8>) ((end * * 4 16) . #<Mom 1/8>))`.
- Set translator property `repeatCountVisibility` to `all-repeat-counts-visible`.
- Set translator property `implicitTimeSignatureVisibility` to `#(#f #t #t)`.
- Set translator property `explicitKeySignatureVisibility` to `#(#t #t #t)`.
- Set translator property `explicitClefVisibility` to `#(#t #t #t)`.
- Set translator property `automaticBars` to `#t`.
- Set translator property `barNumberVisibility` to `first-bar-number-invisible`.
- Set translator property `doubleRepeatType` to `":|:"`.
- Set translator property `defaultBarType` to `"|"`.
- Set translator property `decrescendoSpanner` to `'hairpin`.
- Set translator property `crescendoSpanner` to `'hairpin`.
- Set translator property `firstClef` to `#t`.
- Set translator property `middleCPosition` to `-6`.
- Set translator property `middleCClefPosition` to `-6`.
- Set translator property `clefPosition` to `-2`.
- Set translator property `clefGlyph` to `"clefs.G"`.
- Set translator property `tieWaitForNote` to `#f`.
- Set translator property `melismaBusyProperties` to `'(melismaBusy slurMelismaBusy tieMelismaBusy beamMelismaBusy completionBusy)`.
- Set translator property `drumStyleTable` to `#<hash-table 29/61>`.
- Set translator property `systemStartDelimiter` to `'SystemStartBar`.
- Set translator property `printPartCombineTexts` to `#t`.
- Set translator property `aDueText` to `"a2"`.
- Set translator property `soloIIText` to `"Solo II"`.
- Set translator property `soloText` to `"Solo"`.
- Set translator property `noteToFretFunction` to `determine-frets`.

Context Score can contain Staff, FiguredBass, NoteNames, Devnull, PianoStaff, ChoirStaff, GrandStaff, ChordNames, Lyrics, DrumStaff, StaffGroup, MensuralStaff, GregorianTranscriptionStaff, VaticanaStaff, TabStaff, RhythmicStaff and FretBoards.

This context is built from the following engraver(s):

> `Parenthesis_engraver`

>   Parenthesize objects whose music cause has the `parenthesize` property.

>   This engraver creates the following layout object(s):

>   ParenthesesItem.

> `Bar_number_engraver`

>   A bar number is created whenever `measurePosition` is zero and when there is a bar line (i.e., when `whichBar` is set). It is put on top of all staves, and appears only at the left side of the staff. The staves are taken from `stavesFound`, which is maintained by Staff_collecting_engraver.

>   Properties (read)

>   > `currentBarNumber` (integer)

>   >   Contains the current barnumber. This property is incremented at every bar line.

>   > `whichBar` (string)

>   >   This property is read to determine what type of bar line to create.

>   >   Example:

>   >   >     \set Staff.whichBar = "|:"

>   >   This will create a start-repeat bar in this staff only. Valid values are described in bar-line-interface.

>   > `stavesFound` (list of grobs)

>   >   A list of all staff-symbols found.

>   > `barNumberVisibility` (procedure)

>   >   A Procedure that takes an integer and returns whether the corresponding bar number should be printed.

>   This engraver creates the following layout object(s):

>   BarNumber.

> `Stanza_number_align_engraver`

>   This engraver ensures that stanza numbers are neatly aligned.

> `Vertical_align_engraver`

>   Catch groups (staves, lyrics lines, etc.) and stack them vertically.

>   Properties (read)

>   > `alignAboveContext` (string)

>   >   Where to insert newly created context in vertical alignment.

>   > `alignBelowContext` (string)

>   >   Where to insert newly created context in vertical alignment.

>   This engraver creates the following layout object(s):

>   VerticalAlignment.

> `Grace_spacing_engraver`

>   Bookkeeping of shortest starting and playing notes in grace note runs.

>   Properties (read)

>   > `currentMusicalColumn` (layout object)

>   >   Grob that is X-parent to all non-breakable items (note heads, lyrics, etc.).

>   This engraver creates the following layout object(s):

>   GraceSpacing.

> `Spacing_engraver`

>   Make a `SpacingSpanner` and do bookkeeping of shortest starting and playing notes.

>   Music types accepted:

>   spacing-section-event

>   Properties (read)

>   > `currentMusicalColumn` (layout object)

>   >   Grob that is X-parent to all non-breakable items (note heads, lyrics, etc.).

>   > `currentCommandColumn` (layout object)

>   >   Grob that is X-parent to all current breakable (clef, key signature, etc.) items.

>   > `proportionalNotationDuration` (moment)

>   >   Global override for shortest-playing duration. This is used for switching on proportional notation.

>   This engraver creates the following layout object(s):

>   SpacingSpanner.

> `Break_align_engraver`

>   Align grobs with corresponding `break-align-symbols` into groups, and order the groups according to `breakAlignOrder`. The left edge of the alignment gets a separate group, with a symbol `left-edge`.

>   This engraver creates the following layout object(s):

>   BreakAlignGroup, BreakAlignment and LeftEdge.

> `Metronome_mark_engraver`

>   Engrave metronome marking. This delegates the formatting work to the function in the `metronomeMarkFormatter` property. The mark is put over all staves. The staves are taken from the `stavesFound` property, which is maintained by Staff_collecting_engraver.

>   Properties (read)

>   > `stavesFound` (list of grobs)

>   >   A list of all staff-symbols found.

>   > `metronomeMarkFormatter` (procedure)

>   >   How to produce a metronome markup. Called with four arguments: text, duration, count and context.

>   > `tempoUnitDuration` (duration)

>   >   Unit for specifying tempo.

>   > `tempoUnitCount` (number)

>   >   Count for specifying tempo.

>   > `tempoText` (markup)

>   >   Text for tempo marks.

>   > `tempoHideNote` (boolean)

>   >   Hide the note=count in tempo marks.

>   This engraver creates the following layout object(s):

>   MetronomeMark.

> `Volta_engraver`

>   Make volta brackets.

>   Properties (read)

>   > `repeatCommands` (list)

>   >   This property is a list of commands of the form `(list 'volta x)`, where x is a string or `#f`. `'end-repeat` is also accepted as a command.

>   > `voltaSpannerDuration` (moment)

>   >   This specifies the maximum duration to use for the brackets printed for `\alternative`. This can be used to shrink the length of brackets in the situation where one alternative is very large.

>   > `stavesFound` (list of grobs)

>   >   A list of all staff-symbols found.

>   This engraver creates the following layout object(s):

>   VoltaBracket and VoltaBracketSpanner.

> `Mark_engraver`

>   Create `RehearsalMark` objects. It puts them on top of all staves (which is taken from the property `stavesFound`). If moving this engraver to a different context, Staff_collecting_engraver must move along, otherwise all marks end up on the same Y location.

>   Music types accepted:

>   mark-event

>   Properties (read)

>   > `markFormatter` (procedure)

>   >   A procedure taking as arguments the context and the rehearsal mark. It should return the formatted mark as a markup object.

>   > `rehearsalMark` (integer)

>   >   The last rehearsal mark printed.

>   > `stavesFound` (list of grobs)

>   >   A list of all staff-symbols found.

>   This engraver creates the following layout object(s):

>   RehearsalMark.

> `System_start_delimiter_engraver`

>   Create a system start delimiter (i.e., a `SystemStartBar`, `SystemStartBrace`, `SystemStartBracket` or `SystemStartSquare` spanner).

>   Properties (read)

>   > `systemStartDelimiter` (symbol)

>   >   Which grob to make for the start of the system/staff? Set to `SystemStartBrace`, `SystemStartBracket` or `SystemStartBar`.

>   > `systemStartDelimiterHierarchy` (pair)

>   >   A nested list, indicating the nesting of a start delimiters.

>   > `currentCommandColumn` (layout object)

>   >   Grob that is X-parent to all current breakable (clef, key signature, etc.) items.

>   This engraver creates the following layout object(s):

>   SystemStartBar, SystemStartBrace, SystemStartBracket and SystemStartSquare.

> `Output_property_engraver`

>   Apply a procedure to any grob acknowledged.

>   Music types accepted:

>   apply-output-event

> `Default_bar_line_engraver`

>   This engraver determines what kind of automatic bar lines should be produced, and sets `whichBar` accordingly. It should be at the same level as Timing_translator.

>   Properties (read)

>   > `automaticBars` (boolean)

>   >   If set to false then bar lines will not be printed automatically; they must be explicitly created with a `\bar` command. Unlike the `\cadenzaOn` keyword, measures are still counted. Bar line generation will resume according to that count if this property is unset.

>   > `barAlways` (boolean)

>   >   If set to true a bar line is drawn after each note.

>   > `defaultBarType` (string)

>   >   Set the default type of bar line. See `whichBar` for information on available bar types.

>   >   This variable is read by Timing_translator at Score level.

>   > `measureLength` (moment)

>   >   Length of one measure in the current time signature.

>   > `whichBar` (string)

>   >   This property is read to determine what type of bar line to create.

>   >   Example:

>   >   >     \set Staff.whichBar = "|:"

>   >   This will create a start-repeat bar in this staff only. Valid values are described in bar-line-interface.

>   > `measurePosition` (moment)

>   >   How much of the current measure have we had. This can be set manually to create incomplete measures.

>   Properties (write)

>   > `automaticBars` (boolean)

>   >   If set to false then bar lines will not be printed automatically; they must be explicitly created with a `\bar` command. Unlike the `\cadenzaOn` keyword, measures are still counted. Bar line generation will resume according to that count if this property is unset.

> `Timing_translator`

>   This engraver adds the alias `Timing` to its containing context. Responsible for synchronizing timing information from staves. Normally in `Score`. In order to create polyrhythmic music, this engraver should be removed from `Score` and placed in `Staff`.

>   Properties (read)

>   > `internalBarNumber` (integer)

>   >   Contains the current barnumber. This property is used for internal timekeeping, among others by the `Accidental_engraver`.

>   > `currentBarNumber` (integer)

>   >   Contains the current barnumber. This property is incremented at every bar line.

>   > `measureLength` (moment)

>   >   Length of one measure in the current time signature.

>   > `measurePosition` (moment)

>   >   How much of the current measure have we had. This can be set manually to create incomplete measures.

>   Properties (write)

>   > `internalBarNumber` (integer)

>   >   Contains the current barnumber. This property is used for internal timekeeping, among others by the `Accidental_engraver`.

>   > `currentBarNumber` (integer)

>   >   Contains the current barnumber. This property is incremented at every bar line.

>   > `measurePosition` (moment)

>   >   How much of the current measure have we had. This can be set manually to create incomplete measures.

> `Staff_collecting_engraver`

>   Maintain the `stavesFound` variable.

>   Properties (read)

>   > `stavesFound` (list of grobs)

>   >   A list of all staff-symbols found.

>   Properties (write)

>   > `stavesFound` (list of grobs)

>   >   A list of all staff-symbols found.

> `Repeat_acknowledge_engraver`

>   Acknowledge repeated music, and convert the contents of `repeatCommands` into an appropriate setting for `whichBar`.

>   Properties (read)

>   > `doubleRepeatType` (string)

>   >   Set the default bar line for double repeats.

>   > `repeatCommands` (list)

>   >   This property is a list of commands of the form `(list 'volta x)`, where x is a string or `#f`. `'end-repeat` is also accepted as a command.

>   > `whichBar` (string)

>   >   This property is read to determine what type of bar line to create.

>   >   Example:

>   >   >     \set Staff.whichBar = "|:"

>   >   This will create a start-repeat bar in this staff only. Valid values are described in bar-line-interface.

> `Vertically_spaced_contexts_engraver`

>   Properties (read)

>   > `verticallySpacedContexts` (list)

>   >   List of symbols, containing context names whose vertical axis groups should be taken into account for vertical spacing of systems.

>   Properties (write)

>   > `verticallySpacedContexts` (list)

>   >   List of symbols, containing context names whose vertical axis groups should be taken into account for vertical spacing of systems.

> `Paper_column_engraver`

>   Take care of generating columns.

>   This engraver decides whether a column is breakable. The default is that a column is always breakable. However, every `Bar_engraver` that does not have a barline at a certain point will set `forbidBreaks` in the score context to stop line breaks. In practice, this means that you can make a break point by creating a bar line (assuming that there are no beams or notes that prevent a break point).

>   Music types accepted:

>   label-event and break-event

>   Properties (read)

>   > `forbidBreak` (boolean)

>   >   If set to `##t`, prevent a line break at this point.

>   Properties (write)

>   > `forbidBreak` (boolean)

>   >   If set to `##t`, prevent a line break at this point.

>   > `currentCommandColumn` (layout object)

>   >   Grob that is X-parent to all current breakable (clef, key signature, etc.) items.

>   > `currentMusicalColumn` (layout object)

>   >   Grob that is X-parent to all non-breakable items (note heads, lyrics, etc.).

>   This engraver creates the following layout object(s):

>   NonMusicalPaperColumn and PaperColumn.

### 2.1.20 Staff

Handles clefs, bar lines, keys, accidentals. It can contain `Voice` contexts.

This context creates the following layout object(s):

AccidentalCautionary, AccidentalPlacement, AccidentalSuggestion, Accidental, BarLine, BassFigureAlignmentPositioning, BassFigureAlignment, BassFigureBracket, BassFigureContinuation, BassFigureLine, BassFigure, Clef, DotColumn, InstrumentName, KeyCancellation, KeySignature, LedgerLineSpanner, NoteCollision, OctavateEight, OttavaBracket, PianoPedalBracket, RestCollision, ScriptRow, SostenutoPedalLineSpanner, SostenutoPedal, StaffSpacing, StaffSymbol, SustainPedalLineSpanner, SustainPedal, TimeSignature, UnaCordaPedalLineSpanner, UnaCordaPedal and VerticalAxisGroup.

This context sets the following properties:

- Set translator property `shortInstrumentName` to `'()`.
- Set translator property `instrumentName` to `'()`.
- Set grob-property `minimum-Y-extent` in VerticalAxisGroup to `'(-4 . 4)`.
- Set translator property `ignoreFiguredBassRest` to `#t`.
- Set translator property `createSpacing` to `#t`.
- Set translator property `localKeySignature` to `'()`.

Context Staff can contain Voice and CueVoice.

This context is built from the following engraver(s):

> `Script_row_engraver`

>   Determine order in horizontal side position elements.

>   This engraver creates the following layout object(s):

>   ScriptRow.

> `Figured_bass_position_engraver`

>   Position figured bass alignments over notes.

>   This engraver creates the following layout object(s):

>   BassFigureAlignmentPositioning.

> `Figured_bass_engraver`

>   Make figured bass numbers.

>   Music types accepted:

>   bass-figure-event and rest-event

>   Properties (read)

>   > `figuredBassAlterationDirection` (direction)

>   >   Where to put alterations relative to the main figure.

>   > `figuredBassCenterContinuations` (boolean)

>   >   Whether to vertically center pairs of extender lines. This does not work with three or more lines.

>   > `figuredBassFormatter` (procedure)

>   >   A routine generating a markup for a bass figure.

>   > `implicitBassFigures` (list)

>   >   A list of bass figures that are not printed as numbers, but only as extender lines.

>   > `useBassFigureExtenders` (boolean)

>   >   Whether to use extender lines for repeated bass figures.

>   > `ignoreFiguredBassRest` (boolean)

>   >   Don’t swallow rest events.

>   This engraver creates the following layout object(s):

>   BassFigure, BassFigureAlignment, BassFigureBracket, BassFigureContinuation and BassFigureLine.

> `Axis_group_engraver`

>   Group all objects created in this context in a `VerticalAxisGroup` spanner.

>   Properties (read)

>   > `currentCommandColumn` (layout object)

>   >   Grob that is X-parent to all current breakable (clef, key signature, etc.) items.

>   This engraver creates the following layout object(s):

>   VerticalAxisGroup.

> `String_number_engraver`

>   Swallow string number events. The purpose of this engraver is to process tablatures for normal notation. To provent warnings for unprocessed string number events to obscure real error messages, this engraver swallows them all.

> `Instrument_name_engraver`

>   Create a system start text for instrument or vocal names.

>   Properties (read)

>   > `currentCommandColumn` (layout object)

>   >   Grob that is X-parent to all current breakable (clef, key signature, etc.) items.

>   > `shortInstrumentName` (markup)

>   >   See `instrument`.

>   > `instrumentName` (markup)

>   >   The name to print left of a staff. The `instrument` property labels the staff in the first system, and the `instr` property labels following lines.

>   > `shortVocalName` (markup)

>   >   Name of a vocal line, short version.

>   > `vocalName` (markup)

>   >   Name of a vocal line.

>   This engraver creates the following layout object(s):

>   InstrumentName.

> `Piano_pedal_align_engraver`

>   Align piano pedal symbols and brackets.

>   Properties (read)

>   > `currentCommandColumn` (layout object)

>   >   Grob that is X-parent to all current breakable (clef, key signature, etc.) items.

>   This engraver creates the following layout object(s):

>   SostenutoPedalLineSpanner, SustainPedalLineSpanner and UnaCordaPedalLineSpanner.

> `Piano_pedal_engraver`

>   Engrave piano pedal symbols and brackets.

>   Music types accepted:

>   una-corda-event, sustain-event and sostenuto-event

>   Properties (read)

>   > `currentCommandColumn` (layout object)

>   >   Grob that is X-parent to all current breakable (clef, key signature, etc.) items.

>   > `pedalSostenutoStrings` (list)

>   >   See `pedalSustainStrings`.

>   > `pedalSostenutoStyle` (symbol)

>   >   See `pedalSustainStyle`.

>   > `pedalSustainStrings` (list)

>   >   A list of strings to print for sustain-pedal. Format is `(up updown down)`, where each of the three is the string to print when this is done with the pedal.

>   > `pedalSustainStyle` (symbol)

>   >   A symbol that indicates how to print sustain pedals: `text`, `bracket` or `mixed` (both).

>   > `pedalUnaCordaStrings` (list)

>   >   See `pedalSustainStrings`.

>   > `pedalUnaCordaStyle` (symbol)

>   >   See `pedalSustainStyle`.

>   This engraver creates the following layout object(s):

>   PianoPedalBracket, SostenutoPedal, SustainPedal and UnaCordaPedal.

> `Accidental_engraver`

>   Make accidentals. Catch note heads, ties and notices key-change events. This engraver usually lives at Staff level, but reads the settings for Accidental at `Voice` level, so you can `\override` them at `Voice`.

>   Properties (read)

>   > `autoAccidentals` (list)

>   >   List of different ways to typeset an accidental.

>   >   For determining when to print an accidental, several different rules are tried. The rule that gives the highest number of accidentals is used.

>   >   Each entry in the list is either a symbol or a procedure.

>   >   symbol

>   >     The symbol is the name of the context in which the following rules are to be applied. For example, if context is Score then all staves share accidentals, and if context is Staff then all voices in the same staff share accidentals, but staves do not.

>   >   procedure

>   >     The procedure represents an accidental rule to be applied to the previously specified context.

>   >     The procedure takes the following arguments:

>   >     `context`

>   >       The current context to which the rule should be applied.

>   >     `pitch`

>   >       The pitch of the note to be evaluated.

>   >     `barnum`

>   >       The current bar number.

>   >     `measurepos`

>   >       The current measure position.

>   >     The procedure returns a pair of booleans. The first states whether an extra natural should be added. The second states whether an accidental should be printed. `(#t . #f)` does not make sense.

>   > `autoCautionaries` (list)

>   >   List similar to `autoAccidentals`, but it controls cautionary accidentals rather than normal ones. Both lists are tried, and the one giving the most accidentals wins. In case of draw, a normal accidental is typeset.

>   > `internalBarNumber` (integer)

>   >   Contains the current barnumber. This property is used for internal timekeeping, among others by the `Accidental_engraver`.

>   > `extraNatural` (boolean)

>   >   Whether to typeset an extra natural sign before accidentals changing from a non-natural to another non-natural.

>   > `harmonicAccidentals` (boolean)

>   >   If set, harmonic notes in chords get accidentals.

>   > `keySignature` (list)

>   >   The current key signature. This is an alist containing `(step . alter)` or `((octave . step) . alter)`, where step is a number in the range 0 to 6 and alter a fraction, denoting alteration. For alterations, use symbols, e.g. `keySignature = #`((6 . ,FLAT))`.

>   > `localKeySignature` (list)

>   >   The key signature at this point in the measure. The format is the same as for `keySignature`, but can also contain `((octave . name) . (alter barnumber . measureposition))` pairs.

>   Properties (write)

>   > `localKeySignature` (list)

>   >   The key signature at this point in the measure. The format is the same as for `keySignature`, but can also contain `((octave . name) . (alter barnumber . measureposition))` pairs.

>   This engraver creates the following layout object(s):

>   Accidental, AccidentalCautionary, AccidentalPlacement and AccidentalSuggestion.

> `Rest_collision_engraver`

>   Handle collisions of rests.

>   Properties (read)

>   > `busyGrobs` (list)

>   >   A queue of `(end-moment . GROB)` cons cells. This is for internal (C++) use only. This property contains the grobs which are still busy (e.g. note heads, spanners, etc.).

>   This engraver creates the following layout object(s):

>   RestCollision.

> `Grob_pq_engraver`

>   Administrate when certain grobs (e.g., note heads) stop playing.

>   Properties (read)

>   > `busyGrobs` (list)

>   >   A queue of `(end-moment . GROB)` cons cells. This is for internal (C++) use only. This property contains the grobs which are still busy (e.g. note heads, spanners, etc.).

>   Properties (write)

>   > `busyGrobs` (list)

>   >   A queue of `(end-moment . GROB)` cons cells. This is for internal (C++) use only. This property contains the grobs which are still busy (e.g. note heads, spanners, etc.).

> `Collision_engraver`

>   Collect `NoteColumns`, and as soon as there are two or more, put them in a `NoteCollision` object.

>   This engraver creates the following layout object(s):

>   NoteCollision.

> `Staff_symbol_engraver`

>   Create the constellation of five (default) staff lines.

>   Music types accepted:

>   staff-span-event

>   This engraver creates the following layout object(s):

>   StaffSymbol.

> `Ledger_line_engraver`

>   Create the spanner to draw ledger lines, and notices objects that need ledger lines.

>   This engraver creates the following layout object(s):

>   LedgerLineSpanner.

> `Time_signature_engraver`

>   Create a TimeSignature whenever `timeSignatureFraction` changes.

>   Properties (read)

>   > `implicitTimeSignatureVisibility` (vector)

>   >   break visibility for the default time signature.

>   > `timeSignatureFraction` (pair of numbers)

>   >   A pair of numbers, signifying the time signature. For example, `#'(4 . 4)` is a 4/4 time signature.

>   This engraver creates the following layout object(s):

>   TimeSignature.

> `Key_engraver`

>   Engrave a key signature.

>   Music types accepted:

>   key-change-event

>   Properties (read)

>   > `createKeyOnClefChange` (boolean)

>   >   Print a key signature whenever the clef is changed.

>   > `explicitKeySignatureVisibility` (vector)

>   >   ‘`break-visibility`’ function for explicit key changes. ‘`\override`’ of the `break-visibility` property will set the visibility for normal (i.e., at the start of the line) key signatures.

>   > `extraNatural` (boolean)

>   >   Whether to typeset an extra natural sign before accidentals changing from a non-natural to another non-natural.

>   > `keyAlterationOrder` (list)

>   >   An alist that defines in what order alterations should be printed. The format is `(step . alter)`, where step is a number from 0 to 6 and alter from -2 (sharp) to 2 (flat).

>   > `keySignature` (list)

>   >   The current key signature. This is an alist containing `(step . alter)` or `((octave . step) . alter)`, where step is a number in the range 0 to 6 and alter a fraction, denoting alteration. For alterations, use symbols, e.g. `keySignature = #`((6 . ,FLAT))`.

>   > `lastKeySignature` (list)

>   >   Last key signature before a key signature change.

>   > `printKeyCancellation` (boolean)

>   >   Print restoration alterations before a key signature change.

>   Properties (write)

>   > `keySignature` (list)

>   >   The current key signature. This is an alist containing `(step . alter)` or `((octave . step) . alter)`, where step is a number in the range 0 to 6 and alter a fraction, denoting alteration. For alterations, use symbols, e.g. `keySignature = #`((6 . ,FLAT))`.

>   > `lastKeySignature` (list)

>   >   Last key signature before a key signature change.

>   > `tonic` (pitch)

>   >   The tonic of the current scale.

>   This engraver creates the following layout object(s):

>   KeyCancellation and KeySignature.

> `Clef_engraver`

>   Determine and set reference point for pitches.

>   Properties (read)

>   > `clefGlyph` (string)

>   >   Name of the symbol within the music font.

>   > `clefOctavation` (integer)

>   >   Add this much extra octavation. Values of 7 and -7 are common.

>   > `clefPosition` (number)

>   >   Where should the center of the clef symbol go, measured in half staff spaces from the center of the staff.

>   > `explicitClefVisibility` (vector)

>   >   ‘`break-visibility`’ function for clef changes.

>   > `forceClef` (boolean)

>   >   Show clef symbol, even if it has not changed. Only active for the first clef after the property is set, not for the full staff.

>   This engraver creates the following layout object(s):

>   Clef and OctavateEight.

> `Ottava_spanner_engraver`

>   Create a text spanner when the ottavation property changes.

>   Properties (read)

>   > `ottavation` (markup)

>   >   If set, the text for an ottava spanner. Changing this creates a new text spanner.

>   > `originalMiddleCPosition` (integer)

>   >   Used for temporary overriding middle C in octavation brackets.

>   > `currentMusicalColumn` (layout object)

>   >   Grob that is X-parent to all non-breakable items (note heads, lyrics, etc.).

>   This engraver creates the following layout object(s):

>   OttavaBracket.

> `Staff_collecting_engraver`

>   Maintain the `stavesFound` variable.

>   Properties (read)

>   > `stavesFound` (list of grobs)

>   >   A list of all staff-symbols found.

>   Properties (write)

>   > `stavesFound` (list of grobs)

>   >   A list of all staff-symbols found.

> `Dot_column_engraver`

>   Engrave dots on dotted notes shifted to the right of the note. If omitted, then dots appear on top of the notes.

>   This engraver creates the following layout object(s):

>   DotColumn.

> `Separating_line_group_engraver`

>   Generate objects for computing spacing parameters.

>   Properties (read)

>   > `createSpacing` (boolean)

>   >   Create `StaffSpacing` objects? Should be set for staves.

>   Properties (write)

>   > `hasStaffSpacing` (boolean)

>   >   True if the current `CommandColumn` contains items that will affect spacing.

>   This engraver creates the following layout object(s):

>   StaffSpacing.

> `Font_size_engraver`

>   Put `fontSize` into `font-size` grob property.

>   Properties (read)

>   > `fontSize` (number)

>   >   The relative size of all grobs in a context.

> `Bar_engraver`

>   Create barlines. This engraver is controlled through the `whichBar` property. If it has no bar line to create, it will forbid a linebreak at this point.

>   Properties (read)

>   > `whichBar` (string)

>   >   This property is read to determine what type of bar line to create.

>   >   Example:

>   >   >     \set Staff.whichBar = "|:"

>   >   This will create a start-repeat bar in this staff only. Valid values are described in bar-line-interface.

>   Properties (write)

>   > `forbidBreak` (boolean)

>   >   If set to `##t`, prevent a line break at this point.

>   This engraver creates the following layout object(s):

>   BarLine.

> `Output_property_engraver`

>   Apply a procedure to any grob acknowledged.

>   Music types accepted:

>   apply-output-event

### 2.1.21 StaffGroup

Groups staves while adding a bracket on the left side, grouping the staves together. The bar lines of the contained staves are connected vertically. `StaffGroup` only consists of a collection of staves, with a bracket in front and spanning bar lines.

This context creates the following layout object(s):

Arpeggio, SpanBar, SystemStartBar, SystemStartBrace, SystemStartBracket and SystemStartSquare.

This context sets the following properties:

- Set translator property `systemStartDelimiter` to `'SystemStartBracket`.

Context StaffGroup can contain Staff, StaffGroup, ChoirStaff, FiguredBass, ChordNames, Lyrics, TabStaff, PianoStaff, GrandStaff, DrumStaff and RhythmicStaff.

This context is built from the following engraver(s):

> `System_start_delimiter_engraver`

>   Create a system start delimiter (i.e., a `SystemStartBar`, `SystemStartBrace`, `SystemStartBracket` or `SystemStartSquare` spanner).

>   Properties (read)

>   > `systemStartDelimiter` (symbol)

>   >   Which grob to make for the start of the system/staff? Set to `SystemStartBrace`, `SystemStartBracket` or `SystemStartBar`.

>   > `systemStartDelimiterHierarchy` (pair)

>   >   A nested list, indicating the nesting of a start delimiters.

>   > `currentCommandColumn` (layout object)

>   >   Grob that is X-parent to all current breakable (clef, key signature, etc.) items.

>   This engraver creates the following layout object(s):

>   SystemStartBar, SystemStartBrace, SystemStartBracket and SystemStartSquare.

> `Output_property_engraver`

>   Apply a procedure to any grob acknowledged.

>   Music types accepted:

>   apply-output-event

> `Span_arpeggio_engraver`

>   Make arpeggios that span multiple staves.

>   Properties (read)

>   > `connectArpeggios` (boolean)

>   >   If set, connect arpeggios across piano staff.

>   This engraver creates the following layout object(s):

>   Arpeggio.

> `Span_bar_engraver`

>   Make cross-staff bar lines: It catches all normal bar lines and draws a single span bar across them.

>   This engraver creates the following layout object(s):

>   SpanBar.

### 2.1.22 TabStaff

Context for generating tablature. [DOCME]

This context also accepts commands for the following context(s):

Staff.

This context creates the following layout object(s):

BarLine, BassFigureAlignmentPositioning, BassFigureAlignment, BassFigureBracket, BassFigureContinuation, BassFigureLine, BassFigure, Clef, DotColumn, InstrumentName, LedgerLineSpanner, NoteCollision, OctavateEight, OttavaBracket, PianoPedalBracket, RestCollision, ScriptRow, SostenutoPedalLineSpanner, SostenutoPedal, StaffSpacing, StaffSymbol, SustainPedalLineSpanner, SustainPedal, TimeSignature, UnaCordaPedalLineSpanner, UnaCordaPedal and VerticalAxisGroup.

This context sets the following properties:

- Set translator property `clefPosition` to `0`.
- Set translator property `clefGlyph` to `"clefs.tab"`.
- Set grob-property `avoid-note-head` in Stem to `#t`.
- Set grob-property `staff-space` in StaffSymbol to `1.5`.
- Set translator property `shortInstrumentName` to `'()`.
- Set translator property `instrumentName` to `'()`.
- Set grob-property `minimum-Y-extent` in VerticalAxisGroup to `'(-4 . 4)`.
- Set translator property `ignoreFiguredBassRest` to `#t`.
- Set translator property `createSpacing` to `#t`.
- Set translator property `localKeySignature` to `'()`.

Context TabStaff can contain TabVoice and CueVoice.

This context is built from the following engraver(s):

> `Tab_staff_symbol_engraver`

>   Create a tablature staff symbol, but look at `stringTunings` for the number of lines.

>   Properties (read)

>   > `stringTunings` (list)

>   >   The tablature strings tuning. It is a list of the pitch (in semitones) of each string (starting with the lower one).

>   This engraver creates the following layout object(s):

>   StaffSymbol.

> `Script_row_engraver`

>   Determine order in horizontal side position elements.

>   This engraver creates the following layout object(s):

>   ScriptRow.

> `Figured_bass_position_engraver`

>   Position figured bass alignments over notes.

>   This engraver creates the following layout object(s):

>   BassFigureAlignmentPositioning.

> `Figured_bass_engraver`

>   Make figured bass numbers.

>   Music types accepted:

>   bass-figure-event and rest-event

>   Properties (read)

>   > `figuredBassAlterationDirection` (direction)

>   >   Where to put alterations relative to the main figure.

>   > `figuredBassCenterContinuations` (boolean)

>   >   Whether to vertically center pairs of extender lines. This does not work with three or more lines.

>   > `figuredBassFormatter` (procedure)

>   >   A routine generating a markup for a bass figure.

>   > `implicitBassFigures` (list)

>   >   A list of bass figures that are not printed as numbers, but only as extender lines.

>   > `useBassFigureExtenders` (boolean)

>   >   Whether to use extender lines for repeated bass figures.

>   > `ignoreFiguredBassRest` (boolean)

>   >   Don’t swallow rest events.

>   This engraver creates the following layout object(s):

>   BassFigure, BassFigureAlignment, BassFigureBracket, BassFigureContinuation and BassFigureLine.

> `Axis_group_engraver`

>   Group all objects created in this context in a `VerticalAxisGroup` spanner.

>   Properties (read)

>   > `currentCommandColumn` (layout object)

>   >   Grob that is X-parent to all current breakable (clef, key signature, etc.) items.

>   This engraver creates the following layout object(s):

>   VerticalAxisGroup.

> `Instrument_name_engraver`

>   Create a system start text for instrument or vocal names.

>   Properties (read)

>   > `currentCommandColumn` (layout object)

>   >   Grob that is X-parent to all current breakable (clef, key signature, etc.) items.

>   > `shortInstrumentName` (markup)

>   >   See `instrument`.

>   > `instrumentName` (markup)

>   >   The name to print left of a staff. The `instrument` property labels the staff in the first system, and the `instr` property labels following lines.

>   > `shortVocalName` (markup)

>   >   Name of a vocal line, short version.

>   > `vocalName` (markup)

>   >   Name of a vocal line.

>   This engraver creates the following layout object(s):

>   InstrumentName.

> `Piano_pedal_align_engraver`

>   Align piano pedal symbols and brackets.

>   Properties (read)

>   > `currentCommandColumn` (layout object)

>   >   Grob that is X-parent to all current breakable (clef, key signature, etc.) items.

>   This engraver creates the following layout object(s):

>   SostenutoPedalLineSpanner, SustainPedalLineSpanner and UnaCordaPedalLineSpanner.

> `Piano_pedal_engraver`

>   Engrave piano pedal symbols and brackets.

>   Music types accepted:

>   una-corda-event, sustain-event and sostenuto-event

>   Properties (read)

>   > `currentCommandColumn` (layout object)

>   >   Grob that is X-parent to all current breakable (clef, key signature, etc.) items.

>   > `pedalSostenutoStrings` (list)

>   >   See `pedalSustainStrings`.

>   > `pedalSostenutoStyle` (symbol)

>   >   See `pedalSustainStyle`.

>   > `pedalSustainStrings` (list)

>   >   A list of strings to print for sustain-pedal. Format is `(up updown down)`, where each of the three is the string to print when this is done with the pedal.

>   > `pedalSustainStyle` (symbol)

>   >   A symbol that indicates how to print sustain pedals: `text`, `bracket` or `mixed` (both).

>   > `pedalUnaCordaStrings` (list)

>   >   See `pedalSustainStrings`.

>   > `pedalUnaCordaStyle` (symbol)

>   >   See `pedalSustainStyle`.

>   This engraver creates the following layout object(s):

>   PianoPedalBracket, SostenutoPedal, SustainPedal and UnaCordaPedal.

> `Rest_collision_engraver`

>   Handle collisions of rests.

>   Properties (read)

>   > `busyGrobs` (list)

>   >   A queue of `(end-moment . GROB)` cons cells. This is for internal (C++) use only. This property contains the grobs which are still busy (e.g. note heads, spanners, etc.).

>   This engraver creates the following layout object(s):

>   RestCollision.

> `Grob_pq_engraver`

>   Administrate when certain grobs (e.g., note heads) stop playing.

>   Properties (read)

>   > `busyGrobs` (list)

>   >   A queue of `(end-moment . GROB)` cons cells. This is for internal (C++) use only. This property contains the grobs which are still busy (e.g. note heads, spanners, etc.).

>   Properties (write)

>   > `busyGrobs` (list)

>   >   A queue of `(end-moment . GROB)` cons cells. This is for internal (C++) use only. This property contains the grobs which are still busy (e.g. note heads, spanners, etc.).

> `Collision_engraver`

>   Collect `NoteColumns`, and as soon as there are two or more, put them in a `NoteCollision` object.

>   This engraver creates the following layout object(s):

>   NoteCollision.

> `Staff_symbol_engraver`

>   Create the constellation of five (default) staff lines.

>   Music types accepted:

>   staff-span-event

>   This engraver creates the following layout object(s):

>   StaffSymbol.

> `Ledger_line_engraver`

>   Create the spanner to draw ledger lines, and notices objects that need ledger lines.

>   This engraver creates the following layout object(s):

>   LedgerLineSpanner.

> `Time_signature_engraver`

>   Create a TimeSignature whenever `timeSignatureFraction` changes.

>   Properties (read)

>   > `implicitTimeSignatureVisibility` (vector)

>   >   break visibility for the default time signature.

>   > `timeSignatureFraction` (pair of numbers)

>   >   A pair of numbers, signifying the time signature. For example, `#'(4 . 4)` is a 4/4 time signature.

>   This engraver creates the following layout object(s):

>   TimeSignature.

> `Clef_engraver`

>   Determine and set reference point for pitches.

>   Properties (read)

>   > `clefGlyph` (string)

>   >   Name of the symbol within the music font.

>   > `clefOctavation` (integer)

>   >   Add this much extra octavation. Values of 7 and -7 are common.

>   > `clefPosition` (number)

>   >   Where should the center of the clef symbol go, measured in half staff spaces from the center of the staff.

>   > `explicitClefVisibility` (vector)

>   >   ‘`break-visibility`’ function for clef changes.

>   > `forceClef` (boolean)

>   >   Show clef symbol, even if it has not changed. Only active for the first clef after the property is set, not for the full staff.

>   This engraver creates the following layout object(s):

>   Clef and OctavateEight.

> `Ottava_spanner_engraver`

>   Create a text spanner when the ottavation property changes.

>   Properties (read)

>   > `ottavation` (markup)

>   >   If set, the text for an ottava spanner. Changing this creates a new text spanner.

>   > `originalMiddleCPosition` (integer)

>   >   Used for temporary overriding middle C in octavation brackets.

>   > `currentMusicalColumn` (layout object)

>   >   Grob that is X-parent to all non-breakable items (note heads, lyrics, etc.).

>   This engraver creates the following layout object(s):

>   OttavaBracket.

> `Staff_collecting_engraver`

>   Maintain the `stavesFound` variable.

>   Properties (read)

>   > `stavesFound` (list of grobs)

>   >   A list of all staff-symbols found.

>   Properties (write)

>   > `stavesFound` (list of grobs)

>   >   A list of all staff-symbols found.

> `Dot_column_engraver`

>   Engrave dots on dotted notes shifted to the right of the note. If omitted, then dots appear on top of the notes.

>   This engraver creates the following layout object(s):

>   DotColumn.

> `Separating_line_group_engraver`

>   Generate objects for computing spacing parameters.

>   Properties (read)

>   > `createSpacing` (boolean)

>   >   Create `StaffSpacing` objects? Should be set for staves.

>   Properties (write)

>   > `hasStaffSpacing` (boolean)

>   >   True if the current `CommandColumn` contains items that will affect spacing.

>   This engraver creates the following layout object(s):

>   StaffSpacing.

> `Font_size_engraver`

>   Put `fontSize` into `font-size` grob property.

>   Properties (read)

>   > `fontSize` (number)

>   >   The relative size of all grobs in a context.

> `Bar_engraver`

>   Create barlines. This engraver is controlled through the `whichBar` property. If it has no bar line to create, it will forbid a linebreak at this point.

>   Properties (read)

>   > `whichBar` (string)

>   >   This property is read to determine what type of bar line to create.

>   >   Example:

>   >   >     \set Staff.whichBar = "|:"

>   >   This will create a start-repeat bar in this staff only. Valid values are described in bar-line-interface.

>   Properties (write)

>   > `forbidBreak` (boolean)

>   >   If set to `##t`, prevent a line break at this point.

>   This engraver creates the following layout object(s):

>   BarLine.

> `Output_property_engraver`

>   Apply a procedure to any grob acknowledged.

>   Music types accepted:

>   apply-output-event

### 2.1.23 TabVoice

Context for drawing notes in a Tab staff.

This context also accepts commands for the following context(s):

Voice.

This context creates the following layout object(s):

Arpeggio, Beam, BendAfter, BreathingSign, ClusterSpannerBeacon, ClusterSpanner, CombineTextScript, Dots, DoublePercentRepeatCounter, DoublePercentRepeat, DynamicLineSpanner, DynamicTextSpanner, DynamicText, Glissando, Hairpin, HarmonicParenthesesItem, InstrumentSwitch, LaissezVibrerTieColumn, LaissezVibrerTie, LigatureBracket, MultiMeasureRestNumber, MultiMeasureRestText, MultiMeasureRest, NoteColumn, NoteSpacing, PercentRepeatCounter, PercentRepeat, PhrasingSlur, RepeatSlash, RepeatTieColumn, RepeatTie, Rest, ScriptColumn, Script, Slur, StemTremolo, Stem, TabNoteHead, TextScript, TextSpanner, TieColumn, Tie, TrillPitchAccidental, TrillPitchGroup, TrillPitchHead, TrillSpanner, TupletBracket, TupletNumber and VoiceFollower.

This context sets the following properties:

- Set grob-property `gap` in Glissando to `0.2`.
- Set grob-property `extra-dy` in Glissando to `0.75`.
- Set grob-property `bound-details left` in Glissando to `'((attach-dir . 1) (padding . 0.3))`.
- Set grob-property `bound-details right` in Glissando to `'((attach-dir . -1) (padding . 0.3))`.
- Set grob-property `extra-dy` in Glissando to `0.75`.
- Set grob-property `length-fraction` in Beam to `0.62`.
- Set grob-property `thickness` in Beam to `0.32`.
- Set translator property `localKeySignature` to `'()`.

This context is a ‘bottom’ context; it cannot contain other contexts.

This context is built from the following engraver(s):

> `Tab_harmonic_engraver`

>   In a tablature, parenthesize objects whose music cause has the `parenthesize` property.

>   This engraver creates the following layout object(s):

>   HarmonicParenthesesItem.

> `Tab_note_heads_engraver`

>   Generate one or more tablature noteheads from event of type `NoteEvent`.

>   Music types accepted:

>   string-number-event and note-event

>   Properties (read)

>   > `middleCPosition` (number)

>   >   The place of the middle C, measured in half staff-spaces. Usually determined by looking at `middleCClefPosition` and `middleCOffset`.

>   > `stringTunings` (list)

>   >   The tablature strings tuning. It is a list of the pitch (in semitones) of each string (starting with the lower one).

>   > `minimumFret` (number)

>   >   The tablature auto string-selecting mechanism selects the highest string with a fret at least `minimumFret`.

>   > `tablatureFormat` (procedure)

>   >   A function formatting a tablature note head. Called with three arguments: string number, context and event. It returns the text as a string.

>   > `highStringOne` (boolean)

>   >   Whether the first string is the string with highest pitch on the instrument. This used by the automatic string selector for tablature notation.

>   > `stringOneTopmost` (boolean)

>   >   Whether the first string is printed on the top line of the tablature.

>   This engraver creates the following layout object(s):

>   TabNoteHead.

> `Skip_event_swallow_translator`

>   Swallow `\skip`.

> `Instrument_switch_engraver`

>   Create a cue text for taking instrument.

>   Properties (read)

>   > `instrumentCueName` (markup)

>   >   The name to print if another instrument is to be taken.

>   This engraver creates the following layout object(s):

>   InstrumentSwitch.

> `Grace_engraver`

>   Set font size and other properties for grace notes.

>   Properties (read)

>   > `graceSettings` (list)

>   >   Overrides for grace notes. This property should be manipulated through the `add-grace-property` function.

> `Tuplet_engraver`

>   Catch tuplet events and generate appropriate bracket.

>   Music types accepted:

>   tuplet-span-event

>   Properties (read)

>   > `tupletFullLength` (boolean)

>   >   If set, the tuplet is printed up to the start of the next note.

>   > `tupletFullLengthNote` (boolean)

>   >   If set, end at the next note, otherwise end on the matter (time signatures, etc.) before the note.

>   This engraver creates the following layout object(s):

>   TupletBracket and TupletNumber.

> `Tie_engraver`

>   Generate ties between note heads of equal pitch.

>   Music types accepted:

>   tie-event

>   Properties (read)

>   > `tieWaitForNote` (boolean)

>   >   If true, tied notes do not have to follow each other directly. This can be used for writing out arpeggios.

>   Properties (write)

>   > `tieMelismaBusy` (boolean)

>   >   Signal whether a tie is present.

>   This engraver creates the following layout object(s):

>   Tie and TieColumn.

> `Slur_engraver`

>   Build slur grobs from slur events.

>   Music types accepted:

>   slur-event

>   Properties (read)

>   > `slurMelismaBusy` (boolean)

>   >   Signal if a slur is present.

>   > `doubleSlurs` (boolean)

>   >   If set, two slurs are created for every slurred note, one above and one below the chord.

>   This engraver creates the following layout object(s):

>   Slur.

> `Cluster_spanner_engraver`

>   Engrave a cluster using `Spanner` notation.

>   Music types accepted:

>   cluster-note-event

>   This engraver creates the following layout object(s):

>   ClusterSpanner and ClusterSpannerBeacon.

> `Phrasing_slur_engraver`

>   Print phrasing slurs. Similar to Slur_engraver.

>   Music types accepted:

>   phrasing-slur-event

>   This engraver creates the following layout object(s):

>   PhrasingSlur.

> `Spanner_break_forbid_engraver`

>   Forbid breaks in certain spanners.

> `Note_spacing_engraver`

>   Generate `NoteSpacing`, an object linking horizontal lines for use in spacing.

>   This engraver creates the following layout object(s):

>   NoteSpacing.

> `Rhythmic_column_engraver`

>   Generate `NoteColumn`, an object that groups stems, note heads, and rests.

>   This engraver creates the following layout object(s):

>   NoteColumn.

> `Script_column_engraver`

>   Find potentially colliding scripts and put them into a `ScriptColumn` object; that will fix the collisions.

>   This engraver creates the following layout object(s):

>   ScriptColumn.

> `Script_engraver`

>   Handle note scripted articulations.

>   Music types accepted:

>   articulation-event

>   Properties (read)

>   > `scriptDefinitions` (list)

>   >   The description of scripts. This is used by the `Script_engraver` for typesetting note-superscripts and subscripts. See ‘`scm/script.scm`’ for more information.

>   This engraver creates the following layout object(s):

>   Script.

> `Bend_engraver`

>   Create fall spanners.

>   Music types accepted:

>   bend-after-event

>   This engraver creates the following layout object(s):

>   BendAfter.

> `Dynamic_align_engraver`

>   Align hairpins and dynamic texts on a horizontal line

>   Properties (read)

>   > `currentMusicalColumn` (layout object)

>   >   Grob that is X-parent to all non-breakable items (note heads, lyrics, etc.).

>   This engraver creates the following layout object(s):

>   DynamicLineSpanner.

> `New_dynamic_engraver`

>   Create hairpins, dynamic texts, and their vertical alignments. The symbols are collected onto a `DynamicLineSpanner` grob which takes care of vertical positioning.

>   Music types accepted:

>   span-dynamic-event and absolute-dynamic-event

>   Properties (read)

>   > `crescendoSpanner` (symbol)

>   >   The type of spanner to be used for crescendi. Available values are ‘`hairpin`’ and ‘`text`’. If unset, a hairpin crescendo is used.

>   > `crescendoText` (markup)

>   >   The text to print at start of non-hairpin crescendo, i.e., ‘`cresc.`’.

>   > `currentMusicalColumn` (layout object)

>   >   Grob that is X-parent to all non-breakable items (note heads, lyrics, etc.).

>   > `decrescendoSpanner` (symbol)

>   >   The type of spanner to be used for decrescendi. Available values are ‘`hairpin`’ and ‘`text`’. If unset, a hairpin decrescendo is used.

>   > `decrescendoText` (markup)

>   >   The text to print at start of non-hairpin decrescendo, i.e., ‘`dim.`’.

>   This engraver creates the following layout object(s):

>   DynamicText, DynamicTextSpanner and Hairpin.

> `Text_engraver`

>   Create text scripts.

>   Music types accepted:

>   text-script-event

>   This engraver creates the following layout object(s):

>   TextScript.

> `Part_combine_engraver`

>   Part combine engraver for orchestral scores: Print markings ‘a2’, ‘Solo’, ‘Solo II’, and ‘unisono’.

>   Music types accepted:

>   part-combine-event

>   Properties (read)

>   > `printPartCombineTexts` (boolean)

>   >   Set ‘Solo’ and ‘A due’ texts in the part combiner?

>   > `soloText` (markup)

>   >   The text for the start of a solo when part-combining.

>   > `soloIIText` (markup)

>   >   The text for the start of a solo for voice ‘two’ when part-combining.

>   > `aDueText` (markup)

>   >   Text to print at a unisono passage.

>   This engraver creates the following layout object(s):

>   CombineTextScript.

> `Slash_repeat_engraver`

>   Make beat repeats.

>   Music types accepted:

>   percent-event

>   Properties (read)

>   > `measureLength` (moment)

>   >   Length of one measure in the current time signature.

>   This engraver creates the following layout object(s):

>   RepeatSlash.

> `Percent_repeat_engraver`

>   Make whole bar and double bar repeats.

>   Music types accepted:

>   percent-event

>   Properties (read)

>   > `countPercentRepeats` (boolean)

>   >   If set, produce counters for percent repeats.

>   > `currentCommandColumn` (layout object)

>   >   Grob that is X-parent to all current breakable (clef, key signature, etc.) items.

>   > `measureLength` (moment)

>   >   Length of one measure in the current time signature.

>   > `repeatCountVisibility` (procedure)

>   >   A procedure taking as arguments an integer and context, returning whether the corresponding percent repeat number should be printed when `countPercentRepeats` is set.

>   Properties (write)

>   > `forbidBreak` (boolean)

>   >   If set to `##t`, prevent a line break at this point.

>   This engraver creates the following layout object(s):

>   DoublePercentRepeat, DoublePercentRepeatCounter, PercentRepeat and PercentRepeatCounter.

> `Chord_tremolo_engraver`

>   Generate beams for tremolo repeats.

>   Music types accepted:

>   tremolo-span-event

>   This engraver creates the following layout object(s):

>   Beam.

> `Auto_beam_engraver`

>   Generate beams based on measure characteristics and observed Stems. Uses `beatLength`, `measureLength`, and `measurePosition` to decide when to start and stop a beam. Overriding beaming is done through Stem_engraver properties `stemLeftBeamCount` and `stemRightBeamCount`.

>   Music types accepted:

>   beam-forbid-event

>   Properties (read)

>   > `autoBeaming` (boolean)

>   >   If set to true then beams are generated automatically.

>   > `autoBeamSettings` (list)

>   >   Specifies when automatically generated beams should begin and end. See behavior Setting automatic beam behavior for more information.

>   > `beatLength` (moment)

>   >   The length of one beat in this time signature.

>   > `subdivideBeams` (boolean)

>   >   If set, multiple beams will be subdivided at beat positions by only drawing one beam over the beat.

>   This engraver creates the following layout object(s):

>   Beam.

> `Grace_beam_engraver`

>   Handle `Beam` events by engraving beams. If omitted, then notes are printed with flags instead of beams. Only engraves beams when we are at grace points in time.

>   Music types accepted:

>   beam-event

>   Properties (read)

>   > `beamMelismaBusy` (boolean)

>   >   Signal if a beam is present.

>   > `beatLength` (moment)

>   >   The length of one beat in this time signature.

>   > `subdivideBeams` (boolean)

>   >   If set, multiple beams will be subdivided at beat positions by only drawing one beam over the beat.

>   This engraver creates the following layout object(s):

>   Beam.

> `Beam_engraver`

>   Handle `Beam` events by engraving beams. If omitted, then notes are printed with flags instead of beams.

>   Music types accepted:

>   beam-event

>   Properties (read)

>   > `beamMelismaBusy` (boolean)

>   >   Signal if a beam is present.

>   > `beatLength` (moment)

>   >   The length of one beat in this time signature.

>   > `subdivideBeams` (boolean)

>   >   If set, multiple beams will be subdivided at beat positions by only drawing one beam over the beat.

>   Properties (write)

>   > `forbidBreak` (boolean)

>   >   If set to `##t`, prevent a line break at this point.

>   This engraver creates the following layout object(s):

>   Beam.

> `Stem_engraver`

>   Create stems and single-stem tremolos. It also works together with the beam engraver for overriding beaming.

>   Music types accepted:

>   tremolo-event

>   Properties (read)

>   > `tremoloFlags` (integer)

>   >   The number of tremolo flags to add if no number is specified.

>   > `stemLeftBeamCount` (integer)

>   >   Specify the number of beams to draw on the left side of the next note. Overrides automatic beaming. The value is only used once, and then it is erased.

>   > `stemRightBeamCount` (integer)

>   >   See `stemLeftBeamCount`.

>   This engraver creates the following layout object(s):

>   Stem and StemTremolo.

> `Tweak_engraver`

>   Read the `tweaks` property from the originating event, and set properties.

> `Rest_engraver`

>   Engrave rests.

>   Music types accepted:

>   rest-event

>   Properties (read)

>   > `middleCPosition` (number)

>   >   The place of the middle C, measured in half staff-spaces. Usually determined by looking at `middleCClefPosition` and `middleCOffset`.

>   This engraver creates the following layout object(s):

>   Rest.

> `Dots_engraver`

>   Create Dots objects for rhythmic-head-interfaces.

>   This engraver creates the following layout object(s):

>   Dots.

> `Breathing_sign_engraver`

>   Create a breathing sign.

>   Music types accepted:

>   breathing-event

>   This engraver creates the following layout object(s):

>   BreathingSign.

> `Ligature_bracket_engraver`

>   Handle `Ligature_events` by engraving `Ligature` brackets.

>   Music types accepted:

>   ligature-event

>   This engraver creates the following layout object(s):

>   LigatureBracket.

> `Glissando_engraver`

>   Engrave glissandi.

>   Music types accepted:

>   glissando-event

>   This engraver creates the following layout object(s):

>   Glissando.

> `Note_head_line_engraver`

>   Engrave a line between two note heads, for example a glissando. If `followVoice` is set, staff switches also generate a line.

>   Properties (read)

>   > `followVoice` (boolean)

>   >   If set, note heads are tracked across staff switches by a thin line.

>   This engraver creates the following layout object(s):

>   Glissando and VoiceFollower.

> `Repeat_tie_engraver`

>   Create repeat ties.

>   Music types accepted:

>   repeat-tie-event

>   This engraver creates the following layout object(s):

>   RepeatTie and RepeatTieColumn.

> `Laissez_vibrer_engraver`

>   Create laissez vibrer items.

>   Music types accepted:

>   laissez-vibrer-event

>   This engraver creates the following layout object(s):

>   LaissezVibrerTie and LaissezVibrerTieColumn.

> `Forbid_line_break_engraver`

>   Forbid line breaks when note heads are still playing at some point.

>   Properties (read)

>   > `busyGrobs` (list)

>   >   A queue of `(end-moment . GROB)` cons cells. This is for internal (C++) use only. This property contains the grobs which are still busy (e.g. note heads, spanners, etc.).

>   Properties (write)

>   > `forbidBreak` (boolean)

>   >   If set to `##t`, prevent a line break at this point.

> `Grob_pq_engraver`

>   Administrate when certain grobs (e.g., note heads) stop playing.

>   Properties (read)

>   > `busyGrobs` (list)

>   >   A queue of `(end-moment . GROB)` cons cells. This is for internal (C++) use only. This property contains the grobs which are still busy (e.g. note heads, spanners, etc.).

>   Properties (write)

>   > `busyGrobs` (list)

>   >   A queue of `(end-moment . GROB)` cons cells. This is for internal (C++) use only. This property contains the grobs which are still busy (e.g. note heads, spanners, etc.).

> `Trill_spanner_engraver`

>   Create trill spanner from an event.

>   Music types accepted:

>   trill-span-event

>   Properties (read)

>   > `currentCommandColumn` (layout object)

>   >   Grob that is X-parent to all current breakable (clef, key signature, etc.) items.

>   > `currentMusicalColumn` (layout object)

>   >   Grob that is X-parent to all non-breakable items (note heads, lyrics, etc.).

>   This engraver creates the following layout object(s):

>   TrillSpanner.

> `Text_spanner_engraver`

>   Create text spanner from an event.

>   Music types accepted:

>   text-span-event

>   This engraver creates the following layout object(s):

>   TextSpanner.

> `Multi_measure_rest_engraver`

>   Engrave multi-measure rests that are produced with ‘`R`’. It reads `measurePosition` and `internalBarNumber` to determine what number to print over the MultiMeasureRest. Reads `measureLength` to determine whether it should use a whole rest or a breve rest to represent one measure.

>   Music types accepted:

>   multi-measure-text-event and multi-measure-rest-event

>   Properties (read)

>   > `internalBarNumber` (integer)

>   >   Contains the current barnumber. This property is used for internal timekeeping, among others by the `Accidental_engraver`.

>   > `restNumberThreshold` (number)

>   >   If a multimeasure rest has more measures than this, a number is printed.

>   > `breakableSeparationItem` (layout object)

>   >   The breakable items in this time step, for this staff.

>   > `currentCommandColumn` (layout object)

>   >   Grob that is X-parent to all current breakable (clef, key signature, etc.) items.

>   > `measurePosition` (moment)

>   >   How much of the current measure have we had. This can be set manually to create incomplete measures.

>   > `measureLength` (moment)

>   >   Length of one measure in the current time signature.

>   This engraver creates the following layout object(s):

>   MultiMeasureRest, MultiMeasureRestNumber and MultiMeasureRestText.

> `Arpeggio_engraver`

>   Generate an Arpeggio symbol.

>   Music types accepted:

>   arpeggio-event

>   This engraver creates the following layout object(s):

>   Arpeggio.

> `Output_property_engraver`

>   Apply a procedure to any grob acknowledged.

>   Music types accepted:

>   apply-output-event

> `Pitched_trill_engraver`

>   Print the bracketed note head after a note head with trill.

>   This engraver creates the following layout object(s):

>   TrillPitchAccidental, TrillPitchGroup and TrillPitchHead.

> `Font_size_engraver`

>   Put `fontSize` into `font-size` grob property.

>   Properties (read)

>   > `fontSize` (number)

>   >   The relative size of all grobs in a context.

### 2.1.24 VaticanaStaff

Same as `Staff` context, except that it is accommodated for typesetting Gregorian Chant in the notational style of Editio Vaticana.

This context also accepts commands for the following context(s):

Staff.

This context creates the following layout object(s):

AccidentalCautionary, AccidentalPlacement, AccidentalSuggestion, Accidental, BarLine, BassFigureAlignmentPositioning, BassFigureAlignment, BassFigureBracket, BassFigureContinuation, BassFigureLine, BassFigure, Clef, Custos, DotColumn, InstrumentName, KeyCancellation, KeySignature, LedgerLineSpanner, NoteCollision, OctavateEight, OttavaBracket, PianoPedalBracket, RestCollision, ScriptRow, SostenutoPedalLineSpanner, SostenutoPedal, StaffSpacing, StaffSymbol, SustainPedalLineSpanner, SustainPedal, UnaCordaPedalLineSpanner, UnaCordaPedal and VerticalAxisGroup.

This context sets the following properties:

- Set grob-property `style` in Dots to `'vaticana`.
- Set grob-property `neutral-direction` in Custos to `-1`.
- Set grob-property `neutral-position` in Custos to `3`.
- Set grob-property `style` in Custos to `'vaticana`.
- Set grob-property `glyph-name-alist` in Accidental to `'((-1/2 . accidentals.vaticanaM1) (0 . accidentals.vaticana0) (1/2 . accidentals.mensural1))`.
- Set grob-property `glyph-name-alist` in KeySignature to `'((-1/2 . accidentals.vaticanaM1) (0 . accidentals.vaticana0) (1/2 . accidentals.mensural1))`.
- Set translator property `clefOctavation` to `0`.
- Set translator property `clefPosition` to `1`.
- Set translator property `middleCClefPosition` to `1`.
- Set translator property `middleCPosition` to `1`.
- Set translator property `clefGlyph` to `"clefs.vaticana.do"`.
- Set grob-property `thickness` in StaffSymbol to `0.6`.
- Set grob-property `line-count` in StaffSymbol to `4`.
- Set grob-property `transparent` in BarLine to `#t`.
- Set translator property `shortInstrumentName` to `'()`.
- Set translator property `instrumentName` to `'()`.
- Set grob-property `minimum-Y-extent` in VerticalAxisGroup to `'(-4 . 4)`.
- Set translator property `ignoreFiguredBassRest` to `#t`.
- Set translator property `createSpacing` to `#t`.
- Set translator property `localKeySignature` to `'()`.

Context VaticanaStaff can contain VaticanaVoice and CueVoice.

This context is built from the following engraver(s):

> `Custos_engraver`

>   Engrave custodes.

>   This engraver creates the following layout object(s):

>   Custos.

> `Script_row_engraver`

>   Determine order in horizontal side position elements.

>   This engraver creates the following layout object(s):

>   ScriptRow.

> `Figured_bass_position_engraver`

>   Position figured bass alignments over notes.

>   This engraver creates the following layout object(s):

>   BassFigureAlignmentPositioning.

> `Figured_bass_engraver`

>   Make figured bass numbers.

>   Music types accepted:

>   bass-figure-event and rest-event

>   Properties (read)

>   > `figuredBassAlterationDirection` (direction)

>   >   Where to put alterations relative to the main figure.

>   > `figuredBassCenterContinuations` (boolean)

>   >   Whether to vertically center pairs of extender lines. This does not work with three or more lines.

>   > `figuredBassFormatter` (procedure)

>   >   A routine generating a markup for a bass figure.

>   > `implicitBassFigures` (list)

>   >   A list of bass figures that are not printed as numbers, but only as extender lines.

>   > `useBassFigureExtenders` (boolean)

>   >   Whether to use extender lines for repeated bass figures.

>   > `ignoreFiguredBassRest` (boolean)

>   >   Don’t swallow rest events.

>   This engraver creates the following layout object(s):

>   BassFigure, BassFigureAlignment, BassFigureBracket, BassFigureContinuation and BassFigureLine.

> `Axis_group_engraver`

>   Group all objects created in this context in a `VerticalAxisGroup` spanner.

>   Properties (read)

>   > `currentCommandColumn` (layout object)

>   >   Grob that is X-parent to all current breakable (clef, key signature, etc.) items.

>   This engraver creates the following layout object(s):

>   VerticalAxisGroup.

> `String_number_engraver`

>   Swallow string number events. The purpose of this engraver is to process tablatures for normal notation. To provent warnings for unprocessed string number events to obscure real error messages, this engraver swallows them all.

> `Instrument_name_engraver`

>   Create a system start text for instrument or vocal names.

>   Properties (read)

>   > `currentCommandColumn` (layout object)

>   >   Grob that is X-parent to all current breakable (clef, key signature, etc.) items.

>   > `shortInstrumentName` (markup)

>   >   See `instrument`.

>   > `instrumentName` (markup)

>   >   The name to print left of a staff. The `instrument` property labels the staff in the first system, and the `instr` property labels following lines.

>   > `shortVocalName` (markup)

>   >   Name of a vocal line, short version.

>   > `vocalName` (markup)

>   >   Name of a vocal line.

>   This engraver creates the following layout object(s):

>   InstrumentName.

> `Piano_pedal_align_engraver`

>   Align piano pedal symbols and brackets.

>   Properties (read)

>   > `currentCommandColumn` (layout object)

>   >   Grob that is X-parent to all current breakable (clef, key signature, etc.) items.

>   This engraver creates the following layout object(s):

>   SostenutoPedalLineSpanner, SustainPedalLineSpanner and UnaCordaPedalLineSpanner.

> `Piano_pedal_engraver`

>   Engrave piano pedal symbols and brackets.

>   Music types accepted:

>   una-corda-event, sustain-event and sostenuto-event

>   Properties (read)

>   > `currentCommandColumn` (layout object)

>   >   Grob that is X-parent to all current breakable (clef, key signature, etc.) items.

>   > `pedalSostenutoStrings` (list)

>   >   See `pedalSustainStrings`.

>   > `pedalSostenutoStyle` (symbol)

>   >   See `pedalSustainStyle`.

>   > `pedalSustainStrings` (list)

>   >   A list of strings to print for sustain-pedal. Format is `(up updown down)`, where each of the three is the string to print when this is done with the pedal.

>   > `pedalSustainStyle` (symbol)

>   >   A symbol that indicates how to print sustain pedals: `text`, `bracket` or `mixed` (both).

>   > `pedalUnaCordaStrings` (list)

>   >   See `pedalSustainStrings`.

>   > `pedalUnaCordaStyle` (symbol)

>   >   See `pedalSustainStyle`.

>   This engraver creates the following layout object(s):

>   PianoPedalBracket, SostenutoPedal, SustainPedal and UnaCordaPedal.

> `Accidental_engraver`

>   Make accidentals. Catch note heads, ties and notices key-change events. This engraver usually lives at Staff level, but reads the settings for Accidental at `Voice` level, so you can `\override` them at `Voice`.

>   Properties (read)

>   > `autoAccidentals` (list)

>   >   List of different ways to typeset an accidental.

>   >   For determining when to print an accidental, several different rules are tried. The rule that gives the highest number of accidentals is used.

>   >   Each entry in the list is either a symbol or a procedure.

>   >   symbol

>   >     The symbol is the name of the context in which the following rules are to be applied. For example, if context is Score then all staves share accidentals, and if context is Staff then all voices in the same staff share accidentals, but staves do not.

>   >   procedure

>   >     The procedure represents an accidental rule to be applied to the previously specified context.

>   >     The procedure takes the following arguments:

>   >     `context`

>   >       The current context to which the rule should be applied.

>   >     `pitch`

>   >       The pitch of the note to be evaluated.

>   >     `barnum`

>   >       The current bar number.

>   >     `measurepos`

>   >       The current measure position.

>   >     The procedure returns a pair of booleans. The first states whether an extra natural should be added. The second states whether an accidental should be printed. `(#t . #f)` does not make sense.

>   > `autoCautionaries` (list)

>   >   List similar to `autoAccidentals`, but it controls cautionary accidentals rather than normal ones. Both lists are tried, and the one giving the most accidentals wins. In case of draw, a normal accidental is typeset.

>   > `internalBarNumber` (integer)

>   >   Contains the current barnumber. This property is used for internal timekeeping, among others by the `Accidental_engraver`.

>   > `extraNatural` (boolean)

>   >   Whether to typeset an extra natural sign before accidentals changing from a non-natural to another non-natural.

>   > `harmonicAccidentals` (boolean)

>   >   If set, harmonic notes in chords get accidentals.

>   > `keySignature` (list)

>   >   The current key signature. This is an alist containing `(step . alter)` or `((octave . step) . alter)`, where step is a number in the range 0 to 6 and alter a fraction, denoting alteration. For alterations, use symbols, e.g. `keySignature = #`((6 . ,FLAT))`.

>   > `localKeySignature` (list)

>   >   The key signature at this point in the measure. The format is the same as for `keySignature`, but can also contain `((octave . name) . (alter barnumber . measureposition))` pairs.

>   Properties (write)

>   > `localKeySignature` (list)

>   >   The key signature at this point in the measure. The format is the same as for `keySignature`, but can also contain `((octave . name) . (alter barnumber . measureposition))` pairs.

>   This engraver creates the following layout object(s):

>   Accidental, AccidentalCautionary, AccidentalPlacement and AccidentalSuggestion.

> `Rest_collision_engraver`

>   Handle collisions of rests.

>   Properties (read)

>   > `busyGrobs` (list)

>   >   A queue of `(end-moment . GROB)` cons cells. This is for internal (C++) use only. This property contains the grobs which are still busy (e.g. note heads, spanners, etc.).

>   This engraver creates the following layout object(s):

>   RestCollision.

> `Grob_pq_engraver`

>   Administrate when certain grobs (e.g., note heads) stop playing.

>   Properties (read)

>   > `busyGrobs` (list)

>   >   A queue of `(end-moment . GROB)` cons cells. This is for internal (C++) use only. This property contains the grobs which are still busy (e.g. note heads, spanners, etc.).

>   Properties (write)

>   > `busyGrobs` (list)

>   >   A queue of `(end-moment . GROB)` cons cells. This is for internal (C++) use only. This property contains the grobs which are still busy (e.g. note heads, spanners, etc.).

> `Collision_engraver`

>   Collect `NoteColumns`, and as soon as there are two or more, put them in a `NoteCollision` object.

>   This engraver creates the following layout object(s):

>   NoteCollision.

> `Staff_symbol_engraver`

>   Create the constellation of five (default) staff lines.

>   Music types accepted:

>   staff-span-event

>   This engraver creates the following layout object(s):

>   StaffSymbol.

> `Ledger_line_engraver`

>   Create the spanner to draw ledger lines, and notices objects that need ledger lines.

>   This engraver creates the following layout object(s):

>   LedgerLineSpanner.

> `Key_engraver`

>   Engrave a key signature.

>   Music types accepted:

>   key-change-event

>   Properties (read)

>   > `createKeyOnClefChange` (boolean)

>   >   Print a key signature whenever the clef is changed.

>   > `explicitKeySignatureVisibility` (vector)

>   >   ‘`break-visibility`’ function for explicit key changes. ‘`\override`’ of the `break-visibility` property will set the visibility for normal (i.e., at the start of the line) key signatures.

>   > `extraNatural` (boolean)

>   >   Whether to typeset an extra natural sign before accidentals changing from a non-natural to another non-natural.

>   > `keyAlterationOrder` (list)

>   >   An alist that defines in what order alterations should be printed. The format is `(step . alter)`, where step is a number from 0 to 6 and alter from -2 (sharp) to 2 (flat).

>   > `keySignature` (list)

>   >   The current key signature. This is an alist containing `(step . alter)` or `((octave . step) . alter)`, where step is a number in the range 0 to 6 and alter a fraction, denoting alteration. For alterations, use symbols, e.g. `keySignature = #`((6 . ,FLAT))`.

>   > `lastKeySignature` (list)

>   >   Last key signature before a key signature change.

>   > `printKeyCancellation` (boolean)

>   >   Print restoration alterations before a key signature change.

>   Properties (write)

>   > `keySignature` (list)

>   >   The current key signature. This is an alist containing `(step . alter)` or `((octave . step) . alter)`, where step is a number in the range 0 to 6 and alter a fraction, denoting alteration. For alterations, use symbols, e.g. `keySignature = #`((6 . ,FLAT))`.

>   > `lastKeySignature` (list)

>   >   Last key signature before a key signature change.

>   > `tonic` (pitch)

>   >   The tonic of the current scale.

>   This engraver creates the following layout object(s):

>   KeyCancellation and KeySignature.

> `Clef_engraver`

>   Determine and set reference point for pitches.

>   Properties (read)

>   > `clefGlyph` (string)

>   >   Name of the symbol within the music font.

>   > `clefOctavation` (integer)

>   >   Add this much extra octavation. Values of 7 and -7 are common.

>   > `clefPosition` (number)

>   >   Where should the center of the clef symbol go, measured in half staff spaces from the center of the staff.

>   > `explicitClefVisibility` (vector)

>   >   ‘`break-visibility`’ function for clef changes.

>   > `forceClef` (boolean)

>   >   Show clef symbol, even if it has not changed. Only active for the first clef after the property is set, not for the full staff.

>   This engraver creates the following layout object(s):

>   Clef and OctavateEight.

> `Ottava_spanner_engraver`

>   Create a text spanner when the ottavation property changes.

>   Properties (read)

>   > `ottavation` (markup)

>   >   If set, the text for an ottava spanner. Changing this creates a new text spanner.

>   > `originalMiddleCPosition` (integer)

>   >   Used for temporary overriding middle C in octavation brackets.

>   > `currentMusicalColumn` (layout object)

>   >   Grob that is X-parent to all non-breakable items (note heads, lyrics, etc.).

>   This engraver creates the following layout object(s):

>   OttavaBracket.

> `Staff_collecting_engraver`

>   Maintain the `stavesFound` variable.

>   Properties (read)

>   > `stavesFound` (list of grobs)

>   >   A list of all staff-symbols found.

>   Properties (write)

>   > `stavesFound` (list of grobs)

>   >   A list of all staff-symbols found.

> `Dot_column_engraver`

>   Engrave dots on dotted notes shifted to the right of the note. If omitted, then dots appear on top of the notes.

>   This engraver creates the following layout object(s):

>   DotColumn.

> `Separating_line_group_engraver`

>   Generate objects for computing spacing parameters.

>   Properties (read)

>   > `createSpacing` (boolean)

>   >   Create `StaffSpacing` objects? Should be set for staves.

>   Properties (write)

>   > `hasStaffSpacing` (boolean)

>   >   True if the current `CommandColumn` contains items that will affect spacing.

>   This engraver creates the following layout object(s):

>   StaffSpacing.

> `Font_size_engraver`

>   Put `fontSize` into `font-size` grob property.

>   Properties (read)

>   > `fontSize` (number)

>   >   The relative size of all grobs in a context.

> `Bar_engraver`

>   Create barlines. This engraver is controlled through the `whichBar` property. If it has no bar line to create, it will forbid a linebreak at this point.

>   Properties (read)

>   > `whichBar` (string)

>   >   This property is read to determine what type of bar line to create.

>   >   Example:

>   >   >     \set Staff.whichBar = "|:"

>   >   This will create a start-repeat bar in this staff only. Valid values are described in bar-line-interface.

>   Properties (write)

>   > `forbidBreak` (boolean)

>   >   If set to `##t`, prevent a line break at this point.

>   This engraver creates the following layout object(s):

>   BarLine.

> `Output_property_engraver`

>   Apply a procedure to any grob acknowledged.

>   Music types accepted:

>   apply-output-event

### 2.1.25 VaticanaVoice

Same as `Voice` context, except that it is accommodated for typesetting Gregorian Chant in the notational style of Editio Vaticana.

This context also accepts commands for the following context(s):

Voice.

This context creates the following layout object(s):

Arpeggio, Beam, BendAfter, BreathingSign, ClusterSpannerBeacon, ClusterSpanner, CombineTextScript, DotColumn, Dots, DoublePercentRepeatCounter, DoublePercentRepeat, DynamicLineSpanner, DynamicTextSpanner, DynamicText, Fingering, Glissando, Hairpin, InstrumentSwitch, LaissezVibrerTieColumn, LaissezVibrerTie, MultiMeasureRestNumber, MultiMeasureRestText, MultiMeasureRest, NoteColumn, NoteHead, NoteSpacing, PercentRepeatCounter, PercentRepeat, PhrasingSlur, RepeatSlash, RepeatTieColumn, RepeatTie, Rest, ScriptColumn, Script, StringNumber, StrokeFinger, TextScript, TextSpanner, TieColumn, Tie, TrillPitchAccidental, TrillPitchGroup, TrillPitchHead, TrillSpanner, TupletBracket, TupletNumber, VaticanaLigature and VoiceFollower.

This context sets the following properties:

- Set grob-property `padding` in TextSpanner to `-0.1`.
- Set grob-property `style` in TextSpanner to `'line`.
- Set translator property `autoBeaming` to `#f`.
- Set grob-property `padding` in Script to `0.5`.
- Set grob-property `style` in NoteHead to `'vaticana.punctum`.
- Set translator property `localKeySignature` to `'()`.

This context is a ‘bottom’ context; it cannot contain other contexts.

This context is built from the following engraver(s):

> `Vaticana_ligature_engraver`

>   Handle ligatures by glueing special ligature heads together.

>   Music types accepted:

>   ligature-event and pes-or-flexa-event

>   This engraver creates the following layout object(s):

>   DotColumn and VaticanaLigature.

> `Skip_event_swallow_translator`

>   Swallow `\skip`.

> `Instrument_switch_engraver`

>   Create a cue text for taking instrument.

>   Properties (read)

>   > `instrumentCueName` (markup)

>   >   The name to print if another instrument is to be taken.

>   This engraver creates the following layout object(s):

>   InstrumentSwitch.

> `Grace_engraver`

>   Set font size and other properties for grace notes.

>   Properties (read)

>   > `graceSettings` (list)

>   >   Overrides for grace notes. This property should be manipulated through the `add-grace-property` function.

> `Tuplet_engraver`

>   Catch tuplet events and generate appropriate bracket.

>   Music types accepted:

>   tuplet-span-event

>   Properties (read)

>   > `tupletFullLength` (boolean)

>   >   If set, the tuplet is printed up to the start of the next note.

>   > `tupletFullLengthNote` (boolean)

>   >   If set, end at the next note, otherwise end on the matter (time signatures, etc.) before the note.

>   This engraver creates the following layout object(s):

>   TupletBracket and TupletNumber.

> `Tie_engraver`

>   Generate ties between note heads of equal pitch.

>   Music types accepted:

>   tie-event

>   Properties (read)

>   > `tieWaitForNote` (boolean)

>   >   If true, tied notes do not have to follow each other directly. This can be used for writing out arpeggios.

>   Properties (write)

>   > `tieMelismaBusy` (boolean)

>   >   Signal whether a tie is present.

>   This engraver creates the following layout object(s):

>   Tie and TieColumn.

> `Cluster_spanner_engraver`

>   Engrave a cluster using `Spanner` notation.

>   Music types accepted:

>   cluster-note-event

>   This engraver creates the following layout object(s):

>   ClusterSpanner and ClusterSpannerBeacon.

> `Phrasing_slur_engraver`

>   Print phrasing slurs. Similar to Slur_engraver.

>   Music types accepted:

>   phrasing-slur-event

>   This engraver creates the following layout object(s):

>   PhrasingSlur.

> `Spanner_break_forbid_engraver`

>   Forbid breaks in certain spanners.

> `Note_spacing_engraver`

>   Generate `NoteSpacing`, an object linking horizontal lines for use in spacing.

>   This engraver creates the following layout object(s):

>   NoteSpacing.

> `Rhythmic_column_engraver`

>   Generate `NoteColumn`, an object that groups stems, note heads, and rests.

>   This engraver creates the following layout object(s):

>   NoteColumn.

> `Script_column_engraver`

>   Find potentially colliding scripts and put them into a `ScriptColumn` object; that will fix the collisions.

>   This engraver creates the following layout object(s):

>   ScriptColumn.

> `Script_engraver`

>   Handle note scripted articulations.

>   Music types accepted:

>   articulation-event

>   Properties (read)

>   > `scriptDefinitions` (list)

>   >   The description of scripts. This is used by the `Script_engraver` for typesetting note-superscripts and subscripts. See ‘`scm/script.scm`’ for more information.

>   This engraver creates the following layout object(s):

>   Script.

> `Bend_engraver`

>   Create fall spanners.

>   Music types accepted:

>   bend-after-event

>   This engraver creates the following layout object(s):

>   BendAfter.

> `Fingering_engraver`

>   Create fingering scripts.

>   Music types accepted:

>   stroke-finger-event and fingering-event

>   This engraver creates the following layout object(s):

>   Fingering.

> `Dynamic_align_engraver`

>   Align hairpins and dynamic texts on a horizontal line

>   Properties (read)

>   > `currentMusicalColumn` (layout object)

>   >   Grob that is X-parent to all non-breakable items (note heads, lyrics, etc.).

>   This engraver creates the following layout object(s):

>   DynamicLineSpanner.

> `New_dynamic_engraver`

>   Create hairpins, dynamic texts, and their vertical alignments. The symbols are collected onto a `DynamicLineSpanner` grob which takes care of vertical positioning.

>   Music types accepted:

>   span-dynamic-event and absolute-dynamic-event

>   Properties (read)

>   > `crescendoSpanner` (symbol)

>   >   The type of spanner to be used for crescendi. Available values are ‘`hairpin`’ and ‘`text`’. If unset, a hairpin crescendo is used.

>   > `crescendoText` (markup)

>   >   The text to print at start of non-hairpin crescendo, i.e., ‘`cresc.`’.

>   > `currentMusicalColumn` (layout object)

>   >   Grob that is X-parent to all non-breakable items (note heads, lyrics, etc.).

>   > `decrescendoSpanner` (symbol)

>   >   The type of spanner to be used for decrescendi. Available values are ‘`hairpin`’ and ‘`text`’. If unset, a hairpin decrescendo is used.

>   > `decrescendoText` (markup)

>   >   The text to print at start of non-hairpin decrescendo, i.e., ‘`dim.`’.

>   This engraver creates the following layout object(s):

>   DynamicText, DynamicTextSpanner and Hairpin.

> `Text_engraver`

>   Create text scripts.

>   Music types accepted:

>   text-script-event

>   This engraver creates the following layout object(s):

>   TextScript.

> `Part_combine_engraver`

>   Part combine engraver for orchestral scores: Print markings ‘a2’, ‘Solo’, ‘Solo II’, and ‘unisono’.

>   Music types accepted:

>   part-combine-event

>   Properties (read)

>   > `printPartCombineTexts` (boolean)

>   >   Set ‘Solo’ and ‘A due’ texts in the part combiner?

>   > `soloText` (markup)

>   >   The text for the start of a solo when part-combining.

>   > `soloIIText` (markup)

>   >   The text for the start of a solo for voice ‘two’ when part-combining.

>   > `aDueText` (markup)

>   >   Text to print at a unisono passage.

>   This engraver creates the following layout object(s):

>   CombineTextScript.

> `Slash_repeat_engraver`

>   Make beat repeats.

>   Music types accepted:

>   percent-event

>   Properties (read)

>   > `measureLength` (moment)

>   >   Length of one measure in the current time signature.

>   This engraver creates the following layout object(s):

>   RepeatSlash.

> `Percent_repeat_engraver`

>   Make whole bar and double bar repeats.

>   Music types accepted:

>   percent-event

>   Properties (read)

>   > `countPercentRepeats` (boolean)

>   >   If set, produce counters for percent repeats.

>   > `currentCommandColumn` (layout object)

>   >   Grob that is X-parent to all current breakable (clef, key signature, etc.) items.

>   > `measureLength` (moment)

>   >   Length of one measure in the current time signature.

>   > `repeatCountVisibility` (procedure)

>   >   A procedure taking as arguments an integer and context, returning whether the corresponding percent repeat number should be printed when `countPercentRepeats` is set.

>   Properties (write)

>   > `forbidBreak` (boolean)

>   >   If set to `##t`, prevent a line break at this point.

>   This engraver creates the following layout object(s):

>   DoublePercentRepeat, DoublePercentRepeatCounter, PercentRepeat and PercentRepeatCounter.

> `Chord_tremolo_engraver`

>   Generate beams for tremolo repeats.

>   Music types accepted:

>   tremolo-span-event

>   This engraver creates the following layout object(s):

>   Beam.

> `New_fingering_engraver`

>   Create fingering scripts for notes in a new chord. This engraver is ill-named, since it also takes care of articulations and harmonic note heads.

>   Properties (read)

>   > `fingeringOrientations` (list)

>   >   A list of symbols, containing ‘`left`’, ‘`right`’, ‘`up`’ and/or ‘`down`’. This list determines where fingerings are put relative to the chord being fingered.

>   > `harmonicDots` (boolean)

>   >   If set, harmonic notes in dotted chords get dots.

>   > `strokeFingerOrientations` (list)

>   >   See `fingeringOrientations`.

>   > `stringNumberOrientations` (list)

>   >   See `fingeringOrientations`.

>   This engraver creates the following layout object(s):

>   Fingering, Script, StringNumber and StrokeFinger.

> `Auto_beam_engraver`

>   Generate beams based on measure characteristics and observed Stems. Uses `beatLength`, `measureLength`, and `measurePosition` to decide when to start and stop a beam. Overriding beaming is done through Stem_engraver properties `stemLeftBeamCount` and `stemRightBeamCount`.

>   Music types accepted:

>   beam-forbid-event

>   Properties (read)

>   > `autoBeaming` (boolean)

>   >   If set to true then beams are generated automatically.

>   > `autoBeamSettings` (list)

>   >   Specifies when automatically generated beams should begin and end. See behavior Setting automatic beam behavior for more information.

>   > `beatLength` (moment)

>   >   The length of one beat in this time signature.

>   > `subdivideBeams` (boolean)

>   >   If set, multiple beams will be subdivided at beat positions by only drawing one beam over the beat.

>   This engraver creates the following layout object(s):

>   Beam.

> `Grace_beam_engraver`

>   Handle `Beam` events by engraving beams. If omitted, then notes are printed with flags instead of beams. Only engraves beams when we are at grace points in time.

>   Music types accepted:

>   beam-event

>   Properties (read)

>   > `beamMelismaBusy` (boolean)

>   >   Signal if a beam is present.

>   > `beatLength` (moment)

>   >   The length of one beat in this time signature.

>   > `subdivideBeams` (boolean)

>   >   If set, multiple beams will be subdivided at beat positions by only drawing one beam over the beat.

>   This engraver creates the following layout object(s):

>   Beam.

> `Beam_engraver`

>   Handle `Beam` events by engraving beams. If omitted, then notes are printed with flags instead of beams.

>   Music types accepted:

>   beam-event

>   Properties (read)

>   > `beamMelismaBusy` (boolean)

>   >   Signal if a beam is present.

>   > `beatLength` (moment)

>   >   The length of one beat in this time signature.

>   > `subdivideBeams` (boolean)

>   >   If set, multiple beams will be subdivided at beat positions by only drawing one beam over the beat.

>   Properties (write)

>   > `forbidBreak` (boolean)

>   >   If set to `##t`, prevent a line break at this point.

>   This engraver creates the following layout object(s):

>   Beam.

> `Tweak_engraver`

>   Read the `tweaks` property from the originating event, and set properties.

> `Rest_engraver`

>   Engrave rests.

>   Music types accepted:

>   rest-event

>   Properties (read)

>   > `middleCPosition` (number)

>   >   The place of the middle C, measured in half staff-spaces. Usually determined by looking at `middleCClefPosition` and `middleCOffset`.

>   This engraver creates the following layout object(s):

>   Rest.

> `Dots_engraver`

>   Create Dots objects for rhythmic-head-interfaces.

>   This engraver creates the following layout object(s):

>   Dots.

> `Note_heads_engraver`

>   Generate note heads.

>   Music types accepted:

>   note-event

>   Properties (read)

>   > `middleCPosition` (number)

>   >   The place of the middle C, measured in half staff-spaces. Usually determined by looking at `middleCClefPosition` and `middleCOffset`.

>   > `staffLineLayoutFunction` (procedure)

>   >   Layout of staff lines, `traditional`, or `semitone`.

>   This engraver creates the following layout object(s):

>   NoteHead.

> `Breathing_sign_engraver`

>   Create a breathing sign.

>   Music types accepted:

>   breathing-event

>   This engraver creates the following layout object(s):

>   BreathingSign.

> `Glissando_engraver`

>   Engrave glissandi.

>   Music types accepted:

>   glissando-event

>   This engraver creates the following layout object(s):

>   Glissando.

> `Note_head_line_engraver`

>   Engrave a line between two note heads, for example a glissando. If `followVoice` is set, staff switches also generate a line.

>   Properties (read)

>   > `followVoice` (boolean)

>   >   If set, note heads are tracked across staff switches by a thin line.

>   This engraver creates the following layout object(s):

>   Glissando and VoiceFollower.

> `Repeat_tie_engraver`

>   Create repeat ties.

>   Music types accepted:

>   repeat-tie-event

>   This engraver creates the following layout object(s):

>   RepeatTie and RepeatTieColumn.

> `Laissez_vibrer_engraver`

>   Create laissez vibrer items.

>   Music types accepted:

>   laissez-vibrer-event

>   This engraver creates the following layout object(s):

>   LaissezVibrerTie and LaissezVibrerTieColumn.

> `Forbid_line_break_engraver`

>   Forbid line breaks when note heads are still playing at some point.

>   Properties (read)

>   > `busyGrobs` (list)

>   >   A queue of `(end-moment . GROB)` cons cells. This is for internal (C++) use only. This property contains the grobs which are still busy (e.g. note heads, spanners, etc.).

>   Properties (write)

>   > `forbidBreak` (boolean)

>   >   If set to `##t`, prevent a line break at this point.

> `Grob_pq_engraver`

>   Administrate when certain grobs (e.g., note heads) stop playing.

>   Properties (read)

>   > `busyGrobs` (list)

>   >   A queue of `(end-moment . GROB)` cons cells. This is for internal (C++) use only. This property contains the grobs which are still busy (e.g. note heads, spanners, etc.).

>   Properties (write)

>   > `busyGrobs` (list)

>   >   A queue of `(end-moment . GROB)` cons cells. This is for internal (C++) use only. This property contains the grobs which are still busy (e.g. note heads, spanners, etc.).

> `Trill_spanner_engraver`

>   Create trill spanner from an event.

>   Music types accepted:

>   trill-span-event

>   Properties (read)

>   > `currentCommandColumn` (layout object)

>   >   Grob that is X-parent to all current breakable (clef, key signature, etc.) items.

>   > `currentMusicalColumn` (layout object)

>   >   Grob that is X-parent to all non-breakable items (note heads, lyrics, etc.).

>   This engraver creates the following layout object(s):

>   TrillSpanner.

> `Text_spanner_engraver`

>   Create text spanner from an event.

>   Music types accepted:

>   text-span-event

>   This engraver creates the following layout object(s):

>   TextSpanner.

> `Multi_measure_rest_engraver`

>   Engrave multi-measure rests that are produced with ‘`R`’. It reads `measurePosition` and `internalBarNumber` to determine what number to print over the MultiMeasureRest. Reads `measureLength` to determine whether it should use a whole rest or a breve rest to represent one measure.

>   Music types accepted:

>   multi-measure-text-event and multi-measure-rest-event

>   Properties (read)

>   > `internalBarNumber` (integer)

>   >   Contains the current barnumber. This property is used for internal timekeeping, among others by the `Accidental_engraver`.

>   > `restNumberThreshold` (number)

>   >   If a multimeasure rest has more measures than this, a number is printed.

>   > `breakableSeparationItem` (layout object)

>   >   The breakable items in this time step, for this staff.

>   > `currentCommandColumn` (layout object)

>   >   Grob that is X-parent to all current breakable (clef, key signature, etc.) items.

>   > `measurePosition` (moment)

>   >   How much of the current measure have we had. This can be set manually to create incomplete measures.

>   > `measureLength` (moment)

>   >   Length of one measure in the current time signature.

>   This engraver creates the following layout object(s):

>   MultiMeasureRest, MultiMeasureRestNumber and MultiMeasureRestText.

> `Arpeggio_engraver`

>   Generate an Arpeggio symbol.

>   Music types accepted:

>   arpeggio-event

>   This engraver creates the following layout object(s):

>   Arpeggio.

> `Output_property_engraver`

>   Apply a procedure to any grob acknowledged.

>   Music types accepted:

>   apply-output-event

> `Pitched_trill_engraver`

>   Print the bracketed note head after a note head with trill.

>   This engraver creates the following layout object(s):

>   TrillPitchAccidental, TrillPitchGroup and TrillPitchHead.

> `Font_size_engraver`

>   Put `fontSize` into `font-size` grob property.

>   Properties (read)

>   > `fontSize` (number)

>   >   The relative size of all grobs in a context.

### 2.1.26 Voice

Corresponds to a voice on a staff. This context handles the conversion of dynamic signs, stems, beams, super- and subscripts, slurs, ties, and rests.

You have to instantiate this explicitly if you want to have multiple voices on the same staff.

This context creates the following layout object(s):

Arpeggio, Beam, BendAfter, BreathingSign, ClusterSpannerBeacon, ClusterSpanner, CombineTextScript, Dots, DoublePercentRepeatCounter, DoublePercentRepeat, DynamicLineSpanner, DynamicTextSpanner, DynamicText, Fingering, Glissando, Hairpin, InstrumentSwitch, LaissezVibrerTieColumn, LaissezVibrerTie, LigatureBracket, MultiMeasureRestNumber, MultiMeasureRestText, MultiMeasureRest, NoteColumn, NoteHead, NoteSpacing, PercentRepeatCounter, PercentRepeat, PhrasingSlur, RepeatSlash, RepeatTieColumn, RepeatTie, Rest, ScriptColumn, Script, Slur, StemTremolo, Stem, StringNumber, StrokeFinger, TextScript, TextSpanner, TieColumn, Tie, TrillPitchAccidental, TrillPitchGroup, TrillPitchHead, TrillSpanner, TupletBracket, TupletNumber and VoiceFollower.

This context sets the following properties:

- Set translator property `localKeySignature` to `'()`.

This context is a ‘bottom’ context; it cannot contain other contexts.

This context is built from the following engraver(s):

> `Skip_event_swallow_translator`

>   Swallow `\skip`.

> `Instrument_switch_engraver`

>   Create a cue text for taking instrument.

>   Properties (read)

>   > `instrumentCueName` (markup)

>   >   The name to print if another instrument is to be taken.

>   This engraver creates the following layout object(s):

>   InstrumentSwitch.

> `Grace_engraver`

>   Set font size and other properties for grace notes.

>   Properties (read)

>   > `graceSettings` (list)

>   >   Overrides for grace notes. This property should be manipulated through the `add-grace-property` function.

> `Tuplet_engraver`

>   Catch tuplet events and generate appropriate bracket.

>   Music types accepted:

>   tuplet-span-event

>   Properties (read)

>   > `tupletFullLength` (boolean)

>   >   If set, the tuplet is printed up to the start of the next note.

>   > `tupletFullLengthNote` (boolean)

>   >   If set, end at the next note, otherwise end on the matter (time signatures, etc.) before the note.

>   This engraver creates the following layout object(s):

>   TupletBracket and TupletNumber.

> `Tie_engraver`

>   Generate ties between note heads of equal pitch.

>   Music types accepted:

>   tie-event

>   Properties (read)

>   > `tieWaitForNote` (boolean)

>   >   If true, tied notes do not have to follow each other directly. This can be used for writing out arpeggios.

>   Properties (write)

>   > `tieMelismaBusy` (boolean)

>   >   Signal whether a tie is present.

>   This engraver creates the following layout object(s):

>   Tie and TieColumn.

> `Slur_engraver`

>   Build slur grobs from slur events.

>   Music types accepted:

>   slur-event

>   Properties (read)

>   > `slurMelismaBusy` (boolean)

>   >   Signal if a slur is present.

>   > `doubleSlurs` (boolean)

>   >   If set, two slurs are created for every slurred note, one above and one below the chord.

>   This engraver creates the following layout object(s):

>   Slur.

> `Cluster_spanner_engraver`

>   Engrave a cluster using `Spanner` notation.

>   Music types accepted:

>   cluster-note-event

>   This engraver creates the following layout object(s):

>   ClusterSpanner and ClusterSpannerBeacon.

> `Phrasing_slur_engraver`

>   Print phrasing slurs. Similar to Slur_engraver.

>   Music types accepted:

>   phrasing-slur-event

>   This engraver creates the following layout object(s):

>   PhrasingSlur.

> `Spanner_break_forbid_engraver`

>   Forbid breaks in certain spanners.

> `Note_spacing_engraver`

>   Generate `NoteSpacing`, an object linking horizontal lines for use in spacing.

>   This engraver creates the following layout object(s):

>   NoteSpacing.

> `Rhythmic_column_engraver`

>   Generate `NoteColumn`, an object that groups stems, note heads, and rests.

>   This engraver creates the following layout object(s):

>   NoteColumn.

> `Script_column_engraver`

>   Find potentially colliding scripts and put them into a `ScriptColumn` object; that will fix the collisions.

>   This engraver creates the following layout object(s):

>   ScriptColumn.

> `Script_engraver`

>   Handle note scripted articulations.

>   Music types accepted:

>   articulation-event

>   Properties (read)

>   > `scriptDefinitions` (list)

>   >   The description of scripts. This is used by the `Script_engraver` for typesetting note-superscripts and subscripts. See ‘`scm/script.scm`’ for more information.

>   This engraver creates the following layout object(s):

>   Script.

> `Bend_engraver`

>   Create fall spanners.

>   Music types accepted:

>   bend-after-event

>   This engraver creates the following layout object(s):

>   BendAfter.

> `Fingering_engraver`

>   Create fingering scripts.

>   Music types accepted:

>   stroke-finger-event and fingering-event

>   This engraver creates the following layout object(s):

>   Fingering.

> `Dynamic_align_engraver`

>   Align hairpins and dynamic texts on a horizontal line

>   Properties (read)

>   > `currentMusicalColumn` (layout object)

>   >   Grob that is X-parent to all non-breakable items (note heads, lyrics, etc.).

>   This engraver creates the following layout object(s):

>   DynamicLineSpanner.

> `New_dynamic_engraver`

>   Create hairpins, dynamic texts, and their vertical alignments. The symbols are collected onto a `DynamicLineSpanner` grob which takes care of vertical positioning.

>   Music types accepted:

>   span-dynamic-event and absolute-dynamic-event

>   Properties (read)

>   > `crescendoSpanner` (symbol)

>   >   The type of spanner to be used for crescendi. Available values are ‘`hairpin`’ and ‘`text`’. If unset, a hairpin crescendo is used.

>   > `crescendoText` (markup)

>   >   The text to print at start of non-hairpin crescendo, i.e., ‘`cresc.`’.

>   > `currentMusicalColumn` (layout object)

>   >   Grob that is X-parent to all non-breakable items (note heads, lyrics, etc.).

>   > `decrescendoSpanner` (symbol)

>   >   The type of spanner to be used for decrescendi. Available values are ‘`hairpin`’ and ‘`text`’. If unset, a hairpin decrescendo is used.

>   > `decrescendoText` (markup)

>   >   The text to print at start of non-hairpin decrescendo, i.e., ‘`dim.`’.

>   This engraver creates the following layout object(s):

>   DynamicText, DynamicTextSpanner and Hairpin.

> `Text_engraver`

>   Create text scripts.

>   Music types accepted:

>   text-script-event

>   This engraver creates the following layout object(s):

>   TextScript.

> `Part_combine_engraver`

>   Part combine engraver for orchestral scores: Print markings ‘a2’, ‘Solo’, ‘Solo II’, and ‘unisono’.

>   Music types accepted:

>   part-combine-event

>   Properties (read)

>   > `printPartCombineTexts` (boolean)

>   >   Set ‘Solo’ and ‘A due’ texts in the part combiner?

>   > `soloText` (markup)

>   >   The text for the start of a solo when part-combining.

>   > `soloIIText` (markup)

>   >   The text for the start of a solo for voice ‘two’ when part-combining.

>   > `aDueText` (markup)

>   >   Text to print at a unisono passage.

>   This engraver creates the following layout object(s):

>   CombineTextScript.

> `Slash_repeat_engraver`

>   Make beat repeats.

>   Music types accepted:

>   percent-event

>   Properties (read)

>   > `measureLength` (moment)

>   >   Length of one measure in the current time signature.

>   This engraver creates the following layout object(s):

>   RepeatSlash.

> `Percent_repeat_engraver`

>   Make whole bar and double bar repeats.

>   Music types accepted:

>   percent-event

>   Properties (read)

>   > `countPercentRepeats` (boolean)

>   >   If set, produce counters for percent repeats.

>   > `currentCommandColumn` (layout object)

>   >   Grob that is X-parent to all current breakable (clef, key signature, etc.) items.

>   > `measureLength` (moment)

>   >   Length of one measure in the current time signature.

>   > `repeatCountVisibility` (procedure)

>   >   A procedure taking as arguments an integer and context, returning whether the corresponding percent repeat number should be printed when `countPercentRepeats` is set.

>   Properties (write)

>   > `forbidBreak` (boolean)

>   >   If set to `##t`, prevent a line break at this point.

>   This engraver creates the following layout object(s):

>   DoublePercentRepeat, DoublePercentRepeatCounter, PercentRepeat and PercentRepeatCounter.

> `Chord_tremolo_engraver`

>   Generate beams for tremolo repeats.

>   Music types accepted:

>   tremolo-span-event

>   This engraver creates the following layout object(s):

>   Beam.

> `New_fingering_engraver`

>   Create fingering scripts for notes in a new chord. This engraver is ill-named, since it also takes care of articulations and harmonic note heads.

>   Properties (read)

>   > `fingeringOrientations` (list)

>   >   A list of symbols, containing ‘`left`’, ‘`right`’, ‘`up`’ and/or ‘`down`’. This list determines where fingerings are put relative to the chord being fingered.

>   > `harmonicDots` (boolean)

>   >   If set, harmonic notes in dotted chords get dots.

>   > `strokeFingerOrientations` (list)

>   >   See `fingeringOrientations`.

>   > `stringNumberOrientations` (list)

>   >   See `fingeringOrientations`.

>   This engraver creates the following layout object(s):

>   Fingering, Script, StringNumber and StrokeFinger.

> `Auto_beam_engraver`

>   Generate beams based on measure characteristics and observed Stems. Uses `beatLength`, `measureLength`, and `measurePosition` to decide when to start and stop a beam. Overriding beaming is done through Stem_engraver properties `stemLeftBeamCount` and `stemRightBeamCount`.

>   Music types accepted:

>   beam-forbid-event

>   Properties (read)

>   > `autoBeaming` (boolean)

>   >   If set to true then beams are generated automatically.

>   > `autoBeamSettings` (list)

>   >   Specifies when automatically generated beams should begin and end. See behavior Setting automatic beam behavior for more information.

>   > `beatLength` (moment)

>   >   The length of one beat in this time signature.

>   > `subdivideBeams` (boolean)

>   >   If set, multiple beams will be subdivided at beat positions by only drawing one beam over the beat.

>   This engraver creates the following layout object(s):

>   Beam.

> `Grace_beam_engraver`

>   Handle `Beam` events by engraving beams. If omitted, then notes are printed with flags instead of beams. Only engraves beams when we are at grace points in time.

>   Music types accepted:

>   beam-event

>   Properties (read)

>   > `beamMelismaBusy` (boolean)

>   >   Signal if a beam is present.

>   > `beatLength` (moment)

>   >   The length of one beat in this time signature.

>   > `subdivideBeams` (boolean)

>   >   If set, multiple beams will be subdivided at beat positions by only drawing one beam over the beat.

>   This engraver creates the following layout object(s):

>   Beam.

> `Beam_engraver`

>   Handle `Beam` events by engraving beams. If omitted, then notes are printed with flags instead of beams.

>   Music types accepted:

>   beam-event

>   Properties (read)

>   > `beamMelismaBusy` (boolean)

>   >   Signal if a beam is present.

>   > `beatLength` (moment)

>   >   The length of one beat in this time signature.

>   > `subdivideBeams` (boolean)

>   >   If set, multiple beams will be subdivided at beat positions by only drawing one beam over the beat.

>   Properties (write)

>   > `forbidBreak` (boolean)

>   >   If set to `##t`, prevent a line break at this point.

>   This engraver creates the following layout object(s):

>   Beam.

> `Stem_engraver`

>   Create stems and single-stem tremolos. It also works together with the beam engraver for overriding beaming.

>   Music types accepted:

>   tremolo-event

>   Properties (read)

>   > `tremoloFlags` (integer)

>   >   The number of tremolo flags to add if no number is specified.

>   > `stemLeftBeamCount` (integer)

>   >   Specify the number of beams to draw on the left side of the next note. Overrides automatic beaming. The value is only used once, and then it is erased.

>   > `stemRightBeamCount` (integer)

>   >   See `stemLeftBeamCount`.

>   This engraver creates the following layout object(s):

>   Stem and StemTremolo.

> `Tweak_engraver`

>   Read the `tweaks` property from the originating event, and set properties.

> `Rest_engraver`

>   Engrave rests.

>   Music types accepted:

>   rest-event

>   Properties (read)

>   > `middleCPosition` (number)

>   >   The place of the middle C, measured in half staff-spaces. Usually determined by looking at `middleCClefPosition` and `middleCOffset`.

>   This engraver creates the following layout object(s):

>   Rest.

> `Dots_engraver`

>   Create Dots objects for rhythmic-head-interfaces.

>   This engraver creates the following layout object(s):

>   Dots.

> `Note_heads_engraver`

>   Generate note heads.

>   Music types accepted:

>   note-event

>   Properties (read)

>   > `middleCPosition` (number)

>   >   The place of the middle C, measured in half staff-spaces. Usually determined by looking at `middleCClefPosition` and `middleCOffset`.

>   > `staffLineLayoutFunction` (procedure)

>   >   Layout of staff lines, `traditional`, or `semitone`.

>   This engraver creates the following layout object(s):

>   NoteHead.

> `Breathing_sign_engraver`

>   Create a breathing sign.

>   Music types accepted:

>   breathing-event

>   This engraver creates the following layout object(s):

>   BreathingSign.

> `Ligature_bracket_engraver`

>   Handle `Ligature_events` by engraving `Ligature` brackets.

>   Music types accepted:

>   ligature-event

>   This engraver creates the following layout object(s):

>   LigatureBracket.

> `Glissando_engraver`

>   Engrave glissandi.

>   Music types accepted:

>   glissando-event

>   This engraver creates the following layout object(s):

>   Glissando.

> `Note_head_line_engraver`

>   Engrave a line between two note heads, for example a glissando. If `followVoice` is set, staff switches also generate a line.

>   Properties (read)

>   > `followVoice` (boolean)

>   >   If set, note heads are tracked across staff switches by a thin line.

>   This engraver creates the following layout object(s):

>   Glissando and VoiceFollower.

> `Repeat_tie_engraver`

>   Create repeat ties.

>   Music types accepted:

>   repeat-tie-event

>   This engraver creates the following layout object(s):

>   RepeatTie and RepeatTieColumn.

> `Laissez_vibrer_engraver`

>   Create laissez vibrer items.

>   Music types accepted:

>   laissez-vibrer-event

>   This engraver creates the following layout object(s):

>   LaissezVibrerTie and LaissezVibrerTieColumn.

> `Forbid_line_break_engraver`

>   Forbid line breaks when note heads are still playing at some point.

>   Properties (read)

>   > `busyGrobs` (list)

>   >   A queue of `(end-moment . GROB)` cons cells. This is for internal (C++) use only. This property contains the grobs which are still busy (e.g. note heads, spanners, etc.).

>   Properties (write)

>   > `forbidBreak` (boolean)

>   >   If set to `##t`, prevent a line break at this point.

> `Grob_pq_engraver`

>   Administrate when certain grobs (e.g., note heads) stop playing.

>   Properties (read)

>   > `busyGrobs` (list)

>   >   A queue of `(end-moment . GROB)` cons cells. This is for internal (C++) use only. This property contains the grobs which are still busy (e.g. note heads, spanners, etc.).

>   Properties (write)

>   > `busyGrobs` (list)

>   >   A queue of `(end-moment . GROB)` cons cells. This is for internal (C++) use only. This property contains the grobs which are still busy (e.g. note heads, spanners, etc.).

> `Trill_spanner_engraver`

>   Create trill spanner from an event.

>   Music types accepted:

>   trill-span-event

>   Properties (read)

>   > `currentCommandColumn` (layout object)

>   >   Grob that is X-parent to all current breakable (clef, key signature, etc.) items.

>   > `currentMusicalColumn` (layout object)

>   >   Grob that is X-parent to all non-breakable items (note heads, lyrics, etc.).

>   This engraver creates the following layout object(s):

>   TrillSpanner.

> `Text_spanner_engraver`

>   Create text spanner from an event.

>   Music types accepted:

>   text-span-event

>   This engraver creates the following layout object(s):

>   TextSpanner.

> `Multi_measure_rest_engraver`

>   Engrave multi-measure rests that are produced with ‘`R`’. It reads `measurePosition` and `internalBarNumber` to determine what number to print over the MultiMeasureRest. Reads `measureLength` to determine whether it should use a whole rest or a breve rest to represent one measure.

>   Music types accepted:

>   multi-measure-text-event and multi-measure-rest-event

>   Properties (read)

>   > `internalBarNumber` (integer)

>   >   Contains the current barnumber. This property is used for internal timekeeping, among others by the `Accidental_engraver`.

>   > `restNumberThreshold` (number)

>   >   If a multimeasure rest has more measures than this, a number is printed.

>   > `breakableSeparationItem` (layout object)

>   >   The breakable items in this time step, for this staff.

>   > `currentCommandColumn` (layout object)

>   >   Grob that is X-parent to all current breakable (clef, key signature, etc.) items.

>   > `measurePosition` (moment)

>   >   How much of the current measure have we had. This can be set manually to create incomplete measures.

>   > `measureLength` (moment)

>   >   Length of one measure in the current time signature.

>   This engraver creates the following layout object(s):

>   MultiMeasureRest, MultiMeasureRestNumber and MultiMeasureRestText.

> `Arpeggio_engraver`

>   Generate an Arpeggio symbol.

>   Music types accepted:

>   arpeggio-event

>   This engraver creates the following layout object(s):

>   Arpeggio.

> `Output_property_engraver`

>   Apply a procedure to any grob acknowledged.

>   Music types accepted:

>   apply-output-event

> `Pitched_trill_engraver`

>   Print the bracketed note head after a note head with trill.

>   This engraver creates the following layout object(s):

>   TrillPitchAccidental, TrillPitchGroup and TrillPitchHead.

> `Font_size_engraver`

>   Put `fontSize` into `font-size` grob property.

>   Properties (read)

>   > `fontSize` (number)

>   >   The relative size of all grobs in a context.

## 2.2 Engravers and Performers

See Modifying context plug-ins.

### 2.2.1 Accidental_engraver

Make accidentals. Catch note heads, ties and notices key-change events. This engraver usually lives at Staff level, but reads the settings for Accidental at `Voice` level, so you can `\override` them at `Voice`.

Properties (read)

> `autoAccidentals` (list)

>   List of different ways to typeset an accidental.

>   For determining when to print an accidental, several different rules are tried. The rule that gives the highest number of accidentals is used.

>   Each entry in the list is either a symbol or a procedure.

>   symbol

>     The symbol is the name of the context in which the following rules are to be applied. For example, if context is Score then all staves share accidentals, and if context is Staff then all voices in the same staff share accidentals, but staves do not.

>   procedure

>     The procedure represents an accidental rule to be applied to the previously specified context.

>     The procedure takes the following arguments:

>     `context`

>       The current context to which the rule should be applied.

>     `pitch`

>       The pitch of the note to be evaluated.

>     `barnum`

>       The current bar number.

>     `measurepos`

>       The current measure position.

>     The procedure returns a pair of booleans. The first states whether an extra natural should be added. The second states whether an accidental should be printed. `(#t . #f)` does not make sense.

> `autoCautionaries` (list)

>   List similar to `autoAccidentals`, but it controls cautionary accidentals rather than normal ones. Both lists are tried, and the one giving the most accidentals wins. In case of draw, a normal accidental is typeset.

> `internalBarNumber` (integer)

>   Contains the current barnumber. This property is used for internal timekeeping, among others by the `Accidental_engraver`.

> `extraNatural` (boolean)

>   Whether to typeset an extra natural sign before accidentals changing from a non-natural to another non-natural.

> `harmonicAccidentals` (boolean)

>   If set, harmonic notes in chords get accidentals.

> `keySignature` (list)

>   The current key signature. This is an alist containing `(step . alter)` or `((octave . step) . alter)`, where step is a number in the range 0 to 6 and alter a fraction, denoting alteration. For alterations, use symbols, e.g. `keySignature = #`((6 . ,FLAT))`.

> `localKeySignature` (list)

>   The key signature at this point in the measure. The format is the same as for `keySignature`, but can also contain `((octave . name) . (alter barnumber . measureposition))` pairs.

Properties (write)

> `localKeySignature` (list)

>   The key signature at this point in the measure. The format is the same as for `keySignature`, but can also contain `((octave . name) . (alter barnumber . measureposition))` pairs.

This engraver creates the following layout object(s):

Accidental, AccidentalCautionary, AccidentalPlacement and AccidentalSuggestion.

`Accidental_engraver` is part of the following context(s): GregorianTranscriptionStaff, MensuralStaff, Staff and VaticanaStaff.

### 2.2.2 Ambitus_engraver

This engraver creates the following layout object(s):

AccidentalPlacement, Ambitus, AmbitusAccidental, AmbitusLine and AmbitusNoteHead.

`Ambitus_engraver` is not part of any context.

### 2.2.3 Arpeggio_engraver

Generate an Arpeggio symbol.

Music types accepted:

arpeggio-event

This engraver creates the following layout object(s):

Arpeggio.

`Arpeggio_engraver` is part of the following context(s): CueVoice, GregorianTranscriptionVoice, MensuralVoice, TabVoice, VaticanaVoice and Voice.

### 2.2.4 Auto_beam_engraver

Generate beams based on measure characteristics and observed Stems. Uses `beatLength`, `measureLength`, and `measurePosition` to decide when to start and stop a beam. Overriding beaming is done through Stem_engraver properties `stemLeftBeamCount` and `stemRightBeamCount`.

Music types accepted:

beam-forbid-event

Properties (read)

> `autoBeaming` (boolean)

>   If set to true then beams are generated automatically.

> `autoBeamSettings` (list)

>   Specifies when automatically generated beams should begin and end. See behavior Setting automatic beam behavior for more information.

> `beatLength` (moment)

>   The length of one beat in this time signature.

> `subdivideBeams` (boolean)

>   If set, multiple beams will be subdivided at beat positions by only drawing one beam over the beat.

This engraver creates the following layout object(s):

Beam.

`Auto_beam_engraver` is part of the following context(s): CueVoice, DrumVoice, GregorianTranscriptionVoice, MensuralVoice, TabVoice, VaticanaVoice and Voice.

### 2.2.5 Axis_group_engraver

Group all objects created in this context in a `VerticalAxisGroup` spanner.

Properties (read)

> `currentCommandColumn` (layout object)

>   Grob that is X-parent to all current breakable (clef, key signature, etc.) items.

This engraver creates the following layout object(s):

VerticalAxisGroup.

`Axis_group_engraver` is part of the following context(s): DrumStaff, FretBoards, GregorianTranscriptionStaff, MensuralStaff, NoteNames, RhythmicStaff, Staff, TabStaff and VaticanaStaff.

### 2.2.6 Balloon_engraver

Create balloon texts.

Music types accepted:

annotate-output-event

This engraver creates the following layout object(s):

BalloonTextItem.

`Balloon_engraver` is not part of any context.

### 2.2.7 Bar_engraver

Create barlines. This engraver is controlled through the `whichBar` property. If it has no bar line to create, it will forbid a linebreak at this point.

Properties (read)

> `whichBar` (string)

>   This property is read to determine what type of bar line to create.

>   Example:

>   >     \set Staff.whichBar = "|:"

>   This will create a start-repeat bar in this staff only. Valid values are described in bar-line-interface.

Properties (write)

> `forbidBreak` (boolean)

>   If set to `##t`, prevent a line break at this point.

This engraver creates the following layout object(s):

BarLine.

`Bar_engraver` is part of the following context(s): DrumStaff, GregorianTranscriptionStaff, MensuralStaff, RhythmicStaff, Staff, TabStaff and VaticanaStaff.

### 2.2.8 Bar_number_engraver

A bar number is created whenever `measurePosition` is zero and when there is a bar line (i.e., when `whichBar` is set). It is put on top of all staves, and appears only at the left side of the staff. The staves are taken from `stavesFound`, which is maintained by Staff_collecting_engraver.

Properties (read)

> `currentBarNumber` (integer)

>   Contains the current barnumber. This property is incremented at every bar line.

> `whichBar` (string)

>   This property is read to determine what type of bar line to create.

>   Example:

>   >     \set Staff.whichBar = "|:"

>   This will create a start-repeat bar in this staff only. Valid values are described in bar-line-interface.

> `stavesFound` (list of grobs)

>   A list of all staff-symbols found.

> `barNumberVisibility` (procedure)

>   A Procedure that takes an integer and returns whether the corresponding bar number should be printed.

This engraver creates the following layout object(s):

BarNumber.

`Bar_number_engraver` is part of the following context(s): Score.

### 2.2.9 Beam_engraver

Handle `Beam` events by engraving beams. If omitted, then notes are printed with flags instead of beams.

Music types accepted:

beam-event

Properties (read)

> `beamMelismaBusy` (boolean)

>   Signal if a beam is present.

> `beatLength` (moment)

>   The length of one beat in this time signature.

> `subdivideBeams` (boolean)

>   If set, multiple beams will be subdivided at beat positions by only drawing one beam over the beat.

Properties (write)

> `forbidBreak` (boolean)

>   If set to `##t`, prevent a line break at this point.

This engraver creates the following layout object(s):

Beam.

`Beam_engraver` is part of the following context(s): CueVoice, DrumVoice, GregorianTranscriptionVoice, MensuralVoice, TabVoice, VaticanaVoice and Voice.

### 2.2.10 Beam_performer

Music types accepted:

beam-event

`Beam_performer` is not part of any context.

### 2.2.11 Bend_engraver

Create fall spanners.

Music types accepted:

bend-after-event

This engraver creates the following layout object(s):

BendAfter.

`Bend_engraver` is part of the following context(s): CueVoice, DrumVoice, GregorianTranscriptionVoice, MensuralVoice, TabVoice, VaticanaVoice and Voice.

### 2.2.12 Break_align_engraver

Align grobs with corresponding `break-align-symbols` into groups, and order the groups according to `breakAlignOrder`. The left edge of the alignment gets a separate group, with a symbol `left-edge`.

This engraver creates the following layout object(s):

BreakAlignGroup, BreakAlignment and LeftEdge.

`Break_align_engraver` is part of the following context(s): Score.

### 2.2.13 Breathing_sign_engraver

Create a breathing sign.

Music types accepted:

breathing-event

This engraver creates the following layout object(s):

BreathingSign.

`Breathing_sign_engraver` is part of the following context(s): CueVoice, DrumVoice, GregorianTranscriptionVoice, MensuralVoice, TabVoice, VaticanaVoice and Voice.

### 2.2.14 Chord_name_engraver

Catch note events and generate the appropriate chordname.

Music types accepted:

note-event

Properties (read)

> `chordChanges` (boolean)

>   Only show changes in chords scheme?

> `chordNameExceptions` (list)

>   An alist of chord exceptions. Contains `(chord . markup)` entries.

> `chordNameFunction` (procedure)

>   The function that converts lists of pitches to chord names.

> `chordNoteNamer` (procedure)

>   A function that converts from a pitch object to a text markup. Used for single pitches.

> `chordRootNamer` (procedure)

>   A function that converts from a pitch object to a text markup. Used for chords.

> `chordNameExceptions` (list)

>   An alist of chord exceptions. Contains `(chord . markup)` entries.

> `majorSevenSymbol` (markup)

>   How should the major 7th be formatted in a chord name?

This engraver creates the following layout object(s):

ChordName.

`Chord_name_engraver` is part of the following context(s): ChordNames.

### 2.2.15 Chord_tremolo_engraver

Generate beams for tremolo repeats.

Music types accepted:

tremolo-span-event

This engraver creates the following layout object(s):

Beam.

`Chord_tremolo_engraver` is part of the following context(s): CueVoice, DrumVoice, GregorianTranscriptionVoice, MensuralVoice, TabVoice, VaticanaVoice and Voice.

### 2.2.16 Clef_engraver

Determine and set reference point for pitches.

Properties (read)

> `clefGlyph` (string)

>   Name of the symbol within the music font.

> `clefOctavation` (integer)

>   Add this much extra octavation. Values of 7 and -7 are common.

> `clefPosition` (number)

>   Where should the center of the clef symbol go, measured in half staff spaces from the center of the staff.

> `explicitClefVisibility` (vector)

>   ‘`break-visibility`’ function for clef changes.

> `forceClef` (boolean)

>   Show clef symbol, even if it has not changed. Only active for the first clef after the property is set, not for the full staff.

This engraver creates the following layout object(s):

Clef and OctavateEight.

`Clef_engraver` is part of the following context(s): DrumStaff, GregorianTranscriptionStaff, MensuralStaff, Staff, TabStaff and VaticanaStaff.

### 2.2.17 Cluster_spanner_engraver

Engrave a cluster using `Spanner` notation.

Music types accepted:

cluster-note-event

This engraver creates the following layout object(s):

ClusterSpanner and ClusterSpannerBeacon.

`Cluster_spanner_engraver` is part of the following context(s): CueVoice, GregorianTranscriptionVoice, MensuralVoice, TabVoice, VaticanaVoice and Voice.

### 2.2.18 Collision_engraver

Collect `NoteColumns`, and as soon as there are two or more, put them in a `NoteCollision` object.

This engraver creates the following layout object(s):

NoteCollision.

`Collision_engraver` is part of the following context(s): DrumStaff, GregorianTranscriptionStaff, MensuralStaff, Staff, TabStaff and VaticanaStaff.

### 2.2.19 Completion_heads_engraver

This engraver replaces `Note_heads_engraver`. It plays some trickery to break long notes and automatically tie them into the next measure.

Music types accepted:

tie-event and note-event

Properties (read)

> `middleCPosition` (number)

>   The place of the middle C, measured in half staff-spaces. Usually determined by looking at `middleCClefPosition` and `middleCOffset`.

> `measurePosition` (moment)

>   How much of the current measure have we had. This can be set manually to create incomplete measures.

> `measureLength` (moment)

>   Length of one measure in the current time signature.

Properties (write)

> `completionBusy` (boolean)

>   Whether a completion-note head is playing.

This engraver creates the following layout object(s):

Dots, NoteHead and Tie.

`Completion_heads_engraver` is not part of any context.

### 2.2.20 Control_track_performer

`Control_track_performer` is not part of any context.

### 2.2.21 Custos_engraver

Engrave custodes.

This engraver creates the following layout object(s):

Custos.

`Custos_engraver` is part of the following context(s): MensuralStaff and VaticanaStaff.

### 2.2.22 Default_bar_line_engraver

This engraver determines what kind of automatic bar lines should be produced, and sets `whichBar` accordingly. It should be at the same level as Timing_translator.

Properties (read)

> `automaticBars` (boolean)

>   If set to false then bar lines will not be printed automatically; they must be explicitly created with a `\bar` command. Unlike the `\cadenzaOn` keyword, measures are still counted. Bar line generation will resume according to that count if this property is unset.

> `barAlways` (boolean)

>   If set to true a bar line is drawn after each note.

> `defaultBarType` (string)

>   Set the default type of bar line. See `whichBar` for information on available bar types.

>   This variable is read by Timing_translator at Score level.

> `measureLength` (moment)

>   Length of one measure in the current time signature.

> `whichBar` (string)

>   This property is read to determine what type of bar line to create.

>   Example:

>   >     \set Staff.whichBar = "|:"

>   This will create a start-repeat bar in this staff only. Valid values are described in bar-line-interface.

> `measurePosition` (moment)

>   How much of the current measure have we had. This can be set manually to create incomplete measures.

Properties (write)

> `automaticBars` (boolean)

>   If set to false then bar lines will not be printed automatically; they must be explicitly created with a `\bar` command. Unlike the `\cadenzaOn` keyword, measures are still counted. Bar line generation will resume according to that count if this property is unset.

`Default_bar_line_engraver` is part of the following context(s): Score.

### 2.2.23 Dot_column_engraver

Engrave dots on dotted notes shifted to the right of the note. If omitted, then dots appear on top of the notes.

This engraver creates the following layout object(s):

DotColumn.

`Dot_column_engraver` is part of the following context(s): DrumStaff, GregorianTranscriptionStaff, MensuralStaff, RhythmicStaff, Staff, TabStaff and VaticanaStaff.

### 2.2.24 Dots_engraver

Create Dots objects for rhythmic-head-interfaces.

This engraver creates the following layout object(s):

Dots.

`Dots_engraver` is part of the following context(s): CueVoice, DrumVoice, GregorianTranscriptionVoice, MensuralVoice, TabVoice, VaticanaVoice and Voice.

### 2.2.25 Drum_note_performer

Play drum notes.

Music types accepted:

note-event

`Drum_note_performer` is not part of any context.

### 2.2.26 Drum_notes_engraver

Generate drum note heads.

Music types accepted:

note-event

Properties (read)

> `drumStyleTable` (hash table)

>   A hash table which maps drums to layout settings. Predefined values: ‘`drums-style`’, ‘`timbales-style`’, ‘`congas-style`’, ‘`bongos-style`’, and ‘`percussion-style`’.

>   The layout style is a hash table, containing the drum-pitches (e.g., the symbol ‘`hihat`’) as keys, and a list `(notehead-style script vertical-position)` as values.

This engraver creates the following layout object(s):

NoteHead and Script.

`Drum_notes_engraver` is part of the following context(s): DrumVoice.

### 2.2.27 Dynamic_align_engraver

Align hairpins and dynamic texts on a horizontal line

Properties (read)

> `currentMusicalColumn` (layout object)

>   Grob that is X-parent to all non-breakable items (note heads, lyrics, etc.).

This engraver creates the following layout object(s):

DynamicLineSpanner.

`Dynamic_align_engraver` is part of the following context(s): CueVoice, DrumVoice, GregorianTranscriptionVoice, MensuralVoice, TabVoice, VaticanaVoice and Voice.

### 2.2.28 Dynamic_engraver

Create hairpins, dynamic texts, and their vertical alignments. The symbols are collected onto a `DynamicLineSpanner` grob which takes care of vertical positioning.

Music types accepted:

span-dynamic-event and absolute-dynamic-event

This engraver creates the following layout object(s):

DynamicLineSpanner, DynamicText, DynamicTextSpanner and Hairpin.

`Dynamic_engraver` is not part of any context.

### 2.2.29 Dynamic_performer

Music types accepted:

absolute-dynamic-event, crescendo-event and decrescendo-event

Properties (read)

> `dynamicAbsoluteVolumeFunction` (procedure)

>   [DOCUMENT-ME]

> `instrumentEqualizer` (procedure)

>   A function taking a string (instrument name), and returning a `(min . max)` pair of numbers for the loudness range of the instrument.

> `midiMaximumVolume` (number)

>   Analogous to `midiMinimumVolume`.

> `midiMinimumVolume` (number)

>   Set the minimum loudness for MIDI. Ranges from 0 to 1.

> `midiInstrument` (string)

>   Name of the MIDI instrument to use.

`Dynamic_performer` is not part of any context.

### 2.2.30 Engraver

Base class for engravers. Does nothing, so it is not used.

`Engraver` is not part of any context.

### 2.2.31 Extender_engraver

Create lyric extenders.

Music types accepted:

extender-event

Properties (read)

> `extendersOverRests` (boolean)

>   Whether to continue extenders as they cross a rest.

This engraver creates the following layout object(s):

LyricExtender.

`Extender_engraver` is part of the following context(s): Lyrics.

### 2.2.32 Figured_bass_engraver

Make figured bass numbers.

Music types accepted:

bass-figure-event and rest-event

Properties (read)

> `figuredBassAlterationDirection` (direction)

>   Where to put alterations relative to the main figure.

> `figuredBassCenterContinuations` (boolean)

>   Whether to vertically center pairs of extender lines. This does not work with three or more lines.

> `figuredBassFormatter` (procedure)

>   A routine generating a markup for a bass figure.

> `implicitBassFigures` (list)

>   A list of bass figures that are not printed as numbers, but only as extender lines.

> `useBassFigureExtenders` (boolean)

>   Whether to use extender lines for repeated bass figures.

> `ignoreFiguredBassRest` (boolean)

>   Don’t swallow rest events.

This engraver creates the following layout object(s):

BassFigure, BassFigureAlignment, BassFigureBracket, BassFigureContinuation and BassFigureLine.

`Figured_bass_engraver` is part of the following context(s): DrumStaff, FiguredBass, GregorianTranscriptionStaff, MensuralStaff, Staff, TabStaff and VaticanaStaff.

### 2.2.33 Figured_bass_position_engraver

Position figured bass alignments over notes.

This engraver creates the following layout object(s):

BassFigureAlignmentPositioning.

`Figured_bass_position_engraver` is part of the following context(s): DrumStaff, GregorianTranscriptionStaff, MensuralStaff, Staff, TabStaff and VaticanaStaff.

### 2.2.34 Fingering_engraver

Create fingering scripts.

Music types accepted:

stroke-finger-event and fingering-event

This engraver creates the following layout object(s):

Fingering.

`Fingering_engraver` is part of the following context(s): CueVoice, GregorianTranscriptionVoice, MensuralVoice, VaticanaVoice and Voice.

### 2.2.35 Font_size_engraver

Put `fontSize` into `font-size` grob property.

Properties (read)

> `fontSize` (number)

>   The relative size of all grobs in a context.

`Font_size_engraver` is part of the following context(s): CueVoice, DrumStaff, DrumVoice, FretBoards, GregorianTranscriptionStaff, GregorianTranscriptionVoice, Lyrics, MensuralStaff, MensuralVoice, RhythmicStaff, Staff, TabStaff, TabVoice, VaticanaStaff, VaticanaVoice and Voice.

### 2.2.36 Forbid_line_break_engraver

Forbid line breaks when note heads are still playing at some point.

Properties (read)

> `busyGrobs` (list)

>   A queue of `(end-moment . GROB)` cons cells. This is for internal (C++) use only. This property contains the grobs which are still busy (e.g. note heads, spanners, etc.).

Properties (write)

> `forbidBreak` (boolean)

>   If set to `##t`, prevent a line break at this point.

`Forbid_line_break_engraver` is part of the following context(s): CueVoice, DrumVoice, GregorianTranscriptionVoice, MensuralVoice, TabVoice, VaticanaVoice and Voice.

### 2.2.37 Fretboard_engraver

Generate one or more tablature noteheads from event of type `NoteEvent`.

Music types accepted:

string-number-event and note-event

Properties (read)

> `stringTunings` (list)

>   The tablature strings tuning. It is a list of the pitch (in semitones) of each string (starting with the lower one).

> `minimumFret` (number)

>   The tablature auto string-selecting mechanism selects the highest string with a fret at least `minimumFret`.

> `maximumFretStretch` (number)

>   Don’t allocate frets further than this from specified frets.

> `tablatureFormat` (procedure)

>   A function formatting a tablature note head. Called with three arguments: string number, context and event. It returns the text as a string.

> `highStringOne` (boolean)

>   Whether the first string is the string with highest pitch on the instrument. This used by the automatic string selector for tablature notation.

> `predefinedDiagramTable` (hash table)

>   The hash table of predefined fret diagrams to use in FretBoards.

This engraver creates the following layout object(s):

FretBoard.

`Fretboard_engraver` is part of the following context(s): FretBoards.

### 2.2.38 Glissando_engraver

Engrave glissandi.

Music types accepted:

glissando-event

This engraver creates the following layout object(s):

Glissando.

`Glissando_engraver` is part of the following context(s): CueVoice, GregorianTranscriptionVoice, MensuralVoice, TabVoice, VaticanaVoice and Voice.

### 2.2.39 Grace_beam_engraver

Handle `Beam` events by engraving beams. If omitted, then notes are printed with flags instead of beams. Only engraves beams when we are at grace points in time.

Music types accepted:

beam-event

Properties (read)

> `beamMelismaBusy` (boolean)

>   Signal if a beam is present.

> `beatLength` (moment)

>   The length of one beat in this time signature.

> `subdivideBeams` (boolean)

>   If set, multiple beams will be subdivided at beat positions by only drawing one beam over the beat.

This engraver creates the following layout object(s):

Beam.

`Grace_beam_engraver` is part of the following context(s): CueVoice, DrumVoice, GregorianTranscriptionVoice, MensuralVoice, TabVoice, VaticanaVoice and Voice.

### 2.2.40 Grace_engraver

Set font size and other properties for grace notes.

Properties (read)

> `graceSettings` (list)

>   Overrides for grace notes. This property should be manipulated through the `add-grace-property` function.

`Grace_engraver` is part of the following context(s): CueVoice, DrumVoice, GregorianTranscriptionVoice, MensuralVoice, TabVoice, VaticanaVoice and Voice.

### 2.2.41 Grace_spacing_engraver

Bookkeeping of shortest starting and playing notes in grace note runs.

Properties (read)

> `currentMusicalColumn` (layout object)

>   Grob that is X-parent to all non-breakable items (note heads, lyrics, etc.).

This engraver creates the following layout object(s):

GraceSpacing.

`Grace_spacing_engraver` is part of the following context(s): Score.

### 2.2.42 Grid_line_span_engraver

This engraver makes cross-staff lines: It catches all normal lines and draws a single span line across them.

This engraver creates the following layout object(s):

GridLine.

`Grid_line_span_engraver` is not part of any context.

### 2.2.43 Grid_point_engraver

Generate grid points.

Properties (read)

> `gridInterval` (moment)

>   Interval for which to generate `GridPoint`s.

This engraver creates the following layout object(s):

GridPoint.

`Grid_point_engraver` is not part of any context.

### 2.2.44 Grob_pq_engraver

Administrate when certain grobs (e.g., note heads) stop playing.

Properties (read)

> `busyGrobs` (list)

>   A queue of `(end-moment . GROB)` cons cells. This is for internal (C++) use only. This property contains the grobs which are still busy (e.g. note heads, spanners, etc.).

Properties (write)

> `busyGrobs` (list)

>   A queue of `(end-moment . GROB)` cons cells. This is for internal (C++) use only. This property contains the grobs which are still busy (e.g. note heads, spanners, etc.).

`Grob_pq_engraver` is part of the following context(s): CueVoice, DrumStaff, DrumVoice, GregorianTranscriptionStaff, GregorianTranscriptionVoice, MensuralStaff, MensuralVoice, Staff, TabStaff, TabVoice, VaticanaStaff, VaticanaVoice and Voice.

### 2.2.45 Hara_kiri_engraver

Like `Axis_group_engraver`, but make a hara-kiri spanner, and add interesting items (i.e., note heads, lyric syllables, and normal rests).

Properties (read)

> `keepAliveInterfaces` (list)

>   A list of symbols, signifying grob interfaces that are worth keeping a staff with `remove-empty` set around for.

This engraver creates the following layout object(s):

VerticalAxisGroup.

`Hara_kiri_engraver` is part of the following context(s): ChordNames, FiguredBass and Lyrics.

### 2.2.46 Horizontal_bracket_engraver

Create horizontal brackets over notes for musical analysis purposes.

Music types accepted:

note-grouping-event

This engraver creates the following layout object(s):

HorizontalBracket.

`Horizontal_bracket_engraver` is not part of any context.

### 2.2.47 Hyphen_engraver

Create lyric hyphens and distance constraints between words.

Music types accepted:

hyphen-event

This engraver creates the following layout object(s):

LyricHyphen and LyricSpace.

`Hyphen_engraver` is part of the following context(s): Lyrics.

### 2.2.48 Instrument_name_engraver

Create a system start text for instrument or vocal names.

Properties (read)

> `currentCommandColumn` (layout object)

>   Grob that is X-parent to all current breakable (clef, key signature, etc.) items.

> `shortInstrumentName` (markup)

>   See `instrument`.

> `instrumentName` (markup)

>   The name to print left of a staff. The `instrument` property labels the staff in the first system, and the `instr` property labels following lines.

> `shortVocalName` (markup)

>   Name of a vocal line, short version.

> `vocalName` (markup)

>   Name of a vocal line.

This engraver creates the following layout object(s):

InstrumentName.

`Instrument_name_engraver` is part of the following context(s): DrumStaff, FretBoards, GregorianTranscriptionStaff, Lyrics, MensuralStaff, PianoStaff, RhythmicStaff, Staff, TabStaff and VaticanaStaff.

### 2.2.49 Instrument_switch_engraver

Create a cue text for taking instrument.

Properties (read)

> `instrumentCueName` (markup)

>   The name to print if another instrument is to be taken.

This engraver creates the following layout object(s):

InstrumentSwitch.

`Instrument_switch_engraver` is part of the following context(s): CueVoice, DrumVoice, GregorianTranscriptionVoice, MensuralVoice, TabVoice, VaticanaVoice and Voice.

### 2.2.50 Key_engraver

Engrave a key signature.

Music types accepted:

key-change-event

Properties (read)

> `createKeyOnClefChange` (boolean)

>   Print a key signature whenever the clef is changed.

> `explicitKeySignatureVisibility` (vector)

>   ‘`break-visibility`’ function for explicit key changes. ‘`\override`’ of the `break-visibility` property will set the visibility for normal (i.e., at the start of the line) key signatures.

> `extraNatural` (boolean)

>   Whether to typeset an extra natural sign before accidentals changing from a non-natural to another non-natural.

> `keyAlterationOrder` (list)

>   An alist that defines in what order alterations should be printed. The format is `(step . alter)`, where step is a number from 0 to 6 and alter from -2 (sharp) to 2 (flat).

> `keySignature` (list)

>   The current key signature. This is an alist containing `(step . alter)` or `((octave . step) . alter)`, where step is a number in the range 0 to 6 and alter a fraction, denoting alteration. For alterations, use symbols, e.g. `keySignature = #`((6 . ,FLAT))`.

> `lastKeySignature` (list)

>   Last key signature before a key signature change.

> `printKeyCancellation` (boolean)

>   Print restoration alterations before a key signature change.

Properties (write)

> `keySignature` (list)

>   The current key signature. This is an alist containing `(step . alter)` or `((octave . step) . alter)`, where step is a number in the range 0 to 6 and alter a fraction, denoting alteration. For alterations, use symbols, e.g. `keySignature = #`((6 . ,FLAT))`.

> `lastKeySignature` (list)

>   Last key signature before a key signature change.

> `tonic` (pitch)

>   The tonic of the current scale.

This engraver creates the following layout object(s):

KeyCancellation and KeySignature.

`Key_engraver` is part of the following context(s): GregorianTranscriptionStaff, MensuralStaff, Staff and VaticanaStaff.

### 2.2.51 Key_performer

Music types accepted:

key-change-event

`Key_performer` is not part of any context.

### 2.2.52 Laissez_vibrer_engraver

Create laissez vibrer items.

Music types accepted:

laissez-vibrer-event

This engraver creates the following layout object(s):

LaissezVibrerTie and LaissezVibrerTieColumn.

`Laissez_vibrer_engraver` is part of the following context(s): CueVoice, DrumVoice, GregorianTranscriptionVoice, MensuralVoice, TabVoice, VaticanaVoice and Voice.

### 2.2.53 Ledger_line_engraver

Create the spanner to draw ledger lines, and notices objects that need ledger lines.

This engraver creates the following layout object(s):

LedgerLineSpanner.

`Ledger_line_engraver` is part of the following context(s): DrumStaff, GregorianTranscriptionStaff, MensuralStaff, RhythmicStaff, Staff, TabStaff and VaticanaStaff.

### 2.2.54 Ligature_bracket_engraver

Handle `Ligature_events` by engraving `Ligature` brackets.

Music types accepted:

ligature-event

This engraver creates the following layout object(s):

LigatureBracket.

`Ligature_bracket_engraver` is part of the following context(s): CueVoice, GregorianTranscriptionVoice, TabVoice and Voice.

### 2.2.55 Lyric_engraver

Engrave text for lyrics.

Music types accepted:

lyric-event

Properties (read)

> `ignoreMelismata` (boolean)

>   Ignore melismata for this Lyrics line.

> `lyricMelismaAlignment` (direction)

>   Alignment to use for a melisma syllable.

This engraver creates the following layout object(s):

LyricText.

`Lyric_engraver` is part of the following context(s): Lyrics.

### 2.2.56 Lyric_performer

Music types accepted:

lyric-event

`Lyric_performer` is not part of any context.

### 2.2.57 Mark_engraver

Create `RehearsalMark` objects. It puts them on top of all staves (which is taken from the property `stavesFound`). If moving this engraver to a different context, Staff_collecting_engraver must move along, otherwise all marks end up on the same Y location.

Music types accepted:

mark-event

Properties (read)

> `markFormatter` (procedure)

>   A procedure taking as arguments the context and the rehearsal mark. It should return the formatted mark as a markup object.

> `rehearsalMark` (integer)

>   The last rehearsal mark printed.

> `stavesFound` (list of grobs)

>   A list of all staff-symbols found.

This engraver creates the following layout object(s):

RehearsalMark.

`Mark_engraver` is part of the following context(s): Score.

### 2.2.58 Measure_grouping_engraver

Create `MeasureGrouping` to indicate beat subdivision.

Properties (read)

> `beatLength` (moment)

>   The length of one beat in this time signature.

> `currentMusicalColumn` (layout object)

>   Grob that is X-parent to all non-breakable items (note heads, lyrics, etc.).

> `measurePosition` (moment)

>   How much of the current measure have we had. This can be set manually to create incomplete measures.

> `beatGrouping` (list)

>   A list of beatgroups, e.g., in 5/8 time `'(2 3)`.

This engraver creates the following layout object(s):

MeasureGrouping.

`Measure_grouping_engraver` is not part of any context.

### 2.2.59 Melody_engraver

Create information for context dependent typesetting decisions.

This engraver creates the following layout object(s):

MelodyItem.

`Melody_engraver` is not part of any context.

### 2.2.60 Mensural_ligature_engraver

Handle `Mensural_ligature_events` by glueing special ligature heads together.

Music types accepted:

ligature-event

This engraver creates the following layout object(s):

MensuralLigature.

`Mensural_ligature_engraver` is part of the following context(s): MensuralVoice.

### 2.2.61 Metronome_mark_engraver

Engrave metronome marking. This delegates the formatting work to the function in the `metronomeMarkFormatter` property. The mark is put over all staves. The staves are taken from the `stavesFound` property, which is maintained by Staff_collecting_engraver.

Properties (read)

> `stavesFound` (list of grobs)

>   A list of all staff-symbols found.

> `metronomeMarkFormatter` (procedure)

>   How to produce a metronome markup. Called with four arguments: text, duration, count and context.

> `tempoUnitDuration` (duration)

>   Unit for specifying tempo.

> `tempoUnitCount` (number)

>   Count for specifying tempo.

> `tempoText` (markup)

>   Text for tempo marks.

> `tempoHideNote` (boolean)

>   Hide the note=count in tempo marks.

This engraver creates the following layout object(s):

MetronomeMark.

`Metronome_mark_engraver` is part of the following context(s): Score.

### 2.2.62 Multi_measure_rest_engraver

Engrave multi-measure rests that are produced with ‘`R`’. It reads `measurePosition` and `internalBarNumber` to determine what number to print over the MultiMeasureRest. Reads `measureLength` to determine whether it should use a whole rest or a breve rest to represent one measure.

Music types accepted:

multi-measure-text-event and multi-measure-rest-event

Properties (read)

> `internalBarNumber` (integer)

>   Contains the current barnumber. This property is used for internal timekeeping, among others by the `Accidental_engraver`.

> `restNumberThreshold` (number)

>   If a multimeasure rest has more measures than this, a number is printed.

> `breakableSeparationItem` (layout object)

>   The breakable items in this time step, for this staff.

> `currentCommandColumn` (layout object)

>   Grob that is X-parent to all current breakable (clef, key signature, etc.) items.

> `measurePosition` (moment)

>   How much of the current measure have we had. This can be set manually to create incomplete measures.

> `measureLength` (moment)

>   Length of one measure in the current time signature.

This engraver creates the following layout object(s):

MultiMeasureRest, MultiMeasureRestNumber and MultiMeasureRestText.

`Multi_measure_rest_engraver` is part of the following context(s): CueVoice, DrumVoice, GregorianTranscriptionVoice, MensuralVoice, TabVoice, VaticanaVoice and Voice.

### 2.2.63 New_dynamic_engraver

Create hairpins, dynamic texts, and their vertical alignments. The symbols are collected onto a `DynamicLineSpanner` grob which takes care of vertical positioning.

Music types accepted:

span-dynamic-event and absolute-dynamic-event

Properties (read)

> `crescendoSpanner` (symbol)

>   The type of spanner to be used for crescendi. Available values are ‘`hairpin`’ and ‘`text`’. If unset, a hairpin crescendo is used.

> `crescendoText` (markup)

>   The text to print at start of non-hairpin crescendo, i.e., ‘`cresc.`’.

> `currentMusicalColumn` (layout object)

>   Grob that is X-parent to all non-breakable items (note heads, lyrics, etc.).

> `decrescendoSpanner` (symbol)

>   The type of spanner to be used for decrescendi. Available values are ‘`hairpin`’ and ‘`text`’. If unset, a hairpin decrescendo is used.

> `decrescendoText` (markup)

>   The text to print at start of non-hairpin decrescendo, i.e., ‘`dim.`’.

This engraver creates the following layout object(s):

DynamicText, DynamicTextSpanner and Hairpin.

`New_dynamic_engraver` is part of the following context(s): CueVoice, DrumVoice, GregorianTranscriptionVoice, MensuralVoice, TabVoice, VaticanaVoice and Voice.

### 2.2.64 New_fingering_engraver

Create fingering scripts for notes in a new chord. This engraver is ill-named, since it also takes care of articulations and harmonic note heads.

Properties (read)

> `fingeringOrientations` (list)

>   A list of symbols, containing ‘`left`’, ‘`right`’, ‘`up`’ and/or ‘`down`’. This list determines where fingerings are put relative to the chord being fingered.

> `harmonicDots` (boolean)

>   If set, harmonic notes in dotted chords get dots.

> `strokeFingerOrientations` (list)

>   See `fingeringOrientations`.

> `stringNumberOrientations` (list)

>   See `fingeringOrientations`.

This engraver creates the following layout object(s):

Fingering, Script, StringNumber and StrokeFinger.

`New_fingering_engraver` is part of the following context(s): CueVoice, GregorianTranscriptionVoice, MensuralVoice, VaticanaVoice and Voice.

### 2.2.65 Note_head_line_engraver

Engrave a line between two note heads, for example a glissando. If `followVoice` is set, staff switches also generate a line.

Properties (read)

> `followVoice` (boolean)

>   If set, note heads are tracked across staff switches by a thin line.

This engraver creates the following layout object(s):

Glissando and VoiceFollower.

`Note_head_line_engraver` is part of the following context(s): CueVoice, GregorianTranscriptionVoice, MensuralVoice, TabVoice, VaticanaVoice and Voice.

### 2.2.66 Note_heads_engraver

Generate note heads.

Music types accepted:

note-event

Properties (read)

> `middleCPosition` (number)

>   The place of the middle C, measured in half staff-spaces. Usually determined by looking at `middleCClefPosition` and `middleCOffset`.

> `staffLineLayoutFunction` (procedure)

>   Layout of staff lines, `traditional`, or `semitone`.

This engraver creates the following layout object(s):

NoteHead.

`Note_heads_engraver` is part of the following context(s): CueVoice, GregorianTranscriptionVoice, MensuralVoice, VaticanaVoice and Voice.

### 2.2.67 Note_name_engraver

Print pitches as words.

Music types accepted:

note-event

Properties (read)

> `printOctaveNames` (boolean)

>   Print octave marks for the `NoteNames` context.

This engraver creates the following layout object(s):

NoteName.

`Note_name_engraver` is part of the following context(s): NoteNames.

### 2.2.68 Note_performer

Music types accepted:

note-event

`Note_performer` is not part of any context.

### 2.2.69 Note_spacing_engraver

Generate `NoteSpacing`, an object linking horizontal lines for use in spacing.

This engraver creates the following layout object(s):

NoteSpacing.

`Note_spacing_engraver` is part of the following context(s): CueVoice, DrumVoice, GregorianTranscriptionVoice, MensuralVoice, TabVoice, VaticanaVoice and Voice.

### 2.2.70 Note_swallow_translator

Swallow notes.

`Note_swallow_translator` is part of the following context(s): FiguredBass.

### 2.2.71 Ottava_spanner_engraver

Create a text spanner when the ottavation property changes.

Properties (read)

> `ottavation` (markup)

>   If set, the text for an ottava spanner. Changing this creates a new text spanner.

> `originalMiddleCPosition` (integer)

>   Used for temporary overriding middle C in octavation brackets.

> `currentMusicalColumn` (layout object)

>   Grob that is X-parent to all non-breakable items (note heads, lyrics, etc.).

This engraver creates the following layout object(s):

OttavaBracket.

`Ottava_spanner_engraver` is part of the following context(s): GregorianTranscriptionStaff, MensuralStaff, Staff, TabStaff and VaticanaStaff.

### 2.2.72 Output_property_engraver

Apply a procedure to any grob acknowledged.

Music types accepted:

apply-output-event

`Output_property_engraver` is part of the following context(s): ChordNames, CueVoice, DrumStaff, DrumVoice, FretBoards, GregorianTranscriptionStaff, GregorianTranscriptionVoice, MensuralStaff, MensuralVoice, RhythmicStaff, Score, Staff, StaffGroup, TabStaff, TabVoice, VaticanaStaff, VaticanaVoice and Voice.

### 2.2.73 Page_turn_engraver

Decide where page turns are allowed to go.

Music types accepted:

break-event

Properties (read)

> `minimumPageTurnLength` (moment)

>   Minimum length of a rest for a page turn to be allowed.

> `minimumRepeatLengthForPageTurn` (moment)

>   Minimum length of a repeated section for a page turn to be allowed within that section.

`Page_turn_engraver` is not part of any context.

### 2.2.74 Paper_column_engraver

Take care of generating columns.

This engraver decides whether a column is breakable. The default is that a column is always breakable. However, every `Bar_engraver` that does not have a barline at a certain point will set `forbidBreaks` in the score context to stop line breaks. In practice, this means that you can make a break point by creating a bar line (assuming that there are no beams or notes that prevent a break point).

Music types accepted:

label-event and break-event

Properties (read)

> `forbidBreak` (boolean)

>   If set to `##t`, prevent a line break at this point.

Properties (write)

> `forbidBreak` (boolean)

>   If set to `##t`, prevent a line break at this point.

> `currentCommandColumn` (layout object)

>   Grob that is X-parent to all current breakable (clef, key signature, etc.) items.

> `currentMusicalColumn` (layout object)

>   Grob that is X-parent to all non-breakable items (note heads, lyrics, etc.).

This engraver creates the following layout object(s):

NonMusicalPaperColumn and PaperColumn.

`Paper_column_engraver` is part of the following context(s): Score.

### 2.2.75 Parenthesis_engraver

Parenthesize objects whose music cause has the `parenthesize` property.

This engraver creates the following layout object(s):

ParenthesesItem.

`Parenthesis_engraver` is part of the following context(s): Score.

### 2.2.76 Part_combine_engraver

Part combine engraver for orchestral scores: Print markings ‘a2’, ‘Solo’, ‘Solo II’, and ‘unisono’.

Music types accepted:

part-combine-event

Properties (read)

> `printPartCombineTexts` (boolean)

>   Set ‘Solo’ and ‘A due’ texts in the part combiner?

> `soloText` (markup)

>   The text for the start of a solo when part-combining.

> `soloIIText` (markup)

>   The text for the start of a solo for voice ‘two’ when part-combining.

> `aDueText` (markup)

>   Text to print at a unisono passage.

This engraver creates the following layout object(s):

CombineTextScript.

`Part_combine_engraver` is part of the following context(s): CueVoice, DrumVoice, GregorianTranscriptionVoice, MensuralVoice, TabVoice, VaticanaVoice and Voice.

### 2.2.77 Percent_repeat_engraver

Make whole bar and double bar repeats.

Music types accepted:

percent-event

Properties (read)

> `countPercentRepeats` (boolean)

>   If set, produce counters for percent repeats.

> `currentCommandColumn` (layout object)

>   Grob that is X-parent to all current breakable (clef, key signature, etc.) items.

> `measureLength` (moment)

>   Length of one measure in the current time signature.

> `repeatCountVisibility` (procedure)

>   A procedure taking as arguments an integer and context, returning whether the corresponding percent repeat number should be printed when `countPercentRepeats` is set.

Properties (write)

> `forbidBreak` (boolean)

>   If set to `##t`, prevent a line break at this point.

This engraver creates the following layout object(s):

DoublePercentRepeat, DoublePercentRepeatCounter, PercentRepeat and PercentRepeatCounter.

`Percent_repeat_engraver` is part of the following context(s): CueVoice, DrumVoice, GregorianTranscriptionVoice, MensuralVoice, TabVoice, VaticanaVoice and Voice.

### 2.2.78 Phrasing_slur_engraver

Print phrasing slurs. Similar to Slur_engraver.

Music types accepted:

phrasing-slur-event

This engraver creates the following layout object(s):

PhrasingSlur.

`Phrasing_slur_engraver` is part of the following context(s): CueVoice, DrumVoice, GregorianTranscriptionVoice, MensuralVoice, TabVoice, VaticanaVoice and Voice.

### 2.2.79 Piano_pedal_align_engraver

Align piano pedal symbols and brackets.

Properties (read)

> `currentCommandColumn` (layout object)

>   Grob that is X-parent to all current breakable (clef, key signature, etc.) items.

This engraver creates the following layout object(s):

SostenutoPedalLineSpanner, SustainPedalLineSpanner and UnaCordaPedalLineSpanner.

`Piano_pedal_align_engraver` is part of the following context(s): DrumStaff, GregorianTranscriptionStaff, MensuralStaff, Staff, TabStaff and VaticanaStaff.

### 2.2.80 Piano_pedal_engraver

Engrave piano pedal symbols and brackets.

Music types accepted:

una-corda-event, sustain-event and sostenuto-event

Properties (read)

> `currentCommandColumn` (layout object)

>   Grob that is X-parent to all current breakable (clef, key signature, etc.) items.

> `pedalSostenutoStrings` (list)

>   See `pedalSustainStrings`.

> `pedalSostenutoStyle` (symbol)

>   See `pedalSustainStyle`.

> `pedalSustainStrings` (list)

>   A list of strings to print for sustain-pedal. Format is `(up updown down)`, where each of the three is the string to print when this is done with the pedal.

> `pedalSustainStyle` (symbol)

>   A symbol that indicates how to print sustain pedals: `text`, `bracket` or `mixed` (both).

> `pedalUnaCordaStrings` (list)

>   See `pedalSustainStrings`.

> `pedalUnaCordaStyle` (symbol)

>   See `pedalSustainStyle`.

This engraver creates the following layout object(s):

PianoPedalBracket, SostenutoPedal, SustainPedal and UnaCordaPedal.

`Piano_pedal_engraver` is part of the following context(s): GregorianTranscriptionStaff, MensuralStaff, Staff, TabStaff and VaticanaStaff.

### 2.2.81 Piano_pedal_performer

Music types accepted:

una-corda-event, sustain-event and sostenuto-event

`Piano_pedal_performer` is not part of any context.

### 2.2.82 Pitch_squash_engraver

Set the vertical position of note heads to `squashedPosition`, if that property is set. This can be used to make a single-line staff demonstrating the rhythm of a melody.

Properties (read)

> `squashedPosition` (integer)

>   Vertical position of squashing for Pitch_squash_engraver.

`Pitch_squash_engraver` is part of the following context(s): RhythmicStaff.

### 2.2.83 Pitched_trill_engraver

Print the bracketed note head after a note head with trill.

This engraver creates the following layout object(s):

TrillPitchAccidental, TrillPitchGroup and TrillPitchHead.

`Pitched_trill_engraver` is part of the following context(s): CueVoice, DrumVoice, GregorianTranscriptionVoice, MensuralVoice, TabVoice, VaticanaVoice and Voice.

### 2.2.84 Repeat_acknowledge_engraver

Acknowledge repeated music, and convert the contents of `repeatCommands` into an appropriate setting for `whichBar`.

Properties (read)

> `doubleRepeatType` (string)

>   Set the default bar line for double repeats.

> `repeatCommands` (list)

>   This property is a list of commands of the form `(list 'volta x)`, where x is a string or `#f`. `'end-repeat` is also accepted as a command.

> `whichBar` (string)

>   This property is read to determine what type of bar line to create.

>   Example:

>   >     \set Staff.whichBar = "|:"

>   This will create a start-repeat bar in this staff only. Valid values are described in bar-line-interface.

`Repeat_acknowledge_engraver` is part of the following context(s): Score.

### 2.2.85 Repeat_tie_engraver

Create repeat ties.

Music types accepted:

repeat-tie-event

This engraver creates the following layout object(s):

RepeatTie and RepeatTieColumn.

`Repeat_tie_engraver` is part of the following context(s): CueVoice, DrumVoice, GregorianTranscriptionVoice, MensuralVoice, TabVoice, VaticanaVoice and Voice.

### 2.2.86 Rest_collision_engraver

Handle collisions of rests.

Properties (read)

> `busyGrobs` (list)

>   A queue of `(end-moment . GROB)` cons cells. This is for internal (C++) use only. This property contains the grobs which are still busy (e.g. note heads, spanners, etc.).

This engraver creates the following layout object(s):

RestCollision.

`Rest_collision_engraver` is part of the following context(s): DrumStaff, GregorianTranscriptionStaff, MensuralStaff, Staff, TabStaff and VaticanaStaff.

### 2.2.87 Rest_engraver

Engrave rests.

Music types accepted:

rest-event

Properties (read)

> `middleCPosition` (number)

>   The place of the middle C, measured in half staff-spaces. Usually determined by looking at `middleCClefPosition` and `middleCOffset`.

This engraver creates the following layout object(s):

Rest.

`Rest_engraver` is part of the following context(s): CueVoice, DrumVoice, GregorianTranscriptionVoice, MensuralVoice, TabVoice, VaticanaVoice and Voice.

### 2.2.88 Rest_swallow_translator

Swallow rest.

`Rest_swallow_translator` is part of the following context(s): ChordNames and NoteNames.

### 2.2.89 Rhythmic_column_engraver

Generate `NoteColumn`, an object that groups stems, note heads, and rests.

This engraver creates the following layout object(s):

NoteColumn.

`Rhythmic_column_engraver` is part of the following context(s): CueVoice, DrumVoice, GregorianTranscriptionVoice, MensuralVoice, TabVoice, VaticanaVoice and Voice.

### 2.2.90 Script_column_engraver

Find potentially colliding scripts and put them into a `ScriptColumn` object; that will fix the collisions.

This engraver creates the following layout object(s):

ScriptColumn.

`Script_column_engraver` is part of the following context(s): CueVoice, DrumVoice, GregorianTranscriptionVoice, MensuralVoice, TabVoice, VaticanaVoice and Voice.

### 2.2.91 Script_engraver

Handle note scripted articulations.

Music types accepted:

articulation-event

Properties (read)

> `scriptDefinitions` (list)

>   The description of scripts. This is used by the `Script_engraver` for typesetting note-superscripts and subscripts. See ‘`scm/script.scm`’ for more information.

This engraver creates the following layout object(s):

Script.

`Script_engraver` is part of the following context(s): CueVoice, DrumVoice, GregorianTranscriptionVoice, MensuralVoice, TabVoice, VaticanaVoice and Voice.

### 2.2.92 Script_row_engraver

Determine order in horizontal side position elements.

This engraver creates the following layout object(s):

ScriptRow.

`Script_row_engraver` is part of the following context(s): DrumStaff, GregorianTranscriptionStaff, MensuralStaff, Staff, TabStaff and VaticanaStaff.

### 2.2.93 Separating_line_group_engraver

Generate objects for computing spacing parameters.

Properties (read)

> `createSpacing` (boolean)

>   Create `StaffSpacing` objects? Should be set for staves.

Properties (write)

> `hasStaffSpacing` (boolean)

>   True if the current `CommandColumn` contains items that will affect spacing.

This engraver creates the following layout object(s):

StaffSpacing.

`Separating_line_group_engraver` is part of the following context(s): ChordNames, DrumStaff, FiguredBass, FretBoards, GregorianTranscriptionStaff, MensuralStaff, NoteNames, RhythmicStaff, Staff, TabStaff and VaticanaStaff.

### 2.2.94 Skip_event_swallow_translator

Swallow `\skip`.

`Skip_event_swallow_translator` is part of the following context(s): ChordNames, CueVoice, DrumVoice, FiguredBass, GregorianTranscriptionVoice, Lyrics, MensuralVoice, NoteNames, TabVoice, VaticanaVoice and Voice.

### 2.2.95 Slash_repeat_engraver

Make beat repeats.

Music types accepted:

percent-event

Properties (read)

> `measureLength` (moment)

>   Length of one measure in the current time signature.

This engraver creates the following layout object(s):

RepeatSlash.

`Slash_repeat_engraver` is part of the following context(s): CueVoice, DrumVoice, GregorianTranscriptionVoice, MensuralVoice, TabVoice, VaticanaVoice and Voice.

### 2.2.96 Slur_engraver

Build slur grobs from slur events.

Music types accepted:

slur-event

Properties (read)

> `slurMelismaBusy` (boolean)

>   Signal if a slur is present.

> `doubleSlurs` (boolean)

>   If set, two slurs are created for every slurred note, one above and one below the chord.

This engraver creates the following layout object(s):

Slur.

`Slur_engraver` is part of the following context(s): CueVoice, DrumVoice, GregorianTranscriptionVoice, TabVoice and Voice.

### 2.2.97 Slur_performer

Music types accepted:

slur-event

`Slur_performer` is not part of any context.

### 2.2.98 Spacing_engraver

Make a `SpacingSpanner` and do bookkeeping of shortest starting and playing notes.

Music types accepted:

spacing-section-event

Properties (read)

> `currentMusicalColumn` (layout object)

>   Grob that is X-parent to all non-breakable items (note heads, lyrics, etc.).

> `currentCommandColumn` (layout object)

>   Grob that is X-parent to all current breakable (clef, key signature, etc.) items.

> `proportionalNotationDuration` (moment)

>   Global override for shortest-playing duration. This is used for switching on proportional notation.

This engraver creates the following layout object(s):

SpacingSpanner.

`Spacing_engraver` is part of the following context(s): Score.

### 2.2.99 Span_arpeggio_engraver

Make arpeggios that span multiple staves.

Properties (read)

> `connectArpeggios` (boolean)

>   If set, connect arpeggios across piano staff.

This engraver creates the following layout object(s):

Arpeggio.

`Span_arpeggio_engraver` is part of the following context(s): GrandStaff, PianoStaff and StaffGroup.

### 2.2.100 Span_bar_engraver

Make cross-staff bar lines: It catches all normal bar lines and draws a single span bar across them.

This engraver creates the following layout object(s):

SpanBar.

`Span_bar_engraver` is part of the following context(s): GrandStaff, PianoStaff and StaffGroup.

### 2.2.101 Spanner_break_forbid_engraver

Forbid breaks in certain spanners.

`Spanner_break_forbid_engraver` is part of the following context(s): CueVoice, DrumVoice, GregorianTranscriptionVoice, MensuralVoice, TabVoice, VaticanaVoice and Voice.

### 2.2.102 Staff_collecting_engraver

Maintain the `stavesFound` variable.

Properties (read)

> `stavesFound` (list of grobs)

>   A list of all staff-symbols found.

Properties (write)

> `stavesFound` (list of grobs)

>   A list of all staff-symbols found.

`Staff_collecting_engraver` is part of the following context(s): DrumStaff, GregorianTranscriptionStaff, MensuralStaff, Score, Staff, TabStaff and VaticanaStaff.

### 2.2.103 Staff_performer

`Staff_performer` is not part of any context.

### 2.2.104 Staff_symbol_engraver

Create the constellation of five (default) staff lines.

Music types accepted:

staff-span-event

This engraver creates the following layout object(s):

StaffSymbol.

`Staff_symbol_engraver` is part of the following context(s): DrumStaff, GregorianTranscriptionStaff, MensuralStaff, RhythmicStaff, Staff, TabStaff and VaticanaStaff.

### 2.2.105 Stanza_number_align_engraver

This engraver ensures that stanza numbers are neatly aligned.

`Stanza_number_align_engraver` is part of the following context(s): Score.

### 2.2.106 Stanza_number_engraver

Engrave stanza numbers.

Properties (read)

> `stanza` (markup)

>   Stanza ‘number’ to print before the start of a verse. Use in `Lyrics` context.

This engraver creates the following layout object(s):

StanzaNumber.

`Stanza_number_engraver` is part of the following context(s): Lyrics.

### 2.2.107 Stem_engraver

Create stems and single-stem tremolos. It also works together with the beam engraver for overriding beaming.

Music types accepted:

tremolo-event

Properties (read)

> `tremoloFlags` (integer)

>   The number of tremolo flags to add if no number is specified.

> `stemLeftBeamCount` (integer)

>   Specify the number of beams to draw on the left side of the next note. Overrides automatic beaming. The value is only used once, and then it is erased.

> `stemRightBeamCount` (integer)

>   See `stemLeftBeamCount`.

This engraver creates the following layout object(s):

Stem and StemTremolo.

`Stem_engraver` is part of the following context(s): CueVoice, DrumVoice, GregorianTranscriptionVoice, MensuralVoice, TabVoice and Voice.

### 2.2.108 String_number_engraver

Swallow string number events. The purpose of this engraver is to process tablatures for normal notation. To provent warnings for unprocessed string number events to obscure real error messages, this engraver swallows them all.

`String_number_engraver` is part of the following context(s): GregorianTranscriptionStaff, MensuralStaff, Staff and VaticanaStaff.

### 2.2.109 Swallow_engraver

This engraver swallows everything given to it silently. The purpose of this is to prevent spurious ‘event junked’ warnings.

`Swallow_engraver` is part of the following context(s): Devnull.

### 2.2.110 Swallow_performer

`Swallow_performer` is not part of any context.

### 2.2.111 System_start_delimiter_engraver

Create a system start delimiter (i.e., a `SystemStartBar`, `SystemStartBrace`, `SystemStartBracket` or `SystemStartSquare` spanner).

Properties (read)

> `systemStartDelimiter` (symbol)

>   Which grob to make for the start of the system/staff? Set to `SystemStartBrace`, `SystemStartBracket` or `SystemStartBar`.

> `systemStartDelimiterHierarchy` (pair)

>   A nested list, indicating the nesting of a start delimiters.

> `currentCommandColumn` (layout object)

>   Grob that is X-parent to all current breakable (clef, key signature, etc.) items.

This engraver creates the following layout object(s):

SystemStartBar, SystemStartBrace, SystemStartBracket and SystemStartSquare.

`System_start_delimiter_engraver` is part of the following context(s): ChoirStaff, GrandStaff, PianoStaff, Score and StaffGroup.

### 2.2.112 Tab_harmonic_engraver

In a tablature, parenthesize objects whose music cause has the `parenthesize` property.

This engraver creates the following layout object(s):

HarmonicParenthesesItem.

`Tab_harmonic_engraver` is part of the following context(s): TabVoice.

### 2.2.113 Tab_note_heads_engraver

Generate one or more tablature noteheads from event of type `NoteEvent`.

Music types accepted:

string-number-event and note-event

Properties (read)

> `middleCPosition` (number)

>   The place of the middle C, measured in half staff-spaces. Usually determined by looking at `middleCClefPosition` and `middleCOffset`.

> `stringTunings` (list)

>   The tablature strings tuning. It is a list of the pitch (in semitones) of each string (starting with the lower one).

> `minimumFret` (number)

>   The tablature auto string-selecting mechanism selects the highest string with a fret at least `minimumFret`.

> `tablatureFormat` (procedure)

>   A function formatting a tablature note head. Called with three arguments: string number, context and event. It returns the text as a string.

> `highStringOne` (boolean)

>   Whether the first string is the string with highest pitch on the instrument. This used by the automatic string selector for tablature notation.

> `stringOneTopmost` (boolean)

>   Whether the first string is printed on the top line of the tablature.

This engraver creates the following layout object(s):

TabNoteHead.

`Tab_note_heads_engraver` is part of the following context(s): TabVoice.

### 2.2.114 Tab_staff_symbol_engraver

Create a tablature staff symbol, but look at `stringTunings` for the number of lines.

Properties (read)

> `stringTunings` (list)

>   The tablature strings tuning. It is a list of the pitch (in semitones) of each string (starting with the lower one).

This engraver creates the following layout object(s):

StaffSymbol.

`Tab_staff_symbol_engraver` is part of the following context(s): TabStaff.

### 2.2.115 Tempo_performer

Properties (read)

> `tempoWholesPerMinute` (moment)

>   The tempo in whole notes per minute.

`Tempo_performer` is not part of any context.

### 2.2.116 Text_engraver

Create text scripts.

Music types accepted:

text-script-event

This engraver creates the following layout object(s):

TextScript.

`Text_engraver` is part of the following context(s): CueVoice, DrumVoice, GregorianTranscriptionVoice, MensuralVoice, TabVoice, VaticanaVoice and Voice.

### 2.2.117 Text_spanner_engraver

Create text spanner from an event.

Music types accepted:

text-span-event

This engraver creates the following layout object(s):

TextSpanner.

`Text_spanner_engraver` is part of the following context(s): CueVoice, DrumVoice, GregorianTranscriptionVoice, MensuralVoice, TabVoice, VaticanaVoice and Voice.

### 2.2.118 Tie_engraver

Generate ties between note heads of equal pitch.

Music types accepted:

tie-event

Properties (read)

> `tieWaitForNote` (boolean)

>   If true, tied notes do not have to follow each other directly. This can be used for writing out arpeggios.

Properties (write)

> `tieMelismaBusy` (boolean)

>   Signal whether a tie is present.

This engraver creates the following layout object(s):

Tie and TieColumn.

`Tie_engraver` is part of the following context(s): CueVoice, DrumVoice, GregorianTranscriptionVoice, MensuralVoice, NoteNames, TabVoice, VaticanaVoice and Voice.

### 2.2.119 Tie_performer

Generate ties between note heads of equal pitch.

Music types accepted:

tie-event

Properties (read)

> `tieMelismaBusy` (boolean)

>   Signal whether a tie is present.

`Tie_performer` is not part of any context.

### 2.2.120 Time_signature_engraver

Create a TimeSignature whenever `timeSignatureFraction` changes.

Properties (read)

> `implicitTimeSignatureVisibility` (vector)

>   break visibility for the default time signature.

> `timeSignatureFraction` (pair of numbers)

>   A pair of numbers, signifying the time signature. For example, `#'(4 . 4)` is a 4/4 time signature.

This engraver creates the following layout object(s):

TimeSignature.

`Time_signature_engraver` is part of the following context(s): DrumStaff, GregorianTranscriptionStaff, MensuralStaff, RhythmicStaff, Staff and TabStaff.

### 2.2.121 Time_signature_performer

`Time_signature_performer` is not part of any context.

### 2.2.122 Timing_translator

This engraver adds the alias `Timing` to its containing context. Responsible for synchronizing timing information from staves. Normally in `Score`. In order to create polyrhythmic music, this engraver should be removed from `Score` and placed in `Staff`.

Properties (read)

> `internalBarNumber` (integer)

>   Contains the current barnumber. This property is used for internal timekeeping, among others by the `Accidental_engraver`.

> `currentBarNumber` (integer)

>   Contains the current barnumber. This property is incremented at every bar line.

> `measureLength` (moment)

>   Length of one measure in the current time signature.

> `measurePosition` (moment)

>   How much of the current measure have we had. This can be set manually to create incomplete measures.

Properties (write)

> `internalBarNumber` (integer)

>   Contains the current barnumber. This property is used for internal timekeeping, among others by the `Accidental_engraver`.

> `currentBarNumber` (integer)

>   Contains the current barnumber. This property is incremented at every bar line.

> `measurePosition` (moment)

>   How much of the current measure have we had. This can be set manually to create incomplete measures.

`Timing_translator` is part of the following context(s): Score.

### 2.2.123 Translator

Base class. Not instantiated.

`Translator` is not part of any context.

### 2.2.124 Trill_spanner_engraver

Create trill spanner from an event.

Music types accepted:

trill-span-event

Properties (read)

> `currentCommandColumn` (layout object)

>   Grob that is X-parent to all current breakable (clef, key signature, etc.) items.

> `currentMusicalColumn` (layout object)

>   Grob that is X-parent to all non-breakable items (note heads, lyrics, etc.).

This engraver creates the following layout object(s):

TrillSpanner.

`Trill_spanner_engraver` is part of the following context(s): CueVoice, DrumVoice, GregorianTranscriptionVoice, MensuralVoice, TabVoice, VaticanaVoice and Voice.

### 2.2.125 Tuplet_engraver

Catch tuplet events and generate appropriate bracket.

Music types accepted:

tuplet-span-event

Properties (read)

> `tupletFullLength` (boolean)

>   If set, the tuplet is printed up to the start of the next note.

> `tupletFullLengthNote` (boolean)

>   If set, end at the next note, otherwise end on the matter (time signatures, etc.) before the note.

This engraver creates the following layout object(s):

TupletBracket and TupletNumber.

`Tuplet_engraver` is part of the following context(s): CueVoice, DrumVoice, GregorianTranscriptionVoice, MensuralVoice, TabVoice, VaticanaVoice and Voice.

### 2.2.126 Tweak_engraver

Read the `tweaks` property from the originating event, and set properties.

`Tweak_engraver` is part of the following context(s): CueVoice, DrumVoice, GregorianTranscriptionVoice, MensuralVoice, TabVoice, VaticanaVoice and Voice.

### 2.2.127 Vaticana_ligature_engraver

Handle ligatures by glueing special ligature heads together.

Music types accepted:

ligature-event and pes-or-flexa-event

This engraver creates the following layout object(s):

DotColumn and VaticanaLigature.

`Vaticana_ligature_engraver` is part of the following context(s): VaticanaVoice.

### 2.2.128 Vertical_align_engraver

Catch groups (staves, lyrics lines, etc.) and stack them vertically.

Properties (read)

> `alignAboveContext` (string)

>   Where to insert newly created context in vertical alignment.

> `alignBelowContext` (string)

>   Where to insert newly created context in vertical alignment.

This engraver creates the following layout object(s):

VerticalAlignment.

`Vertical_align_engraver` is part of the following context(s): Score.

### 2.2.129 Vertically_spaced_contexts_engraver

Properties (read)

> `verticallySpacedContexts` (list)

>   List of symbols, containing context names whose vertical axis groups should be taken into account for vertical spacing of systems.

Properties (write)

> `verticallySpacedContexts` (list)

>   List of symbols, containing context names whose vertical axis groups should be taken into account for vertical spacing of systems.

`Vertically_spaced_contexts_engraver` is part of the following context(s): Score.

### 2.2.130 Volta_engraver

Make volta brackets.

Properties (read)

> `repeatCommands` (list)

>   This property is a list of commands of the form `(list 'volta x)`, where x is a string or `#f`. `'end-repeat` is also accepted as a command.

> `voltaSpannerDuration` (moment)

>   This specifies the maximum duration to use for the brackets printed for `\alternative`. This can be used to shrink the length of brackets in the situation where one alternative is very large.

> `stavesFound` (list of grobs)

>   A list of all staff-symbols found.

This engraver creates the following layout object(s):

VoltaBracket and VoltaBracketSpanner.

`Volta_engraver` is part of the following context(s): Score.

## 2.3 Tunable context properties

`aDueText` (markup)

  Text to print at a unisono passage.

`alignAboveContext` (string)

  Where to insert newly created context in vertical alignment.

`alignBassFigureAccidentals` (boolean)

  If true, then the accidentals are aligned in bass figure context.

`alignBelowContext` (string)

  Where to insert newly created context in vertical alignment.

`associatedVoice` (string)

  Name of the `Voice` that has the melody for this `Lyrics` line.

`autoAccidentals` (list)

  List of different ways to typeset an accidental.

  For determining when to print an accidental, several different rules are tried. The rule that gives the highest number of accidentals is used.

  Each entry in the list is either a symbol or a procedure.

  symbol

    The symbol is the name of the context in which the following rules are to be applied. For example, if context is Score then all staves share accidentals, and if context is Staff then all voices in the same staff share accidentals, but staves do not.

  procedure

    The procedure represents an accidental rule to be applied to the previously specified context.

    The procedure takes the following arguments:

    `context`

      The current context to which the rule should be applied.

    `pitch`

      The pitch of the note to be evaluated.

    `barnum`

      The current bar number.

    `measurepos`

      The current measure position.

    The procedure returns a pair of booleans. The first states whether an extra natural should be added. The second states whether an accidental should be printed. `(#t . #f)` does not make sense.

`autoBeamCheck` (procedure)

  A procedure taking three arguments, context, dir [start/stop (-1 or 1)], and test [shortest note in the beam]. A non-`#f` return value starts or stops the auto beam.

`autoBeamSettings` (list)

  Specifies when automatically generated beams should begin and end. See behavior Setting automatic beam behavior for more information.

`autoBeaming` (boolean)

  If set to true then beams are generated automatically.

`autoCautionaries` (list)

  List similar to `autoAccidentals`, but it controls cautionary accidentals rather than normal ones. Both lists are tried, and the one giving the most accidentals wins. In case of draw, a normal accidental is typeset.

`automaticBars` (boolean)

  If set to false then bar lines will not be printed automatically; they must be explicitly created with a `\bar` command. Unlike the `\cadenzaOn` keyword, measures are still counted. Bar line generation will resume according to that count if this property is unset.

`barAlways` (boolean)

  If set to true a bar line is drawn after each note.

`barCheckSynchronize` (boolean)

  If true then reset `measurePosition` when finding a bar check.

`barNumberVisibility` (procedure)

  A Procedure that takes an integer and returns whether the corresponding bar number should be printed.

`bassFigureFormatFunction` (procedure)

  A procedure that is called to produce the formatting for a `BassFigure` grob. It takes a list of `BassFigureEvent`s, a context, and the grob to format.

`bassStaffProperties` (list)

  An alist of property settings to apply for the down staff of `PianoStaff`. Used by `\autochange`.

`beatGrouping` (list)

  A list of beatgroups, e.g., in 5/8 time `'(2 3)`.

`beatLength` (moment)

  The length of one beat in this time signature.

`chordChanges` (boolean)

  Only show changes in chords scheme?

`chordNameExceptions` (list)

  An alist of chord exceptions. Contains `(chord . markup)` entries.

`chordNameExceptionsFull` (list)

  An alist of full chord exceptions. Contains `(chord . markup)` entries.

`chordNameExceptionsPartial` (list)

  An alist of partial chord exceptions. Contains `(chord . (prefix-markup suffix-markup))` entries.

`chordNameFunction` (procedure)

  The function that converts lists of pitches to chord names.

`chordNameSeparator` (markup)

  The markup object used to separate parts of a chord name.

`chordNoteNamer` (procedure)

  A function that converts from a pitch object to a text markup. Used for single pitches.

`chordPrefixSpacer` (number)

  The space added between the root symbol and the prefix of a chord name.

`chordRootNamer` (procedure)

  A function that converts from a pitch object to a text markup. Used for chords.

`clefGlyph` (string)

  Name of the symbol within the music font.

`clefOctavation` (integer)

  Add this much extra octavation. Values of 7 and -7 are common.

`clefPosition` (number)

  Where should the center of the clef symbol go, measured in half staff spaces from the center of the staff.

`completionBusy` (boolean)

  Whether a completion-note head is playing.

`connectArpeggios` (boolean)

  If set, connect arpeggios across piano staff.

`countPercentRepeats` (boolean)

  If set, produce counters for percent repeats.

`createKeyOnClefChange` (boolean)

  Print a key signature whenever the clef is changed.

`createSpacing` (boolean)

  Create `StaffSpacing` objects? Should be set for staves.

`crescendoSpanner` (symbol)

  The type of spanner to be used for crescendi. Available values are ‘`hairpin`’ and ‘`text`’. If unset, a hairpin crescendo is used.

`crescendoText` (markup)

  The text to print at start of non-hairpin crescendo, i.e., ‘`cresc.`’.

`currentBarNumber` (integer)

  Contains the current barnumber. This property is incremented at every bar line.

`decrescendoSpanner` (symbol)

  The type of spanner to be used for decrescendi. Available values are ‘`hairpin`’ and ‘`text`’. If unset, a hairpin decrescendo is used.

`decrescendoText` (markup)

  The text to print at start of non-hairpin decrescendo, i.e., ‘`dim.`’.

`defaultBarType` (string)

  Set the default type of bar line. See `whichBar` for information on available bar types.

  This variable is read by Timing_translator at Score level.

`doubleRepeatType` (string)

  Set the default bar line for double repeats.

`doubleSlurs` (boolean)

  If set, two slurs are created for every slurred note, one above and one below the chord.

`drumPitchTable` (hash table)

  A table mapping percussion instruments (symbols) to pitches.

`drumStyleTable` (hash table)

  A hash table which maps drums to layout settings. Predefined values: ‘`drums-style`’, ‘`timbales-style`’, ‘`congas-style`’, ‘`bongos-style`’, and ‘`percussion-style`’.

  The layout style is a hash table, containing the drum-pitches (e.g., the symbol ‘`hihat`’) as keys, and a list `(notehead-style script vertical-position)` as values.

`explicitClefVisibility` (vector)

  ‘`break-visibility`’ function for clef changes.

`explicitKeySignatureVisibility` (vector)

  ‘`break-visibility`’ function for explicit key changes. ‘`\override`’ of the `break-visibility` property will set the visibility for normal (i.e., at the start of the line) key signatures.

`extendersOverRests` (boolean)

  Whether to continue extenders as they cross a rest.

`extraNatural` (boolean)

  Whether to typeset an extra natural sign before accidentals changing from a non-natural to another non-natural.

`figuredBassAlterationDirection` (direction)

  Where to put alterations relative to the main figure.

`figuredBassCenterContinuations` (boolean)

  Whether to vertically center pairs of extender lines. This does not work with three or more lines.

`figuredBassFormatter` (procedure)

  A routine generating a markup for a bass figure.

`figuredBassPlusDirection` (direction)

  Where to put plus signs relative to the main figure.

`fingeringOrientations` (list)

  A list of symbols, containing ‘`left`’, ‘`right`’, ‘`up`’ and/or ‘`down`’. This list determines where fingerings are put relative to the chord being fingered.

`firstClef` (boolean)

  If true, create a new clef when starting a staff.

`followVoice` (boolean)

  If set, note heads are tracked across staff switches by a thin line.

`fontSize` (number)

  The relative size of all grobs in a context.

`forbidBreak` (boolean)

  If set to `##t`, prevent a line break at this point.

`forceClef` (boolean)

  Show clef symbol, even if it has not changed. Only active for the first clef after the property is set, not for the full staff.

`gridInterval` (moment)

  Interval for which to generate `GridPoint`s.

`harmonicAccidentals` (boolean)

  If set, harmonic notes in chords get accidentals.

`harmonicDots` (boolean)

  If set, harmonic notes in dotted chords get dots.

`highStringOne` (boolean)

  Whether the first string is the string with highest pitch on the instrument. This used by the automatic string selector for tablature notation.

`ignoreBarChecks` (boolean)

  Ignore bar checks.

`ignoreFiguredBassRest` (boolean)

  Don’t swallow rest events.

`ignoreMelismata` (boolean)

  Ignore melismata for this Lyrics line.

`implicitBassFigures` (list)

  A list of bass figures that are not printed as numbers, but only as extender lines.

`implicitTimeSignatureVisibility` (vector)

  break visibility for the default time signature.

`instrumentCueName` (markup)

  The name to print if another instrument is to be taken.

`instrumentEqualizer` (procedure)

  A function taking a string (instrument name), and returning a `(min . max)` pair of numbers for the loudness range of the instrument.

`instrumentName` (markup)

  The name to print left of a staff. The `instrument` property labels the staff in the first system, and the `instr` property labels following lines.

`instrumentTransposition` (pitch)

  Define the transposition of the instrument. Its value is the pitch that sounds like middle C. This is used to transpose the MIDI output, and `\quote`s.

`internalBarNumber` (integer)

  Contains the current barnumber. This property is used for internal timekeeping, among others by the `Accidental_engraver`.

`keepAliveInterfaces` (list)

  A list of symbols, signifying grob interfaces that are worth keeping a staff with `remove-empty` set around for.

`keyAlterationOrder` (list)

  An alist that defines in what order alterations should be printed. The format is `(step . alter)`, where step is a number from 0 to 6 and alter from -2 (sharp) to 2 (flat).

`keySignature` (list)

  The current key signature. This is an alist containing `(step . alter)` or `((octave . step) . alter)`, where step is a number in the range 0 to 6 and alter a fraction, denoting alteration. For alterations, use symbols, e.g. `keySignature = #`((6 . ,FLAT))`.

`lyricMelismaAlignment` (direction)

  Alignment to use for a melisma syllable.

`majorSevenSymbol` (markup)

  How should the major 7th be formatted in a chord name?

`markFormatter` (procedure)

  A procedure taking as arguments the context and the rehearsal mark. It should return the formatted mark as a markup object.

`maximumFretStretch` (number)

  Don’t allocate frets further than this from specified frets.

`measureLength` (moment)

  Length of one measure in the current time signature.

`measurePosition` (moment)

  How much of the current measure have we had. This can be set manually to create incomplete measures.

`melismaBusyProperties` (list)

  A list of properties (symbols) to determine whether a melisma is playing. Setting this property will influence how lyrics are aligned to notes. For example, if set to `#'(melismaBusy beamMelismaBusy)`, only manual melismata and manual beams are considered. Possible values include `melismaBusy`, `slurMelismaBusy`, `tieMelismaBusy`, and `beamMelismaBusy`.

`metronomeMarkFormatter` (procedure)

  How to produce a metronome markup. Called with four arguments: text, duration, count and context.

`middleCClefPosition` (number)

  The position of the middle C, as determined only by the clef. This can be calculated by looking at `clefPosition` and `clefGlyph`.

`middleCOffset` (number)

  The offset of middle C from the position given by `middleCClefPosition` This is used for ottava brackets.

`middleCPosition` (number)

  The place of the middle C, measured in half staff-spaces. Usually determined by looking at `middleCClefPosition` and `middleCOffset`.

`midiInstrument` (string)

  Name of the MIDI instrument to use.

`midiMaximumVolume` (number)

  Analogous to `midiMinimumVolume`.

`midiMinimumVolume` (number)

  Set the minimum loudness for MIDI. Ranges from 0 to 1.

`minimumFret` (number)

  The tablature auto string-selecting mechanism selects the highest string with a fret at least `minimumFret`.

`minimumPageTurnLength` (moment)

  Minimum length of a rest for a page turn to be allowed.

`minimumRepeatLengthForPageTurn` (moment)

  Minimum length of a repeated section for a page turn to be allowed within that section.

`noteToFretFunction` (procedure)

  How to produce a fret diagram. Parameters: A list of note events and a list of tabstring events.

`ottavation` (markup)

  If set, the text for an ottava spanner. Changing this creates a new text spanner.

`output` (unknown)

  The output produced by a score-level translator during music interpretation.

`pedalSostenutoStrings` (list)

  See `pedalSustainStrings`.

`pedalSostenutoStyle` (symbol)

  See `pedalSustainStyle`.

`pedalSustainStrings` (list)

  A list of strings to print for sustain-pedal. Format is `(up updown down)`, where each of the three is the string to print when this is done with the pedal.

`pedalSustainStyle` (symbol)

  A symbol that indicates how to print sustain pedals: `text`, `bracket` or `mixed` (both).

`pedalUnaCordaStrings` (list)

  See `pedalSustainStrings`.

`pedalUnaCordaStyle` (symbol)

  See `pedalSustainStyle`.

`predefinedDiagramTable` (hash table)

  The hash table of predefined fret diagrams to use in FretBoards.

`printKeyCancellation` (boolean)

  Print restoration alterations before a key signature change.

`printOctaveNames` (boolean)

  Print octave marks for the `NoteNames` context.

`printPartCombineTexts` (boolean)

  Set ‘Solo’ and ‘A due’ texts in the part combiner?

`proportionalNotationDuration` (moment)

  Global override for shortest-playing duration. This is used for switching on proportional notation.

`recordEventSequence` (procedure)

  When `Recording_group_engraver` is in this context, then upon termination of the context, this function is called with current context and a list of music objects. The list of contains entries with start times, music objects and whether they are processed in this context.

`rehearsalMark` (integer)

  The last rehearsal mark printed.

`repeatCommands` (list)

  This property is a list of commands of the form `(list 'volta x)`, where x is a string or `#f`. `'end-repeat` is also accepted as a command.

`repeatCountVisibility` (procedure)

  A procedure taking as arguments an integer and context, returning whether the corresponding percent repeat number should be printed when `countPercentRepeats` is set.

`restNumberThreshold` (number)

  If a multimeasure rest has more measures than this, a number is printed.

`shapeNoteStyles` (vector)

  Vector of symbols, listing style for each note head relative to the tonic (qv.) of the scale.

`shortInstrumentName` (markup)

  See `instrument`.

`shortVocalName` (markup)

  Name of a vocal line, short version.

`skipBars` (boolean)

  If set to true, then skip the empty bars that are produced by multimeasure notes and rests. These bars will not appear on the printed output. If not set (the default), multimeasure notes and rests expand into their full length, printing the appropriate number of empty bars so that synchronization with other voices is preserved.

  >     {
  >       r1 r1*3 R1*3
  >       \set Score.skipBars= ##t
  >       r1*3 R1*3
  >     }

`skipTypesetting` (boolean)

  If true, no typesetting is done, speeding up the interpretation phase. Useful for debugging large scores.

`soloIIText` (markup)

  The text for the start of a solo for voice ‘two’ when part-combining.

`soloText` (markup)

  The text for the start of a solo when part-combining.

`squashedPosition` (integer)

  Vertical position of squashing for Pitch_squash_engraver.

`staffLineLayoutFunction` (procedure)

  Layout of staff lines, `traditional`, or `semitone`.

`stanza` (markup)

  Stanza ‘number’ to print before the start of a verse. Use in `Lyrics` context.

`stemLeftBeamCount` (integer)

  Specify the number of beams to draw on the left side of the next note. Overrides automatic beaming. The value is only used once, and then it is erased.

`stemRightBeamCount` (integer)

  See `stemLeftBeamCount`.

`stringNumberOrientations` (list)

  See `fingeringOrientations`.

`stringOneTopmost` (boolean)

  Whether the first string is printed on the top line of the tablature.

`stringTunings` (list)

  The tablature strings tuning. It is a list of the pitch (in semitones) of each string (starting with the lower one).

`strokeFingerOrientations` (list)

  See `fingeringOrientations`.

`subdivideBeams` (boolean)

  If set, multiple beams will be subdivided at beat positions by only drawing one beam over the beat.

`suggestAccidentals` (boolean)

  If set, accidentals are typeset as cautionary suggestions over the note.

`systemStartDelimiter` (symbol)

  Which grob to make for the start of the system/staff? Set to `SystemStartBrace`, `SystemStartBracket` or `SystemStartBar`.

`systemStartDelimiterHierarchy` (pair)

  A nested list, indicating the nesting of a start delimiters.

`tablatureFormat` (procedure)

  A function formatting a tablature note head. Called with three arguments: string number, context and event. It returns the text as a string.

`tempoHideNote` (boolean)

  Hide the note=count in tempo marks.

`tempoText` (markup)

  Text for tempo marks.

`tempoUnitCount` (number)

  Count for specifying tempo.

`tempoUnitDuration` (duration)

  Unit for specifying tempo.

`tempoWholesPerMinute` (moment)

  The tempo in whole notes per minute.

`tieWaitForNote` (boolean)

  If true, tied notes do not have to follow each other directly. This can be used for writing out arpeggios.

`timeSignatureFraction` (pair of numbers)

  A pair of numbers, signifying the time signature. For example, `#'(4 . 4)` is a 4/4 time signature.

`timing` (boolean)

  Keep administration of measure length, position, bar number, etc.? Switch off for cadenzas.

`tonic` (pitch)

  The tonic of the current scale.

`trebleStaffProperties` (list)

  An alist of property settings to apply for the up staff of `PianoStaff`. Used by `\autochange`.

`tremoloFlags` (integer)

  The number of tremolo flags to add if no number is specified.

`tupletFullLength` (boolean)

  If set, the tuplet is printed up to the start of the next note.

`tupletFullLengthNote` (boolean)

  If set, end at the next note, otherwise end on the matter (time signatures, etc.) before the note.

`tupletSpannerDuration` (moment)

  Normally, a tuplet bracket is as wide as the `\times` expression that gave rise to it. By setting this property, you can make brackets last shorter.

  >     {
  >       \set tupletSpannerDuration = #(ly:make-moment 1 4)
  >       \times 2/3 { c8 c c c c c }
  >     }

`useBassFigureExtenders` (boolean)

  Whether to use extender lines for repeated bass figures.

`verticallySpacedContexts` (list)

  List of symbols, containing context names whose vertical axis groups should be taken into account for vertical spacing of systems.

`vocalName` (markup)

  Name of a vocal line.

`voltaSpannerDuration` (moment)

  This specifies the maximum duration to use for the brackets printed for `\alternative`. This can be used to shrink the length of brackets in the situation where one alternative is very large.

`whichBar` (string)

  This property is read to determine what type of bar line to create.

  Example:

  >     \set Staff.whichBar = "|:"

  This will create a start-repeat bar in this staff only. Valid values are described in bar-line-interface.

## 2.4 Internal context properties

`associatedVoiceContext` (context)

  The context object of the `Voice` that has the melody for this `Lyrics`.

`barCheckLastFail` (moment)

  Where in the measure did the last barcheck fail?

`beamMelismaBusy` (boolean)

  Signal if a beam is present.

`breakableSeparationItem` (layout object)

  The breakable items in this time step, for this staff.

`busyGrobs` (list)

  A queue of `(end-moment . GROB)` cons cells. This is for internal (C++) use only. This property contains the grobs which are still busy (e.g. note heads, spanners, etc.).

`currentCommandColumn` (layout object)

  Grob that is X-parent to all current breakable (clef, key signature, etc.) items.

`currentMusicalColumn` (layout object)

  Grob that is X-parent to all non-breakable items (note heads, lyrics, etc.).

`dynamicAbsoluteVolumeFunction` (procedure)

  [DOCUMENT-ME]

`finalizations` (list)

  A list of expressions to evaluate before proceeding to next time step. This is an internal variable.

`graceSettings` (list)

  Overrides for grace notes. This property should be manipulated through the `add-grace-property` function.

`hasStaffSpacing` (boolean)

  True if the current `CommandColumn` contains items that will affect spacing.

`instrumentSupport` (list of grobs)

  A list of grobs to attach the instrument name to.

`lastKeySignature` (list)

  Last key signature before a key signature change.

`localKeySignature` (list)

  The key signature at this point in the measure. The format is the same as for `keySignature`, but can also contain `((octave . name) . (alter barnumber . measureposition))` pairs.

`melismaBusy` (boolean)

  Signifies whether a melisma is active. This can be used to signal melismas on top of those automatically detected.

`originalMiddleCPosition` (integer)

  Used for temporary overriding middle C in octavation brackets.

`quotedEventTypes` (list)

  A list of symbols, representing the event types that should be duplicated for `\quote` commands.

`rootSystem` (layout object)

  The System object.

`scriptDefinitions` (list)

  The description of scripts. This is used by the `Script_engraver` for typesetting note-superscripts and subscripts. See ‘`scm/script.scm`’ for more information.

`slurMelismaBusy` (boolean)

  Signal if a slur is present.

`stavesFound` (list of grobs)

  A list of all staff-symbols found.

`tieMelismaBusy` (boolean)

  Signal whether a tie is present.

# 3. Backend

## 3.1 All layout objects

### 3.1.1 Accidental

Accidental objects are created by: Accidental_engraver.

Standard settings:

> `avoid-slur` (symbol):

>   `'inside`

>   Method of handling slur collisions. Choices are `around`, `inside`, `outside`. If unset, scripts and slurs ignore each other. `around` only moves the script if there is a collision; `outside` always moves the script.

> `glyph-name-alist` (list):

>   `'((0 . accidentals.natural) (-1/2 . accidentals.flat) (1/2 . accidentals.sharp) (1 . accidentals.doublesharp) (-1 . accidentals.flatflat) (3/4 . accidentals.sharp.slashslash.stemstemstem) (1/4 . accidentals.sharp.slashslash.stem) (-1/4 . accidentals.mirroredflat) (-3/4 . accidentals.mirroredflat.flat))`

>   An alist of key-string pairs.

> `alteration` (number):

>   `accidental-interface::calc-alteration`

>   Alteration numbers for accidental.

> `stencil` (unknown):

>   `ly:accidental-interface::print`

>   The symbol to print.

> `Y-extent` (pair of numbers):

>   `ly:accidental-interface::height`

>   Hard coded extent in Y direction.

> `X-extent` (pair of numbers):

>   `ly:accidental-interface::width`

>   Hard coded extent in X direction.

This object supports the following interface(s): item-interface, font-interface, accidental-interface and grob-interface.

### 3.1.2 AccidentalCautionary

AccidentalCautionary objects are created by: Accidental_engraver.

Standard settings:

> `avoid-slur` (symbol):

>   `'inside`

>   Method of handling slur collisions. Choices are `around`, `inside`, `outside`. If unset, scripts and slurs ignore each other. `around` only moves the script if there is a collision; `outside` always moves the script.

> `parenthesized` (boolean):

>   `#t`

>   Parenthesize this grob.

> `glyph-name-alist` (list):

>   `'((0 . accidentals.natural) (-1/2 . accidentals.flat) (1/2 . accidentals.sharp) (1 . accidentals.doublesharp) (-1 . accidentals.flatflat) (3/4 . accidentals.sharp.slashslash.stemstemstem) (1/4 . accidentals.sharp.slashslash.stem) (-1/4 . accidentals.mirroredflat) (-3/4 . accidentals.mirroredflat.flat))`

>   An alist of key-string pairs.

> `alteration` (number):

>   `accidental-interface::calc-alteration`

>   Alteration numbers for accidental.

> `stencil` (unknown):

>   `ly:accidental-interface::print`

>   The symbol to print.

> `Y-extent` (pair of numbers):

>   `ly:accidental-interface::height`

>   Hard coded extent in Y direction.

This object supports the following interface(s): item-interface, font-interface, accidental-interface and grob-interface.

### 3.1.3 AccidentalPlacement

AccidentalPlacement objects are created by: Accidental_engraver and Ambitus_engraver.

Standard settings:

> `left-padding` (dimension, in staff space):

>   `0.2`

>   The amount of space that is put left to an object (e.g., a group of accidentals).

> `script-priority` (number):

>   `-100`

>   A sorting key that determines in what order a script is within a stack of scripts.

> `direction` (direction):

>   `-1`

>   If `side-axis` is `0` (or `#X`), then this property determines whether the object is placed `#LEFT`, `#CENTER` or `#RIGHT` with respect to the other object. Otherwise, it determines whether the object is placed `#UP`, `#CENTER` or `#DOWN`. Numerical values may also be used: `#UP`=`1`, `#DOWN`=`-1`, `#LEFT`=`-1`, `#RIGHT`=`1`, `#CENTER`=`0`.

> `X-extent` (pair of numbers):

>   `ly:axis-group-interface::width`

>   Hard coded extent in X direction.

> `right-padding` (dimension, in staff space):

>   `0.15`

>   Space to insert on the right side of an object (e.g., between note and its accidentals).

This object supports the following interface(s): item-interface, accidental-placement-interface and grob-interface.

### 3.1.4 AccidentalSuggestion

AccidentalSuggestion objects are created by: Accidental_engraver.

Standard settings:

> `stencil` (unknown):

>   `ly:accidental-interface::print`

>   The symbol to print.

> `X-extent` (pair of numbers):

>   `ly:accidental-interface::width`

>   Hard coded extent in X direction.

> `Y-extent` (pair of numbers):

>   `ly:accidental-interface::height`

>   Hard coded extent in Y direction.

> `X-offset` (number):

>   `#<simple-closure (#<primitive-generic +> #<simple-closure (#<primitive-procedure ly:self-alignment-interface::centered-on-x-parent>) > #<simple-closure (#<primitive-procedure ly:self-alignment-interface::x-aligned-on-self>) >) >`

>   The horizontal amount that this object is moved relative to its X-parent.

> `self-alignment-X` (number):

>   `0`

>   Specify alignment of an object. The value `-1` means left aligned, `0` centered, and `1` right-aligned in X direction. Other numerical values may also be specified.

> `font-size` (number):

>   `-2`

>   The font size, compared to the ‘normal’ size. `0` is style-sheet’s normal size, `-1` is smaller, `+1` is bigger. Each step of 1 is approximately 12% larger; 6 steps are exactly a factor 2 larger. Fractional values are allowed.

> `glyph-name-alist` (list):

>   `'((0 . accidentals.natural) (-1/2 . accidentals.flat) (1/2 . accidentals.sharp) (1 . accidentals.doublesharp) (-1 . accidentals.flatflat) (3/4 . accidentals.sharp.slashslash.stemstemstem) (1/4 . accidentals.sharp.slashslash.stem) (-1/4 . accidentals.mirroredflat) (-3/4 . accidentals.mirroredflat.flat))`

>   An alist of key-string pairs.

> `alteration` (number):

>   `accidental-interface::calc-alteration`

>   Alteration numbers for accidental.

> `Y-offset` (number):

>   `ly:side-position-interface::y-aligned-side`

>   The vertical amount that this object is moved relative to its Y-parent.

> `direction` (direction):

>   `1`

>   If `side-axis` is `0` (or `#X`), then this property determines whether the object is placed `#LEFT`, `#CENTER` or `#RIGHT` with respect to the other object. Otherwise, it determines whether the object is placed `#UP`, `#CENTER` or `#DOWN`. Numerical values may also be used: `#UP`=`1`, `#DOWN`=`-1`, `#LEFT`=`-1`, `#RIGHT`=`1`, `#CENTER`=`0`.

> `staff-padding` (dimension, in staff space):

>   `0.25`

>   Maintain this much space between reference points and the staff. Its effect is to align objects of differing sizes (like the dynamics p and f) on their baselines.

> `outside-staff-priority` (number):

>   `0`

>   If set, the grob is positioned outside the staff in such a way as to avoid all collisions. In case of a potential collision, the grob with the smaller `outside-staff-priority` is closer to the staff.

> `script-priority` (number):

>   `0`

>   A sorting key that determines in what order a script is within a stack of scripts.

> `side-axis` (number):

>   `1`

>   If the value is `#X` (or equivalently `0`), the object is placed horizontally next to the other object. If the value is `#Y` or `1`, it is placed vertically.

This object supports the following interface(s): side-position-interface, self-alignment-interface, script-interface, item-interface, font-interface, accidental-suggestion-interface, accidental-interface and grob-interface.

### 3.1.5 Ambitus

Ambitus objects are created by: Ambitus_engraver.

Standard settings:

> `axes` (list):

>   `'(0 1)`

>   List of axis numbers. In the case of alignment grobs, this should contain only one number.

> `X-extent` (pair of numbers):

>   `ly:axis-group-interface::width`

>   Hard coded extent in X direction.

> `Y-extent` (pair of numbers):

>   `ly:axis-group-interface::height`

>   Hard coded extent in Y direction.

> `space-alist` (list):

>   `'((clef extra-space . 0.5) (key-signature extra-space . 0.0) (staff-bar extra-space . 0.0) (time-signature extra-space . 0.0) (first-note fixed-space . 0.0))`

>   A table that specifies distances between prefatory items, like clef and time-signature. The format is an alist of spacing tuples: `(break-align-symbol type . distance)`, where type can be the symbols `minimum-space` or `extra-space`.

> `non-musical` (boolean):

>   `#t`

>   True if the grob belongs to a `NonMusicalPaperColumn`.

> `break-align-symbol` (symbol):

>   `'ambitus`

>   This key is used for aligning and spacing breakable items.

> `break-visibility` (vector):

>   `#(#f #f #t)`

>   A vector of 3 booleans, `#(end-of-line unbroken begin-of-line)`. `#t` means visible, `#f` means killed.

This object supports the following interface(s): item-interface, break-aligned-interface, axis-group-interface, ambitus-interface and grob-interface.

### 3.1.6 AmbitusAccidental

AmbitusAccidental objects are created by: Ambitus_engraver.

Standard settings:

> `font-family` (symbol):

>   `'music`

>   The font family is the broadest category for selecting text fonts. Options include: `sans`, `roman`.

> `padding` (dimension, in staff space):

>   `0.5`

>   Add this much extra space between objects that are next to each other.

> `X-offset` (number):

>   `ly:side-position-interface::x-aligned-side`

>   The horizontal amount that this object is moved relative to its X-parent.

> `direction` (direction):

>   `-1`

>   If `side-axis` is `0` (or `#X`), then this property determines whether the object is placed `#LEFT`, `#CENTER` or `#RIGHT` with respect to the other object. Otherwise, it determines whether the object is placed `#UP`, `#CENTER` or `#DOWN`. Numerical values may also be used: `#UP`=`1`, `#DOWN`=`-1`, `#LEFT`=`-1`, `#RIGHT`=`1`, `#CENTER`=`0`.

> `stencil` (unknown):

>   `ly:accidental-interface::print`

>   The symbol to print.

> `Y-extent` (pair of numbers):

>   `ly:accidental-interface::height`

>   Hard coded extent in Y direction.

> `glyph-name-alist` (list):

>   `'((0 . accidentals.natural) (-1/2 . accidentals.flat) (1/2 . accidentals.sharp) (1 . accidentals.doublesharp) (-1 . accidentals.flatflat) (3/4 . accidentals.sharp.slashslash.stemstemstem) (1/4 . accidentals.sharp.slashslash.stem) (-1/4 . accidentals.mirroredflat) (-3/4 . accidentals.mirroredflat.flat))`

>   An alist of key-string pairs.

> `side-axis` (number):

>   `0`

>   If the value is `#X` (or equivalently `0`), the object is placed horizontally next to the other object. If the value is `#Y` or `1`, it is placed vertically.

This object supports the following interface(s): side-position-interface, item-interface, font-interface, break-aligned-interface, accidental-interface and grob-interface.

### 3.1.7 AmbitusLine

AmbitusLine objects are created by: Ambitus_engraver.

Standard settings:

> `stencil` (unknown):

>   `ly:ambitus::print`

>   The symbol to print.

> `thickness` (number):

>   `2`

>   Line thickness, generally measured in `line-thickness`.

> `X-offset` (number):

>   `ly:self-alignment-interface::centered-on-x-parent`

>   The horizontal amount that this object is moved relative to its X-parent.

This object supports the following interface(s): staff-symbol-referencer-interface, item-interface, font-interface, ambitus-interface and grob-interface.

### 3.1.8 AmbitusNoteHead

AmbitusNoteHead objects are created by: Ambitus_engraver.

Standard settings:

> `duration-log` (integer):

>   `2`

>   The 2-log of the note head duration, i.e., `0` = whole note, `1` = half note, etc.

> `stencil` (unknown):

>   `ly:note-head::print`

>   The symbol to print.

> `Y-offset` (number):

>   `ly:staff-symbol-referencer::callback`

>   The vertical amount that this object is moved relative to its Y-parent.

This object supports the following interface(s): staff-symbol-referencer-interface, rhythmic-head-interface, note-head-interface, ledgered-interface, item-interface, font-interface, ambitus-interface and grob-interface.

### 3.1.9 Arpeggio

Arpeggio objects are created by: Arpeggio_engraver and Span_arpeggio_engraver.

Standard settings:

> `X-extent` (pair of numbers):

>   `ly:arpeggio::width`

>   Hard coded extent in X direction.

> `stencil` (unknown):

>   `ly:arpeggio::print`

>   The symbol to print.

> `Y-offset` (number):

>   `ly:staff-symbol-referencer::callback`

>   The vertical amount that this object is moved relative to its Y-parent.

> `X-offset` (number):

>   `ly:side-position-interface::x-aligned-side`

>   The horizontal amount that this object is moved relative to its X-parent.

> `direction` (direction):

>   `-1`

>   If `side-axis` is `0` (or `#X`), then this property determines whether the object is placed `#LEFT`, `#CENTER` or `#RIGHT` with respect to the other object. Otherwise, it determines whether the object is placed `#UP`, `#CENTER` or `#DOWN`. Numerical values may also be used: `#UP`=`1`, `#DOWN`=`-1`, `#LEFT`=`-1`, `#RIGHT`=`1`, `#CENTER`=`0`.

> `positions` (pair of numbers):

>   `ly:arpeggio::calc-positions`

>   Pair of staff coordinates `(left . right)`, where both left and right are in `staff-space` units of the current staff. For slurs, this value selects which slur candidate to use; if extreme positions are requested, the closest one is taken.

> `padding` (dimension, in staff space):

>   `0.5`

>   Add this much extra space between objects that are next to each other.

> `script-priority` (number):

>   `0`

>   A sorting key that determines in what order a script is within a stack of scripts.

> `side-axis` (number):

>   `0`

>   If the value is `#X` (or equivalently `0`), the object is placed horizontally next to the other object. If the value is `#Y` or `1`, it is placed vertically.

> `staff-position` (number):

>   `0.0`

>   Vertical position, measured in half staff spaces, counted from the middle line.

> `Y-extent` (pair of numbers):

>   `ly:arpeggio::height`

>   Hard coded extent in Y direction.

This object supports the following interface(s): staff-symbol-referencer-interface, side-position-interface, item-interface, font-interface, arpeggio-interface and grob-interface.

### 3.1.10 BalloonTextItem

BalloonTextItem objects are created by: Balloon_engraver.

Standard settings:

> `stencil` (unknown):

>   `ly:balloon-interface::print`

>   The symbol to print.

> `text` (markup):

>   `#<procedure #f (grob)>`

>   Text markup. See Formatting text.

> `X-offset` (number):

>   `#<procedure #f (grob)>`

>   The horizontal amount that this object is moved relative to its X-parent.

> `Y-offset` (number):

>   `#<procedure #f (grob)>`

>   The vertical amount that this object is moved relative to its Y-parent.

This object supports the following interface(s): text-interface, item-interface, font-interface, balloon-interface and grob-interface.

### 3.1.11 BarLine

BarLine objects are created by: Bar_engraver.

Standard settings:

> `break-align-symbol` (symbol):

>   `'staff-bar`

>   This key is used for aligning and spacing breakable items.

> `break-align-anchor` (number):

>   `ly:bar-line::calc-anchor`

>   Grobs aligned to this break-align grob will have their X-offsets shifted by this number. In bar lines, for example, this is used to position grobs relative to the (visual) center of the bar line.

> `glyph` (string):

>   `"|"`

>   A string determining what ‘style’ of glyph is typeset. Valid choices depend on the function that is reading this property.

> `gap` (dimension, in staff space):

>   `0.4`

>   Size of a gap in a variable symbol.

> `layer` (integer):

>   `0`

>   The output layer (a value between 0 and 2): Layers define the order of printing objects. Objects in lower layers are overprinted by objects in higher layers.

> `break-visibility` (vector):

>   `bar-line::calc-break-visibility`

>   A vector of 3 booleans, `#(end-of-line unbroken begin-of-line)`. `#t` means visible, `#f` means killed.

> `non-musical` (boolean):

>   `#t`

>   True if the grob belongs to a `NonMusicalPaperColumn`.

> `stencil` (unknown):

>   `ly:bar-line::print`

>   The symbol to print.

> `bar-size` (dimension, in staff space):

>   `ly:bar-line::calc-bar-size`

>   The size of a bar line.

> `allow-span-bar` (boolean):

>   `#t`

>   If false, no inter-staff bar line will be created below this bar line.

> `space-alist` (list):

>   `'((time-signature extra-space . 0.75) (custos minimum-space . 2.0) (clef minimum-space . 1.0) (key-signature extra-space . 1.0) (key-cancellation extra-space . 1.0) (first-note fixed-space . 1.3) (next-note semi-fixed-space . 0.9) (right-edge extra-space . 0.0))`

>   A table that specifies distances between prefatory items, like clef and time-signature. The format is an alist of spacing tuples: `(break-align-symbol type . distance)`, where type can be the symbols `minimum-space` or `extra-space`.

> `kern` (dimension, in staff space):

>   `3.0`

>   Amount of extra white space to add. For bar lines, this is the amount of space after a thick line.

> `thin-kern` (number):

>   `3.0`

>   The space after a hair-line in a bar line.

> `hair-thickness` (number):

>   `1.9`

>   Thickness of the thin line in a bar line.

> `thick-thickness` (number):

>   `6.0`

>   Bar line thickness, measured in `line-thickness`.

This object supports the following interface(s): item-interface, font-interface, break-aligned-interface, bar-line-interface and grob-interface.

### 3.1.12 BarNumber

BarNumber objects are created by: Bar_number_engraver.

Standard settings:

> `stencil` (unknown):

>   `ly:text-interface::print`

>   The symbol to print.

> `non-musical` (boolean):

>   `#t`

>   True if the grob belongs to a `NonMusicalPaperColumn`.

> `break-visibility` (vector):

>   `#(#f #f #t)`

>   A vector of 3 booleans, `#(end-of-line unbroken begin-of-line)`. `#t` means visible, `#f` means killed.

> `padding` (dimension, in staff space):

>   `1.0`

>   Add this much extra space between objects that are next to each other.

> `direction` (direction):

>   `1`

>   If `side-axis` is `0` (or `#X`), then this property determines whether the object is placed `#LEFT`, `#CENTER` or `#RIGHT` with respect to the other object. Otherwise, it determines whether the object is placed `#UP`, `#CENTER` or `#DOWN`. Numerical values may also be used: `#UP`=`1`, `#DOWN`=`-1`, `#LEFT`=`-1`, `#RIGHT`=`1`, `#CENTER`=`0`.

> `font-family` (symbol):

>   `'roman`

>   The font family is the broadest category for selecting text fonts. Options include: `sans`, `roman`.

> `font-size` (number):

>   `-2`

>   The font size, compared to the ‘normal’ size. `0` is style-sheet’s normal size, `-1` is smaller, `+1` is bigger. Each step of 1 is approximately 12% larger; 6 steps are exactly a factor 2 larger. Fractional values are allowed.

> `Y-offset` (number):

>   `ly:side-position-interface::y-aligned-side`

>   The vertical amount that this object is moved relative to its Y-parent.

> `side-axis` (number):

>   `1`

>   If the value is `#X` (or equivalently `0`), the object is placed horizontally next to the other object. If the value is `#Y` or `1`, it is placed vertically.

> `outside-staff-priority` (number):

>   `100`

>   If set, the grob is positioned outside the staff in such a way as to avoid all collisions. In case of a potential collision, the grob with the smaller `outside-staff-priority` is closer to the staff.

> `X-offset` (number):

>   `#<simple-closure (#<primitive-generic +> #<simple-closure (#<primitive-procedure ly:break-alignable-interface::self-align-callback>) > #<simple-closure (#<primitive-procedure ly:self-alignment-interface::x-aligned-on-self>) >) >`

>   The horizontal amount that this object is moved relative to its X-parent.

> `self-alignment-X` (number):

>   `1`

>   Specify alignment of an object. The value `-1` means left aligned, `0` centered, and `1` right-aligned in X direction. Other numerical values may also be specified.

> `break-align-symbols` (list):

>   `'(left-edge staff-bar)`

>   A list of symbols that determine which break-aligned grobs to align this to. If the grob selected by the first symbol in the list is invisible due to break-visibility, we will align to the next grob (and so on).

This object supports the following interface(s): text-interface, side-position-interface, self-alignment-interface, item-interface, font-interface, break-alignable-interface and grob-interface.

### 3.1.13 BassFigure

BassFigure objects are created by: Figured_bass_engraver.

Standard settings:

> `stencil` (unknown):

>   `ly:text-interface::print`

>   The symbol to print.

This object supports the following interface(s): text-interface, rhythmic-grob-interface, item-interface, font-interface, bass-figure-interface and grob-interface.

### 3.1.14 BassFigureAlignment

BassFigureAlignment objects are created by: Figured_bass_engraver.

Standard settings:

> `axes` (list):

>   `'(1)`

>   List of axis numbers. In the case of alignment grobs, this should contain only one number.

> `threshold` (pair of numbers):

>   `'(2 . 1000)`

>   `(min . max)`, where min and max are dimensions in staff space.

> `Y-extent` (pair of numbers):

>   `ly:axis-group-interface::height`

>   Hard coded extent in Y direction.

> `stacking-dir` (direction):

>   `-1`

>   Stack objects in which direction?

> `padding` (dimension, in staff space):

>   `0.2`

>   Add this much extra space between objects that are next to each other.

This object supports the following interface(s): spanner-interface, bass-figure-alignment-interface, axis-group-interface, align-interface and grob-interface.

### 3.1.15 BassFigureAlignmentPositioning

BassFigureAlignmentPositioning objects are created by: Figured_bass_position_engraver.

Standard settings:

> `Y-offset` (number):

>   `ly:side-position-interface::y-aligned-side`

>   The vertical amount that this object is moved relative to its Y-parent.

> `side-axis` (number):

>   `1`

>   If the value is `#X` (or equivalently `0`), the object is placed horizontally next to the other object. If the value is `#Y` or `1`, it is placed vertically.

> `direction` (direction):

>   `1`

>   If `side-axis` is `0` (or `#X`), then this property determines whether the object is placed `#LEFT`, `#CENTER` or `#RIGHT` with respect to the other object. Otherwise, it determines whether the object is placed `#UP`, `#CENTER` or `#DOWN`. Numerical values may also be used: `#UP`=`1`, `#DOWN`=`-1`, `#LEFT`=`-1`, `#RIGHT`=`1`, `#CENTER`=`0`.

> `Y-extent` (pair of numbers):

>   `ly:axis-group-interface::height`

>   Hard coded extent in Y direction.

> `axes` (list):

>   `'(1)`

>   List of axis numbers. In the case of alignment grobs, this should contain only one number.

> `staff-padding` (dimension, in staff space):

>   `1.0`

>   Maintain this much space between reference points and the staff. Its effect is to align objects of differing sizes (like the dynamics p and f) on their baselines.

> `padding` (dimension, in staff space):

>   `0.5`

>   Add this much extra space between objects that are next to each other.

This object supports the following interface(s): spanner-interface, side-position-interface, axis-group-interface and grob-interface.

### 3.1.16 BassFigureBracket

BassFigureBracket objects are created by: Figured_bass_engraver.

Standard settings:

> `stencil` (unknown):

>   `ly:enclosing-bracket::print`

>   The symbol to print.

> `X-extent` (pair of numbers):

>   `ly:enclosing-bracket::width`

>   Hard coded extent in X direction.

> `edge-height` (pair):

>   `'(0.2 . 0.2)`

>   A pair of numbers specifying the heights of the vertical edges: `(left-height . right-height)`.

This object supports the following interface(s): item-interface, enclosing-bracket-interface and grob-interface.

### 3.1.17 BassFigureContinuation

BassFigureContinuation objects are created by: Figured_bass_engraver.

Standard settings:

> `stencil` (unknown):

>   `ly:figured-bass-continuation::print`

>   The symbol to print.

> `Y-offset` (number):

>   `ly:figured-bass-continuation::center-on-figures`

>   The vertical amount that this object is moved relative to its Y-parent.

This object supports the following interface(s): spanner-interface, figured-bass-continuation-interface and grob-interface.

### 3.1.18 BassFigureLine

BassFigureLine objects are created by: Figured_bass_engraver.

Standard settings:

> `axes` (list):

>   `'(1)`

>   List of axis numbers. In the case of alignment grobs, this should contain only one number.

> `Y-extent` (pair of numbers):

>   `ly:axis-group-interface::height`

>   Hard coded extent in Y direction.

> `vertical-skylines` (unknown):

>   `ly:axis-group-interface::calc-skylines`

>   Two skylines, one above and one below this grob.

This object supports the following interface(s): spanner-interface, axis-group-interface and grob-interface.

### 3.1.19 Beam

Beam objects are created by: Auto_beam_engraver, Beam_engraver, Chord_tremolo_engraver and Grace_beam_engraver.

Standard settings:

> `gap` (dimension, in staff space):

>   `0.8`

>   Size of a gap in a variable symbol.

> `positions` (pair of numbers):

>   `#<simple-closure #<simple-closure (#<procedure chain-grob-member-functions (grob value . funcs)> (#<primitive-procedure cons> 0 0) #<primitive-procedure ly:beam::calc-least-squares-positions> #<primitive-procedure ly:beam::slope-damping> #<primitive-procedure ly:beam::shift-region-to-valid> #<primitive-procedure ly:beam::quanting>) > >`

>   Pair of staff coordinates `(left . right)`, where both left and right are in `staff-space` units of the current staff. For slurs, this value selects which slur candidate to use; if extreme positions are requested, the closest one is taken.

> `concaveness` (number):

>   `ly:beam::calc-concaveness`

>   A beam is concave if its inner stems are closer to the beam than the two outside stems. This number is a measure of the closeness of the inner stems. It is used for damping the slope of the beam.

> `direction` (direction):

>   `ly:beam::calc-direction`

>   If `side-axis` is `0` (or `#X`), then this property determines whether the object is placed `#LEFT`, `#CENTER` or `#RIGHT` with respect to the other object. Otherwise, it determines whether the object is placed `#UP`, `#CENTER` or `#DOWN`. Numerical values may also be used: `#UP`=`1`, `#DOWN`=`-1`, `#LEFT`=`-1`, `#RIGHT`=`1`, `#CENTER`=`0`.

> `beaming` (pair):

>   `ly:beam::calc-beaming`

>   Pair of number lists. Each number list specifies which beams to make. `0` is the central beam, `1` is the next beam toward the note, etc. This information is used to determine how to connect the beaming patterns from stem to stem inside a beam.

> `stencil` (unknown):

>   `ly:beam::print`

>   The symbol to print.

> `clip-edges` (boolean):

>   `#t`

>   Allow outward pointing beamlets at the edges of beams?

> `thickness` (number):

>   `0.48`

>   Line thickness, generally measured in `line-thickness`.

> `neutral-direction` (direction):

>   `-1`

>   Which direction to take in the center of the staff.

> `beamed-stem-shorten` (list):

>   `'(1.0 0.5 0.25)`

>   How much to shorten beamed stems, when their direction is forced. It is a list, since the value is different depending on the number of flags and beams.

> `damping` (number):

>   `1`

>   Amount of beam slope damping.

> `auto-knee-gap` (dimension, in staff space):

>   `5.5`

>   If a gap is found between note heads where a horizontal beam fits that is larger than this number, make a kneed beam.

> `font-family` (symbol):

>   `'roman`

>   The font family is the broadest category for selecting text fonts. Options include: `sans`, `roman`.

This object supports the following interface(s): unbreakable-spanner-interface, staff-symbol-referencer-interface, spanner-interface, font-interface, beam-interface and grob-interface.

### 3.1.20 BendAfter

BendAfter objects are created by: Bend_engraver.

Standard settings:

> `stencil` (unknown):

>   `bend::print`

>   The symbol to print.

> `minimum-length` (dimension, in staff space):

>   `0.5`

>   Try to make a spanner at least this long, normally in the horizontal direction. This requires an appropriate callback for the `springs-and-rods` property. If added to a `Tie`, this sets the minimum distance between noteheads.

> `thickness` (number):

>   `2.0`

>   Line thickness, generally measured in `line-thickness`.

This object supports the following interface(s): spanner-interface, bend-after-interface and grob-interface.

### 3.1.21 BreakAlignGroup

BreakAlignGroup objects are created by: Break_align_engraver.

Standard settings:

> `axes` (list):

>   `'(0)`

>   List of axis numbers. In the case of alignment grobs, this should contain only one number.

> `X-extent` (pair of numbers):

>   `ly:axis-group-interface::width`

>   Hard coded extent in X direction.

> `break-align-anchor` (number):

>   `ly:break-aligned-interface::calc-average-anchor`

>   Grobs aligned to this break-align grob will have their X-offsets shifted by this number. In bar lines, for example, this is used to position grobs relative to the (visual) center of the bar line.

> `break-visibility` (vector):

>   `ly:break-aligned-interface::calc-break-visibility`

>   A vector of 3 booleans, `#(end-of-line unbroken begin-of-line)`. `#t` means visible, `#f` means killed.

This object supports the following interface(s): item-interface, break-aligned-interface, axis-group-interface and grob-interface.

### 3.1.22 BreakAlignment

BreakAlignment objects are created by: Break_align_engraver.

Standard settings:

> `non-musical` (boolean):

>   `#t`

>   True if the grob belongs to a `NonMusicalPaperColumn`.

> `stacking-dir` (direction):

>   `1`

>   Stack objects in which direction?

> `X-extent` (pair of numbers):

>   `ly:axis-group-interface::width`

>   Hard coded extent in X direction.

> `break-align-orders` (vector):

>   `#((left-edge ambitus breathing-sign clef staff-bar key-cancellation key-signature time-signature custos) (left-edge ambitus breathing-sign clef staff-bar key-cancellation key-signature staff time-signature custos) (left-edge ambitus breathing-sign clef key-cancellation key-signature staff-bar time-signature custos))`

>   Defines the order in which prefatory matter (clefs, key signatures) appears. The format is a vector of length 3, where each element is one order for end-of-line, middle of line, and start-of-line, respectively. An order is a list of symbols.

>   For example, clefs are put after key signatures by setting

>   >     \override Score.BreakAlignment #'break-align-orders =
>   >       #(make-vector 3 '(span-bar
>   >                         breathing-sign
>   >                         staff-bar
>   >                         key
>   >                         clef
>   >                         time-signature))

> `axes` (list):

>   `'(0)`

>   List of axis numbers. In the case of alignment grobs, this should contain only one number.

This object supports the following interface(s): item-interface, break-alignment-interface, axis-group-interface and grob-interface.

### 3.1.23 BreathingSign

BreathingSign objects are created by: Breathing_sign_engraver.

Standard settings:

> `break-align-symbol` (symbol):

>   `'breathing-sign`

>   This key is used for aligning and spacing breakable items.

> `non-musical` (boolean):

>   `#t`

>   True if the grob belongs to a `NonMusicalPaperColumn`.

> `space-alist` (list):

>   `'((ambitus extra-space . 2.0) (custos minimum-space . 1.0) (key-signature minimum-space . 1.5) (time-signature minimum-space . 1.5) (staff-bar minimum-space . 1.5) (clef minimum-space . 2.0) (first-note fixed-space . 1.0) (right-edge extra-space . 0.1))`

>   A table that specifies distances between prefatory items, like clef and time-signature. The format is an alist of spacing tuples: `(break-align-symbol type . distance)`, where type can be the symbols `minimum-space` or `extra-space`.

> `stencil` (unknown):

>   `ly:text-interface::print`

>   The symbol to print.

> `text` (markup):

>   `'(#<procedure musicglyph-markup (layout props glyph-name)> scripts.rcomma)`

>   Text markup. See Formatting text.

> `Y-offset` (number):

>   `ly:breathing-sign::offset-callback`

>   The vertical amount that this object is moved relative to its Y-parent.

> `break-visibility` (vector):

>   `#(#t #t #f)`

>   A vector of 3 booleans, `#(end-of-line unbroken begin-of-line)`. `#t` means visible, `#f` means killed.

This object supports the following interface(s): text-interface, item-interface, font-interface, breathing-sign-interface, break-aligned-interface and grob-interface.

### 3.1.24 ChordName

ChordName objects are created by: Chord_name_engraver.

Standard settings:

> `stencil` (unknown):

>   `ly:text-interface::print`

>   The symbol to print.

> `after-line-breaking` (boolean):

>   `ly:chord-name::after-line-breaking`

>   Dummy property, used to trigger callback for `after-line-breaking`.

> `word-space` (dimension, in staff space):

>   `0.0`

>   Space to insert between words in texts.

> `font-family` (symbol):

>   `'sans`

>   The font family is the broadest category for selecting text fonts. Options include: `sans`, `roman`.

> `font-size` (number):

>   `1.5`

>   The font size, compared to the ‘normal’ size. `0` is style-sheet’s normal size, `-1` is smaller, `+1` is bigger. Each step of 1 is approximately 12% larger; 6 steps are exactly a factor 2 larger. Fractional values are allowed.

This object supports the following interface(s): text-interface, rhythmic-grob-interface, item-interface, font-interface, chord-name-interface and grob-interface.

### 3.1.25 Clef

Clef objects are created by: Clef_engraver.

Standard settings:

> `stencil` (unknown):

>   `ly:clef::print`

>   The symbol to print.

> `non-musical` (boolean):

>   `#t`

>   True if the grob belongs to a `NonMusicalPaperColumn`.

> `avoid-slur` (symbol):

>   `'inside`

>   Method of handling slur collisions. Choices are `around`, `inside`, `outside`. If unset, scripts and slurs ignore each other. `around` only moves the script if there is a collision; `outside` always moves the script.

> `font-family` (symbol):

>   `'music`

>   The font family is the broadest category for selecting text fonts. Options include: `sans`, `roman`.

> `break-align-symbol` (symbol):

>   `'clef`

>   This key is used for aligning and spacing breakable items.

> `break-align-anchor` (number):

>   `ly:break-aligned-interface::calc-extent-aligned-anchor`

>   Grobs aligned to this break-align grob will have their X-offsets shifted by this number. In bar lines, for example, this is used to position grobs relative to the (visual) center of the bar line.

> `break-visibility` (vector):

>   `#(#f #f #t)`

>   A vector of 3 booleans, `#(end-of-line unbroken begin-of-line)`. `#t` means visible, `#f` means killed.

> `space-alist` (list):

>   `'((ambitus extra-space . 2.0) (staff-bar extra-space . 0.7) (key-cancellation minimum-space . 3.5) (key-signature minimum-space . 3.5) (time-signature minimum-space . 4.2) (first-note minimum-fixed-space . 5.0) (next-note extra-space . 0.5) (right-edge extra-space . 0.5))`

>   A table that specifies distances between prefatory items, like clef and time-signature. The format is an alist of spacing tuples: `(break-align-symbol type . distance)`, where type can be the symbols `minimum-space` or `extra-space`.

> `Y-offset` (number):

>   `ly:staff-symbol-referencer::callback`

>   The vertical amount that this object is moved relative to its Y-parent.

This object supports the following interface(s): staff-symbol-referencer-interface, item-interface, font-interface, clef-interface, break-aligned-interface and grob-interface.

### 3.1.26 ClusterSpanner

ClusterSpanner objects are created by: Cluster_spanner_engraver.

Standard settings:

> `springs-and-rods` (boolean):

>   `ly:spanner::set-spacing-rods`

>   Dummy variable for triggering spacing routines.

> `stencil` (unknown):

>   `ly:cluster::print`

>   The symbol to print.

> `minimum-length` (dimension, in staff space):

>   `0.0`

>   Try to make a spanner at least this long, normally in the horizontal direction. This requires an appropriate callback for the `springs-and-rods` property. If added to a `Tie`, this sets the minimum distance between noteheads.

> `padding` (dimension, in staff space):

>   `0.25`

>   Add this much extra space between objects that are next to each other.

> `style` (symbol):

>   `'ramp`

>   This setting determines in what style a grob is typeset. Valid choices depend on the `stencil` callback reading this property.

This object supports the following interface(s): spanner-interface, cluster-interface and grob-interface.

### 3.1.27 ClusterSpannerBeacon

ClusterSpannerBeacon objects are created by: Cluster_spanner_engraver.

Standard settings:

> `Y-extent` (pair of numbers):

>   `ly:cluster-beacon::height`

>   Hard coded extent in Y direction.

This object supports the following interface(s): rhythmic-grob-interface, item-interface, cluster-beacon-interface and grob-interface.

### 3.1.28 CombineTextScript

CombineTextScript objects are created by: Part_combine_engraver.

Standard settings:

> `stencil` (unknown):

>   `ly:text-interface::print`

>   The symbol to print.

> `extra-spacing-width` (pair of numbers):

>   `'(+inf.0 . -inf.0)`

>   In the horizontal spacing problem, we pad each item by this amount (by adding the ‘car’ on the left side of the item and adding the ‘cdr’ on the right side of the item). In order to make a grob take up no horizontal space at all, set this to `(+inf.0 . -inf.0)`.

> `Y-offset` (number):

>   `ly:side-position-interface::y-aligned-side`

>   The vertical amount that this object is moved relative to its Y-parent.

> `X-offset` (number):

>   `ly:self-alignment-interface::x-aligned-on-self`

>   The horizontal amount that this object is moved relative to its X-parent.

> `direction` (direction):

>   `1`

>   If `side-axis` is `0` (or `#X`), then this property determines whether the object is placed `#LEFT`, `#CENTER` or `#RIGHT` with respect to the other object. Otherwise, it determines whether the object is placed `#UP`, `#CENTER` or `#DOWN`. Numerical values may also be used: `#UP`=`1`, `#DOWN`=`-1`, `#LEFT`=`-1`, `#RIGHT`=`1`, `#CENTER`=`0`.

> `padding` (dimension, in staff space):

>   `0.5`

>   Add this much extra space between objects that are next to each other.

> `staff-padding` (dimension, in staff space):

>   `0.5`

>   Maintain this much space between reference points and the staff. Its effect is to align objects of differing sizes (like the dynamics p and f) on their baselines.

> `script-priority` (number):

>   `200`

>   A sorting key that determines in what order a script is within a stack of scripts.

> `baseline-skip` (dimension, in staff space):

>   `2`

>   Distance between base lines of multiple lines of text.

> `side-axis` (number):

>   `1`

>   If the value is `#X` (or equivalently `0`), the object is placed horizontally next to the other object. If the value is `#Y` or `1`, it is placed vertically.

> `avoid-slur` (symbol):

>   `'outside`

>   Method of handling slur collisions. Choices are `around`, `inside`, `outside`. If unset, scripts and slurs ignore each other. `around` only moves the script if there is a collision; `outside` always moves the script.

> `font-series` (symbol):

>   `'bold`

>   Select the series of a font. Choices include `medium`, `bold`, `bold-narrow`, etc.

This object supports the following interface(s): text-script-interface, text-interface, side-position-interface, item-interface, font-interface and grob-interface.

### 3.1.29 Custos

Custos objects are created by: Custos_engraver.

Standard settings:

> `break-align-symbol` (symbol):

>   `'custos`

>   This key is used for aligning and spacing breakable items.

> `non-musical` (boolean):

>   `#t`

>   True if the grob belongs to a `NonMusicalPaperColumn`.

> `stencil` (unknown):

>   `ly:custos::print`

>   The symbol to print.

> `break-visibility` (vector):

>   `#(#t #f #f)`

>   A vector of 3 booleans, `#(end-of-line unbroken begin-of-line)`. `#t` means visible, `#f` means killed.

> `style` (symbol):

>   `'vaticana`

>   This setting determines in what style a grob is typeset. Valid choices depend on the `stencil` callback reading this property.

> `neutral-direction` (direction):

>   `-1`

>   Which direction to take in the center of the staff.

> `Y-offset` (number):

>   `ly:staff-symbol-referencer::callback`

>   The vertical amount that this object is moved relative to its Y-parent.

> `space-alist` (list):

>   `'((first-note minimum-fixed-space . 0.0) (right-edge extra-space . 0.1))`

>   A table that specifies distances between prefatory items, like clef and time-signature. The format is an alist of spacing tuples: `(break-align-symbol type . distance)`, where type can be the symbols `minimum-space` or `extra-space`.

This object supports the following interface(s): staff-symbol-referencer-interface, item-interface, font-interface, custos-interface, break-aligned-interface and grob-interface.

### 3.1.30 DotColumn

DotColumn objects are created by: Dot_column_engraver and Vaticana_ligature_engraver.

Standard settings:

> `axes` (list):

>   `'(0)`

>   List of axis numbers. In the case of alignment grobs, this should contain only one number.

> `direction` (direction):

>   `1`

>   If `side-axis` is `0` (or `#X`), then this property determines whether the object is placed `#LEFT`, `#CENTER` or `#RIGHT` with respect to the other object. Otherwise, it determines whether the object is placed `#UP`, `#CENTER` or `#DOWN`. Numerical values may also be used: `#UP`=`1`, `#DOWN`=`-1`, `#LEFT`=`-1`, `#RIGHT`=`1`, `#CENTER`=`0`.

> `X-extent` (pair of numbers):

>   `ly:axis-group-interface::width`

>   Hard coded extent in X direction.

This object supports the following interface(s): item-interface, dot-column-interface, axis-group-interface and grob-interface.

### 3.1.31 Dots

Dots objects are created by: Completion_heads_engraver and Dots_engraver.

Standard settings:

> `stencil` (unknown):

>   `ly:dots::print`

>   The symbol to print.

> `dot-count` (integer):

>   `dots::calc-dot-count`

>   The number of dots.

> `staff-position` (number):

>   `dots::calc-staff-position`

>   Vertical position, measured in half staff spaces, counted from the middle line.

This object supports the following interface(s): staff-symbol-referencer-interface, item-interface, font-interface, dots-interface and grob-interface.

### 3.1.32 DoublePercentRepeat

DoublePercentRepeat objects are created by: Percent_repeat_engraver.

Standard settings:

> `stencil` (unknown):

>   `ly:percent-repeat-item-interface::double-percent`

>   The symbol to print.

> `non-musical` (boolean):

>   `#t`

>   True if the grob belongs to a `NonMusicalPaperColumn`.

> `slope` (number):

>   `1.0`

>   The slope of this object.

> `dot-negative-kern` (number):

>   `0.75`

>   The space to remove between a dot and a slash in percent repeat glyphs. Larger values bring the two elements closer together.

> `slash-negative-kern` (number):

>   `1.6`

>   The space to remove between slashes in percent repeat glyphs. Larger values bring the two elements closer together.

> `font-encoding` (symbol):

>   `'fetaMusic`

>   The font encoding is the broadest category for selecting a font. Currently, only lilypond’s system fonts (Emmentaler and Aybabtu) are using this property. Available values are `fetaMusic` (Emmentaler), `fetaBraces` (Aybabtu), `fetaNumber` (Emmentaler), and `fetaDynamic` (Emmentaler).

> `width` (dimension, in staff space):

>   `2.0`

>   The width of a grob measured in staff space.

> `thickness` (number):

>   `0.48`

>   Line thickness, generally measured in `line-thickness`.

> `break-align-symbol` (symbol):

>   `'staff-bar`

>   This key is used for aligning and spacing breakable items.

> `break-visibility` (vector):

>   `#(#t #t #f)`

>   A vector of 3 booleans, `#(end-of-line unbroken begin-of-line)`. `#t` means visible, `#f` means killed.

This object supports the following interface(s): percent-repeat-item-interface, percent-repeat-interface, item-interface, font-interface, break-aligned-interface and grob-interface.

### 3.1.33 DoublePercentRepeatCounter

DoublePercentRepeatCounter objects are created by: Percent_repeat_engraver.

Standard settings:

> `stencil` (unknown):

>   `ly:text-interface::print`

>   The symbol to print.

> `X-offset` (number):

>   `#<simple-closure (#<primitive-generic +> #<simple-closure (#<primitive-procedure ly:self-alignment-interface::centered-on-y-parent>) > #<simple-closure (#<primitive-procedure ly:self-alignment-interface::x-aligned-on-self>) >) >`

>   The horizontal amount that this object is moved relative to its X-parent.

> `Y-offset` (number):

>   `ly:side-position-interface::y-aligned-side`

>   The vertical amount that this object is moved relative to its Y-parent.

> `font-encoding` (symbol):

>   `'fetaNumber`

>   The font encoding is the broadest category for selecting a font. Currently, only lilypond’s system fonts (Emmentaler and Aybabtu) are using this property. Available values are `fetaMusic` (Emmentaler), `fetaBraces` (Aybabtu), `fetaNumber` (Emmentaler), and `fetaDynamic` (Emmentaler).

> `self-alignment-X` (number):

>   `0`

>   Specify alignment of an object. The value `-1` means left aligned, `0` centered, and `1` right-aligned in X direction. Other numerical values may also be specified.

> `font-size` (number):

>   `-2`

>   The font size, compared to the ‘normal’ size. `0` is style-sheet’s normal size, `-1` is smaller, `+1` is bigger. Each step of 1 is approximately 12% larger; 6 steps are exactly a factor 2 larger. Fractional values are allowed.

> `direction` (direction):

>   `1`

>   If `side-axis` is `0` (or `#X`), then this property determines whether the object is placed `#LEFT`, `#CENTER` or `#RIGHT` with respect to the other object. Otherwise, it determines whether the object is placed `#UP`, `#CENTER` or `#DOWN`. Numerical values may also be used: `#UP`=`1`, `#DOWN`=`-1`, `#LEFT`=`-1`, `#RIGHT`=`1`, `#CENTER`=`0`.

> `padding` (dimension, in staff space):

>   `0.2`

>   Add this much extra space between objects that are next to each other.

> `staff-padding` (dimension, in staff space):

>   `0.25`

>   Maintain this much space between reference points and the staff. Its effect is to align objects of differing sizes (like the dynamics p and f) on their baselines.

> `side-axis` (number):

>   `1`

>   If the value is `#X` (or equivalently `0`), the object is placed horizontally next to the other object. If the value is `#Y` or `1`, it is placed vertically.

This object supports the following interface(s): text-interface, side-position-interface, self-alignment-interface, percent-repeat-item-interface, percent-repeat-interface, item-interface, font-interface and grob-interface.

### 3.1.34 DynamicLineSpanner

DynamicLineSpanner objects are created by: Dynamic_align_engraver and Dynamic_engraver.

Standard settings:

> `axes` (list):

>   `'(1)`

>   List of axis numbers. In the case of alignment grobs, this should contain only one number.

> `Y-offset` (number):

>   `ly:side-position-interface::y-aligned-side`

>   The vertical amount that this object is moved relative to its Y-parent.

> `staff-padding` (dimension, in staff space):

>   `0.1`

>   Maintain this much space between reference points and the staff. Its effect is to align objects of differing sizes (like the dynamics p and f) on their baselines.

> `padding` (dimension, in staff space):

>   `0.6`

>   Add this much extra space between objects that are next to each other.

> `slur-padding` (number):

>   `0.3`

>   Extra distance between slur and script.

> `minimum-space` (dimension, in staff space):

>   `1.2`

>   Minimum distance that the victim should move (after padding).

> `direction` (direction):

>   `-1`

>   If `side-axis` is `0` (or `#X`), then this property determines whether the object is placed `#LEFT`, `#CENTER` or `#RIGHT` with respect to the other object. Otherwise, it determines whether the object is placed `#UP`, `#CENTER` or `#DOWN`. Numerical values may also be used: `#UP`=`1`, `#DOWN`=`-1`, `#LEFT`=`-1`, `#RIGHT`=`1`, `#CENTER`=`0`.

> `side-axis` (number):

>   `1`

>   If the value is `#X` (or equivalently `0`), the object is placed horizontally next to the other object. If the value is `#Y` or `1`, it is placed vertically.

> `outside-staff-priority` (number):

>   `250`

>   If set, the grob is positioned outside the staff in such a way as to avoid all collisions. In case of a potential collision, the grob with the smaller `outside-staff-priority` is closer to the staff.

> `Y-extent` (pair of numbers):

>   `ly:axis-group-interface::height`

>   Hard coded extent in Y direction.

> `X-extent` (pair of numbers):

>   `ly:axis-group-interface::width`

>   Hard coded extent in X direction.

This object supports the following interface(s): spanner-interface, side-position-interface, dynamic-line-spanner-interface, dynamic-interface, axis-group-interface and grob-interface.

### 3.1.35 DynamicText

DynamicText objects are created by: Dynamic_engraver and New_dynamic_engraver.

Standard settings:

> `stencil` (unknown):

>   `ly:text-interface::print`

>   The symbol to print.

> `direction` (direction):

>   `ly:script-interface::calc-direction`

>   If `side-axis` is `0` (or `#X`), then this property determines whether the object is placed `#LEFT`, `#CENTER` or `#RIGHT` with respect to the other object. Otherwise, it determines whether the object is placed `#UP`, `#CENTER` or `#DOWN`. Numerical values may also be used: `#UP`=`1`, `#DOWN`=`-1`, `#LEFT`=`-1`, `#RIGHT`=`1`, `#CENTER`=`0`.

> `X-offset` (number):

>   `ly:self-alignment-interface::x-aligned-on-self`

>   The horizontal amount that this object is moved relative to its X-parent.

> `self-alignment-X` (number):

>   `0`

>   Specify alignment of an object. The value `-1` means left aligned, `0` centered, and `1` right-aligned in X direction. Other numerical values may also be specified.

> `Y-offset` (number):

>   `ly:self-alignment-interface::y-aligned-on-self`

>   The vertical amount that this object is moved relative to its Y-parent.

> `self-alignment-Y` (number):

>   `0`

>   Like `self-alignment-X` but for the Y axis.

> `font-series` (symbol):

>   `'bold`

>   Select the series of a font. Choices include `medium`, `bold`, `bold-narrow`, etc.

> `font-encoding` (symbol):

>   `'fetaDynamic`

>   The font encoding is the broadest category for selecting a font. Currently, only lilypond’s system fonts (Emmentaler and Aybabtu) are using this property. Available values are `fetaMusic` (Emmentaler), `fetaBraces` (Aybabtu), `fetaNumber` (Emmentaler), and `fetaDynamic` (Emmentaler).

> `font-shape` (symbol):

>   `'italic`

>   Select the shape of a font. Choices include `upright`, `italic`, `caps`.

> `extra-spacing-width` (pair of numbers):

>   `'(+inf.0 . -inf.0)`

>   In the horizontal spacing problem, we pad each item by this amount (by adding the ‘car’ on the left side of the item and adding the ‘cdr’ on the right side of the item). In order to make a grob take up no horizontal space at all, set this to `(+inf.0 . -inf.0)`.

> `outside-staff-priority` (number):

>   `250`

>   If set, the grob is positioned outside the staff in such a way as to avoid all collisions. In case of a potential collision, the grob with the smaller `outside-staff-priority` is closer to the staff.

This object supports the following interface(s): text-interface, self-alignment-interface, script-interface, item-interface, font-interface, dynamic-interface and grob-interface.

### 3.1.36 DynamicTextSpanner

DynamicTextSpanner objects are created by: Dynamic_engraver and New_dynamic_engraver.

Standard settings:

> `font-shape` (symbol):

>   `'italic`

>   Select the shape of a font. Choices include `upright`, `italic`, `caps`.

> `style` (symbol):

>   `'dashed-line`

>   This setting determines in what style a grob is typeset. Valid choices depend on the `stencil` callback reading this property.

> `minimum-Y-extent` (pair of numbers):

>   `'(-1 . 1)`

>   Minimum size of an object in Y dimension, measured in `staff-space` units.

> `bound-details` (list):

>   `'((right (attach-dir . -1) (Y . 0) (padding . 0.75)) (right-broken (attach-dir . 1) (padding . 0.0)) (left (attach-dir . -1) (Y . 0) (stencil-offset 0 . -0.5) (padding . 0.5)) (left-broken (attach-dir . 1)))`

>   An alist of properties for determining attachments of spanners to edges.

> `stencil` (unknown):

>   `ly:line-spanner::print`

>   The symbol to print.

> `left-bound-info` (list):

>   `ly:line-spanner::calc-left-bound-info-and-text`

>   An alist of properties for determining attachments of spanners to edges.

> `right-bound-info` (list):

>   `ly:line-spanner::calc-right-bound-info`

>   An alist of properties for determining attachments of spanners to edges.

> `font-size` (number):

>   `1`

>   The font size, compared to the ‘normal’ size. `0` is style-sheet’s normal size, `-1` is smaller, `+1` is bigger. Each step of 1 is approximately 12% larger; 6 steps are exactly a factor 2 larger. Fractional values are allowed.

> `dash-fraction` (number):

>   `0.2`

>   Size of the dashes, relative to `dash-period`. Should be between `0.0` (no line) and `1.0` (continuous line).

> `dash-period` (number):

>   `3.0`

>   The length of one dash together with whitespace. If negative, no line is drawn at all.

This object supports the following interface(s): text-interface, spanner-interface, line-spanner-interface, line-interface, font-interface, dynamic-text-spanner-interface, dynamic-interface and grob-interface.

### 3.1.37 Fingering

Fingering objects are created by: Fingering_engraver and New_fingering_engraver.

Standard settings:

> `padding` (dimension, in staff space):

>   `0.5`

>   Add this much extra space between objects that are next to each other.

> `avoid-slur` (symbol):

>   `'around`

>   Method of handling slur collisions. Choices are `around`, `inside`, `outside`. If unset, scripts and slurs ignore each other. `around` only moves the script if there is a collision; `outside` always moves the script.

> `slur-padding` (number):

>   `0.2`

>   Extra distance between slur and script.

> `staff-padding` (dimension, in staff space):

>   `0.5`

>   Maintain this much space between reference points and the staff. Its effect is to align objects of differing sizes (like the dynamics p and f) on their baselines.

> `self-alignment-X` (number):

>   `0`

>   Specify alignment of an object. The value `-1` means left aligned, `0` centered, and `1` right-aligned in X direction. Other numerical values may also be specified.

> `self-alignment-Y` (number):

>   `0`

>   Like `self-alignment-X` but for the Y axis.

> `script-priority` (number):

>   `100`

>   A sorting key that determines in what order a script is within a stack of scripts.

> `stencil` (unknown):

>   `ly:text-interface::print`

>   The symbol to print.

> `direction` (direction):

>   `ly:script-interface::calc-direction`

>   If `side-axis` is `0` (or `#X`), then this property determines whether the object is placed `#LEFT`, `#CENTER` or `#RIGHT` with respect to the other object. Otherwise, it determines whether the object is placed `#UP`, `#CENTER` or `#DOWN`. Numerical values may also be used: `#UP`=`1`, `#DOWN`=`-1`, `#LEFT`=`-1`, `#RIGHT`=`1`, `#CENTER`=`0`.

> `text` (markup):

>   `fingering::calc-text`

>   Text markup. See Formatting text.

> `font-encoding` (symbol):

>   `'fetaNumber`

>   The font encoding is the broadest category for selecting a font. Currently, only lilypond’s system fonts (Emmentaler and Aybabtu) are using this property. Available values are `fetaMusic` (Emmentaler), `fetaBraces` (Aybabtu), `fetaNumber` (Emmentaler), and `fetaDynamic` (Emmentaler).

> `font-size` (number):

>   `-5`

>   The font size, compared to the ‘normal’ size. `0` is style-sheet’s normal size, `-1` is smaller, `+1` is bigger. Each step of 1 is approximately 12% larger; 6 steps are exactly a factor 2 larger. Fractional values are allowed.

This object supports the following interface(s): text-script-interface, text-interface, side-position-interface, self-alignment-interface, item-interface, font-interface, finger-interface and grob-interface.

### 3.1.38 FretBoard

FretBoard objects are created by: Fretboard_engraver.

Standard settings:

> `stencil` (unknown):

>   `fret-board::calc-stencil`

>   The symbol to print.

> `fret-diagram-details` (list):

>   `'((finger-code . below-string))`

>   An alist of detailed grob properties for fret diagrams. Each alist entry consists of a `(property . value)` pair. The properties which can be included in `fret-diagram-details` include the following:

>   - `barre-type` – Type of barre indication used. Choices include `curved`, `straight`, and `none`. Default `curved`.
>   - `capo-thickness` – Thickness of capo indicator, in multiples of fret-space. Default value 0.5.
>   - `dot-color` – Color of dots. Options include `black` and `white`. Default `black`.
>   - `dot-label-font-mag` – Magnification for font used to label fret dots. Default value 1.
>   - `dot-position` – Location of dot in fret space. Default 0.6 for dots without labels, 0.95-`dot-radius` for dots with labels.
>   - `dot-radius` – Radius of dots, in terms of fret spaces. Default value 0.425 for labeled dots, 0.25 for unlabeled dots.
>   - `finger-code` – Code for the type of fingering indication used. Options include `none`, `in-dot`, and `below-string`. Default `none` for markup fret diagrams, `below-string` for `FretBoards` fret diagrams.
>   - `fret-count` – The number of frets. Default 4.
>   - `fret-label-font-mag` – The magnification of the font used to label the lowest fret number. Default 0.5.
>   - `fret-label-vertical-offset` – The offset of the fret label from the center of the fret in direction parallel to strings. Default 0.
>   - `label-dir` – Side to which the fret label is attached. `-1`, `#LEFT`, or `#DOWN` for left or down; `1`, `#RIGHT`, or `#UP` for right or up. Default `#RIGHT`.
>   - `mute-string` – Character string to be used to indicate muted string. Default `"x"`.
>   - `number-type` – Type of numbers to use in fret label. Choices include `roman-lower`, `roman-upper`, and `arabic`. Default `roman-lower`.
>   - `open-string` – Character string to be used to indicate open string. Default `"o"`.
>   - `orientation` – Orientation of fret-diagram. Options include `normal`, `landscape`, and `opposing-landscape`. Default `normal`.
>   - `string-count` – The number of strings. Default 6.
>   - `string-label-font-mag` – The magnification of the font used to label fingerings at the string, rather than in the dot. Default value 0.6 for `normal` orientation, 0.5 for `landscape` and `opposing-landscape`.
>   - `string-thickness-factor` – Factor for changing thickness of each string in the fret diagram. Thickness of string k is given by `thickness` * (1+`string-thickness-factor`) ^ (k-1). Default 0.
>   - `top-fret-thickness` – The thickness of the top fret line, as a multiple of the standard thickness. Default value 3.
>   - `xo-font-magnification` – Magnification used for mute and open string indicators. Default value 0.5.
>   - `xo-padding` – Padding for open and mute indicators from top fret. Default value 0.25.

This object supports the following interface(s): item-interface, fret-diagram-interface, font-interface and grob-interface.

### 3.1.39 Glissando

Glissando objects are created by: Glissando_engraver and Note_head_line_engraver.

Standard settings:

> `style` (symbol):

>   `'line`

>   This setting determines in what style a grob is typeset. Valid choices depend on the `stencil` callback reading this property.

> `gap` (dimension, in staff space):

>   `0.5`

>   Size of a gap in a variable symbol.

> `zigzag-width` (dimension, in staff space):

>   `0.75`

>   The width of one zigzag squiggle. This number is adjusted slightly so that the glissando line can be constructed from a whole number of squiggles.

> `X-extent` (pair of numbers):

>   `#f`

>   Hard coded extent in X direction.

> `Y-extent` (pair of numbers):

>   `#f`

>   Hard coded extent in Y direction.

> `bound-details` (list):

>   `'((right (attach-dir . 0) (padding . 1.5)) (left (attach-dir . 0) (padding . 1.5)))`

>   An alist of properties for determining attachments of spanners to edges.

> `stencil` (unknown):

>   `ly:line-spanner::print`

>   The symbol to print.

> `left-bound-info` (list):

>   `ly:line-spanner::calc-left-bound-info`

>   An alist of properties for determining attachments of spanners to edges.

> `right-bound-info` (list):

>   `ly:line-spanner::calc-right-bound-info`

>   An alist of properties for determining attachments of spanners to edges.

This object supports the following interface(s): unbreakable-spanner-interface, spanner-interface, line-spanner-interface, line-interface and grob-interface.

### 3.1.40 GraceSpacing

GraceSpacing objects are created by: Grace_spacing_engraver.

Standard settings:

> `common-shortest-duration` (moment):

>   `grace-spacing::calc-shortest-duration`

>   The most common shortest note length. This is used in spacing. Enlarging this sets the score tighter.

> `spacing-increment` (number):

>   `0.8`

>   Add this much space for a doubled duration. Typically, the width of a note head. See also spacing-spanner-interface.

> `shortest-duration-space` (dimension, in staff space):

>   `1.6`

>   Start with this much space for the shortest duration. This is expressed in `spacing-increment` as unit. See also spacing-spanner-interface.

This object supports the following interface(s): spanner-interface, spacing-options-interface, grace-spacing-interface and grob-interface.

### 3.1.41 GridLine

GridLine objects are created by: Grid_line_span_engraver.

Standard settings:

> `X-extent` (pair of numbers):

>   `ly:grid-line-interface::width`

>   Hard coded extent in X direction.

> `stencil` (unknown):

>   `ly:grid-line-interface::print`

>   The symbol to print.

> `self-alignment-X` (number):

>   `0`

>   Specify alignment of an object. The value `-1` means left aligned, `0` centered, and `1` right-aligned in X direction. Other numerical values may also be specified.

> `X-offset` (number):

>   `#<simple-closure (#<primitive-generic +> #<simple-closure (#<primitive-procedure ly:self-alignment-interface::centered-on-x-parent>) > #<simple-closure (#<primitive-procedure ly:self-alignment-interface::x-aligned-on-self>) >) >`

>   The horizontal amount that this object is moved relative to its X-parent.

> `layer` (integer):

>   `0`

>   The output layer (a value between 0 and 2): Layers define the order of printing objects. Objects in lower layers are overprinted by objects in higher layers.

This object supports the following interface(s): self-alignment-interface, item-interface, grid-line-interface and grob-interface.

### 3.1.42 GridPoint

GridPoint objects are created by: Grid_point_engraver.

Standard settings:

> `X-extent` (pair of numbers):

>   `'(0 . 0)`

>   Hard coded extent in X direction.

> `Y-extent` (pair of numbers):

>   `'(0 . 0)`

>   Hard coded extent in Y direction.

This object supports the following interface(s): item-interface, grid-point-interface and grob-interface.

### 3.1.43 Hairpin

Hairpin objects are created by: Dynamic_engraver and New_dynamic_engraver.

Standard settings:

> `stencil` (unknown):

>   `ly:hairpin::print`

>   The symbol to print.

> `springs-and-rods` (boolean):

>   `ly:spanner::set-spacing-rods`

>   Dummy variable for triggering spacing routines.

> `after-line-breaking` (boolean):

>   `ly:hairpin::after-line-breaking`

>   Dummy property, used to trigger callback for `after-line-breaking`.

> `grow-direction` (direction):

>   `hairpin::calc-grow-direction`

>   Crescendo or decrescendo?

> `circled-tip` (boolean):

>   `#f`

>   Put a circle at start/end of hairpins (al/del niente).

> `to-barline` (boolean):

>   `#t`

>   If true, the spanner will stop at the bar line just before it would otherwise stop.

> `thickness` (number):

>   `1.0`

>   Line thickness, generally measured in `line-thickness`.

> `height` (dimension, in staff space):

>   `0.6666`

>   Height of an object in `staff-space` units.

> `minimum-length` (dimension, in staff space):

>   `2.0`

>   Try to make a spanner at least this long, normally in the horizontal direction. This requires an appropriate callback for the `springs-and-rods` property. If added to a `Tie`, this sets the minimum distance between noteheads.

> `bound-padding` (number):

>   `1.0`

>   The amount of padding to insert around spanner bounds.

> `self-alignment-Y` (number):

>   `0`

>   Like `self-alignment-X` but for the Y axis.

> `Y-offset` (number):

>   `ly:self-alignment-interface::y-aligned-on-self`

>   The vertical amount that this object is moved relative to its Y-parent.

This object supports the following interface(s): spanner-interface, self-alignment-interface, line-interface, hairpin-interface, dynamic-interface and grob-interface.

### 3.1.44 HarmonicParenthesesItem

HarmonicParenthesesItem objects are created by: Tab_harmonic_engraver.

Standard settings:

> `stencil` (unknown):

>   `parentheses-item::print`

>   The symbol to print.

> `padding` (dimension, in staff space):

>   `0`

>   Add this much extra space between objects that are next to each other.

> `stencils` (list):

>   `parentheses-item::calc-angled-bracket-stencils`

>   Multiple stencils, used as intermediate value.

This object supports the following interface(s): parentheses-interface, item-interface, font-interface and grob-interface.

### 3.1.45 HorizontalBracket

HorizontalBracket objects are created by: Horizontal_bracket_engraver.

Standard settings:

> `thickness` (number):

>   `1.0`

>   Line thickness, generally measured in `line-thickness`.

> `stencil` (unknown):

>   `ly:horizontal-bracket::print`

>   The symbol to print.

> `Y-offset` (number):

>   `ly:side-position-interface::y-aligned-side`

>   The vertical amount that this object is moved relative to its Y-parent.

> `connect-to-neighbor` (pair):

>   `ly:tuplet-bracket::calc-connect-to-neighbors`

>   Pair of booleans, indicating whether this grob looks as a continued break.

> `padding` (dimension, in staff space):

>   `0.2`

>   Add this much extra space between objects that are next to each other.

> `staff-padding` (dimension, in staff space):

>   `0.2`

>   Maintain this much space between reference points and the staff. Its effect is to align objects of differing sizes (like the dynamics p and f) on their baselines.

> `direction` (direction):

>   `-1`

>   If `side-axis` is `0` (or `#X`), then this property determines whether the object is placed `#LEFT`, `#CENTER` or `#RIGHT` with respect to the other object. Otherwise, it determines whether the object is placed `#UP`, `#CENTER` or `#DOWN`. Numerical values may also be used: `#UP`=`1`, `#DOWN`=`-1`, `#LEFT`=`-1`, `#RIGHT`=`1`, `#CENTER`=`0`.

> `side-axis` (number):

>   `1`

>   If the value is `#X` (or equivalently `0`), the object is placed horizontally next to the other object. If the value is `#Y` or `1`, it is placed vertically.

> `bracket-flare` (pair of numbers):

>   `'(0.5 . 0.5)`

>   A pair of numbers specifying how much edges of brackets should slant outward. Value `0.0` means straight edges.

This object supports the following interface(s): spanner-interface, side-position-interface, line-interface, horizontal-bracket-interface and grob-interface.

### 3.1.46 InstrumentName

InstrumentName objects are created by: Instrument_name_engraver.

Standard settings:

> `padding` (dimension, in staff space):

>   `0.3`

>   Add this much extra space between objects that are next to each other.

> `stencil` (unknown):

>   `ly:system-start-text::print`

>   The symbol to print.

> `X-offset` (number):

>   `ly:side-position-interface::x-aligned-side`

>   The horizontal amount that this object is moved relative to its X-parent.

> `direction` (direction):

>   `-1`

>   If `side-axis` is `0` (or `#X`), then this property determines whether the object is placed `#LEFT`, `#CENTER` or `#RIGHT` with respect to the other object. Otherwise, it determines whether the object is placed `#UP`, `#CENTER` or `#DOWN`. Numerical values may also be used: `#UP`=`1`, `#DOWN`=`-1`, `#LEFT`=`-1`, `#RIGHT`=`1`, `#CENTER`=`0`.

> `self-alignment-Y` (number):

>   `0`

>   Like `self-alignment-X` but for the Y axis.

> `self-alignment-X` (number):

>   `0`

>   Specify alignment of an object. The value `-1` means left aligned, `0` centered, and `1` right-aligned in X direction. Other numerical values may also be specified.

This object supports the following interface(s): system-start-text-interface, spanner-interface, side-position-interface, self-alignment-interface, font-interface and grob-interface.

### 3.1.47 InstrumentSwitch

InstrumentSwitch objects are created by: Instrument_switch_engraver.

Standard settings:

> `padding` (dimension, in staff space):

>   `0.5`

>   Add this much extra space between objects that are next to each other.

> `stencil` (unknown):

>   `ly:text-interface::print`

>   The symbol to print.

> `Y-offset` (number):

>   `ly:side-position-interface::y-aligned-side`

>   The vertical amount that this object is moved relative to its Y-parent.

> `X-offset` (number):

>   `ly:self-alignment-interface::x-aligned-on-self`

>   The horizontal amount that this object is moved relative to its X-parent.

> `staff-padding` (dimension, in staff space):

>   `0.5`

>   Maintain this much space between reference points and the staff. Its effect is to align objects of differing sizes (like the dynamics p and f) on their baselines.

> `direction` (direction):

>   `1`

>   If `side-axis` is `0` (or `#X`), then this property determines whether the object is placed `#LEFT`, `#CENTER` or `#RIGHT` with respect to the other object. Otherwise, it determines whether the object is placed `#UP`, `#CENTER` or `#DOWN`. Numerical values may also be used: `#UP`=`1`, `#DOWN`=`-1`, `#LEFT`=`-1`, `#RIGHT`=`1`, `#CENTER`=`0`.

> `side-axis` (number):

>   `1`

>   If the value is `#X` (or equivalently `0`), the object is placed horizontally next to the other object. If the value is `#Y` or `1`, it is placed vertically.

> `self-alignment-X` (number):

>   `-1`

>   Specify alignment of an object. The value `-1` means left aligned, `0` centered, and `1` right-aligned in X direction. Other numerical values may also be specified.

> `outside-staff-priority` (number):

>   `500`

>   If set, the grob is positioned outside the staff in such a way as to avoid all collisions. In case of a potential collision, the grob with the smaller `outside-staff-priority` is closer to the staff.

> `extra-spacing-width` (pair of numbers):

>   `'(+inf.0 . -inf.0)`

>   In the horizontal spacing problem, we pad each item by this amount (by adding the ‘car’ on the left side of the item and adding the ‘cdr’ on the right side of the item). In order to make a grob take up no horizontal space at all, set this to `(+inf.0 . -inf.0)`.

This object supports the following interface(s): text-interface, side-position-interface, self-alignment-interface, item-interface, font-interface and grob-interface.

### 3.1.48 KeyCancellation

KeyCancellation objects are created by: Key_engraver.

Standard settings:

> `stencil` (unknown):

>   `ly:key-signature-interface::print`

>   The symbol to print.

> `glyph-name-alist` (list):

>   `'((0 . accidentals.natural))`

>   An alist of key-string pairs.

> `space-alist` (list):

>   `'((time-signature extra-space . 1.25) (staff-bar extra-space . 0.6) (key-signature extra-space . 0.5) (right-edge extra-space . 0.5) (first-note fixed-space . 2.5))`

>   A table that specifies distances between prefatory items, like clef and time-signature. The format is an alist of spacing tuples: `(break-align-symbol type . distance)`, where type can be the symbols `minimum-space` or `extra-space`.

> `Y-offset` (number):

>   `ly:staff-symbol-referencer::callback`

>   The vertical amount that this object is moved relative to its Y-parent.

> `break-align-symbol` (symbol):

>   `'key-cancellation`

>   This key is used for aligning and spacing breakable items.

> `break-visibility` (vector):

>   `#(#t #t #f)`

>   A vector of 3 booleans, `#(end-of-line unbroken begin-of-line)`. `#t` means visible, `#f` means killed.

> `non-musical` (boolean):

>   `#t`

>   True if the grob belongs to a `NonMusicalPaperColumn`.

This object supports the following interface(s): staff-symbol-referencer-interface, key-signature-interface, key-cancellation-interface, item-interface, font-interface, break-aligned-interface and grob-interface.

### 3.1.49 KeySignature

KeySignature objects are created by: Key_engraver.

Standard settings:

> `stencil` (unknown):

>   `ly:key-signature-interface::print`

>   The symbol to print.

> `avoid-slur` (symbol):

>   `'inside`

>   Method of handling slur collisions. Choices are `around`, `inside`, `outside`. If unset, scripts and slurs ignore each other. `around` only moves the script if there is a collision; `outside` always moves the script.

> `glyph-name-alist` (list):

>   `'((0 . accidentals.natural) (-1/2 . accidentals.flat) (1/2 . accidentals.sharp) (1 . accidentals.doublesharp) (-1 . accidentals.flatflat) (3/4 . accidentals.sharp.slashslash.stemstemstem) (1/4 . accidentals.sharp.slashslash.stem) (-1/4 . accidentals.mirroredflat) (-3/4 . accidentals.mirroredflat.flat))`

>   An alist of key-string pairs.

> `space-alist` (list):

>   `'((time-signature extra-space . 1.15) (staff-bar extra-space . 1.1) (right-edge extra-space . 0.5) (first-note fixed-space . 2.5))`

>   A table that specifies distances between prefatory items, like clef and time-signature. The format is an alist of spacing tuples: `(break-align-symbol type . distance)`, where type can be the symbols `minimum-space` or `extra-space`.

> `Y-offset` (number):

>   `ly:staff-symbol-referencer::callback`

>   The vertical amount that this object is moved relative to its Y-parent.

> `break-align-symbol` (symbol):

>   `'key-signature`

>   This key is used for aligning and spacing breakable items.

> `break-align-anchor` (number):

>   `ly:break-aligned-interface::calc-extent-aligned-anchor`

>   Grobs aligned to this break-align grob will have their X-offsets shifted by this number. In bar lines, for example, this is used to position grobs relative to the (visual) center of the bar line.

> `break-visibility` (vector):

>   `#(#f #f #t)`

>   A vector of 3 booleans, `#(end-of-line unbroken begin-of-line)`. `#t` means visible, `#f` means killed.

> `non-musical` (boolean):

>   `#t`

>   True if the grob belongs to a `NonMusicalPaperColumn`.

This object supports the following interface(s): staff-symbol-referencer-interface, key-signature-interface, item-interface, font-interface, break-aligned-interface and grob-interface.

### 3.1.50 LaissezVibrerTie

LaissezVibrerTie objects are created by: Laissez_vibrer_engraver.

Standard settings:

> `stencil` (unknown):

>   `ly:tie::print`

>   The symbol to print.

> `control-points` (list):

>   `ly:semi-tie::calc-control-points`

>   List of offsets (number pairs) that form control points for the tie, slur, or bracket shape. For Béziers, this should list the control points of a third-order Bézier curve.

> `direction` (direction):

>   `ly:tie::calc-direction`

>   If `side-axis` is `0` (or `#X`), then this property determines whether the object is placed `#LEFT`, `#CENTER` or `#RIGHT` with respect to the other object. Otherwise, it determines whether the object is placed `#UP`, `#CENTER` or `#DOWN`. Numerical values may also be used: `#UP`=`1`, `#DOWN`=`-1`, `#LEFT`=`-1`, `#RIGHT`=`1`, `#CENTER`=`0`.

> `head-direction` (direction):

>   `-1`

>   Are the note heads left or right in a semitie?

> `thickness` (number):

>   `1.0`

>   Line thickness, generally measured in `line-thickness`.

This object supports the following interface(s): semi-tie-interface, item-interface and grob-interface.

### 3.1.51 LaissezVibrerTieColumn

LaissezVibrerTieColumn objects are created by: Laissez_vibrer_engraver.

Standard settings:

> `X-extent` (pair of numbers):

>   `#f`

>   Hard coded extent in X direction.

> `Y-extent` (pair of numbers):

>   `#f`

>   Hard coded extent in Y direction.

> `head-direction` (direction):

>   `-1`

>   Are the note heads left or right in a semitie?

This object supports the following interface(s): semi-tie-column-interface, item-interface and grob-interface.

### 3.1.52 LedgerLineSpanner

LedgerLineSpanner objects are created by: Ledger_line_engraver.

Standard settings:

> `springs-and-rods` (boolean):

>   `ly:ledger-line-spanner::set-spacing-rods`

>   Dummy variable for triggering spacing routines.

> `stencil` (unknown):

>   `ly:ledger-line-spanner::print`

>   The symbol to print.

> `X-extent` (pair of numbers):

>   `#f`

>   Hard coded extent in X direction.

> `Y-extent` (pair of numbers):

>   `#f`

>   Hard coded extent in Y direction.

> `minimum-length-fraction` (number):

>   `0.25`

>   Minimum length of ledger line as fraction of note head size.

> `length-fraction` (number):

>   `0.25`

>   Multiplier for lengths. Used for determining ledger lines and stem lengths.

> `layer` (integer):

>   `0`

>   The output layer (a value between 0 and 2): Layers define the order of printing objects. Objects in lower layers are overprinted by objects in higher layers.

This object supports the following interface(s): spanner-interface, ledger-line-spanner-interface and grob-interface.

### 3.1.53 LeftEdge

LeftEdge objects are created by: Break_align_engraver.

Standard settings:

> `break-align-symbol` (symbol):

>   `'left-edge`

>   This key is used for aligning and spacing breakable items.

> `break-align-anchor` (number):

>   `ly:break-aligned-interface::calc-extent-aligned-anchor`

>   Grobs aligned to this break-align grob will have their X-offsets shifted by this number. In bar lines, for example, this is used to position grobs relative to the (visual) center of the bar line.

> `X-extent` (pair of numbers):

>   `'(0 . 0)`

>   Hard coded extent in X direction.

> `non-musical` (boolean):

>   `#t`

>   True if the grob belongs to a `NonMusicalPaperColumn`.

> `break-visibility` (vector):

>   `#(#t #f #t)`

>   A vector of 3 booleans, `#(end-of-line unbroken begin-of-line)`. `#t` means visible, `#f` means killed.

> `space-alist` (list):

>   `'((custos extra-space . 0.0) (ambitus extra-space . 2.0) (time-signature extra-space . 1.0) (staff-bar extra-space . 0.0) (breathing-sign minimum-space . 0.0) (clef extra-space . 0.8) (first-note fixed-space . 2.0) (right-edge extra-space . 0.0) (key-signature extra-space . 0.0) (key-cancellation extra-space . 0.0))`

>   A table that specifies distances between prefatory items, like clef and time-signature. The format is an alist of spacing tuples: `(break-align-symbol type . distance)`, where type can be the symbols `minimum-space` or `extra-space`.

This object supports the following interface(s): item-interface, break-aligned-interface and grob-interface.

### 3.1.54 LigatureBracket

LigatureBracket objects are created by: Ligature_bracket_engraver.

Standard settings:

> `padding` (dimension, in staff space):

>   `2.0`

>   Add this much extra space between objects that are next to each other.

> `thickness` (number):

>   `1.6`

>   Line thickness, generally measured in `line-thickness`.

> `edge-height` (pair):

>   `'(0.7 . 0.7)`

>   A pair of numbers specifying the heights of the vertical edges: `(left-height . right-height)`.

> `shorten-pair` (pair of numbers):

>   `'(-0.2 . -0.2)`

>   The lengths to shorten a text-spanner on both sides, for example a pedal bracket. Positive values shorten the text-spanner, while negative values lengthen it.

> `direction` (direction):

>   `1`

>   If `side-axis` is `0` (or `#X`), then this property determines whether the object is placed `#LEFT`, `#CENTER` or `#RIGHT` with respect to the other object. Otherwise, it determines whether the object is placed `#UP`, `#CENTER` or `#DOWN`. Numerical values may also be used: `#UP`=`1`, `#DOWN`=`-1`, `#LEFT`=`-1`, `#RIGHT`=`1`, `#CENTER`=`0`.

> `positions` (pair of numbers):

>   `ly:tuplet-bracket::calc-positions`

>   Pair of staff coordinates `(left . right)`, where both left and right are in `staff-space` units of the current staff. For slurs, this value selects which slur candidate to use; if extreme positions are requested, the closest one is taken.

> `stencil` (unknown):

>   `ly:tuplet-bracket::print`

>   The symbol to print.

> `staff-padding` (dimension, in staff space):

>   `0.25`

>   Maintain this much space between reference points and the staff. Its effect is to align objects of differing sizes (like the dynamics p and f) on their baselines.

> `connect-to-neighbor` (pair):

>   `ly:tuplet-bracket::calc-connect-to-neighbors`

>   Pair of booleans, indicating whether this grob looks as a continued break.

> `control-points` (list):

>   `ly:tuplet-bracket::calc-control-points`

>   List of offsets (number pairs) that form control points for the tie, slur, or bracket shape. For Béziers, this should list the control points of a third-order Bézier curve.

This object supports the following interface(s): tuplet-bracket-interface, spanner-interface, line-interface and grob-interface.

### 3.1.55 LyricExtender

LyricExtender objects are created by: Extender_engraver.

Standard settings:

> `stencil` (unknown):

>   `ly:lyric-extender::print`

>   The symbol to print.

> `thickness` (number):

>   `0.8`

>   Line thickness, generally measured in `line-thickness`.

> `minimum-length` (dimension, in staff space):

>   `1.5`

>   Try to make a spanner at least this long, normally in the horizontal direction. This requires an appropriate callback for the `springs-and-rods` property. If added to a `Tie`, this sets the minimum distance between noteheads.

> `Y-extent` (pair of numbers):

>   `'(0 . 0)`

>   Hard coded extent in Y direction.

This object supports the following interface(s): spanner-interface, lyric-interface, lyric-extender-interface and grob-interface.

### 3.1.56 LyricHyphen

LyricHyphen objects are created by: Hyphen_engraver.

Standard settings:

> `thickness` (number):

>   `1.3`

>   Line thickness, generally measured in `line-thickness`.

> `height` (dimension, in staff space):

>   `0.42`

>   Height of an object in `staff-space` units.

> `dash-period` (number):

>   `10.0`

>   The length of one dash together with whitespace. If negative, no line is drawn at all.

> `length` (dimension, in staff space):

>   `0.66`

>   User override for the stem length of unbeamed stems.

> `minimum-length` (dimension, in staff space):

>   `0.3`

>   Try to make a spanner at least this long, normally in the horizontal direction. This requires an appropriate callback for the `springs-and-rods` property. If added to a `Tie`, this sets the minimum distance between noteheads.

> `minimum-distance` (dimension, in staff space):

>   `0.1`

>   Minimum distance between rest and notes or beam.

> `padding` (dimension, in staff space):

>   `0.07`

>   Add this much extra space between objects that are next to each other.

> `springs-and-rods` (boolean):

>   `ly:lyric-hyphen::set-spacing-rods`

>   Dummy variable for triggering spacing routines.

> `stencil` (unknown):

>   `ly:lyric-hyphen::print`

>   The symbol to print.

> `Y-extent` (pair of numbers):

>   `'(0 . 0)`

>   Hard coded extent in Y direction.

This object supports the following interface(s): spanner-interface, lyric-interface, lyric-hyphen-interface, font-interface and grob-interface.

### 3.1.57 LyricSpace

LyricSpace objects are created by: Hyphen_engraver.

Standard settings:

> `minimum-distance` (dimension, in staff space):

>   `0.45`

>   Minimum distance between rest and notes or beam.

> `springs-and-rods` (boolean):

>   `ly:lyric-hyphen::set-spacing-rods`

>   Dummy variable for triggering spacing routines.

> `padding` (dimension, in staff space):

>   `0.0`

>   Add this much extra space between objects that are next to each other.

> `Y-extent` (pair of numbers):

>   `#f`

>   Hard coded extent in Y direction.

> `X-extent` (pair of numbers):

>   `#f`

>   Hard coded extent in X direction.

This object supports the following interface(s): spanner-interface, lyric-hyphen-interface and grob-interface.

### 3.1.58 LyricText

LyricText objects are created by: Lyric_engraver.

Standard settings:

> `stencil` (unknown):

>   `lyric-text::print`

>   The symbol to print.

> `text` (markup):

>   `#<procedure #f (grob)>`

>   Text markup. See Formatting text.

> `X-offset` (number):

>   `ly:self-alignment-interface::aligned-on-x-parent`

>   The horizontal amount that this object is moved relative to its X-parent.

> `self-alignment-X` (number):

>   `0`

>   Specify alignment of an object. The value `-1` means left aligned, `0` centered, and `1` right-aligned in X direction. Other numerical values may also be specified.

> `word-space` (dimension, in staff space):

>   `0.6`

>   Space to insert between words in texts.

> `font-series` (symbol):

>   `'bold-narrow`

>   Select the series of a font. Choices include `medium`, `bold`, `bold-narrow`, etc.

> `font-size` (number):

>   `1.0`

>   The font size, compared to the ‘normal’ size. `0` is style-sheet’s normal size, `-1` is smaller, `+1` is bigger. Each step of 1 is approximately 12% larger; 6 steps are exactly a factor 2 larger. Fractional values are allowed.

> `extra-spacing-width` (pair of numbers):

>   `'(0.0 . 0.0)`

>   In the horizontal spacing problem, we pad each item by this amount (by adding the ‘car’ on the left side of the item and adding the ‘cdr’ on the right side of the item). In order to make a grob take up no horizontal space at all, set this to `(+inf.0 . -inf.0)`.

This object supports the following interface(s): text-interface, self-alignment-interface, rhythmic-grob-interface, lyric-syllable-interface, item-interface, font-interface and grob-interface.

### 3.1.59 MeasureGrouping

MeasureGrouping objects are created by: Measure_grouping_engraver.

Standard settings:

> `Y-offset` (number):

>   `ly:side-position-interface::y-aligned-side`

>   The vertical amount that this object is moved relative to its Y-parent.

> `side-axis` (number):

>   `1`

>   If the value is `#X` (or equivalently `0`), the object is placed horizontally next to the other object. If the value is `#Y` or `1`, it is placed vertically.

> `stencil` (unknown):

>   `ly:measure-grouping::print`

>   The symbol to print.

> `padding` (dimension, in staff space):

>   `2`

>   Add this much extra space between objects that are next to each other.

> `direction` (direction):

>   `1`

>   If `side-axis` is `0` (or `#X`), then this property determines whether the object is placed `#LEFT`, `#CENTER` or `#RIGHT` with respect to the other object. Otherwise, it determines whether the object is placed `#UP`, `#CENTER` or `#DOWN`. Numerical values may also be used: `#UP`=`1`, `#DOWN`=`-1`, `#LEFT`=`-1`, `#RIGHT`=`1`, `#CENTER`=`0`.

> `thickness` (number):

>   `1`

>   Line thickness, generally measured in `line-thickness`.

> `height` (dimension, in staff space):

>   `2.0`

>   Height of an object in `staff-space` units.

> `staff-padding` (dimension, in staff space):

>   `3`

>   Maintain this much space between reference points and the staff. Its effect is to align objects of differing sizes (like the dynamics p and f) on their baselines.

This object supports the following interface(s): spanner-interface, side-position-interface, measure-grouping-interface and grob-interface.

### 3.1.60 MelodyItem

MelodyItem objects are created by: Melody_engraver.

Standard settings:

> `neutral-direction` (direction):

>   `-1`

>   Which direction to take in the center of the staff.

This object supports the following interface(s): melody-spanner-interface, item-interface and grob-interface.

### 3.1.61 MensuralLigature

MensuralLigature objects are created by: Mensural_ligature_engraver.

Standard settings:

> `thickness` (number):

>   `1.4`

>   Line thickness, generally measured in `line-thickness`.

> `stencil` (unknown):

>   `ly:mensural-ligature::print`

>   The symbol to print.

This object supports the following interface(s): spanner-interface, mensural-ligature-interface, font-interface and grob-interface.

### 3.1.62 MetronomeMark

MetronomeMark objects are created by: Metronome_mark_engraver.

Standard settings:

> `stencil` (unknown):

>   `ly:text-interface::print`

>   The symbol to print.

> `Y-offset` (number):

>   `ly:side-position-interface::y-aligned-side`

>   The vertical amount that this object is moved relative to its Y-parent.

> `direction` (direction):

>   `1`

>   If `side-axis` is `0` (or `#X`), then this property determines whether the object is placed `#LEFT`, `#CENTER` or `#RIGHT` with respect to the other object. Otherwise, it determines whether the object is placed `#UP`, `#CENTER` or `#DOWN`. Numerical values may also be used: `#UP`=`1`, `#DOWN`=`-1`, `#LEFT`=`-1`, `#RIGHT`=`1`, `#CENTER`=`0`.

> `padding` (dimension, in staff space):

>   `0.8`

>   Add this much extra space between objects that are next to each other.

> `side-axis` (number):

>   `1`

>   If the value is `#X` (or equivalently `0`), the object is placed horizontally next to the other object. If the value is `#Y` or `1`, it is placed vertically.

> `extra-spacing-width` (pair of numbers):

>   `'(+inf.0 . -inf.0)`

>   In the horizontal spacing problem, we pad each item by this amount (by adding the ‘car’ on the left side of the item and adding the ‘cdr’ on the right side of the item). In order to make a grob take up no horizontal space at all, set this to `(+inf.0 . -inf.0)`.

> `outside-staff-priority` (number):

>   `1000`

>   If set, the grob is positioned outside the staff in such a way as to avoid all collisions. In case of a potential collision, the grob with the smaller `outside-staff-priority` is closer to the staff.

This object supports the following interface(s): text-interface, side-position-interface, metronome-mark-interface, item-interface, font-interface and grob-interface.

### 3.1.63 MultiMeasureRest

MultiMeasureRest objects are created by: Multi_measure_rest_engraver.

Standard settings:

> `stencil` (unknown):

>   `ly:multi-measure-rest::print`

>   The symbol to print.

> `springs-and-rods` (boolean):

>   `ly:multi-measure-rest::set-spacing-rods`

>   Dummy variable for triggering spacing routines.

> `Y-offset` (number):

>   `ly:staff-symbol-referencer::callback`

>   The vertical amount that this object is moved relative to its Y-parent.

> `staff-position` (number):

>   `0`

>   Vertical position, measured in half staff spaces, counted from the middle line.

> `expand-limit` (integer):

>   `10`

>   Maximum number of measures expanded in church rests.

> `thick-thickness` (number):

>   `6.6`

>   Bar line thickness, measured in `line-thickness`.

> `hair-thickness` (number):

>   `2.0`

>   Thickness of the thin line in a bar line.

> `padding` (dimension, in staff space):

>   `1`

>   Add this much extra space between objects that are next to each other.

This object supports the following interface(s): staff-symbol-referencer-interface, spanner-interface, rest-interface, multi-measure-rest-interface, multi-measure-interface, font-interface and grob-interface.

### 3.1.64 MultiMeasureRestNumber

MultiMeasureRestNumber objects are created by: Multi_measure_rest_engraver.

Standard settings:

> `bound-padding` (number):

>   `2.0`

>   The amount of padding to insert around spanner bounds.

> `springs-and-rods` (boolean):

>   `ly:multi-measure-rest::set-text-rods`

>   Dummy variable for triggering spacing routines.

> `stencil` (unknown):

>   `ly:text-interface::print`

>   The symbol to print.

> `X-offset` (number):

>   `#<simple-closure (#<primitive-generic +> #<simple-closure (#<primitive-procedure ly:self-alignment-interface::x-aligned-on-self>) > #<simple-closure (#<primitive-procedure ly:self-alignment-interface::x-centered-on-y-parent>) >) >`

>   The horizontal amount that this object is moved relative to its X-parent.

> `Y-offset` (number):

>   `ly:side-position-interface::y-aligned-side`

>   The vertical amount that this object is moved relative to its Y-parent.

> `side-axis` (number):

>   `1`

>   If the value is `#X` (or equivalently `0`), the object is placed horizontally next to the other object. If the value is `#Y` or `1`, it is placed vertically.

> `self-alignment-X` (number):

>   `0`

>   Specify alignment of an object. The value `-1` means left aligned, `0` centered, and `1` right-aligned in X direction. Other numerical values may also be specified.

> `direction` (direction):

>   `1`

>   If `side-axis` is `0` (or `#X`), then this property determines whether the object is placed `#LEFT`, `#CENTER` or `#RIGHT` with respect to the other object. Otherwise, it determines whether the object is placed `#UP`, `#CENTER` or `#DOWN`. Numerical values may also be used: `#UP`=`1`, `#DOWN`=`-1`, `#LEFT`=`-1`, `#RIGHT`=`1`, `#CENTER`=`0`.

> `padding` (dimension, in staff space):

>   `0.4`

>   Add this much extra space between objects that are next to each other.

> `staff-padding` (dimension, in staff space):

>   `0.4`

>   Maintain this much space between reference points and the staff. Its effect is to align objects of differing sizes (like the dynamics p and f) on their baselines.

> `font-encoding` (symbol):

>   `'fetaNumber`

>   The font encoding is the broadest category for selecting a font. Currently, only lilypond’s system fonts (Emmentaler and Aybabtu) are using this property. Available values are `fetaMusic` (Emmentaler), `fetaBraces` (Aybabtu), `fetaNumber` (Emmentaler), and `fetaDynamic` (Emmentaler).

This object supports the following interface(s): text-interface, spanner-interface, side-position-interface, self-alignment-interface, multi-measure-interface, font-interface and grob-interface.

### 3.1.65 MultiMeasureRestText

MultiMeasureRestText objects are created by: Multi_measure_rest_engraver.

Standard settings:

> `stencil` (unknown):

>   `ly:text-interface::print`

>   The symbol to print.

> `X-offset` (number):

>   `#<simple-closure (#<primitive-generic +> #<simple-closure (#<primitive-procedure ly:self-alignment-interface::x-centered-on-y-parent>) > #<simple-closure (#<primitive-procedure ly:self-alignment-interface::x-aligned-on-self>) >) >`

>   The horizontal amount that this object is moved relative to its X-parent.

> `Y-offset` (number):

>   `ly:side-position-interface::y-aligned-side`

>   The vertical amount that this object is moved relative to its Y-parent.

> `self-alignment-X` (number):

>   `0`

>   Specify alignment of an object. The value `-1` means left aligned, `0` centered, and `1` right-aligned in X direction. Other numerical values may also be specified.

> `direction` (direction):

>   `1`

>   If `side-axis` is `0` (or `#X`), then this property determines whether the object is placed `#LEFT`, `#CENTER` or `#RIGHT` with respect to the other object. Otherwise, it determines whether the object is placed `#UP`, `#CENTER` or `#DOWN`. Numerical values may also be used: `#UP`=`1`, `#DOWN`=`-1`, `#LEFT`=`-1`, `#RIGHT`=`1`, `#CENTER`=`0`.

> `padding` (dimension, in staff space):

>   `0.2`

>   Add this much extra space between objects that are next to each other.

> `staff-padding` (dimension, in staff space):

>   `0.25`

>   Maintain this much space between reference points and the staff. Its effect is to align objects of differing sizes (like the dynamics p and f) on their baselines.

> `outside-staff-priority` (number):

>   `450`

>   If set, the grob is positioned outside the staff in such a way as to avoid all collisions. In case of a potential collision, the grob with the smaller `outside-staff-priority` is closer to the staff.

This object supports the following interface(s): text-interface, spanner-interface, side-position-interface, self-alignment-interface, multi-measure-interface, font-interface and grob-interface.

### 3.1.66 NonMusicalPaperColumn

NonMusicalPaperColumn objects are created by: Paper_column_engraver.

Standard settings:

> `allow-loose-spacing` (boolean):

>   `#t`

>   If set, column can be detached from main spacing.

> `axes` (list):

>   `'(0)`

>   List of axis numbers. In the case of alignment grobs, this should contain only one number.

> `before-line-breaking` (boolean):

>   `ly:paper-column::before-line-breaking`

>   Dummy property, used to trigger a callback function.

> `X-extent` (pair of numbers):

>   `ly:axis-group-interface::width`

>   Hard coded extent in X direction.

> `horizontal-skylines` (unknown):

>   `ly:separation-item::calc-skylines`

>   Two skylines, one to the left and one to the right of this grob.

> `non-musical` (boolean):

>   `#t`

>   True if the grob belongs to a `NonMusicalPaperColumn`.

> `line-break-permission` (symbol):

>   `'allow`

>   Instructs the line breaker on whether to put a line break at this column. Can be `force` or `allow`.

> `page-break-permission` (symbol):

>   `'allow`

>   Instructs the page breaker on whether to put a page break at this column. Can be `force` or `allow`.

> `full-measure-extra-space` (number):

>   `1.0`

>   Extra space that is allocated at the beginning of a measure with only one note. This property is read from the NonMusicalPaperColumn that begins the measure.

This object supports the following interface(s): spaceable-grob-interface, separation-item-interface, paper-column-interface, item-interface, font-interface, axis-group-interface and grob-interface.

### 3.1.67 NoteCollision

NoteCollision objects are created by: Collision_engraver.

Standard settings:

> `axes` (list):

>   `'(0 1)`

>   List of axis numbers. In the case of alignment grobs, this should contain only one number.

> `X-extent` (pair of numbers):

>   `ly:axis-group-interface::width`

>   Hard coded extent in X direction.

> `Y-extent` (pair of numbers):

>   `ly:axis-group-interface::height`

>   Hard coded extent in Y direction.

> `prefer-dotted-right` (boolean):

>   `#t`

>   For note collisions, prefer to shift dotted up-note to the right, rather than shifting just the dot.

This object supports the following interface(s): note-collision-interface, item-interface, axis-group-interface and grob-interface.

### 3.1.68 NoteColumn

NoteColumn objects are created by: Rhythmic_column_engraver.

Standard settings:

> `axes` (list):

>   `'(0 1)`

>   List of axis numbers. In the case of alignment grobs, this should contain only one number.

> `X-extent` (pair of numbers):

>   `ly:axis-group-interface::width`

>   Hard coded extent in X direction.

> `Y-extent` (pair of numbers):

>   `ly:axis-group-interface::height`

>   Hard coded extent in Y direction.

> `horizontal-skylines` (unknown):

>   `ly:separation-item::calc-skylines`

>   Two skylines, one to the left and one to the right of this grob.

This object supports the following interface(s): separation-item-interface, note-column-interface, item-interface, axis-group-interface and grob-interface.

### 3.1.69 NoteHead

NoteHead objects are created by: Completion_heads_engraver, Drum_notes_engraver and Note_heads_engraver.

Standard settings:

> `stencil` (unknown):

>   `ly:note-head::print`

>   The symbol to print.

> `duration-log` (integer):

>   `note-head::calc-duration-log`

>   The 2-log of the note head duration, i.e., `0` = whole note, `1` = half note, etc.

> `stem-attachment` (pair of numbers):

>   `ly:note-head::calc-stem-attachment`

>   An `(x . y)` pair where the stem attaches to the notehead.

> `Y-offset` (number):

>   `ly:staff-symbol-referencer::callback`

>   The vertical amount that this object is moved relative to its Y-parent.

> `X-offset` (number):

>   `ly:note-head::stem-x-shift`

>   The horizontal amount that this object is moved relative to its X-parent.

This object supports the following interface(s): vaticana-ligature-interface, staff-symbol-referencer-interface, rhythmic-head-interface, rhythmic-grob-interface, note-head-interface, mensural-ligature-interface, ledgered-interface, item-interface, gregorian-ligature-interface, font-interface and grob-interface.

### 3.1.70 NoteName

NoteName objects are created by: Note_name_engraver.

Standard settings:

> `stencil` (unknown):

>   `ly:text-interface::print`

>   The symbol to print.

This object supports the following interface(s): text-interface, note-name-interface, item-interface, font-interface and grob-interface.

### 3.1.71 NoteSpacing

NoteSpacing objects are created by: Note_spacing_engraver.

Standard settings:

> `stem-spacing-correction` (number):

>   `0.5`

>   Optical correction amount for stems that are placed in tight configurations. For opposite directions, this amount is the correction for two normal sized stems that overlap completely.

> `same-direction-correction` (number):

>   `0.25`

>   Optical correction amount for stems that are placed in tight configurations. This amount is used for stems with the same direction to compensate for note head to stem distance.

> `space-to-barline` (boolean):

>   `#t`

>   If set, the distance between a note and the following non-musical column will be measured to the bar line instead of to the beginning of the non-musical column. If there is a clef change followed by a bar line, for example, this means that we will try to space the non-musical column as though the clef is not there.

> `knee-spacing-correction` (number):

>   `1.0`

>   Factor for the optical correction amount for kneed beams. Set between `0` for no correction and `1` for full correction.

This object supports the following interface(s): spacing-interface, note-spacing-interface, item-interface and grob-interface.

### 3.1.72 OctavateEight

OctavateEight objects are created by: Clef_engraver.

Standard settings:

> `self-alignment-X` (number):

>   `0`

>   Specify alignment of an object. The value `-1` means left aligned, `0` centered, and `1` right-aligned in X direction. Other numerical values may also be specified.

> `break-visibility` (vector):

>   `#(#f #f #t)`

>   A vector of 3 booleans, `#(end-of-line unbroken begin-of-line)`. `#t` means visible, `#f` means killed.

> `X-offset` (number):

>   `#<simple-closure (#<primitive-generic +> #<simple-closure (#<primitive-procedure ly:self-alignment-interface::x-aligned-on-self>) > #<simple-closure (#<primitive-procedure ly:self-alignment-interface::centered-on-x-parent>) >) >`

>   The horizontal amount that this object is moved relative to its X-parent.

> `Y-offset` (number):

>   `ly:side-position-interface::y-aligned-side`

>   The vertical amount that this object is moved relative to its Y-parent.

> `stencil` (unknown):

>   `ly:text-interface::print`

>   The symbol to print.

> `font-shape` (symbol):

>   `'italic`

>   Select the shape of a font. Choices include `upright`, `italic`, `caps`.

> `staff-padding` (dimension, in staff space):

>   `0.2`

>   Maintain this much space between reference points and the staff. Its effect is to align objects of differing sizes (like the dynamics p and f) on their baselines.

> `font-size` (number):

>   `-4`

>   The font size, compared to the ‘normal’ size. `0` is style-sheet’s normal size, `-1` is smaller, `+1` is bigger. Each step of 1 is approximately 12% larger; 6 steps are exactly a factor 2 larger. Fractional values are allowed.

This object supports the following interface(s): text-interface, side-position-interface, self-alignment-interface, item-interface, font-interface and grob-interface.

### 3.1.73 OttavaBracket

OttavaBracket objects are created by: Ottava_spanner_engraver.

Standard settings:

> `Y-offset` (number):

>   `ly:side-position-interface::y-aligned-side`

>   The vertical amount that this object is moved relative to its Y-parent.

> `stencil` (unknown):

>   `ly:ottava-bracket::print`

>   The symbol to print.

> `font-shape` (symbol):

>   `'italic`

>   Select the shape of a font. Choices include `upright`, `italic`, `caps`.

> `shorten-pair` (pair of numbers):

>   `'(0.0 . -0.6)`

>   The lengths to shorten a text-spanner on both sides, for example a pedal bracket. Positive values shorten the text-spanner, while negative values lengthen it.

> `staff-padding` (dimension, in staff space):

>   `1.0`

>   Maintain this much space between reference points and the staff. Its effect is to align objects of differing sizes (like the dynamics p and f) on their baselines.

> `padding` (dimension, in staff space):

>   `0.5`

>   Add this much extra space between objects that are next to each other.

> `minimum-length` (dimension, in staff space):

>   `1.0`

>   Try to make a spanner at least this long, normally in the horizontal direction. This requires an appropriate callback for the `springs-and-rods` property. If added to a `Tie`, this sets the minimum distance between noteheads.

> `style` (symbol):

>   `'dashed-line`

>   This setting determines in what style a grob is typeset. Valid choices depend on the `stencil` callback reading this property.

> `dash-fraction` (number):

>   `0.3`

>   Size of the dashes, relative to `dash-period`. Should be between `0.0` (no line) and `1.0` (continuous line).

> `edge-height` (pair):

>   `'(0 . 1.2)`

>   A pair of numbers specifying the heights of the vertical edges: `(left-height . right-height)`.

> `direction` (direction):

>   `1`

>   If `side-axis` is `0` (or `#X`), then this property determines whether the object is placed `#LEFT`, `#CENTER` or `#RIGHT` with respect to the other object. Otherwise, it determines whether the object is placed `#UP`, `#CENTER` or `#DOWN`. Numerical values may also be used: `#UP`=`1`, `#DOWN`=`-1`, `#LEFT`=`-1`, `#RIGHT`=`1`, `#CENTER`=`0`.

> `outside-staff-priority` (number):

>   `400`

>   If set, the grob is positioned outside the staff in such a way as to avoid all collisions. In case of a potential collision, the grob with the smaller `outside-staff-priority` is closer to the staff.

This object supports the following interface(s): text-interface, spanner-interface, side-position-interface, ottava-bracket-interface, line-interface, horizontal-bracket-interface, font-interface and grob-interface.

### 3.1.74 PaperColumn

PaperColumn objects are created by: Paper_column_engraver.

Standard settings:

> `axes` (list):

>   `'(0)`

>   List of axis numbers. In the case of alignment grobs, this should contain only one number.

> `allow-loose-spacing` (boolean):

>   `#t`

>   If set, column can be detached from main spacing.

> `before-line-breaking` (boolean):

>   `ly:paper-column::before-line-breaking`

>   Dummy property, used to trigger a callback function.

> `horizontal-skylines` (unknown):

>   `ly:separation-item::calc-skylines`

>   Two skylines, one to the left and one to the right of this grob.

> `X-extent` (pair of numbers):

>   `ly:axis-group-interface::width`

>   Hard coded extent in X direction.

This object supports the following interface(s): spaceable-grob-interface, separation-item-interface, paper-column-interface, item-interface, font-interface, axis-group-interface and grob-interface.

### 3.1.75 ParenthesesItem

ParenthesesItem objects are created by: Parenthesis_engraver.

Standard settings:

> `stencil` (unknown):

>   `parentheses-item::print`

>   The symbol to print.

> `stencils` (list):

>   `parentheses-item::calc-parenthesis-stencils`

>   Multiple stencils, used as intermediate value.

> `font-size` (number):

>   `-6`

>   The font size, compared to the ‘normal’ size. `0` is style-sheet’s normal size, `-1` is smaller, `+1` is bigger. Each step of 1 is approximately 12% larger; 6 steps are exactly a factor 2 larger. Fractional values are allowed.

> `padding` (dimension, in staff space):

>   `0.2`

>   Add this much extra space between objects that are next to each other.

This object supports the following interface(s): parentheses-interface, item-interface, font-interface and grob-interface.

### 3.1.76 PercentRepeat

PercentRepeat objects are created by: Percent_repeat_engraver.

Standard settings:

> `springs-and-rods` (boolean):

>   `ly:multi-measure-rest::set-spacing-rods`

>   Dummy variable for triggering spacing routines.

> `stencil` (unknown):

>   `ly:multi-measure-rest::percent`

>   The symbol to print.

> `slope` (number):

>   `1.0`

>   The slope of this object.

> `thickness` (number):

>   `0.48`

>   Line thickness, generally measured in `line-thickness`.

> `dot-negative-kern` (number):

>   `0.75`

>   The space to remove between a dot and a slash in percent repeat glyphs. Larger values bring the two elements closer together.

> `font-encoding` (symbol):

>   `'fetaMusic`

>   The font encoding is the broadest category for selecting a font. Currently, only lilypond’s system fonts (Emmentaler and Aybabtu) are using this property. Available values are `fetaMusic` (Emmentaler), `fetaBraces` (Aybabtu), `fetaNumber` (Emmentaler), and `fetaDynamic` (Emmentaler).

This object supports the following interface(s): spanner-interface, percent-repeat-interface, multi-measure-rest-interface, font-interface and grob-interface.

### 3.1.77 PercentRepeatCounter

PercentRepeatCounter objects are created by: Percent_repeat_engraver.

Standard settings:

> `stencil` (unknown):

>   `ly:text-interface::print`

>   The symbol to print.

> `X-offset` (number):

>   `#<simple-closure (#<primitive-generic +> #<simple-closure (#<primitive-procedure ly:self-alignment-interface::x-centered-on-y-parent>) > #<simple-closure (#<primitive-procedure ly:self-alignment-interface::x-aligned-on-self>) >) >`

>   The horizontal amount that this object is moved relative to its X-parent.

> `Y-offset` (number):

>   `ly:side-position-interface::y-aligned-side`

>   The vertical amount that this object is moved relative to its Y-parent.

> `self-alignment-X` (number):

>   `0`

>   Specify alignment of an object. The value `-1` means left aligned, `0` centered, and `1` right-aligned in X direction. Other numerical values may also be specified.

> `direction` (direction):

>   `1`

>   If `side-axis` is `0` (or `#X`), then this property determines whether the object is placed `#LEFT`, `#CENTER` or `#RIGHT` with respect to the other object. Otherwise, it determines whether the object is placed `#UP`, `#CENTER` or `#DOWN`. Numerical values may also be used: `#UP`=`1`, `#DOWN`=`-1`, `#LEFT`=`-1`, `#RIGHT`=`1`, `#CENTER`=`0`.

> `padding` (dimension, in staff space):

>   `0.2`

>   Add this much extra space between objects that are next to each other.

> `staff-padding` (dimension, in staff space):

>   `0.25`

>   Maintain this much space between reference points and the staff. Its effect is to align objects of differing sizes (like the dynamics p and f) on their baselines.

> `font-size` (number):

>   `-2`

>   The font size, compared to the ‘normal’ size. `0` is style-sheet’s normal size, `-1` is smaller, `+1` is bigger. Each step of 1 is approximately 12% larger; 6 steps are exactly a factor 2 larger. Fractional values are allowed.

> `font-encoding` (symbol):

>   `'fetaNumber`

>   The font encoding is the broadest category for selecting a font. Currently, only lilypond’s system fonts (Emmentaler and Aybabtu) are using this property. Available values are `fetaMusic` (Emmentaler), `fetaBraces` (Aybabtu), `fetaNumber` (Emmentaler), and `fetaDynamic` (Emmentaler).

This object supports the following interface(s): text-interface, spanner-interface, side-position-interface, self-alignment-interface, percent-repeat-interface, font-interface and grob-interface.

### 3.1.78 PhrasingSlur

PhrasingSlur objects are created by: Phrasing_slur_engraver.

Standard settings:

> `control-points` (list):

>   `ly:slur::calc-control-points`

>   List of offsets (number pairs) that form control points for the tie, slur, or bracket shape. For Béziers, this should list the control points of a third-order Bézier curve.

> `direction` (direction):

>   `ly:slur::calc-direction`

>   If `side-axis` is `0` (or `#X`), then this property determines whether the object is placed `#LEFT`, `#CENTER` or `#RIGHT` with respect to the other object. Otherwise, it determines whether the object is placed `#UP`, `#CENTER` or `#DOWN`. Numerical values may also be used: `#UP`=`1`, `#DOWN`=`-1`, `#LEFT`=`-1`, `#RIGHT`=`1`, `#CENTER`=`0`.

> `springs-and-rods` (boolean):

>   `ly:spanner::set-spacing-rods`

>   Dummy variable for triggering spacing routines.

> `Y-extent` (pair of numbers):

>   `ly:slur::height`

>   Hard coded extent in Y direction.

> `stencil` (unknown):

>   `ly:slur::print`

>   The symbol to print.

> `thickness` (number):

>   `1.1`

>   Line thickness, generally measured in `line-thickness`.

> `minimum-length` (dimension, in staff space):

>   `1.5`

>   Try to make a spanner at least this long, normally in the horizontal direction. This requires an appropriate callback for the `springs-and-rods` property. If added to a `Tie`, this sets the minimum distance between noteheads.

> `height-limit` (dimension, in staff space):

>   `2.0`

>   Maximum slur height: The longer the slur, the closer it is to this height.

> `ratio` (number):

>   `0.333`

>   Parameter for slur shape. The higher this number, the quicker the slur attains its `height-limit`.

This object supports the following interface(s): spanner-interface, slur-interface and grob-interface.

### 3.1.79 PianoPedalBracket

PianoPedalBracket objects are created by: Piano_pedal_engraver.

Standard settings:

> `stencil` (unknown):

>   `ly:piano-pedal-bracket::print`

>   The symbol to print.

> `style` (symbol):

>   `'line`

>   This setting determines in what style a grob is typeset. Valid choices depend on the `stencil` callback reading this property.

> `bound-padding` (number):

>   `1.0`

>   The amount of padding to insert around spanner bounds.

> `direction` (direction):

>   `-1`

>   If `side-axis` is `0` (or `#X`), then this property determines whether the object is placed `#LEFT`, `#CENTER` or `#RIGHT` with respect to the other object. Otherwise, it determines whether the object is placed `#UP`, `#CENTER` or `#DOWN`. Numerical values may also be used: `#UP`=`1`, `#DOWN`=`-1`, `#LEFT`=`-1`, `#RIGHT`=`1`, `#CENTER`=`0`.

> `bracket-flare` (pair of numbers):

>   `'(0.5 . 0.5)`

>   A pair of numbers specifying how much edges of brackets should slant outward. Value `0.0` means straight edges.

> `edge-height` (pair):

>   `'(1.0 . 1.0)`

>   A pair of numbers specifying the heights of the vertical edges: `(left-height . right-height)`.

> `shorten-pair` (pair of numbers):

>   `'(0.0 . 0.0)`

>   The lengths to shorten a text-spanner on both sides, for example a pedal bracket. Positive values shorten the text-spanner, while negative values lengthen it.

> `thickness` (number):

>   `1.0`

>   Line thickness, generally measured in `line-thickness`.

This object supports the following interface(s): spanner-interface, piano-pedal-interface, piano-pedal-bracket-interface, line-interface and grob-interface.

### 3.1.80 RehearsalMark

RehearsalMark objects are created by: Mark_engraver.

Standard settings:

> `stencil` (unknown):

>   `ly:text-interface::print`

>   The symbol to print.

> `X-offset` (number):

>   `#<simple-closure (#<primitive-generic +> #<simple-closure (#<primitive-procedure ly:break-alignable-interface::self-align-callback>) > #<simple-closure (#<primitive-procedure ly:self-alignment-interface::x-aligned-on-self>) >) >`

>   The horizontal amount that this object is moved relative to its X-parent.

> `Y-offset` (number):

>   `ly:side-position-interface::y-aligned-side`

>   The vertical amount that this object is moved relative to its Y-parent.

> `extra-spacing-width` (pair of numbers):

>   `'(+inf.0 . -inf.0)`

>   In the horizontal spacing problem, we pad each item by this amount (by adding the ‘car’ on the left side of the item and adding the ‘cdr’ on the right side of the item). In order to make a grob take up no horizontal space at all, set this to `(+inf.0 . -inf.0)`.

> `self-alignment-X` (number):

>   `0`

>   Specify alignment of an object. The value `-1` means left aligned, `0` centered, and `1` right-aligned in X direction. Other numerical values may also be specified.

> `direction` (direction):

>   `1`

>   If `side-axis` is `0` (or `#X`), then this property determines whether the object is placed `#LEFT`, `#CENTER` or `#RIGHT` with respect to the other object. Otherwise, it determines whether the object is placed `#UP`, `#CENTER` or `#DOWN`. Numerical values may also be used: `#UP`=`1`, `#DOWN`=`-1`, `#LEFT`=`-1`, `#RIGHT`=`1`, `#CENTER`=`0`.

> `non-musical` (boolean):

>   `#t`

>   True if the grob belongs to a `NonMusicalPaperColumn`.

> `font-size` (number):

>   `2`

>   The font size, compared to the ‘normal’ size. `0` is style-sheet’s normal size, `-1` is smaller, `+1` is bigger. Each step of 1 is approximately 12% larger; 6 steps are exactly a factor 2 larger. Fractional values are allowed.

> `baseline-skip` (dimension, in staff space):

>   `2`

>   Distance between base lines of multiple lines of text.

> `break-visibility` (vector):

>   `#(#f #t #t)`

>   A vector of 3 booleans, `#(end-of-line unbroken begin-of-line)`. `#t` means visible, `#f` means killed.

> `break-align-symbols` (list):

>   `'(staff-bar clef)`

>   A list of symbols that determine which break-aligned grobs to align this to. If the grob selected by the first symbol in the list is invisible due to break-visibility, we will align to the next grob (and so on).

> `padding` (dimension, in staff space):

>   `0.8`

>   Add this much extra space between objects that are next to each other.

> `outside-staff-priority` (number):

>   `1500`

>   If set, the grob is positioned outside the staff in such a way as to avoid all collisions. In case of a potential collision, the grob with the smaller `outside-staff-priority` is closer to the staff.

This object supports the following interface(s): text-interface, side-position-interface, self-alignment-interface, mark-interface, item-interface, font-interface, break-alignable-interface and grob-interface.

### 3.1.81 RepeatSlash

RepeatSlash objects are created by: Slash_repeat_engraver.

Standard settings:

> `stencil` (unknown):

>   `ly:percent-repeat-item-interface::beat-slash`

>   The symbol to print.

> `thickness` (number):

>   `0.48`

>   Line thickness, generally measured in `line-thickness`.

> `slope` (number):

>   `1.7`

>   The slope of this object.

This object supports the following interface(s): rhythmic-grob-interface, percent-repeat-item-interface, percent-repeat-interface, item-interface and grob-interface.

### 3.1.82 RepeatTie

RepeatTie objects are created by: Repeat_tie_engraver.

Standard settings:

> `stencil` (unknown):

>   `ly:tie::print`

>   The symbol to print.

> `control-points` (list):

>   `ly:semi-tie::calc-control-points`

>   List of offsets (number pairs) that form control points for the tie, slur, or bracket shape. For Béziers, this should list the control points of a third-order Bézier curve.

> `direction` (direction):

>   `ly:tie::calc-direction`

>   If `side-axis` is `0` (or `#X`), then this property determines whether the object is placed `#LEFT`, `#CENTER` or `#RIGHT` with respect to the other object. Otherwise, it determines whether the object is placed `#UP`, `#CENTER` or `#DOWN`. Numerical values may also be used: `#UP`=`1`, `#DOWN`=`-1`, `#LEFT`=`-1`, `#RIGHT`=`1`, `#CENTER`=`0`.

> `thickness` (number):

>   `1.0`

>   Line thickness, generally measured in `line-thickness`.

> `head-direction` (direction):

>   `1`

>   Are the note heads left or right in a semitie?

This object supports the following interface(s): semi-tie-interface, item-interface and grob-interface.

### 3.1.83 RepeatTieColumn

RepeatTieColumn objects are created by: Repeat_tie_engraver.

Standard settings:

> `X-extent` (pair of numbers):

>   `#f`

>   Hard coded extent in X direction.

> `Y-extent` (pair of numbers):

>   `#f`

>   Hard coded extent in Y direction.

> `direction` (direction):

>   `ly:tie::calc-direction`

>   If `side-axis` is `0` (or `#X`), then this property determines whether the object is placed `#LEFT`, `#CENTER` or `#RIGHT` with respect to the other object. Otherwise, it determines whether the object is placed `#UP`, `#CENTER` or `#DOWN`. Numerical values may also be used: `#UP`=`1`, `#DOWN`=`-1`, `#LEFT`=`-1`, `#RIGHT`=`1`, `#CENTER`=`0`.

> `head-direction` (direction):

>   `ly:semi-tie-column::calc-head-direction`

>   Are the note heads left or right in a semitie?

This object supports the following interface(s): semi-tie-column-interface, item-interface and grob-interface.

### 3.1.84 Rest

Rest objects are created by: Rest_engraver.

Standard settings:

> `stencil` (unknown):

>   `ly:rest::print`

>   The symbol to print.

> `duration-log` (integer):

>   `stem::calc-duration-log`

>   The 2-log of the note head duration, i.e., `0` = whole note, `1` = half note, etc.

> `X-extent` (pair of numbers):

>   `ly:rest::width`

>   Hard coded extent in X direction.

> `Y-extent` (pair of numbers):

>   `ly:rest::height`

>   Hard coded extent in Y direction.

> `Y-offset` (number):

>   `ly:rest::y-offset-callback`

>   The vertical amount that this object is moved relative to its Y-parent.

> `minimum-distance` (dimension, in staff space):

>   `0.25`

>   Minimum distance between rest and notes or beam.

This object supports the following interface(s): staff-symbol-referencer-interface, rhythmic-head-interface, rhythmic-grob-interface, rest-interface, item-interface, font-interface and grob-interface.

### 3.1.85 RestCollision

RestCollision objects are created by: Rest_collision_engraver.

Standard settings:

> `minimum-distance` (dimension, in staff space):

>   `0.75`

>   Minimum distance between rest and notes or beam.

This object supports the following interface(s): rest-collision-interface, item-interface and grob-interface.

### 3.1.86 Script

Script objects are created by: Drum_notes_engraver, New_fingering_engraver and Script_engraver.

Standard settings:

> `staff-padding` (dimension, in staff space):

>   `0.25`

>   Maintain this much space between reference points and the staff. Its effect is to align objects of differing sizes (like the dynamics p and f) on their baselines.

> `X-offset` (number):

>   `script-interface::calc-x-offset`

>   The horizontal amount that this object is moved relative to its X-parent.

> `Y-offset` (number):

>   `ly:side-position-interface::y-aligned-side`

>   The vertical amount that this object is moved relative to its Y-parent.

> `side-axis` (number):

>   `1`

>   If the value is `#X` (or equivalently `0`), the object is placed horizontally next to the other object. If the value is `#Y` or `1`, it is placed vertically.

> `stencil` (unknown):

>   `ly:script-interface::print`

>   The symbol to print.

> `direction` (direction):

>   `ly:script-interface::calc-direction`

>   If `side-axis` is `0` (or `#X`), then this property determines whether the object is placed `#LEFT`, `#CENTER` or `#RIGHT` with respect to the other object. Otherwise, it determines whether the object is placed `#UP`, `#CENTER` or `#DOWN`. Numerical values may also be used: `#UP`=`1`, `#DOWN`=`-1`, `#LEFT`=`-1`, `#RIGHT`=`1`, `#CENTER`=`0`.

> `font-encoding` (symbol):

>   `'fetaMusic`

>   The font encoding is the broadest category for selecting a font. Currently, only lilypond’s system fonts (Emmentaler and Aybabtu) are using this property. Available values are `fetaMusic` (Emmentaler), `fetaBraces` (Aybabtu), `fetaNumber` (Emmentaler), and `fetaDynamic` (Emmentaler).

This object supports the following interface(s): side-position-interface, script-interface, item-interface, font-interface and grob-interface.

### 3.1.87 ScriptColumn

ScriptColumn objects are created by: Script_column_engraver.

Standard settings:

> `before-line-breaking` (boolean):

>   `ly:script-column::before-line-breaking`

>   Dummy property, used to trigger a callback function.

This object supports the following interface(s): script-column-interface, item-interface and grob-interface.

### 3.1.88 ScriptRow

ScriptRow objects are created by: Script_row_engraver.

Standard settings:

> `before-line-breaking` (boolean):

>   `ly:script-column::row-before-line-breaking`

>   Dummy property, used to trigger a callback function.

This object supports the following interface(s): script-column-interface, item-interface and grob-interface.

### 3.1.89 SeparationItem

SeparationItem objects are not created by any engraver.

Standard settings:

> `avoid-slur` (symbol):

>   `'inside`

>   Method of handling slur collisions. Choices are `around`, `inside`, `outside`. If unset, scripts and slurs ignore each other. `around` only moves the script if there is a collision; `outside` always moves the script.

> `X-extent` (pair of numbers):

>   `ly:axis-group-interface::width`

>   Hard coded extent in X direction.

> `Y-extent` (pair of numbers):

>   `ly:axis-group-interface::height`

>   Hard coded extent in Y direction.

> `horizontal-skylines` (unknown):

>   `ly:separation-item::calc-skylines`

>   Two skylines, one to the left and one to the right of this grob.

> `stencil` (unknown):

>   `ly:separation-item::print`

>   The symbol to print.

This object supports the following interface(s): separation-item-interface, item-interface and grob-interface.

### 3.1.90 Slur

Slur objects are created by: Slur_engraver.

Standard settings:

> `control-points` (list):

>   `ly:slur::calc-control-points`

>   List of offsets (number pairs) that form control points for the tie, slur, or bracket shape. For Béziers, this should list the control points of a third-order Bézier curve.

> `direction` (direction):

>   `ly:slur::calc-direction`

>   If `side-axis` is `0` (or `#X`), then this property determines whether the object is placed `#LEFT`, `#CENTER` or `#RIGHT` with respect to the other object. Otherwise, it determines whether the object is placed `#UP`, `#CENTER` or `#DOWN`. Numerical values may also be used: `#UP`=`1`, `#DOWN`=`-1`, `#LEFT`=`-1`, `#RIGHT`=`1`, `#CENTER`=`0`.

> `springs-and-rods` (boolean):

>   `ly:spanner::set-spacing-rods`

>   Dummy variable for triggering spacing routines.

> `Y-extent` (pair of numbers):

>   `ly:slur::height`

>   Hard coded extent in Y direction.

> `stencil` (unknown):

>   `ly:slur::print`

>   The symbol to print.

> `thickness` (number):

>   `1.2`

>   Line thickness, generally measured in `line-thickness`.

> `line-thickness` (number):

>   `0.8`

>   The thickness of the tie or slur contour.

> `minimum-length` (dimension, in staff space):

>   `1.5`

>   Try to make a spanner at least this long, normally in the horizontal direction. This requires an appropriate callback for the `springs-and-rods` property. If added to a `Tie`, this sets the minimum distance between noteheads.

> `height-limit` (dimension, in staff space):

>   `2.0`

>   Maximum slur height: The longer the slur, the closer it is to this height.

> `ratio` (number):

>   `0.25`

>   Parameter for slur shape. The higher this number, the quicker the slur attains its `height-limit`.

> `avoid-slur` (symbol):

>   `'inside`

>   Method of handling slur collisions. Choices are `around`, `inside`, `outside`. If unset, scripts and slurs ignore each other. `around` only moves the script if there is a collision; `outside` always moves the script.

This object supports the following interface(s): spanner-interface, slur-interface and grob-interface.

### 3.1.91 SostenutoPedal

SostenutoPedal objects are created by: Piano_pedal_engraver.

Standard settings:

> `stencil` (unknown):

>   `ly:text-interface::print`

>   The symbol to print.

> `direction` (direction):

>   `1`

>   If `side-axis` is `0` (or `#X`), then this property determines whether the object is placed `#LEFT`, `#CENTER` or `#RIGHT` with respect to the other object. Otherwise, it determines whether the object is placed `#UP`, `#CENTER` or `#DOWN`. Numerical values may also be used: `#UP`=`1`, `#DOWN`=`-1`, `#LEFT`=`-1`, `#RIGHT`=`1`, `#CENTER`=`0`.

> `X-offset` (number):

>   `ly:self-alignment-interface::x-aligned-on-self`

>   The horizontal amount that this object is moved relative to its X-parent.

> `extra-spacing-width` (pair of numbers):

>   `'(+inf.0 . -inf.0)`

>   In the horizontal spacing problem, we pad each item by this amount (by adding the ‘car’ on the left side of the item and adding the ‘cdr’ on the right side of the item). In order to make a grob take up no horizontal space at all, set this to `(+inf.0 . -inf.0)`.

> `padding` (dimension, in staff space):

>   `0.0`

>   Add this much extra space between objects that are next to each other.

> `font-shape` (symbol):

>   `'italic`

>   Select the shape of a font. Choices include `upright`, `italic`, `caps`.

> `self-alignment-X` (number):

>   `0`

>   Specify alignment of an object. The value `-1` means left aligned, `0` centered, and `1` right-aligned in X direction. Other numerical values may also be specified.

This object supports the following interface(s): text-interface, self-alignment-interface, piano-pedal-script-interface, item-interface, font-interface and grob-interface.

### 3.1.92 SostenutoPedalLineSpanner

SostenutoPedalLineSpanner objects are created by: Piano_pedal_align_engraver.

Standard settings:

> `axes` (list):

>   `'(1)`

>   List of axis numbers. In the case of alignment grobs, this should contain only one number.

> `Y-extent` (pair of numbers):

>   `ly:axis-group-interface::height`

>   Hard coded extent in Y direction.

> `X-extent` (pair of numbers):

>   `ly:axis-group-interface::width`

>   Hard coded extent in X direction.

> `Y-offset` (number):

>   `ly:side-position-interface::y-aligned-side`

>   The vertical amount that this object is moved relative to its Y-parent.

> `outside-staff-priority` (number):

>   `1000`

>   If set, the grob is positioned outside the staff in such a way as to avoid all collisions. In case of a potential collision, the grob with the smaller `outside-staff-priority` is closer to the staff.

> `side-axis` (number):

>   `1`

>   If the value is `#X` (or equivalently `0`), the object is placed horizontally next to the other object. If the value is `#Y` or `1`, it is placed vertically.

> `staff-padding` (dimension, in staff space):

>   `1.0`

>   Maintain this much space between reference points and the staff. Its effect is to align objects of differing sizes (like the dynamics p and f) on their baselines.

> `padding` (dimension, in staff space):

>   `1.2`

>   Add this much extra space between objects that are next to each other.

> `minimum-space` (dimension, in staff space):

>   `1.0`

>   Minimum distance that the victim should move (after padding).

> `direction` (direction):

>   `-1`

>   If `side-axis` is `0` (or `#X`), then this property determines whether the object is placed `#LEFT`, `#CENTER` or `#RIGHT` with respect to the other object. Otherwise, it determines whether the object is placed `#UP`, `#CENTER` or `#DOWN`. Numerical values may also be used: `#UP`=`1`, `#DOWN`=`-1`, `#LEFT`=`-1`, `#RIGHT`=`1`, `#CENTER`=`0`.

This object supports the following interface(s): spanner-interface, side-position-interface, piano-pedal-interface, axis-group-interface and grob-interface.

### 3.1.93 SpacingSpanner

SpacingSpanner objects are created by: Spacing_engraver.

Standard settings:

> `springs-and-rods` (boolean):

>   `ly:spacing-spanner::set-springs`

>   Dummy variable for triggering spacing routines.

> `common-shortest-duration` (moment):

>   `ly:spacing-spanner::calc-common-shortest-duration`

>   The most common shortest note length. This is used in spacing. Enlarging this sets the score tighter.

> `average-spacing-wishes` (boolean):

>   `#t`

>   If set, the spacing wishes are averaged over staves.

> `shortest-duration-space` (dimension, in staff space):

>   `2.0`

>   Start with this much space for the shortest duration. This is expressed in `spacing-increment` as unit. See also spacing-spanner-interface.

> `spacing-increment` (number):

>   `1.2`

>   Add this much space for a doubled duration. Typically, the width of a note head. See also spacing-spanner-interface.

> `base-shortest-duration` (moment):

>   `#<Mom 3/16>`

>   Spacing is based on the shortest notes in a piece. Normally, pieces are spaced as if notes at least as short as this are present.

This object supports the following interface(s): spanner-interface, spacing-spanner-interface, spacing-options-interface and grob-interface.

### 3.1.94 SpanBar

SpanBar objects are created by: Span_bar_engraver.

Standard settings:

> `break-align-symbol` (symbol):

>   `'staff-bar`

>   This key is used for aligning and spacing breakable items.

> `Y-extent` (pair of numbers):

>   `ly:axis-group-interface::height`

>   Hard coded extent in Y direction.

> `layer` (integer):

>   `0`

>   The output layer (a value between 0 and 2): Layers define the order of printing objects. Objects in lower layers are overprinted by objects in higher layers.

> `non-musical` (boolean):

>   `#t`

>   True if the grob belongs to a `NonMusicalPaperColumn`.

> `stencil` (unknown):

>   `ly:span-bar::print`

>   The symbol to print.

> `bar-size` (dimension, in staff space):

>   `ly:span-bar::calc-bar-size`

>   The size of a bar line.

> `X-extent` (pair of numbers):

>   `ly:span-bar::width`

>   Hard coded extent in X direction.

> `before-line-breaking` (boolean):

>   `ly:span-bar::before-line-breaking`

>   Dummy property, used to trigger a callback function.

> `allow-span-bar` (boolean):

>   `#t`

>   If false, no inter-staff bar line will be created below this bar line.

> `kern` (dimension, in staff space):

>   `3.0`

>   Amount of extra white space to add. For bar lines, this is the amount of space after a thick line.

> `thin-kern` (number):

>   `3.0`

>   The space after a hair-line in a bar line.

> `hair-thickness` (number):

>   `1.6`

>   Thickness of the thin line in a bar line.

> `thick-thickness` (number):

>   `6.0`

>   Bar line thickness, measured in `line-thickness`.

This object supports the following interface(s): span-bar-interface, item-interface, font-interface, bar-line-interface and grob-interface.

### 3.1.95 StaffSpacing

StaffSpacing objects are created by: Separating_line_group_engraver.

Standard settings:

> `non-musical` (boolean):

>   `#t`

>   True if the grob belongs to a `NonMusicalPaperColumn`.

> `stem-spacing-correction` (number):

>   `0.4`

>   Optical correction amount for stems that are placed in tight configurations. For opposite directions, this amount is the correction for two normal sized stems that overlap completely.

This object supports the following interface(s): staff-spacing-interface, spacing-interface, item-interface and grob-interface.

### 3.1.96 StaffSymbol

StaffSymbol objects are created by: Staff_symbol_engraver and Tab_staff_symbol_engraver.

Standard settings:

> `Y-extent` (pair of numbers):

>   `ly:staff-symbol::height`

>   Hard coded extent in Y direction.

> `stencil` (unknown):

>   `ly:staff-symbol::print`

>   The symbol to print.

> `line-count` (integer):

>   `5`

>   The number of staff lines.

> `ledger-line-thickness` (pair of numbers):

>   `'(1.0 . 0.1)`

>   The thickness of ledger lines. It is the sum of 2 numbers: The first is the factor for line thickness, and the second for staff space. Both contributions are added.

> `layer` (integer):

>   `0`

>   The output layer (a value between 0 and 2): Layers define the order of printing objects. Objects in lower layers are overprinted by objects in higher layers.

This object supports the following interface(s): staff-symbol-interface, spanner-interface and grob-interface.

### 3.1.97 StanzaNumber

StanzaNumber objects are created by: Stanza_number_engraver.

Standard settings:

> `stencil` (unknown):

>   `ly:text-interface::print`

>   The symbol to print.

> `font-series` (symbol):

>   `'bold`

>   Select the series of a font. Choices include `medium`, `bold`, `bold-narrow`, etc.

> `padding` (dimension, in staff space):

>   `1.0`

>   Add this much extra space between objects that are next to each other.

> `X-offset` (number):

>   `ly:side-position-interface::x-aligned-side`

>   The horizontal amount that this object is moved relative to its X-parent.

> `side-axis` (number):

>   `0`

>   If the value is `#X` (or equivalently `0`), the object is placed horizontally next to the other object. If the value is `#Y` or `1`, it is placed vertically.

> `direction` (direction):

>   `-1`

>   If `side-axis` is `0` (or `#X`), then this property determines whether the object is placed `#LEFT`, `#CENTER` or `#RIGHT` with respect to the other object. Otherwise, it determines whether the object is placed `#UP`, `#CENTER` or `#DOWN`. Numerical values may also be used: `#UP`=`1`, `#DOWN`=`-1`, `#LEFT`=`-1`, `#RIGHT`=`1`, `#CENTER`=`0`.

This object supports the following interface(s): text-interface, stanza-number-interface, side-position-interface, item-interface, font-interface and grob-interface.

### 3.1.98 Stem

Stem objects are created by: Stem_engraver.

Standard settings:

> `direction` (direction):

>   `ly:stem::calc-direction`

>   If `side-axis` is `0` (or `#X`), then this property determines whether the object is placed `#LEFT`, `#CENTER` or `#RIGHT` with respect to the other object. Otherwise, it determines whether the object is placed `#UP`, `#CENTER` or `#DOWN`. Numerical values may also be used: `#UP`=`1`, `#DOWN`=`-1`, `#LEFT`=`-1`, `#RIGHT`=`1`, `#CENTER`=`0`.

> `duration-log` (integer):

>   `stem::calc-duration-log`

>   The 2-log of the note head duration, i.e., `0` = whole note, `1` = half note, etc.

> `default-direction` (direction):

>   `ly:stem::calc-default-direction`

>   Direction determined by note head positions.

> `stem-end-position` (number):

>   `ly:stem::calc-stem-end-position`

>   Where does the stem end (the end is opposite to the support-head)?

> `neutral-direction` (direction):

>   `-1`

>   Which direction to take in the center of the staff.

> `stencil` (unknown):

>   `ly:stem::print`

>   The symbol to print.

> `X-extent` (pair of numbers):

>   `ly:stem::width`

>   Hard coded extent in X direction.

> `Y-extent` (pair of numbers):

>   `ly:stem::height`

>   Hard coded extent in Y direction.

> `length` (dimension, in staff space):

>   `ly:stem::calc-length`

>   User override for the stem length of unbeamed stems.

> `thickness` (number):

>   `1.3`

>   Line thickness, generally measured in `line-thickness`.

> `flag` (unknown):

>   `ly:stem::calc-flag`

>   A function returning the full flag stencil for the `Stem`, which is passed to the function as the only argument. The default ly:stem::calc-stencil function uses the `flag-style` property to determine the correct glyph for the flag. By providing your own function, you can create arbitrary flags.

> `beamlet-default-length` (pair):

>   `'(1.1 . 1.1)`

>   A pair of numbers. The first number specifies the default length of a beamlet that sticks out of the left hand side of this stem; the second number specifies the default length of the beamlet to the right. The actual length of a beamlet is determined by taking either the default length or the length specified by `beamlet-max-length-proportion`, whichever is smaller.

> `beamlet-max-length-proportion` (pair):

>   `'(0.75 . 0.75)`

>   The maximum length of a beamlet, as a proportion of the distance between two adjacent stems.

> `X-offset` (number):

>   `ly:stem::offset-callback`

>   The horizontal amount that this object is moved relative to its X-parent.

> `Y-offset` (number):

>   `ly:staff-symbol-referencer::callback`

>   The vertical amount that this object is moved relative to its Y-parent.

This object supports the following interface(s): stem-interface, item-interface, font-interface and grob-interface.

### 3.1.99 StemTremolo

StemTremolo objects are created by: Stem_engraver.

Standard settings:

> `Y-extent` (pair of numbers):

>   `ly:stem-tremolo::height`

>   Hard coded extent in Y direction.

> `X-extent` (pair of numbers):

>   `ly:stem-tremolo::width`

>   Hard coded extent in X direction.

> `stencil` (unknown):

>   `ly:stem-tremolo::print`

>   The symbol to print.

> `slope` (number):

>   `ly:stem-tremolo::calc-slope`

>   The slope of this object.

> `beam-width` (dimension, in staff space):

>   `ly:stem-tremolo::calc-width`

>   Width of the tremolo sign.

> `style` (symbol):

>   `ly:stem-tremolo::calc-style`

>   This setting determines in what style a grob is typeset. Valid choices depend on the `stencil` callback reading this property.

> `beam-thickness` (dimension, in staff space):

>   `0.48`

>   Beam thickness, measured in `staff-space` units.

This object supports the following interface(s): stem-tremolo-interface, item-interface and grob-interface.

### 3.1.100 StringNumber

StringNumber objects are created by: New_fingering_engraver.

Standard settings:

> `stencil` (unknown):

>   `print-circled-text-callback`

>   The symbol to print.

> `text` (markup):

>   `string-number::calc-text`

>   Text markup. See Formatting text.

> `padding` (dimension, in staff space):

>   `0.5`

>   Add this much extra space between objects that are next to each other.

> `staff-padding` (dimension, in staff space):

>   `0.5`

>   Maintain this much space between reference points and the staff. Its effect is to align objects of differing sizes (like the dynamics p and f) on their baselines.

> `self-alignment-X` (number):

>   `0`

>   Specify alignment of an object. The value `-1` means left aligned, `0` centered, and `1` right-aligned in X direction. Other numerical values may also be specified.

> `self-alignment-Y` (number):

>   `0`

>   Like `self-alignment-X` but for the Y axis.

> `script-priority` (number):

>   `100`

>   A sorting key that determines in what order a script is within a stack of scripts.

> `avoid-slur` (symbol):

>   `'around`

>   Method of handling slur collisions. Choices are `around`, `inside`, `outside`. If unset, scripts and slurs ignore each other. `around` only moves the script if there is a collision; `outside` always moves the script.

> `font-encoding` (symbol):

>   `'fetaNumber`

>   The font encoding is the broadest category for selecting a font. Currently, only lilypond’s system fonts (Emmentaler and Aybabtu) are using this property. Available values are `fetaMusic` (Emmentaler), `fetaBraces` (Aybabtu), `fetaNumber` (Emmentaler), and `fetaDynamic` (Emmentaler).

> `font-size` (number):

>   `-5`

>   The font size, compared to the ‘normal’ size. `0` is style-sheet’s normal size, `-1` is smaller, `+1` is bigger. Each step of 1 is approximately 12% larger; 6 steps are exactly a factor 2 larger. Fractional values are allowed.

This object supports the following interface(s): text-script-interface, text-interface, string-number-interface, side-position-interface, self-alignment-interface, item-interface, font-interface and grob-interface.

### 3.1.101 StrokeFinger

StrokeFinger objects are created by: New_fingering_engraver.

Standard settings:

> `stencil` (unknown):

>   `ly:text-interface::print`

>   The symbol to print.

> `text` (markup):

>   `stroke-finger::calc-text`

>   Text markup. See Formatting text.

> `digit-names` (unknown):

>   `#(p i m a x)`

>   Names for string finger digits.

> `padding` (dimension, in staff space):

>   `0.5`

>   Add this much extra space between objects that are next to each other.

> `staff-padding` (dimension, in staff space):

>   `0.5`

>   Maintain this much space between reference points and the staff. Its effect is to align objects of differing sizes (like the dynamics p and f) on their baselines.

> `self-alignment-X` (number):

>   `0`

>   Specify alignment of an object. The value `-1` means left aligned, `0` centered, and `1` right-aligned in X direction. Other numerical values may also be specified.

> `self-alignment-Y` (number):

>   `0`

>   Like `self-alignment-X` but for the Y axis.

> `script-priority` (number):

>   `100`

>   A sorting key that determines in what order a script is within a stack of scripts.

> `font-shape` (symbol):

>   `'italic`

>   Select the shape of a font. Choices include `upright`, `italic`, `caps`.

> `font-size` (number):

>   `-4`

>   The font size, compared to the ‘normal’ size. `0` is style-sheet’s normal size, `-1` is smaller, `+1` is bigger. Each step of 1 is approximately 12% larger; 6 steps are exactly a factor 2 larger. Fractional values are allowed.

This object supports the following interface(s): text-script-interface, text-interface, stroke-finger-interface, side-position-interface, self-alignment-interface, item-interface, font-interface and grob-interface.

### 3.1.102 SustainPedal

SustainPedal objects are created by: Piano_pedal_engraver.

Standard settings:

> `extra-spacing-width` (pair of numbers):

>   `'(+inf.0 . -inf.0)`

>   In the horizontal spacing problem, we pad each item by this amount (by adding the ‘car’ on the left side of the item and adding the ‘cdr’ on the right side of the item). In order to make a grob take up no horizontal space at all, set this to `(+inf.0 . -inf.0)`.

> `stencil` (unknown):

>   `ly:sustain-pedal::print`

>   The symbol to print.

> `self-alignment-X` (number):

>   `0`

>   Specify alignment of an object. The value `-1` means left aligned, `0` centered, and `1` right-aligned in X direction. Other numerical values may also be specified.

> `direction` (direction):

>   `1`

>   If `side-axis` is `0` (or `#X`), then this property determines whether the object is placed `#LEFT`, `#CENTER` or `#RIGHT` with respect to the other object. Otherwise, it determines whether the object is placed `#UP`, `#CENTER` or `#DOWN`. Numerical values may also be used: `#UP`=`1`, `#DOWN`=`-1`, `#LEFT`=`-1`, `#RIGHT`=`1`, `#CENTER`=`0`.

> `padding` (dimension, in staff space):

>   `0.0`

>   Add this much extra space between objects that are next to each other.

> `X-offset` (number):

>   `ly:self-alignment-interface::x-aligned-on-self`

>   The horizontal amount that this object is moved relative to its X-parent.

This object supports the following interface(s): text-interface, self-alignment-interface, piano-pedal-script-interface, piano-pedal-interface, item-interface, font-interface and grob-interface.

### 3.1.103 SustainPedalLineSpanner

SustainPedalLineSpanner objects are created by: Piano_pedal_align_engraver.

Standard settings:

> `axes` (list):

>   `'(1)`

>   List of axis numbers. In the case of alignment grobs, this should contain only one number.

> `Y-extent` (pair of numbers):

>   `ly:axis-group-interface::height`

>   Hard coded extent in Y direction.

> `X-extent` (pair of numbers):

>   `ly:axis-group-interface::width`

>   Hard coded extent in X direction.

> `Y-offset` (number):

>   `ly:side-position-interface::y-aligned-side`

>   The vertical amount that this object is moved relative to its Y-parent.

> `outside-staff-priority` (number):

>   `1000`

>   If set, the grob is positioned outside the staff in such a way as to avoid all collisions. In case of a potential collision, the grob with the smaller `outside-staff-priority` is closer to the staff.

> `side-axis` (number):

>   `1`

>   If the value is `#X` (or equivalently `0`), the object is placed horizontally next to the other object. If the value is `#Y` or `1`, it is placed vertically.

> `padding` (dimension, in staff space):

>   `1.2`

>   Add this much extra space between objects that are next to each other.

> `staff-padding` (dimension, in staff space):

>   `1.2`

>   Maintain this much space between reference points and the staff. Its effect is to align objects of differing sizes (like the dynamics p and f) on their baselines.

> `minimum-space` (dimension, in staff space):

>   `1.0`

>   Minimum distance that the victim should move (after padding).

> `direction` (direction):

>   `-1`

>   If `side-axis` is `0` (or `#X`), then this property determines whether the object is placed `#LEFT`, `#CENTER` or `#RIGHT` with respect to the other object. Otherwise, it determines whether the object is placed `#UP`, `#CENTER` or `#DOWN`. Numerical values may also be used: `#UP`=`1`, `#DOWN`=`-1`, `#LEFT`=`-1`, `#RIGHT`=`1`, `#CENTER`=`0`.

This object supports the following interface(s): spanner-interface, side-position-interface, piano-pedal-interface, axis-group-interface and grob-interface.

### 3.1.104 System

System objects are not created by any engraver.

Standard settings:

> `axes` (list):

>   `'(0 1)`

>   List of axis numbers. In the case of alignment grobs, this should contain only one number.

> `X-extent` (pair of numbers):

>   `ly:axis-group-interface::width`

>   Hard coded extent in X direction.

> `Y-extent` (pair of numbers):

>   `ly:axis-group-interface::height`

>   Hard coded extent in Y direction.

> `vertical-skylines` (unknown):

>   `ly:axis-group-interface::calc-skylines`

>   Two skylines, one above and one below this grob.

> `max-stretch` (number):

>   `ly:axis-group-interface::calc-max-stretch`

>   The maximum amount that this `VerticalAxisGroup` can be vertically stretched (for example, in order to better fill a page).

This object supports the following interface(s): system-interface, spanner-interface, axis-group-interface and grob-interface.

### 3.1.105 SystemStartBar

SystemStartBar objects are created by: System_start_delimiter_engraver.

Standard settings:

> `Y-extent` (pair of numbers):

>   `#f`

>   Hard coded extent in Y direction.

> `padding` (dimension, in staff space):

>   `-0.1`

>   Add this much extra space between objects that are next to each other.

> `X-offset` (number):

>   `ly:side-position-interface::x-aligned-side`

>   The horizontal amount that this object is moved relative to its X-parent.

> `direction` (direction):

>   `-1`

>   If `side-axis` is `0` (or `#X`), then this property determines whether the object is placed `#LEFT`, `#CENTER` or `#RIGHT` with respect to the other object. Otherwise, it determines whether the object is placed `#UP`, `#CENTER` or `#DOWN`. Numerical values may also be used: `#UP`=`1`, `#DOWN`=`-1`, `#LEFT`=`-1`, `#RIGHT`=`1`, `#CENTER`=`0`.

> `style` (symbol):

>   `'bar-line`

>   This setting determines in what style a grob is typeset. Valid choices depend on the `stencil` callback reading this property.

> `collapse-height` (dimension, in staff space):

>   `5.0`

>   Minimum height of system start delimiter. If equal or smaller, the bracket/brace/line is removed.

> `thickness` (number):

>   `1.6`

>   Line thickness, generally measured in `line-thickness`.

> `stencil` (unknown):

>   `ly:system-start-delimiter::print`

>   The symbol to print.

This object supports the following interface(s): system-start-delimiter-interface, spanner-interface, side-position-interface and grob-interface.

### 3.1.106 SystemStartBrace

SystemStartBrace objects are created by: System_start_delimiter_engraver.

Standard settings:

> `style` (symbol):

>   `'brace`

>   This setting determines in what style a grob is typeset. Valid choices depend on the `stencil` callback reading this property.

> `padding` (dimension, in staff space):

>   `0.3`

>   Add this much extra space between objects that are next to each other.

> `stencil` (unknown):

>   `ly:system-start-delimiter::print`

>   The symbol to print.

> `collapse-height` (dimension, in staff space):

>   `5.0`

>   Minimum height of system start delimiter. If equal or smaller, the bracket/brace/line is removed.

> `X-offset` (number):

>   `ly:side-position-interface::x-aligned-side`

>   The horizontal amount that this object is moved relative to its X-parent.

> `direction` (direction):

>   `-1`

>   If `side-axis` is `0` (or `#X`), then this property determines whether the object is placed `#LEFT`, `#CENTER` or `#RIGHT` with respect to the other object. Otherwise, it determines whether the object is placed `#UP`, `#CENTER` or `#DOWN`. Numerical values may also be used: `#UP`=`1`, `#DOWN`=`-1`, `#LEFT`=`-1`, `#RIGHT`=`1`, `#CENTER`=`0`.

> `font-encoding` (symbol):

>   `'fetaBraces`

>   The font encoding is the broadest category for selecting a font. Currently, only lilypond’s system fonts (Emmentaler and Aybabtu) are using this property. Available values are `fetaMusic` (Emmentaler), `fetaBraces` (Aybabtu), `fetaNumber` (Emmentaler), and `fetaDynamic` (Emmentaler).

> `Y-extent` (pair of numbers):

>   `#f`

>   Hard coded extent in Y direction.

This object supports the following interface(s): system-start-delimiter-interface, spanner-interface, side-position-interface, font-interface and grob-interface.

### 3.1.107 SystemStartBracket

SystemStartBracket objects are created by: System_start_delimiter_engraver.

Standard settings:

> `Y-extent` (pair of numbers):

>   `#f`

>   Hard coded extent in Y direction.

> `padding` (dimension, in staff space):

>   `0.8`

>   Add this much extra space between objects that are next to each other.

> `X-offset` (number):

>   `ly:side-position-interface::x-aligned-side`

>   The horizontal amount that this object is moved relative to its X-parent.

> `direction` (direction):

>   `-1`

>   If `side-axis` is `0` (or `#X`), then this property determines whether the object is placed `#LEFT`, `#CENTER` or `#RIGHT` with respect to the other object. Otherwise, it determines whether the object is placed `#UP`, `#CENTER` or `#DOWN`. Numerical values may also be used: `#UP`=`1`, `#DOWN`=`-1`, `#LEFT`=`-1`, `#RIGHT`=`1`, `#CENTER`=`0`.

> `stencil` (unknown):

>   `ly:system-start-delimiter::print`

>   The symbol to print.

> `style` (symbol):

>   `'bracket`

>   This setting determines in what style a grob is typeset. Valid choices depend on the `stencil` callback reading this property.

> `collapse-height` (dimension, in staff space):

>   `5.0`

>   Minimum height of system start delimiter. If equal or smaller, the bracket/brace/line is removed.

> `thickness` (number):

>   `0.45`

>   Line thickness, generally measured in `line-thickness`.

This object supports the following interface(s): system-start-delimiter-interface, spanner-interface, side-position-interface, font-interface and grob-interface.

### 3.1.108 SystemStartSquare

SystemStartSquare objects are created by: System_start_delimiter_engraver.

Standard settings:

> `Y-extent` (pair of numbers):

>   `#f`

>   Hard coded extent in Y direction.

> `X-offset` (number):

>   `ly:side-position-interface::x-aligned-side`

>   The horizontal amount that this object is moved relative to its X-parent.

> `direction` (direction):

>   `-1`

>   If `side-axis` is `0` (or `#X`), then this property determines whether the object is placed `#LEFT`, `#CENTER` or `#RIGHT` with respect to the other object. Otherwise, it determines whether the object is placed `#UP`, `#CENTER` or `#DOWN`. Numerical values may also be used: `#UP`=`1`, `#DOWN`=`-1`, `#LEFT`=`-1`, `#RIGHT`=`1`, `#CENTER`=`0`.

> `stencil` (unknown):

>   `ly:system-start-delimiter::print`

>   The symbol to print.

> `style` (symbol):

>   `'line-bracket`

>   This setting determines in what style a grob is typeset. Valid choices depend on the `stencil` callback reading this property.

> `thickness` (number):

>   `1.0`

>   Line thickness, generally measured in `line-thickness`.

This object supports the following interface(s): system-start-delimiter-interface, spanner-interface, side-position-interface, font-interface and grob-interface.

### 3.1.109 TabNoteHead

TabNoteHead objects are created by: Tab_note_heads_engraver.

Standard settings:

> `stencil` (unknown):

>   `ly:text-interface::print`

>   The symbol to print.

> `duration-log` (integer):

>   `note-head::calc-duration-log`

>   The 2-log of the note head duration, i.e., `0` = whole note, `1` = half note, etc.

> `Y-offset` (number):

>   `ly:staff-symbol-referencer::callback`

>   The vertical amount that this object is moved relative to its Y-parent.

> `X-offset` (number):

>   `ly:self-alignment-interface::x-aligned-on-self`

>   The horizontal amount that this object is moved relative to its X-parent.

> `direction` (direction):

>   `0`

>   If `side-axis` is `0` (or `#X`), then this property determines whether the object is placed `#LEFT`, `#CENTER` or `#RIGHT` with respect to the other object. Otherwise, it determines whether the object is placed `#UP`, `#CENTER` or `#DOWN`. Numerical values may also be used: `#UP`=`1`, `#DOWN`=`-1`, `#LEFT`=`-1`, `#RIGHT`=`1`, `#CENTER`=`0`.

> `font-size` (number):

>   `-2`

>   The font size, compared to the ‘normal’ size. `0` is style-sheet’s normal size, `-1` is smaller, `+1` is bigger. Each step of 1 is approximately 12% larger; 6 steps are exactly a factor 2 larger. Fractional values are allowed.

> `stem-attachment` (pair of numbers):

>   `'(0.0 . 1.35)`

>   An `(x . y)` pair where the stem attaches to the notehead.

> `font-series` (symbol):

>   `'bold`

>   Select the series of a font. Choices include `medium`, `bold`, `bold-narrow`, etc.

This object supports the following interface(s): text-interface, staff-symbol-referencer-interface, rhythmic-head-interface, rhythmic-grob-interface, note-head-interface, item-interface, font-interface and grob-interface.

### 3.1.110 TextScript

TextScript objects are created by: Text_engraver.

Standard settings:

> `extra-spacing-width` (pair of numbers):

>   `'(+inf.0 . -inf.0)`

>   In the horizontal spacing problem, we pad each item by this amount (by adding the ‘car’ on the left side of the item and adding the ‘cdr’ on the right side of the item). In order to make a grob take up no horizontal space at all, set this to `(+inf.0 . -inf.0)`.

> `X-offset` (number):

>   `ly:self-alignment-interface::x-aligned-on-self`

>   The horizontal amount that this object is moved relative to its X-parent.

> `Y-offset` (number):

>   `ly:side-position-interface::y-aligned-side`

>   The vertical amount that this object is moved relative to its Y-parent.

> `side-axis` (number):

>   `1`

>   If the value is `#X` (or equivalently `0`), the object is placed horizontally next to the other object. If the value is `#Y` or `1`, it is placed vertically.

> `direction` (direction):

>   `-1`

>   If `side-axis` is `0` (or `#X`), then this property determines whether the object is placed `#LEFT`, `#CENTER` or `#RIGHT` with respect to the other object. Otherwise, it determines whether the object is placed `#UP`, `#CENTER` or `#DOWN`. Numerical values may also be used: `#UP`=`1`, `#DOWN`=`-1`, `#LEFT`=`-1`, `#RIGHT`=`1`, `#CENTER`=`0`.

> `padding` (dimension, in staff space):

>   `0.5`

>   Add this much extra space between objects that are next to each other.

> `staff-padding` (dimension, in staff space):

>   `0.5`

>   Maintain this much space between reference points and the staff. Its effect is to align objects of differing sizes (like the dynamics p and f) on their baselines.

> `stencil` (unknown):

>   `ly:text-interface::print`

>   The symbol to print.

> `direction` (direction):

>   `-1`

>   If `side-axis` is `0` (or `#X`), then this property determines whether the object is placed `#LEFT`, `#CENTER` or `#RIGHT` with respect to the other object. Otherwise, it determines whether the object is placed `#UP`, `#CENTER` or `#DOWN`. Numerical values may also be used: `#UP`=`1`, `#DOWN`=`-1`, `#LEFT`=`-1`, `#RIGHT`=`1`, `#CENTER`=`0`.

> `outside-staff-priority` (number):

>   `450`

>   If set, the grob is positioned outside the staff in such a way as to avoid all collisions. In case of a potential collision, the grob with the smaller `outside-staff-priority` is closer to the staff.

> `avoid-slur` (symbol):

>   `'around`

>   Method of handling slur collisions. Choices are `around`, `inside`, `outside`. If unset, scripts and slurs ignore each other. `around` only moves the script if there is a collision; `outside` always moves the script.

> `slur-padding` (number):

>   `0.5`

>   Extra distance between slur and script.

> `script-priority` (number):

>   `200`

>   A sorting key that determines in what order a script is within a stack of scripts.

This object supports the following interface(s): text-script-interface, text-interface, side-position-interface, self-alignment-interface, item-interface, instrument-specific-markup-interface, font-interface and grob-interface.

### 3.1.111 TextSpanner

TextSpanner objects are created by: Text_spanner_engraver.

Standard settings:

> `Y-offset` (number):

>   `ly:side-position-interface::y-aligned-side`

>   The vertical amount that this object is moved relative to its Y-parent.

> `font-shape` (symbol):

>   `'italic`

>   Select the shape of a font. Choices include `upright`, `italic`, `caps`.

> `style` (symbol):

>   `'dashed-line`

>   This setting determines in what style a grob is typeset. Valid choices depend on the `stencil` callback reading this property.

> `staff-padding` (dimension, in staff space):

>   `0.8`

>   Maintain this much space between reference points and the staff. Its effect is to align objects of differing sizes (like the dynamics p and f) on their baselines.

> `dash-fraction` (number):

>   `0.2`

>   Size of the dashes, relative to `dash-period`. Should be between `0.0` (no line) and `1.0` (continuous line).

> `dash-period` (number):

>   `3.0`

>   The length of one dash together with whitespace. If negative, no line is drawn at all.

> `side-axis` (number):

>   `1`

>   If the value is `#X` (or equivalently `0`), the object is placed horizontally next to the other object. If the value is `#Y` or `1`, it is placed vertically.

> `direction` (direction):

>   `1`

>   If `side-axis` is `0` (or `#X`), then this property determines whether the object is placed `#LEFT`, `#CENTER` or `#RIGHT` with respect to the other object. Otherwise, it determines whether the object is placed `#UP`, `#CENTER` or `#DOWN`. Numerical values may also be used: `#UP`=`1`, `#DOWN`=`-1`, `#LEFT`=`-1`, `#RIGHT`=`1`, `#CENTER`=`0`.

> `outside-staff-priority` (number):

>   `350`

>   If set, the grob is positioned outside the staff in such a way as to avoid all collisions. In case of a potential collision, the grob with the smaller `outside-staff-priority` is closer to the staff.

> `left-bound-info` (list):

>   `ly:line-spanner::calc-left-bound-info`

>   An alist of properties for determining attachments of spanners to edges.

> `right-bound-info` (list):

>   `ly:line-spanner::calc-right-bound-info`

>   An alist of properties for determining attachments of spanners to edges.

> `bound-details` (list):

>   `'((left (Y . 0) (padding . 0.25) (attach-dir . -1)) (right (Y . 0) (padding . 0.25)))`

>   An alist of properties for determining attachments of spanners to edges.

> `stencil` (unknown):

>   `ly:line-spanner::print`

>   The symbol to print.

This object supports the following interface(s): spanner-interface, side-position-interface, line-spanner-interface, line-interface, font-interface and grob-interface.

### 3.1.112 Tie

Tie objects are created by: Completion_heads_engraver and Tie_engraver.

Standard settings:

> `control-points` (list):

>   `ly:tie::calc-control-points`

>   List of offsets (number pairs) that form control points for the tie, slur, or bracket shape. For Béziers, this should list the control points of a third-order Bézier curve.

> `springs-and-rods` (boolean):

>   `ly:spanner::set-spacing-rods`

>   Dummy variable for triggering spacing routines.

> `avoid-slur` (symbol):

>   `'inside`

>   Method of handling slur collisions. Choices are `around`, `inside`, `outside`. If unset, scripts and slurs ignore each other. `around` only moves the script if there is a collision; `outside` always moves the script.

> `direction` (direction):

>   `ly:tie::calc-direction`

>   If `side-axis` is `0` (or `#X`), then this property determines whether the object is placed `#LEFT`, `#CENTER` or `#RIGHT` with respect to the other object. Otherwise, it determines whether the object is placed `#UP`, `#CENTER` or `#DOWN`. Numerical values may also be used: `#UP`=`1`, `#DOWN`=`-1`, `#LEFT`=`-1`, `#RIGHT`=`1`, `#CENTER`=`0`.

> `neutral-direction` (direction):

>   `1`

>   Which direction to take in the center of the staff.

> `stencil` (unknown):

>   `ly:tie::print`

>   The symbol to print.

> `font-size` (number):

>   `-6`

>   The font size, compared to the ‘normal’ size. `0` is style-sheet’s normal size, `-1` is smaller, `+1` is bigger. Each step of 1 is approximately 12% larger; 6 steps are exactly a factor 2 larger. Fractional values are allowed.

> `thickness` (number):

>   `1.2`

>   Line thickness, generally measured in `line-thickness`.

> `line-thickness` (number):

>   `0.8`

>   The thickness of the tie or slur contour.

This object supports the following interface(s): tie-interface, spanner-interface and grob-interface.

### 3.1.113 TieColumn

TieColumn objects are created by: Tie_engraver.

Standard settings:

> `before-line-breaking` (boolean):

>   `ly:tie-column::before-line-breaking`

>   Dummy property, used to trigger a callback function.

> `X-extent` (pair of numbers):

>   `#f`

>   Hard coded extent in X direction.

> `Y-extent` (pair of numbers):

>   `#f`

>   Hard coded extent in Y direction.

This object supports the following interface(s): tie-column-interface, spanner-interface and grob-interface.

### 3.1.114 TimeSignature

TimeSignature objects are created by: Time_signature_engraver.

Standard settings:

> `stencil` (unknown):

>   `ly:time-signature::print`

>   The symbol to print.

> `break-align-symbol` (symbol):

>   `'time-signature`

>   This key is used for aligning and spacing breakable items.

> `break-align-anchor` (number):

>   `ly:break-aligned-interface::calc-extent-aligned-anchor`

>   Grobs aligned to this break-align grob will have their X-offsets shifted by this number. In bar lines, for example, this is used to position grobs relative to the (visual) center of the bar line.

> `break-visibility` (vector):

>   `#(#t #t #t)`

>   A vector of 3 booleans, `#(end-of-line unbroken begin-of-line)`. `#t` means visible, `#f` means killed.

> `avoid-slur` (symbol):

>   `'inside`

>   Method of handling slur collisions. Choices are `around`, `inside`, `outside`. If unset, scripts and slurs ignore each other. `around` only moves the script if there is a collision; `outside` always moves the script.

> `extra-spacing-height` (pair of numbers):

>   `'(-1.0 . 1.0)`

>   In the horizontal spacing problem, we increase the height of each item by this amount (by adding the ‘car’ to the bottom of the item and adding the ‘cdr’ to the top of the item). In order to make a grob infinitely high (to prevent the horizontal spacing problem from placing any other grobs above or below this grob), set this to `(-inf.0 . +inf.0)`.

> `space-alist` (list):

>   `'((first-note fixed-space . 2.0) (right-edge extra-space . 0.5) (staff-bar minimum-space . 2.0))`

>   A table that specifies distances between prefatory items, like clef and time-signature. The format is an alist of spacing tuples: `(break-align-symbol type . distance)`, where type can be the symbols `minimum-space` or `extra-space`.

> `non-musical` (boolean):

>   `#t`

>   True if the grob belongs to a `NonMusicalPaperColumn`.

> `style` (symbol):

>   `'C`

>   This setting determines in what style a grob is typeset. Valid choices depend on the `stencil` callback reading this property.

This object supports the following interface(s): time-signature-interface, item-interface, font-interface, break-aligned-interface and grob-interface.

### 3.1.115 TrillPitchAccidental

TrillPitchAccidental objects are created by: Pitched_trill_engraver.

Standard settings:

> `X-offset` (number):

>   `ly:side-position-interface::x-aligned-side`

>   The horizontal amount that this object is moved relative to its X-parent.

> `padding` (dimension, in staff space):

>   `0.2`

>   Add this much extra space between objects that are next to each other.

> `direction` (direction):

>   `-1`

>   If `side-axis` is `0` (or `#X`), then this property determines whether the object is placed `#LEFT`, `#CENTER` or `#RIGHT` with respect to the other object. Otherwise, it determines whether the object is placed `#UP`, `#CENTER` or `#DOWN`. Numerical values may also be used: `#UP`=`1`, `#DOWN`=`-1`, `#LEFT`=`-1`, `#RIGHT`=`1`, `#CENTER`=`0`.

> `font-size` (number):

>   `-4`

>   The font size, compared to the ‘normal’ size. `0` is style-sheet’s normal size, `-1` is smaller, `+1` is bigger. Each step of 1 is approximately 12% larger; 6 steps are exactly a factor 2 larger. Fractional values are allowed.

> `side-axis` (number):

>   `0`

>   If the value is `#X` (or equivalently `0`), the object is placed horizontally next to the other object. If the value is `#Y` or `1`, it is placed vertically.

> `stencil` (unknown):

>   `ly:accidental-interface::print`

>   The symbol to print.

> `Y-extent` (pair of numbers):

>   `ly:accidental-interface::height`

>   Hard coded extent in Y direction.

> `glyph-name-alist` (list):

>   `'((0 . accidentals.natural) (-1/2 . accidentals.flat) (1/2 . accidentals.sharp) (1 . accidentals.doublesharp) (-1 . accidentals.flatflat) (3/4 . accidentals.sharp.slashslash.stemstemstem) (1/4 . accidentals.sharp.slashslash.stem) (-1/4 . accidentals.mirroredflat) (-3/4 . accidentals.mirroredflat.flat))`

>   An alist of key-string pairs.

This object supports the following interface(s): trill-pitch-accidental-interface, side-position-interface, item-interface, font-interface, accidental-interface and grob-interface.

### 3.1.116 TrillPitchGroup

TrillPitchGroup objects are created by: Pitched_trill_engraver.

Standard settings:

> `X-offset` (number):

>   `ly:side-position-interface::x-aligned-side`

>   The horizontal amount that this object is moved relative to its X-parent.

> `axes` (list):

>   `'(0)`

>   List of axis numbers. In the case of alignment grobs, this should contain only one number.

> `font-size` (number):

>   `-4`

>   The font size, compared to the ‘normal’ size. `0` is style-sheet’s normal size, `-1` is smaller, `+1` is bigger. Each step of 1 is approximately 12% larger; 6 steps are exactly a factor 2 larger. Fractional values are allowed.

> `stencil` (unknown):

>   `parenthesize-elements`

>   The symbol to print.

> `stencils` (list):

>   `parentheses-item::calc-parenthesis-stencils`

>   Multiple stencils, used as intermediate value.

> `direction` (direction):

>   `1`

>   If `side-axis` is `0` (or `#X`), then this property determines whether the object is placed `#LEFT`, `#CENTER` or `#RIGHT` with respect to the other object. Otherwise, it determines whether the object is placed `#UP`, `#CENTER` or `#DOWN`. Numerical values may also be used: `#UP`=`1`, `#DOWN`=`-1`, `#LEFT`=`-1`, `#RIGHT`=`1`, `#CENTER`=`0`.

> `side-axis` (number):

>   `0`

>   If the value is `#X` (or equivalently `0`), the object is placed horizontally next to the other object. If the value is `#Y` or `1`, it is placed vertically.

> `padding` (dimension, in staff space):

>   `0.3`

>   Add this much extra space between objects that are next to each other.

This object supports the following interface(s): side-position-interface, parentheses-interface, note-head-interface, item-interface, font-interface, axis-group-interface and grob-interface.

### 3.1.117 TrillPitchHead

TrillPitchHead objects are created by: Pitched_trill_engraver.

Standard settings:

> `stencil` (unknown):

>   `ly:note-head::print`

>   The symbol to print.

> `duration-log` (integer):

>   `2`

>   The 2-log of the note head duration, i.e., `0` = whole note, `1` = half note, etc.

> `Y-offset` (number):

>   `ly:staff-symbol-referencer::callback`

>   The vertical amount that this object is moved relative to its Y-parent.

> `font-size` (number):

>   `-4`

>   The font size, compared to the ‘normal’ size. `0` is style-sheet’s normal size, `-1` is smaller, `+1` is bigger. Each step of 1 is approximately 12% larger; 6 steps are exactly a factor 2 larger. Fractional values are allowed.

This object supports the following interface(s): staff-symbol-referencer-interface, rhythmic-head-interface, pitched-trill-interface, ledgered-interface, item-interface, font-interface and grob-interface.

### 3.1.118 TrillSpanner

TrillSpanner objects are created by: Trill_spanner_engraver.

Standard settings:

> `left-bound-info` (list):

>   `ly:line-spanner::calc-left-bound-info`

>   An alist of properties for determining attachments of spanners to edges.

> `right-bound-info` (list):

>   `ly:line-spanner::calc-right-bound-info`

>   An alist of properties for determining attachments of spanners to edges.

> `bound-details` (list):

>   `'((left (text #<procedure translate-scaled-markup (layout props offset arg)> (0.0 . -1.0) (#<procedure musicglyph-markup (layout props glyph-name)> scripts.trill)) (Y . 0) (stencil-offset -0.5 . 0) (padding . 1.5) (attach-dir . 0) (anchor-alignment . 0.15)) (left-broken (end-on-note . #t)) (right (Y . 0)))`

>   An alist of properties for determining attachments of spanners to edges.

> `stencil` (unknown):

>   `ly:line-spanner::print`

>   The symbol to print.

> `style` (symbol):

>   `'trill`

>   This setting determines in what style a grob is typeset. Valid choices depend on the `stencil` callback reading this property.

> `staff-padding` (dimension, in staff space):

>   `1.0`

>   Maintain this much space between reference points and the staff. Its effect is to align objects of differing sizes (like the dynamics p and f) on their baselines.

> `padding` (dimension, in staff space):

>   `0.5`

>   Add this much extra space between objects that are next to each other.

> `direction` (direction):

>   `1`

>   If `side-axis` is `0` (or `#X`), then this property determines whether the object is placed `#LEFT`, `#CENTER` or `#RIGHT` with respect to the other object. Otherwise, it determines whether the object is placed `#UP`, `#CENTER` or `#DOWN`. Numerical values may also be used: `#UP`=`1`, `#DOWN`=`-1`, `#LEFT`=`-1`, `#RIGHT`=`1`, `#CENTER`=`0`.

> `Y-offset` (number):

>   `ly:side-position-interface::y-aligned-side`

>   The vertical amount that this object is moved relative to its Y-parent.

> `side-axis` (number):

>   `1`

>   If the value is `#X` (or equivalently `0`), the object is placed horizontally next to the other object. If the value is `#Y` or `1`, it is placed vertically.

> `outside-staff-priority` (number):

>   `50`

>   If set, the grob is positioned outside the staff in such a way as to avoid all collisions. In case of a potential collision, the grob with the smaller `outside-staff-priority` is closer to the staff.

This object supports the following interface(s): trill-spanner-interface, spanner-interface, side-position-interface, line-spanner-interface, line-interface, font-interface and grob-interface.

### 3.1.119 TupletBracket

TupletBracket objects are created by: Tuplet_engraver.

Standard settings:

> `padding` (dimension, in staff space):

>   `1.1`

>   Add this much extra space between objects that are next to each other.

> `thickness` (number):

>   `1.6`

>   Line thickness, generally measured in `line-thickness`.

> `edge-height` (pair):

>   `'(0.7 . 0.7)`

>   A pair of numbers specifying the heights of the vertical edges: `(left-height . right-height)`.

> `shorten-pair` (pair of numbers):

>   `'(-0.2 . -0.2)`

>   The lengths to shorten a text-spanner on both sides, for example a pedal bracket. Positive values shorten the text-spanner, while negative values lengthen it.

> `staff-padding` (dimension, in staff space):

>   `0.25`

>   Maintain this much space between reference points and the staff. Its effect is to align objects of differing sizes (like the dynamics p and f) on their baselines.

> `full-length-to-extent` (boolean):

>   `#t`

>   Run to the extent of the column for a full-length tuplet bracket.

> `direction` (direction):

>   `ly:tuplet-bracket::calc-direction`

>   If `side-axis` is `0` (or `#X`), then this property determines whether the object is placed `#LEFT`, `#CENTER` or `#RIGHT` with respect to the other object. Otherwise, it determines whether the object is placed `#UP`, `#CENTER` or `#DOWN`. Numerical values may also be used: `#UP`=`1`, `#DOWN`=`-1`, `#LEFT`=`-1`, `#RIGHT`=`1`, `#CENTER`=`0`.

> `positions` (pair of numbers):

>   `ly:tuplet-bracket::calc-positions`

>   Pair of staff coordinates `(left . right)`, where both left and right are in `staff-space` units of the current staff. For slurs, this value selects which slur candidate to use; if extreme positions are requested, the closest one is taken.

> `connect-to-neighbor` (pair):

>   `ly:tuplet-bracket::calc-connect-to-neighbors`

>   Pair of booleans, indicating whether this grob looks as a continued break.

> `control-points` (list):

>   `ly:tuplet-bracket::calc-control-points`

>   List of offsets (number pairs) that form control points for the tie, slur, or bracket shape. For Béziers, this should list the control points of a third-order Bézier curve.

> `stencil` (unknown):

>   `ly:tuplet-bracket::print`

>   The symbol to print.

This object supports the following interface(s): tuplet-bracket-interface, spanner-interface, line-interface and grob-interface.

### 3.1.120 TupletNumber

TupletNumber objects are created by: Tuplet_engraver.

Standard settings:

> `stencil` (unknown):

>   `ly:tuplet-number::print`

>   The symbol to print.

> `text` (markup):

>   `tuplet-number::calc-denominator-text`

>   Text markup. See Formatting text.

> `font-shape` (symbol):

>   `'italic`

>   Select the shape of a font. Choices include `upright`, `italic`, `caps`.

> `font-size` (number):

>   `-2`

>   The font size, compared to the ‘normal’ size. `0` is style-sheet’s normal size, `-1` is smaller, `+1` is bigger. Each step of 1 is approximately 12% larger; 6 steps are exactly a factor 2 larger. Fractional values are allowed.

> `avoid-slur` (symbol):

>   `'inside`

>   Method of handling slur collisions. Choices are `around`, `inside`, `outside`. If unset, scripts and slurs ignore each other. `around` only moves the script if there is a collision; `outside` always moves the script.

This object supports the following interface(s): tuplet-number-interface, text-interface, spanner-interface, font-interface and grob-interface.

### 3.1.121 UnaCordaPedal

UnaCordaPedal objects are created by: Piano_pedal_engraver.

Standard settings:

> `stencil` (unknown):

>   `ly:text-interface::print`

>   The symbol to print.

> `font-shape` (symbol):

>   `'italic`

>   Select the shape of a font. Choices include `upright`, `italic`, `caps`.

> `extra-spacing-width` (pair of numbers):

>   `'(+inf.0 . -inf.0)`

>   In the horizontal spacing problem, we pad each item by this amount (by adding the ‘car’ on the left side of the item and adding the ‘cdr’ on the right side of the item). In order to make a grob take up no horizontal space at all, set this to `(+inf.0 . -inf.0)`.

> `self-alignment-X` (number):

>   `0`

>   Specify alignment of an object. The value `-1` means left aligned, `0` centered, and `1` right-aligned in X direction. Other numerical values may also be specified.

> `direction` (direction):

>   `1`

>   If `side-axis` is `0` (or `#X`), then this property determines whether the object is placed `#LEFT`, `#CENTER` or `#RIGHT` with respect to the other object. Otherwise, it determines whether the object is placed `#UP`, `#CENTER` or `#DOWN`. Numerical values may also be used: `#UP`=`1`, `#DOWN`=`-1`, `#LEFT`=`-1`, `#RIGHT`=`1`, `#CENTER`=`0`.

> `padding` (dimension, in staff space):

>   `0.0`

>   Add this much extra space between objects that are next to each other.

> `X-offset` (number):

>   `ly:self-alignment-interface::x-aligned-on-self`

>   The horizontal amount that this object is moved relative to its X-parent.

This object supports the following interface(s): text-interface, self-alignment-interface, piano-pedal-script-interface, item-interface, font-interface and grob-interface.

### 3.1.122 UnaCordaPedalLineSpanner

UnaCordaPedalLineSpanner objects are created by: Piano_pedal_align_engraver.

Standard settings:

> `axes` (list):

>   `'(1)`

>   List of axis numbers. In the case of alignment grobs, this should contain only one number.

> `Y-extent` (pair of numbers):

>   `ly:axis-group-interface::height`

>   Hard coded extent in Y direction.

> `X-extent` (pair of numbers):

>   `ly:axis-group-interface::width`

>   Hard coded extent in X direction.

> `Y-offset` (number):

>   `ly:side-position-interface::y-aligned-side`

>   The vertical amount that this object is moved relative to its Y-parent.

> `outside-staff-priority` (number):

>   `1000`

>   If set, the grob is positioned outside the staff in such a way as to avoid all collisions. In case of a potential collision, the grob with the smaller `outside-staff-priority` is closer to the staff.

> `side-axis` (number):

>   `1`

>   If the value is `#X` (or equivalently `0`), the object is placed horizontally next to the other object. If the value is `#Y` or `1`, it is placed vertically.

> `padding` (dimension, in staff space):

>   `1.2`

>   Add this much extra space between objects that are next to each other.

> `staff-padding` (dimension, in staff space):

>   `1.2`

>   Maintain this much space between reference points and the staff. Its effect is to align objects of differing sizes (like the dynamics p and f) on their baselines.

> `minimum-space` (dimension, in staff space):

>   `1.0`

>   Minimum distance that the victim should move (after padding).

> `direction` (direction):

>   `-1`

>   If `side-axis` is `0` (or `#X`), then this property determines whether the object is placed `#LEFT`, `#CENTER` or `#RIGHT` with respect to the other object. Otherwise, it determines whether the object is placed `#UP`, `#CENTER` or `#DOWN`. Numerical values may also be used: `#UP`=`1`, `#DOWN`=`-1`, `#LEFT`=`-1`, `#RIGHT`=`1`, `#CENTER`=`0`.

This object supports the following interface(s): spanner-interface, side-position-interface, piano-pedal-interface, axis-group-interface and grob-interface.

### 3.1.123 VaticanaLigature

VaticanaLigature objects are created by: Vaticana_ligature_engraver.

Standard settings:

> `thickness` (number):

>   `0.6`

>   Line thickness, generally measured in `line-thickness`.

> `stencil` (unknown):

>   `ly:vaticana-ligature::print`

>   The symbol to print.

This object supports the following interface(s): vaticana-ligature-interface, spanner-interface, font-interface and grob-interface.

### 3.1.124 VerticalAlignment

VerticalAlignment objects are created by: Vertical_align_engraver.

Standard settings:

> `axes` (list):

>   `'(1)`

>   List of axis numbers. In the case of alignment grobs, this should contain only one number.

> `after-line-breaking` (boolean):

>   `ly:align-interface::stretch-after-break`

>   Dummy property, used to trigger callback for `after-line-breaking`.

> `Y-extent` (pair of numbers):

>   `ly:axis-group-interface::height`

>   Hard coded extent in Y direction.

> `X-extent` (pair of numbers):

>   `ly:axis-group-interface::width`

>   Hard coded extent in X direction.

> `stacking-dir` (direction):

>   `-1`

>   Stack objects in which direction?

> `padding` (dimension, in staff space):

>   `0.5`

>   Add this much extra space between objects that are next to each other.

> `vertical-skylines` (unknown):

>   `ly:axis-group-interface::combine-skylines`

>   Two skylines, one above and one below this grob.

> `max-stretch` (number):

>   `0`

>   The maximum amount that this `VerticalAxisGroup` can be vertically stretched (for example, in order to better fill a page).

This object supports the following interface(s): spanner-interface, axis-group-interface, align-interface and grob-interface.

### 3.1.125 VerticalAxisGroup

VerticalAxisGroup objects are created by: Axis_group_engraver and Hara_kiri_engraver.

Standard settings:

> `axes` (list):

>   `'(1)`

>   List of axis numbers. In the case of alignment grobs, this should contain only one number.

> `Y-offset` (number):

>   `ly:hara-kiri-group-spanner::force-hara-kiri-callback`

>   The vertical amount that this object is moved relative to its Y-parent.

> `Y-extent` (pair of numbers):

>   `ly:hara-kiri-group-spanner::y-extent`

>   Hard coded extent in Y direction.

> `X-extent` (pair of numbers):

>   `ly:axis-group-interface::width`

>   Hard coded extent in X direction.

> `vertical-skylines` (unknown):

>   `ly:hara-kiri-group-spanner::calc-skylines`

>   Two skylines, one above and one below this grob.

> `max-stretch` (number):

>   `ly:axis-group-interface::calc-max-stretch`

>   The maximum amount that this `VerticalAxisGroup` can be vertically stretched (for example, in order to better fill a page).

> `stencil` (unknown):

>   `ly:axis-group-interface::print`

>   The symbol to print.

This object supports the following interface(s): vertically-spaceable-interface, spanner-interface, hara-kiri-group-spanner-interface, axis-group-interface and grob-interface.

### 3.1.126 VoiceFollower

VoiceFollower objects are created by: Note_head_line_engraver.

Standard settings:

> `style` (symbol):

>   `'line`

>   This setting determines in what style a grob is typeset. Valid choices depend on the `stencil` callback reading this property.

> `gap` (dimension, in staff space):

>   `0.5`

>   Size of a gap in a variable symbol.

> `non-musical` (boolean):

>   `#t`

>   True if the grob belongs to a `NonMusicalPaperColumn`.

> `X-extent` (pair of numbers):

>   `#f`

>   Hard coded extent in X direction.

> `Y-extent` (pair of numbers):

>   `#f`

>   Hard coded extent in Y direction.

> `bound-details` (list):

>   `'((right (attach-dir . 0) (padding . 1.5)) (left (attach-dir . 0) (padding . 1.5)))`

>   An alist of properties for determining attachments of spanners to edges.

> `stencil` (unknown):

>   `ly:line-spanner::print`

>   The symbol to print.

> `left-bound-info` (list):

>   `ly:line-spanner::calc-left-bound-info`

>   An alist of properties for determining attachments of spanners to edges.

> `right-bound-info` (list):

>   `ly:line-spanner::calc-right-bound-info`

>   An alist of properties for determining attachments of spanners to edges.

This object supports the following interface(s): spanner-interface, line-spanner-interface, line-interface and grob-interface.

### 3.1.127 VoltaBracket

VoltaBracket objects are created by: Volta_engraver.

Standard settings:

> `stencil` (unknown):

>   `ly:volta-bracket-interface::print`

>   The symbol to print.

> `font-encoding` (symbol):

>   `'fetaNumber`

>   The font encoding is the broadest category for selecting a font. Currently, only lilypond’s system fonts (Emmentaler and Aybabtu) are using this property. Available values are `fetaMusic` (Emmentaler), `fetaBraces` (Aybabtu), `fetaNumber` (Emmentaler), and `fetaDynamic` (Emmentaler).

> `thickness` (number):

>   `1.6`

>   Line thickness, generally measured in `line-thickness`.

> `edge-height` (pair):

>   `'(2.0 . 2.0)`

>   A pair of numbers specifying the heights of the vertical edges: `(left-height . right-height)`.

> `font-size` (number):

>   `-4`

>   The font size, compared to the ‘normal’ size. `0` is style-sheet’s normal size, `-1` is smaller, `+1` is bigger. Each step of 1 is approximately 12% larger; 6 steps are exactly a factor 2 larger. Fractional values are allowed.

> `word-space` (dimension, in staff space):

>   `0.6`

>   Space to insert between words in texts.

> `direction` (direction):

>   `1`

>   If `side-axis` is `0` (or `#X`), then this property determines whether the object is placed `#LEFT`, `#CENTER` or `#RIGHT` with respect to the other object. Otherwise, it determines whether the object is placed `#UP`, `#CENTER` or `#DOWN`. Numerical values may also be used: `#UP`=`1`, `#DOWN`=`-1`, `#LEFT`=`-1`, `#RIGHT`=`1`, `#CENTER`=`0`.

This object supports the following interface(s): volta-bracket-interface, text-interface, spanner-interface, side-position-interface, line-interface, horizontal-bracket-interface, font-interface and grob-interface.

### 3.1.128 VoltaBracketSpanner

VoltaBracketSpanner objects are created by: Volta_engraver.

Standard settings:

> `axes` (list):

>   `'(1)`

>   List of axis numbers. In the case of alignment grobs, this should contain only one number.

> `side-axis` (number):

>   `1`

>   If the value is `#X` (or equivalently `0`), the object is placed horizontally next to the other object. If the value is `#Y` or `1`, it is placed vertically.

> `direction` (direction):

>   `1`

>   If `side-axis` is `0` (or `#X`), then this property determines whether the object is placed `#LEFT`, `#CENTER` or `#RIGHT` with respect to the other object. Otherwise, it determines whether the object is placed `#UP`, `#CENTER` or `#DOWN`. Numerical values may also be used: `#UP`=`1`, `#DOWN`=`-1`, `#LEFT`=`-1`, `#RIGHT`=`1`, `#CENTER`=`0`.

> `padding` (dimension, in staff space):

>   `1`

>   Add this much extra space between objects that are next to each other.

> `Y-offset` (number):

>   `ly:side-position-interface::y-aligned-side`

>   The vertical amount that this object is moved relative to its Y-parent.

> `outside-staff-priority` (number):

>   `100`

>   If set, the grob is positioned outside the staff in such a way as to avoid all collisions. In case of a potential collision, the grob with the smaller `outside-staff-priority` is closer to the staff.

> `Y-extent` (pair of numbers):

>   `ly:axis-group-interface::height`

>   Hard coded extent in Y direction.

> `X-extent` (pair of numbers):

>   `ly:axis-group-interface::width`

>   Hard coded extent in X direction.

> `no-alignment` (boolean):

>   `#t`

>   If set, don’t place this grob in a `VerticalAlignment`; rather, place it using its own `Y-offset` callback.

This object supports the following interface(s): spanner-interface, side-position-interface, axis-group-interface and grob-interface.

## 3.2 Graphical Object Interfaces

### 3.2.1 accidental-interface

A single accidental.

#### User settable properties:

> `alteration` (number)

>   Alteration numbers for accidental.

> `avoid-slur` (symbol)

>   Method of handling slur collisions. Choices are `around`, `inside`, `outside`. If unset, scripts and slurs ignore each other. `around` only moves the script if there is a collision; `outside` always moves the script.

> `glyph-name-alist` (list)

>   An alist of key-string pairs.

> `parenthesized` (boolean)

>   Parenthesize this grob.

> `restore-first` (boolean)

>   Print a natural before the accidental.

#### Internal properties:

> `forced` (boolean)

>   Manually forced accidental.

> `tie` (layout object)

>   A pointer to a `Tie` object.

This grob interface is used in the following graphical object(s): Accidental, AccidentalCautionary, AccidentalSuggestion, AmbitusAccidental and TrillPitchAccidental.

### 3.2.2 accidental-placement-interface

Resolve accidental collisions.

#### User settable properties:

> `direction` (direction)

>   If `side-axis` is `0` (or `#X`), then this property determines whether the object is placed `#LEFT`, `#CENTER` or `#RIGHT` with respect to the other object. Otherwise, it determines whether the object is placed `#UP`, `#CENTER` or `#DOWN`. Numerical values may also be used: `#UP`=`1`, `#DOWN`=`-1`, `#LEFT`=`-1`, `#RIGHT`=`1`, `#CENTER`=`0`.

> `left-padding` (dimension, in staff space)

>   The amount of space that is put left to an object (e.g., a group of accidentals).

> `padding` (dimension, in staff space)

>   Add this much extra space between objects that are next to each other.

> `right-padding` (dimension, in staff space)

>   Space to insert on the right side of an object (e.g., between note and its accidentals).

> `script-priority` (number)

>   A sorting key that determines in what order a script is within a stack of scripts.

#### Internal properties:

> `accidental-grobs` (list)

>   An alist with `(notename . groblist)` entries.

> `positioning-done` (boolean)

>   Used to signal that a positioning element did its job. This ensures that a positioning is only done once.

This grob interface is used in the following graphical object(s): AccidentalPlacement.

### 3.2.3 accidental-suggestion-interface

An accidental, printed as a suggestion (typically: vertically over a note).

This grob interface is used in the following graphical object(s): AccidentalSuggestion.

### 3.2.4 align-interface

Order grobs from top to bottom, left to right, right to left or bottom to top. For vertical alignments of staves, the `break-system-details` of the left NonMusicalPaperColumn may be set to tune vertical spacing. Set `alignment-extra-space` to add extra space for staves. Set `fixed-alignment-extra-space` to force staves in `PianoStaff`s further apart.

#### User settable properties:

> `align-dir` (direction)

>   Which side to align? `-1`: left side, `0`: around center of width, `1`: right side.

> `axes` (list)

>   List of axis numbers. In the case of alignment grobs, this should contain only one number.

> `padding` (dimension, in staff space)

>   Add this much extra space between objects that are next to each other.

> `stacking-dir` (direction)

>   Stack objects in which direction?

> `threshold` (pair of numbers)

>   `(min . max)`, where min and max are dimensions in staff space.

#### Internal properties:

> `elements` (unknown)

>   A list of grobs; the type is depending on the grob where this is set in.

> `positioning-done` (boolean)

>   Used to signal that a positioning element did its job. This ensures that a positioning is only done once.

This grob interface is used in the following graphical object(s): BassFigureAlignment and VerticalAlignment.

### 3.2.5 ambitus-interface

The line between note heads for a pitch range.

#### User settable properties:

> `thickness` (number)

>   Line thickness, generally measured in `line-thickness`.

#### Internal properties:

> `join-heads` (boolean)

>   Whether to join the note heads of an ambitus grob with a vertical line.

> `note-heads` (unknown)

>   A list of note head grobs.

This grob interface is used in the following graphical object(s): Ambitus, AmbitusLine and AmbitusNoteHead.

### 3.2.6 arpeggio-interface

Functions and settings for drawing an arpeggio symbol (a wavy line left to noteheads.

#### User settable properties:

> `arpeggio-direction` (direction)

>   If set, put an arrow on the arpeggio squiggly line.

> `positions` (pair of numbers)

>   Pair of staff coordinates `(left . right)`, where both left and right are in `staff-space` units of the current staff. For slurs, this value selects which slur candidate to use; if extreme positions are requested, the closest one is taken.

> `script-priority` (number)

>   A sorting key that determines in what order a script is within a stack of scripts.

#### Internal properties:

> `stems` (unknown)

>   A list of stem objects, corresponding to the notes that the arpeggio has to be before.

This grob interface is used in the following graphical object(s): Arpeggio.

### 3.2.7 axis-group-interface

An object that groups other layout objects.

#### User settable properties:

> `axes` (list)

>   List of axis numbers. In the case of alignment grobs, this should contain only one number.

> `keep-fixed-while-stretching` (boolean)

>   A grob with this property set to true is fixed relative to the staff above it when systems are stretched.

> `max-stretch` (number)

>   The maximum amount that this `VerticalAxisGroup` can be vertically stretched (for example, in order to better fill a page).

> `no-alignment` (boolean)

>   If set, don’t place this grob in a `VerticalAlignment`; rather, place it using its own `Y-offset` callback.

> `vertical-skylines` (unknown)

>   Two skylines, one above and one below this grob.

#### Internal properties:

> `X-common` (layout object)

>   Common reference point for axis group.

> `Y-common` (layout object)

>   See `X-common`.

> `adjacent-pure-heights` (vector)

>   Used by a `VerticalAxisGroup` to cache the `Y-extent`s of different column ranges.

> `elements` (unknown)

>   A list of grobs; the type is depending on the grob where this is set in.

> `pure-Y-common` (layout object)

>   A cache of the `common_refpoint_of_array` of the `elements` grob set.

> `pure-relevant-items` (unknown)

>   A subset of elements that are relevant for finding the `pure-Y-extent`.

> `pure-relevant-spanners` (unknown)

>   A subset of elements that are relevant for finding the `pure-Y-extent`.

This grob interface is used in the following graphical object(s): Ambitus, BassFigureAlignment, BassFigureAlignmentPositioning, BassFigureLine, BreakAlignGroup, BreakAlignment, DotColumn, DynamicLineSpanner, NonMusicalPaperColumn, NoteCollision, NoteColumn, PaperColumn, SostenutoPedalLineSpanner, SustainPedalLineSpanner, System, TrillPitchGroup, UnaCordaPedalLineSpanner, VerticalAlignment, VerticalAxisGroup and VoltaBracketSpanner.

### 3.2.8 balloon-interface

A collection of routines to put text balloons around an object.

#### User settable properties:

> `padding` (dimension, in staff space)

>   Add this much extra space between objects that are next to each other.

> `text` (markup)

>   Text markup. See Formatting text.

This grob interface is used in the following graphical object(s): BalloonTextItem.

### 3.2.9 bar-line-interface

Bar line.

Print a special bar symbol. It replaces the regular bar symbol with a special symbol. The argument bartype is a string which specifies the kind of bar line to print. Options are `:|`, `|:`, `:|:`, `:|.|:`, `:|.:`, `||`, `|.`, `.|`, `.|.`, `|.|`, `:` and `dashed`.

These produce, respectively, a right repeat, a left repeat, a thick double repeat, a thin-thick-thin double repeat, a thin-thick double repeat, a double bar, a start bar, an end bar, a thick double bar, a thin-thick-thin bar, a dotted bar and a dashed bar. In addition, there is an option `||:` which is equivalent to `|:` except at line breaks, where it produces a double bar (`||`) at the end of the line and a repeat sign (`|:`) at the beginning of the new line.

If bartype is set to `empty` then nothing is printed, but a line break is allowed at that spot.

`gap` is used for the gaps in dashed bar lines.

#### User settable properties:

> `allow-span-bar` (boolean)

>   If false, no inter-staff bar line will be created below this bar line.

> `bar-size` (dimension, in staff space)

>   The size of a bar line.

> `gap` (dimension, in staff space)

>   Size of a gap in a variable symbol.

> `glyph` (string)

>   A string determining what ‘style’ of glyph is typeset. Valid choices depend on the function that is reading this property.

> `hair-thickness` (number)

>   Thickness of the thin line in a bar line.

> `kern` (dimension, in staff space)

>   Amount of extra white space to add. For bar lines, this is the amount of space after a thick line.

> `thick-thickness` (number)

>   Bar line thickness, measured in `line-thickness`.

> `thin-kern` (number)

>   The space after a hair-line in a bar line.

#### Internal properties:

> `bar-extent` (pair of numbers)

>   The Y-extent of the actual bar line. This may differ from `Y-extent` because it does not include the dots in a repeat bar line.

> `glyph-name` (string)

>   The glyph name within the font.

This grob interface is used in the following graphical object(s): BarLine and SpanBar.

### 3.2.10 bass-figure-alignment-interface

Align a bass figure.

This grob interface is used in the following graphical object(s): BassFigureAlignment.

### 3.2.11 bass-figure-interface

A bass figure text.

#### User settable properties:

> `implicit` (boolean)

>   Is this an implicit bass figure?

This grob interface is used in the following graphical object(s): BassFigure.

### 3.2.12 beam-interface

A beam.

The `thickness` property is the weight of beams, measured in staffspace. The `direction` property is not user-serviceable. Use the `direction` property of `Stem` instead.

#### User settable properties:

> `annotation` (string)

>   Annotate a grob for debug purposes.

> `auto-knee-gap` (dimension, in staff space)

>   If a gap is found between note heads where a horizontal beam fits that is larger than this number, make a kneed beam.

> `beamed-stem-shorten` (list)

>   How much to shorten beamed stems, when their direction is forced. It is a list, since the value is different depending on the number of flags and beams.

> `beaming` (pair)

>   Pair of number lists. Each number list specifies which beams to make. `0` is the central beam, `1` is the next beam toward the note, etc. This information is used to determine how to connect the beaming patterns from stem to stem inside a beam.

> `break-overshoot` (pair of numbers)

>   How much does a broken spanner stick out of its bounds?

> `clip-edges` (boolean)

>   Allow outward pointing beamlets at the edges of beams?

> `concaveness` (number)

>   A beam is concave if its inner stems are closer to the beam than the two outside stems. This number is a measure of the closeness of the inner stems. It is used for damping the slope of the beam.

> `damping` (number)

>   Amount of beam slope damping.

> `direction` (direction)

>   If `side-axis` is `0` (or `#X`), then this property determines whether the object is placed `#LEFT`, `#CENTER` or `#RIGHT` with respect to the other object. Otherwise, it determines whether the object is placed `#UP`, `#CENTER` or `#DOWN`. Numerical values may also be used: `#UP`=`1`, `#DOWN`=`-1`, `#LEFT`=`-1`, `#RIGHT`=`1`, `#CENTER`=`0`.

> `gap` (dimension, in staff space)

>   Size of a gap in a variable symbol.

> `gap-count` (integer)

>   Number of gapped beams for tremolo.

> `grow-direction` (direction)

>   Crescendo or decrescendo?

> `inspect-quants` (pair of numbers)

>   If debugging is set, set beam and slur quants to this position, and print the respective scores.

> `knee` (boolean)

>   Is this beam kneed?

> `length-fraction` (number)

>   Multiplier for lengths. Used for determining ledger lines and stem lengths.

> `neutral-direction` (direction)

>   Which direction to take in the center of the staff.

> `positions` (pair of numbers)

>   Pair of staff coordinates `(left . right)`, where both left and right are in `staff-space` units of the current staff. For slurs, this value selects which slur candidate to use; if extreme positions are requested, the closest one is taken.

> `thickness` (number)

>   Line thickness, generally measured in `line-thickness`.

#### Internal properties:

> `details` (list)

>   Alist of parameters for detailed grob behavior.

>   More information on the allowed parameters can be found by inspecting ‘`lily/slur-scoring.cc`’, ‘`lily/beam-quanting.cc`’, and ‘`lily/tie-formatting-problem.cc`’. Setting `debug-tie-scoring`, `debug-beam-scoring` or `debug-slur-scoring` also provides useful clues.

> `least-squares-dy` (number)

>   The ideal beam slope, without damping.

> `normal-stems` (unknown)

>   An array of visible stems.

> `quant-score` (string)

>   The beam quanting score; stored for debugging.

> `quantized-positions` (pair of numbers)

>   The beam positions after quanting.

> `shorten` (dimension, in staff space)

>   The amount of space that a stem is shortened. Internally used to distribute beam shortening over stems.

> `stems` (unknown)

>   A list of stem objects, corresponding to the notes that the arpeggio has to be before.

This grob interface is used in the following graphical object(s): Beam.

### 3.2.13 bend-after-interface

A doit or drop.

#### User settable properties:

> `thickness` (number)

>   Line thickness, generally measured in `line-thickness`.

#### Internal properties:

> `delta-position` (number)

>   The vertical position difference.

This grob interface is used in the following graphical object(s): BendAfter.

### 3.2.14 break-alignable-interface

Object that is aligned on a break alignment.

#### User settable properties:

> `break-align-symbols` (list)

>   A list of symbols that determine which break-aligned grobs to align this to. If the grob selected by the first symbol in the list is invisible due to break-visibility, we will align to the next grob (and so on).

This grob interface is used in the following graphical object(s): BarNumber and RehearsalMark.

### 3.2.15 break-aligned-interface

Items that are aligned in prefatory matter.

The spacing of these items is controlled by the `space-alist` property. It contains a list `break-align-symbol`s with a specification of the associated space. The space specification can be

`(minimum-space . spc))`

  Pad space until the distance is spc.

`(fixed-space . spc)`

  Set a fixed space.

`(semi-fixed-space . spc)`

  Set a space. Half of it is fixed and half is stretchable. (does not work at start of line. fixme)

`(extra-space . spc)`

  Add spc amount of space.

Special keys for the alist are `first-note` and `next-note`, signifying the first note on a line, and the next note halfway a line.

Rules for this spacing are much more complicated than this. See [Wanske] page 126–134, [Ross] page 143–147.

#### User settable properties:

> `break-align-anchor` (number)

>   Grobs aligned to this break-align grob will have their X-offsets shifted by this number. In bar lines, for example, this is used to position grobs relative to the (visual) center of the bar line.

> `break-align-anchor-alignment` (number)

>   Read by `ly:break-aligned-interface::calc-extent-aligned-anchor` for aligning an anchor to a grob’s extent

> `break-align-symbol` (symbol)

>   This key is used for aligning and spacing breakable items.

> `space-alist` (list)

>   A table that specifies distances between prefatory items, like clef and time-signature. The format is an alist of spacing tuples: `(break-align-symbol type . distance)`, where type can be the symbols `minimum-space` or `extra-space`.

This grob interface is used in the following graphical object(s): Ambitus, AmbitusAccidental, BarLine, BreakAlignGroup, BreathingSign, Clef, Custos, DoublePercentRepeat, KeyCancellation, KeySignature, LeftEdge and TimeSignature.

### 3.2.16 break-alignment-interface

The object that performs break alignment. See break-aligned-interface.

#### User settable properties:

> `break-align-orders` (vector)

>   Defines the order in which prefatory matter (clefs, key signatures) appears. The format is a vector of length 3, where each element is one order for end-of-line, middle of line, and start-of-line, respectively. An order is a list of symbols.

>   For example, clefs are put after key signatures by setting

>   >     \override Score.BreakAlignment #'break-align-orders =
>   >       #(make-vector 3 '(span-bar
>   >                         breathing-sign
>   >                         staff-bar
>   >                         key
>   >                         clef
>   >                         time-signature))

#### Internal properties:

> `positioning-done` (boolean)

>   Used to signal that a positioning element did its job. This ensures that a positioning is only done once.

This grob interface is used in the following graphical object(s): BreakAlignment.

### 3.2.17 breathing-sign-interface

A breathing sign.

#### User settable properties:

> `direction` (direction)

>   If `side-axis` is `0` (or `#X`), then this property determines whether the object is placed `#LEFT`, `#CENTER` or `#RIGHT` with respect to the other object. Otherwise, it determines whether the object is placed `#UP`, `#CENTER` or `#DOWN`. Numerical values may also be used: `#UP`=`1`, `#DOWN`=`-1`, `#LEFT`=`-1`, `#RIGHT`=`1`, `#CENTER`=`0`.

This grob interface is used in the following graphical object(s): BreathingSign.

### 3.2.18 chord-name-interface

A chord name.

#### Internal properties:

> `begin-of-line-visible` (boolean)

>   Used for marking `ChordNames` that should only show changes.

This grob interface is used in the following graphical object(s): ChordName.

### 3.2.19 clef-interface

A clef sign.

#### User settable properties:

> `full-size-change` (boolean)

>   Don’t make a change clef smaller.

> `glyph` (string)

>   A string determining what ‘style’ of glyph is typeset. Valid choices depend on the function that is reading this property.

> `non-default` (boolean)

>   Set for manually specified clefs.

#### Internal properties:

> `glyph-name` (string)

>   The glyph name within the font.

This grob interface is used in the following graphical object(s): Clef.

### 3.2.20 cluster-beacon-interface

A place holder for the cluster spanner to determine the vertical extents of a cluster spanner at this X position.

#### User settable properties:

> `positions` (pair of numbers)

>   Pair of staff coordinates `(left . right)`, where both left and right are in `staff-space` units of the current staff. For slurs, this value selects which slur candidate to use; if extreme positions are requested, the closest one is taken.

This grob interface is used in the following graphical object(s): ClusterSpannerBeacon.

### 3.2.21 cluster-interface

A graphically drawn musical cluster.

`padding` adds to the vertical extent of the shape (top and bottom).

The property `style` controls the shape of cluster segments. Valid values include `leftsided-stairs`, `rightsided-stairs`, `centered-stairs`, and `ramp`.

#### User settable properties:

> `padding` (dimension, in staff space)

>   Add this much extra space between objects that are next to each other.

> `style` (symbol)

>   This setting determines in what style a grob is typeset. Valid choices depend on the `stencil` callback reading this property.

#### Internal properties:

> `columns` (unknown)

>   A list of grobs, typically containing `PaperColumn` or `NoteColumn` objects.

This grob interface is used in the following graphical object(s): ClusterSpanner.

### 3.2.22 custos-interface

A custos object. `style` can have four valid values: `mensural`, `vaticana`, `medicaea`, and `hufnagel`. `mensural` is the default style.

#### User settable properties:

> `neutral-direction` (direction)

>   Which direction to take in the center of the staff.

> `neutral-position` (number)

>   Position (in half staff spaces) where to flip the direction of custos stem.

> `style` (symbol)

>   This setting determines in what style a grob is typeset. Valid choices depend on the `stencil` callback reading this property.

This grob interface is used in the following graphical object(s): Custos.

### 3.2.23 dot-column-interface

Group dot objects so they form a column, and position dots so they do not clash with staff lines.

#### User settable properties:

> `direction` (direction)

>   If `side-axis` is `0` (or `#X`), then this property determines whether the object is placed `#LEFT`, `#CENTER` or `#RIGHT` with respect to the other object. Otherwise, it determines whether the object is placed `#UP`, `#CENTER` or `#DOWN`. Numerical values may also be used: `#UP`=`1`, `#DOWN`=`-1`, `#LEFT`=`-1`, `#RIGHT`=`1`, `#CENTER`=`0`.

#### Internal properties:

> `dots` (unknown)

>   Multiple `Dots` objects.

> `positioning-done` (boolean)

>   Used to signal that a positioning element did its job. This ensures that a positioning is only done once.

This grob interface is used in the following graphical object(s): DotColumn.

### 3.2.24 dots-interface

The dots to go with a notehead or rest. `direction` sets the preferred direction to move in case of staff line collisions. `style` defaults to undefined, which is normal 19th/20th century traditional style. Set `style` to `vaticana` for ancient type dots.

#### User settable properties:

> `direction` (direction)

>   If `side-axis` is `0` (or `#X`), then this property determines whether the object is placed `#LEFT`, `#CENTER` or `#RIGHT` with respect to the other object. Otherwise, it determines whether the object is placed `#UP`, `#CENTER` or `#DOWN`. Numerical values may also be used: `#UP`=`1`, `#DOWN`=`-1`, `#LEFT`=`-1`, `#RIGHT`=`1`, `#CENTER`=`0`.

> `dot-count` (integer)

>   The number of dots.

> `style` (symbol)

>   This setting determines in what style a grob is typeset. Valid choices depend on the `stencil` callback reading this property.

This grob interface is used in the following graphical object(s): Dots.

### 3.2.25 dynamic-interface

Any kind of loudness sign.

This grob interface is used in the following graphical object(s): DynamicLineSpanner, DynamicText, DynamicTextSpanner and Hairpin.

### 3.2.26 dynamic-line-spanner-interface

Dynamic line spanner.

#### User settable properties:

> `avoid-slur` (symbol)

>   Method of handling slur collisions. Choices are `around`, `inside`, `outside`. If unset, scripts and slurs ignore each other. `around` only moves the script if there is a collision; `outside` always moves the script.

This grob interface is used in the following graphical object(s): DynamicLineSpanner.

### 3.2.27 dynamic-text-spanner-interface

Dynamic text spanner.

#### User settable properties:

> `text` (markup)

>   Text markup. See Formatting text.

This grob interface is used in the following graphical object(s): DynamicTextSpanner.

### 3.2.28 enclosing-bracket-interface

Brackets alongside bass figures.

#### User settable properties:

> `bracket-flare` (pair of numbers)

>   A pair of numbers specifying how much edges of brackets should slant outward. Value `0.0` means straight edges.

> `edge-height` (pair)

>   A pair of numbers specifying the heights of the vertical edges: `(left-height . right-height)`.

> `padding` (dimension, in staff space)

>   Add this much extra space between objects that are next to each other.

> `shorten-pair` (pair of numbers)

>   The lengths to shorten a text-spanner on both sides, for example a pedal bracket. Positive values shorten the text-spanner, while negative values lengthen it.

> `thickness` (number)

>   Line thickness, generally measured in `line-thickness`.

#### Internal properties:

> `elements` (unknown)

>   A list of grobs; the type is depending on the grob where this is set in.

This grob interface is used in the following graphical object(s): BassFigureBracket.

### 3.2.29 figured-bass-continuation-interface

Simple extender line between bounds.

#### User settable properties:

> `padding` (dimension, in staff space)

>   Add this much extra space between objects that are next to each other.

> `thickness` (number)

>   Line thickness, generally measured in `line-thickness`.

#### Internal properties:

> `figures` (unknown)

>   Figured bass objects for continuation line.

This grob interface is used in the following graphical object(s): BassFigureContinuation.

### 3.2.30 finger-interface

A fingering instruction.

This grob interface is used in the following graphical object(s): Fingering.

### 3.2.31 font-interface

Any symbol that is typeset through fixed sets of glyphs, (i.e., fonts).

#### User settable properties:

> `font-encoding` (symbol)

>   The font encoding is the broadest category for selecting a font. Currently, only lilypond’s system fonts (Emmentaler and Aybabtu) are using this property. Available values are `fetaMusic` (Emmentaler), `fetaBraces` (Aybabtu), `fetaNumber` (Emmentaler), and `fetaDynamic` (Emmentaler).

> `font-family` (symbol)

>   The font family is the broadest category for selecting text fonts. Options include: `sans`, `roman`.

> `font-name` (string)

>   Specifies a file name (without extension) of the font to load. This setting overrides selection using `font-family`, `font-series` and `font-shape`.

> `font-series` (symbol)

>   Select the series of a font. Choices include `medium`, `bold`, `bold-narrow`, etc.

> `font-shape` (symbol)

>   Select the shape of a font. Choices include `upright`, `italic`, `caps`.

> `font-size` (number)

>   The font size, compared to the ‘normal’ size. `0` is style-sheet’s normal size, `-1` is smaller, `+1` is bigger. Each step of 1 is approximately 12% larger; 6 steps are exactly a factor 2 larger. Fractional values are allowed.

#### Internal properties:

> `font` (font metric)

>   A cached font metric object.

This grob interface is used in the following graphical object(s): Accidental, AccidentalCautionary, AccidentalSuggestion, AmbitusAccidental, AmbitusLine, AmbitusNoteHead, Arpeggio, BalloonTextItem, BarLine, BarNumber, BassFigure, Beam, BreathingSign, ChordName, Clef, CombineTextScript, Custos, Dots, DoublePercentRepeat, DoublePercentRepeatCounter, DynamicText, DynamicTextSpanner, Fingering, FretBoard, HarmonicParenthesesItem, InstrumentName, InstrumentSwitch, KeyCancellation, KeySignature, LyricHyphen, LyricText, MensuralLigature, MetronomeMark, MultiMeasureRest, MultiMeasureRestNumber, MultiMeasureRestText, NonMusicalPaperColumn, NoteHead, NoteName, OctavateEight, OttavaBracket, PaperColumn, ParenthesesItem, PercentRepeat, PercentRepeatCounter, RehearsalMark, Rest, Script, SostenutoPedal, SpanBar, StanzaNumber, Stem, StringNumber, StrokeFinger, SustainPedal, SystemStartBrace, SystemStartBracket, SystemStartSquare, TabNoteHead, TextScript, TextSpanner, TimeSignature, TrillPitchAccidental, TrillPitchGroup, TrillPitchHead, TrillSpanner, TupletNumber, UnaCordaPedal, VaticanaLigature and VoltaBracket.

### 3.2.32 fret-diagram-interface

A fret diagram

#### User settable properties:

> `align-dir` (direction)

>   Which side to align? `-1`: left side, `0`: around center of width, `1`: right side.

> `dot-placement-list` (list)

>   List consisting of `(description string-number fret-number finger-number)` entries used to define fret diagrams.

> `fret-diagram-details` (list)

>   An alist of detailed grob properties for fret diagrams. Each alist entry consists of a `(property . value)` pair. The properties which can be included in `fret-diagram-details` include the following:

>   - `barre-type` – Type of barre indication used. Choices include `curved`, `straight`, and `none`. Default `curved`.
>   - `capo-thickness` – Thickness of capo indicator, in multiples of fret-space. Default value 0.5.
>   - `dot-color` – Color of dots. Options include `black` and `white`. Default `black`.
>   - `dot-label-font-mag` – Magnification for font used to label fret dots. Default value 1.
>   - `dot-position` – Location of dot in fret space. Default 0.6 for dots without labels, 0.95-`dot-radius` for dots with labels.
>   - `dot-radius` – Radius of dots, in terms of fret spaces. Default value 0.425 for labeled dots, 0.25 for unlabeled dots.
>   - `finger-code` – Code for the type of fingering indication used. Options include `none`, `in-dot`, and `below-string`. Default `none` for markup fret diagrams, `below-string` for `FretBoards` fret diagrams.
>   - `fret-count` – The number of frets. Default 4.
>   - `fret-label-font-mag` – The magnification of the font used to label the lowest fret number. Default 0.5.
>   - `fret-label-vertical-offset` – The offset of the fret label from the center of the fret in direction parallel to strings. Default 0.
>   - `label-dir` – Side to which the fret label is attached. `-1`, `#LEFT`, or `#DOWN` for left or down; `1`, `#RIGHT`, or `#UP` for right or up. Default `#RIGHT`.
>   - `mute-string` – Character string to be used to indicate muted string. Default `"x"`.
>   - `number-type` – Type of numbers to use in fret label. Choices include `roman-lower`, `roman-upper`, and `arabic`. Default `roman-lower`.
>   - `open-string` – Character string to be used to indicate open string. Default `"o"`.
>   - `orientation` – Orientation of fret-diagram. Options include `normal`, `landscape`, and `opposing-landscape`. Default `normal`.
>   - `string-count` – The number of strings. Default 6.
>   - `string-label-font-mag` – The magnification of the font used to label fingerings at the string, rather than in the dot. Default value 0.6 for `normal` orientation, 0.5 for `landscape` and `opposing-landscape`.
>   - `string-thickness-factor` – Factor for changing thickness of each string in the fret diagram. Thickness of string k is given by `thickness` * (1+`string-thickness-factor`) ^ (k-1). Default 0.
>   - `top-fret-thickness` – The thickness of the top fret line, as a multiple of the standard thickness. Default value 3.
>   - `xo-font-magnification` – Magnification used for mute and open string indicators. Default value 0.5.
>   - `xo-padding` – Padding for open and mute indicators from top fret. Default value 0.25.
> `size` (number)

>   Size of object, relative to standard size.

> `thickness` (number)

>   Line thickness, generally measured in `line-thickness`.

This grob interface is used in the following graphical object(s): FretBoard.

### 3.2.33 grace-spacing-interface

Keep track of durations in a run of grace notes.

#### User settable properties:

> `common-shortest-duration` (moment)

>   The most common shortest note length. This is used in spacing. Enlarging this sets the score tighter.

#### Internal properties:

> `columns` (unknown)

>   A list of grobs, typically containing `PaperColumn` or `NoteColumn` objects.

This grob interface is used in the following graphical object(s): GraceSpacing.

### 3.2.34 gregorian-ligature-interface

A gregorian ligature.

#### Internal properties:

> `ascendens` (boolean)

>   Is this neume of ascending type?

> `auctum` (boolean)

>   Is this neume liquescentically augmented?

> `cavum` (boolean)

>   Is this neume outlined?

> `context-info` (integer)

>   Within a ligature, the final glyph or shape of a head may be affected by the left and/or right neighbour head. `context-info` holds for each head such information about the left and right neighbour, encoded as a bit mask.

> `deminutum` (boolean)

>   Is this neume deminished?

> `descendens` (boolean)

>   Is this neume of descendent type?

> `inclinatum` (boolean)

>   Is this neume an inclinatum?

> `linea` (boolean)

>   Attach vertical lines to this neume?

> `oriscus` (boolean)

>   Is this neume an oriscus?

> `pes-or-flexa` (boolean)

>   Shall this neume be joined with the previous head?

> `prefix-set` (number)

>   A bit mask that holds all Gregorian head prefixes, such as `\virga` or `\quilisma`.

> `quilisma` (boolean)

>   Is this neume a quilisma?

> `stropha` (boolean)

>   Is this neume a stropha?

> `virga` (boolean)

>   Is this neume a virga?

This grob interface is used in the following graphical object(s): NoteHead.

### 3.2.35 grid-line-interface

A line that is spanned between grid-points.

#### User settable properties:

> `thickness` (number)

>   Line thickness, generally measured in `line-thickness`.

#### Internal properties:

> `elements` (unknown)

>   A list of grobs; the type is depending on the grob where this is set in.

This grob interface is used in the following graphical object(s): GridLine.

### 3.2.36 grid-point-interface

A spanning point for grid lines.

This grob interface is used in the following graphical object(s): GridPoint.

### 3.2.37 grob-interface

A grob represents a piece of music notation.

All grobs have an X and Y position on the page. These X and Y positions are stored in a relative format, thus they can easily be combined by stacking them, hanging one grob to the side of another, or coupling them into grouping objects.

Each grob has a reference point (a.k.a. parent): The position of a grob is stored relative to that reference point. For example, the X reference point of a staccato dot usually is the note head that it applies to. When the note head is moved, the staccato dot moves along automatically.

A grob is often associated with a symbol, but some grobs do not print any symbols. They take care of grouping objects. For example, there is a separate grob that stacks staves vertically. The NoteCollision object is also an abstract grob: It only moves around chords, but doesn’t print anything.

Grobs have properties (Scheme variables) that can be read and set. Two types of them exist: immutable and mutable. Immutable variables define the default style and behavior. They are shared between many objects. They can be changed using `\override` and `\revert`. Mutable properties are variables that are specific to one grob. Typically, lists of other objects, or results from computations are stored in mutable properties. In particular, every call to `set-grob-property` (or its C++ equivalent) sets a mutable property.

The properties `after-line-breaking` and `before-line-breaking` are dummies that are not user-serviceable.

#### User settable properties:

> `X-extent` (pair of numbers)

>   Hard coded extent in X direction.

> `X-offset` (number)

>   The horizontal amount that this object is moved relative to its X-parent.

> `Y-extent` (pair of numbers)

>   Hard coded extent in Y direction.

> `Y-offset` (number)

>   The vertical amount that this object is moved relative to its Y-parent.

> `after-line-breaking` (boolean)

>   Dummy property, used to trigger callback for `after-line-breaking`.

> `avoid-slur` (symbol)

>   Method of handling slur collisions. Choices are `around`, `inside`, `outside`. If unset, scripts and slurs ignore each other. `around` only moves the script if there is a collision; `outside` always moves the script.

> `before-line-breaking` (boolean)

>   Dummy property, used to trigger a callback function.

> `color` (list)

>   The color of this grob.

> `extra-X-extent` (pair of numbers)

>   A grob is enlarged in X dimension by this much.

> `extra-Y-extent` (pair of numbers)

>   A grob is enlarged in Y dimension by this much.

> `extra-offset` (pair of numbers)

>   A pair representing an offset. This offset is added just before outputting the symbol, so the typesetting engine is completely oblivious to it. The values are measured in `staff-space` units of the staff’s `StaffSymbol`.

> `layer` (integer)

>   The output layer (a value between 0 and 2): Layers define the order of printing objects. Objects in lower layers are overprinted by objects in higher layers.

> `minimum-X-extent` (pair of numbers)

>   Minimum size of an object in X dimension, measured in `staff-space` units.

> `minimum-Y-extent` (pair of numbers)

>   Minimum size of an object in Y dimension, measured in `staff-space` units.

> `outside-staff-horizontal-padding` (number)

>   By default, an outside-staff-object can be placed so that is it very close to another grob horizontally. If this property is set, the outside-staff-object is raised so that it is not so close to its neighbor.

> `outside-staff-padding` (number)

>   The padding to place between this grob and the staff when spacing according to `outside-staff-priority`.

> `outside-staff-priority` (number)

>   If set, the grob is positioned outside the staff in such a way as to avoid all collisions. In case of a potential collision, the grob with the smaller `outside-staff-priority` is closer to the staff.

> `rotation` (list)

>   Number of degrees to rotate this object, and what point to rotate around. For example, `#'(45 0 0)` rotates by 45 degrees around the center of this object.

> `springs-and-rods` (boolean)

>   Dummy variable for triggering spacing routines.

> `stencil` (unknown)

>   The symbol to print.

> `transparent` (boolean)

>   This makes the grob invisible.

#### Internal properties:

> `axis-group-parent-X` (layout object)

>   Containing X axis group.

> `axis-group-parent-Y` (layout object)

>   Containing Y axis group.

> `cause` (any type)

>   Any kind of causation objects (i.e., music, or perhaps translator) that was the cause for this grob.

> `cross-staff` (boolean)

>   For a beam or a stem, this is true if we depend on inter-staff spacing.

> `interfaces` (list)

>   A list of symbols indicating the interfaces supported by this object. It is initialized from the `meta` field.

> `meta` (list)

>   Provide meta information. It is an alist with the entries `name` and `interfaces`.

> `pure-Y-offset-in-progress` (boolean)

>   A debugging aid for catching cyclic dependencies.

> `staff-symbol` (layout object)

>   The staff symbol grob that we are in.

This grob interface is used in the following graphical object(s): Accidental, AccidentalCautionary, AccidentalPlacement, AccidentalSuggestion, Ambitus, AmbitusAccidental, AmbitusLine, AmbitusNoteHead, Arpeggio, BalloonTextItem, BarLine, BarNumber, BassFigure, BassFigureAlignment, BassFigureAlignmentPositioning, BassFigureBracket, BassFigureContinuation, BassFigureLine, Beam, BendAfter, BreakAlignGroup, BreakAlignment, BreathingSign, ChordName, Clef, ClusterSpanner, ClusterSpannerBeacon, CombineTextScript, Custos, DotColumn, Dots, DoublePercentRepeat, DoublePercentRepeatCounter, DynamicLineSpanner, DynamicText, DynamicTextSpanner, Fingering, FretBoard, Glissando, GraceSpacing, GridLine, GridPoint, Hairpin, HarmonicParenthesesItem, HorizontalBracket, InstrumentName, InstrumentSwitch, KeyCancellation, KeySignature, LaissezVibrerTie, LaissezVibrerTieColumn, LedgerLineSpanner, LeftEdge, LigatureBracket, LyricExtender, LyricHyphen, LyricSpace, LyricText, MeasureGrouping, MelodyItem, MensuralLigature, MetronomeMark, MultiMeasureRest, MultiMeasureRestNumber, MultiMeasureRestText, NonMusicalPaperColumn, NoteCollision, NoteColumn, NoteHead, NoteName, NoteSpacing, OctavateEight, OttavaBracket, PaperColumn, ParenthesesItem, PercentRepeat, PercentRepeatCounter, PhrasingSlur, PianoPedalBracket, RehearsalMark, RepeatSlash, RepeatTie, RepeatTieColumn, Rest, RestCollision, Script, ScriptColumn, ScriptRow, SeparationItem, Slur, SostenutoPedal, SostenutoPedalLineSpanner, SpacingSpanner, SpanBar, StaffSpacing, StaffSymbol, StanzaNumber, Stem, StemTremolo, StringNumber, StrokeFinger, SustainPedal, SustainPedalLineSpanner, System, SystemStartBar, SystemStartBrace, SystemStartBracket, SystemStartSquare, TabNoteHead, TextScript, TextSpanner, Tie, TieColumn, TimeSignature, TrillPitchAccidental, TrillPitchGroup, TrillPitchHead, TrillSpanner, TupletBracket, TupletNumber, UnaCordaPedal, UnaCordaPedalLineSpanner, VaticanaLigature, VerticalAlignment, VerticalAxisGroup, VoiceFollower, VoltaBracket and VoltaBracketSpanner.

### 3.2.38 hairpin-interface

A hairpin crescendo or decrescendo.

#### User settable properties:

> `bound-padding` (number)

>   The amount of padding to insert around spanner bounds.

> `circled-tip` (boolean)

>   Put a circle at start/end of hairpins (al/del niente).

> `grow-direction` (direction)

>   Crescendo or decrescendo?

> `height` (dimension, in staff space)

>   Height of an object in `staff-space` units.

#### Internal properties:

> `adjacent-hairpins` (unknown)

>   A list of directly neighboring hairpins.

This grob interface is used in the following graphical object(s): Hairpin.

### 3.2.39 hara-kiri-group-spanner-interface

A group spanner that keeps track of interesting items. If it doesn’t contain any after line breaking, it removes itself and all its children.

#### User settable properties:

> `remove-empty` (boolean)

>   If set, remove group if it contains no interesting items.

> `remove-first` (boolean)

>   Remove the first staff of an orchestral score?

#### Internal properties:

> `important-column-ranks` (vector)

>   A cache of columns that contain `items-worth-living` data.

> `items-worth-living` (unknown)

>   A list of interesting items. If empty in a particular staff, then that staff is erased.

This grob interface is used in the following graphical object(s): VerticalAxisGroup.

### 3.2.40 horizontal-bracket-interface

A horizontal bracket encompassing notes.

#### User settable properties:

> `bracket-flare` (pair of numbers)

>   A pair of numbers specifying how much edges of brackets should slant outward. Value `0.0` means straight edges.

> `connect-to-neighbor` (pair)

>   Pair of booleans, indicating whether this grob looks as a continued break.

> `edge-height` (pair)

>   A pair of numbers specifying the heights of the vertical edges: `(left-height . right-height)`.

> `shorten-pair` (pair of numbers)

>   The lengths to shorten a text-spanner on both sides, for example a pedal bracket. Positive values shorten the text-spanner, while negative values lengthen it.

#### Internal properties:

> `columns` (unknown)

>   A list of grobs, typically containing `PaperColumn` or `NoteColumn` objects.

This grob interface is used in the following graphical object(s): HorizontalBracket, OttavaBracket and VoltaBracket.

### 3.2.41 instrument-specific-markup-interface

Instrument-specific markup (like fret boards or harp pedal diagrams).

#### User settable properties:

> `fret-diagram-details` (list)

>   An alist of detailed grob properties for fret diagrams. Each alist entry consists of a `(property . value)` pair. The properties which can be included in `fret-diagram-details` include the following:

>   - `barre-type` – Type of barre indication used. Choices include `curved`, `straight`, and `none`. Default `curved`.
>   - `capo-thickness` – Thickness of capo indicator, in multiples of fret-space. Default value 0.5.
>   - `dot-color` – Color of dots. Options include `black` and `white`. Default `black`.
>   - `dot-label-font-mag` – Magnification for font used to label fret dots. Default value 1.
>   - `dot-position` – Location of dot in fret space. Default 0.6 for dots without labels, 0.95-`dot-radius` for dots with labels.
>   - `dot-radius` – Radius of dots, in terms of fret spaces. Default value 0.425 for labeled dots, 0.25 for unlabeled dots.
>   - `finger-code` – Code for the type of fingering indication used. Options include `none`, `in-dot`, and `below-string`. Default `none` for markup fret diagrams, `below-string` for `FretBoards` fret diagrams.
>   - `fret-count` – The number of frets. Default 4.
>   - `fret-label-font-mag` – The magnification of the font used to label the lowest fret number. Default 0.5.
>   - `fret-label-vertical-offset` – The offset of the fret label from the center of the fret in direction parallel to strings. Default 0.
>   - `label-dir` – Side to which the fret label is attached. `-1`, `#LEFT`, or `#DOWN` for left or down; `1`, `#RIGHT`, or `#UP` for right or up. Default `#RIGHT`.
>   - `mute-string` – Character string to be used to indicate muted string. Default `"x"`.
>   - `number-type` – Type of numbers to use in fret label. Choices include `roman-lower`, `roman-upper`, and `arabic`. Default `roman-lower`.
>   - `open-string` – Character string to be used to indicate open string. Default `"o"`.
>   - `orientation` – Orientation of fret-diagram. Options include `normal`, `landscape`, and `opposing-landscape`. Default `normal`.
>   - `string-count` – The number of strings. Default 6.
>   - `string-label-font-mag` – The magnification of the font used to label fingerings at the string, rather than in the dot. Default value 0.6 for `normal` orientation, 0.5 for `landscape` and `opposing-landscape`.
>   - `string-thickness-factor` – Factor for changing thickness of each string in the fret diagram. Thickness of string k is given by `thickness` * (1+`string-thickness-factor`) ^ (k-1). Default 0.
>   - `top-fret-thickness` – The thickness of the top fret line, as a multiple of the standard thickness. Default value 3.
>   - `xo-font-magnification` – Magnification used for mute and open string indicators. Default value 0.5.
>   - `xo-padding` – Padding for open and mute indicators from top fret. Default value 0.25.
> `harp-pedal-details` (list)

>   An alist of detailed grob properties for harp pedal diagrams. Each alist entry consists of a `(property . value)` pair. The properties which can be included in harp-pedal-details include the following:

>   - `box-offset` – Vertical shift of the center of flat/sharp pedal boxes above/below the horizontal line. Default value 0.8.
>   - `box-width` – Width of each pedal box. Default value 0.4.
>   - `box-height` – Height of each pedal box. Default value 1.0.
>   - `space-before-divider` – Space between boxes before the first divider (so that the diagram can be made symmetric). Default value 0.8.
>   - `space-after-divider` – Space between boxes after the first divider. Default value 0.8.
>   - `circle-thickness` – Thickness (in unit of the line-thickness) of the ellipse around circled pedals. Default value 0.5.
>   - `circle-x-padding` – Padding in X direction of the ellipse around circled pedals. Default value 0.15.
>   - `circle-y-padding` – Padding in Y direction of the ellipse around circled pedals. Default value 0.2.
> `size` (number)

>   Size of object, relative to standard size.

> `thickness` (number)

>   Line thickness, generally measured in `line-thickness`.

This grob interface is used in the following graphical object(s): TextScript.

### 3.2.42 item-interface

Grobs can be distinguished in their role in the horizontal spacing. Many grobs define constraints on the spacing by their sizes, for example, note heads, clefs, stems, and all other symbols with a fixed shape. These grobs form a subtype called `Item`.

Some items need special treatment for line breaking. For example, a clef is normally only printed at the start of a line (i.e., after a line break). To model this, ‘breakable’ items (clef, key signature, bar lines, etc.) are copied twice. Then we have three versions of each breakable item: one version if there is no line break, one version that is printed before the line break (at the end of a system), and one version that is printed after the line break.

Whether these versions are visible and take up space is determined by the outcome of the `break-visibility` grob property, which is a function taking a direction (`-1`, `0` or `1`) as an argument. It returns a cons of booleans, signifying whether this grob should be transparent and have no extent.

The following variables for `break-visibility` are predefined:

>                grob will show:   before  no     after
>                                  break   break  break
>       all-invisible              no      no     no
>       begin-of-line-visible      no      no     yes
>       end-of-line-visible        yes     no     no
>       all-visible                yes     yes    yes
>       begin-of-line-invisible    yes     yes    no
>       end-of-line-invisible      no      yes    yes
>       center-invisible           yes      no    yes

#### User settable properties:

> `break-visibility` (vector)

>   A vector of 3 booleans, `#(end-of-line unbroken begin-of-line)`. `#t` means visible, `#f` means killed.

> `extra-spacing-height` (pair of numbers)

>   In the horizontal spacing problem, we increase the height of each item by this amount (by adding the ‘car’ to the bottom of the item and adding the ‘cdr’ to the top of the item). In order to make a grob infinitely high (to prevent the horizontal spacing problem from placing any other grobs above or below this grob), set this to `(-inf.0 . +inf.0)`.

> `extra-spacing-width` (pair of numbers)

>   In the horizontal spacing problem, we pad each item by this amount (by adding the ‘car’ on the left side of the item and adding the ‘cdr’ on the right side of the item). In order to make a grob take up no horizontal space at all, set this to `(+inf.0 . -inf.0)`.

> `non-musical` (boolean)

>   True if the grob belongs to a `NonMusicalPaperColumn`.

This grob interface is used in the following graphical object(s): Accidental, AccidentalCautionary, AccidentalPlacement, AccidentalSuggestion, Ambitus, AmbitusAccidental, AmbitusLine, AmbitusNoteHead, Arpeggio, BalloonTextItem, BarLine, BarNumber, BassFigure, BassFigureBracket, BreakAlignGroup, BreakAlignment, BreathingSign, ChordName, Clef, ClusterSpannerBeacon, CombineTextScript, Custos, DotColumn, Dots, DoublePercentRepeat, DoublePercentRepeatCounter, DynamicText, Fingering, FretBoard, GridLine, GridPoint, HarmonicParenthesesItem, InstrumentSwitch, KeyCancellation, KeySignature, LaissezVibrerTie, LaissezVibrerTieColumn, LeftEdge, LyricText, MelodyItem, MetronomeMark, NonMusicalPaperColumn, NoteCollision, NoteColumn, NoteHead, NoteName, NoteSpacing, OctavateEight, PaperColumn, ParenthesesItem, RehearsalMark, RepeatSlash, RepeatTie, RepeatTieColumn, Rest, RestCollision, Script, ScriptColumn, ScriptRow, SeparationItem, SostenutoPedal, SpanBar, StaffSpacing, StanzaNumber, Stem, StemTremolo, StringNumber, StrokeFinger, SustainPedal, TabNoteHead, TextScript, TimeSignature, TrillPitchAccidental, TrillPitchGroup, TrillPitchHead and UnaCordaPedal.

### 3.2.43 key-cancellation-interface

A key cancellation.

This grob interface is used in the following graphical object(s): KeyCancellation.

### 3.2.44 key-signature-interface

A group of accidentals, to be printed as signature sign.

#### User settable properties:

> `alteration-alist` (list)

>   List of `(pitch . accidental)` pairs for key signature.

> `c0-position` (integer)

>   An integer indicating the position of middle C.

> `glyph-name-alist` (list)

>   An alist of key-string pairs.

> `padding` (dimension, in staff space)

>   Add this much extra space between objects that are next to each other.

> `padding-pairs` (list)

>   An alist mapping `(name . name)` to distances.

This grob interface is used in the following graphical object(s): KeyCancellation and KeySignature.

### 3.2.45 ledger-line-spanner-interface

This spanner draws the ledger lines of a staff. This is a separate grob because it has to process all potential collisions between all note heads.

#### User settable properties:

> `gap` (dimension, in staff space)

>   Size of a gap in a variable symbol.

> `length-fraction` (number)

>   Multiplier for lengths. Used for determining ledger lines and stem lengths.

> `minimum-length-fraction` (number)

>   Minimum length of ledger line as fraction of note head size.

> `thickness` (number)

>   Line thickness, generally measured in `line-thickness`.

#### Internal properties:

> `note-heads` (unknown)

>   A list of note head grobs.

This grob interface is used in the following graphical object(s): LedgerLineSpanner.

### 3.2.46 ledgered-interface

Objects that need ledger lines, typically note heads. See also ledger-line-spanner-interface.

#### User settable properties:

> `no-ledgers` (boolean)

>   If set, don’t draw ledger lines on this object.

This grob interface is used in the following graphical object(s): AmbitusNoteHead, NoteHead and TrillPitchHead.

### 3.2.47 ligature-bracket-interface

A bracket indicating a ligature in the original edition.

#### User settable properties:

> `height` (dimension, in staff space)

>   Height of an object in `staff-space` units.

> `thickness` (number)

>   Line thickness, generally measured in `line-thickness`.

> `width` (dimension, in staff space)

>   The width of a grob measured in staff space.

This grob interface is not used in any graphical object.

### 3.2.48 ligature-interface

A ligature.

This grob interface is not used in any graphical object.

### 3.2.49 line-interface

Generic line objects. Any object using lines supports this. The property `style` can be `line`, `dashed-line`, `trill`, `dotted-line` or `zigzag`.

For `dashed-line`, the length of the dashes is tuned with `dash-fraction`. If the latter is set to 0, a dotted line is produced. If `dash-period` is negative, the line is made transparent.

#### User settable properties:

> `arrow-length` (number)

>   Arrow length.

> `arrow-width` (number)

>   Arrow width.

> `dash-fraction` (number)

>   Size of the dashes, relative to `dash-period`. Should be between `0.0` (no line) and `1.0` (continuous line).

> `dash-period` (number)

>   The length of one dash together with whitespace. If negative, no line is drawn at all.

> `style` (symbol)

>   This setting determines in what style a grob is typeset. Valid choices depend on the `stencil` callback reading this property.

> `thickness` (number)

>   Line thickness, generally measured in `line-thickness`.

> `zigzag-length` (dimension, in staff space)

>   The length of the lines of a zigzag, relative to `zigzag-width`. A value of `1` gives 60-degree zigzags.

> `zigzag-width` (dimension, in staff space)

>   The width of one zigzag squiggle. This number is adjusted slightly so that the glissando line can be constructed from a whole number of squiggles.

This grob interface is used in the following graphical object(s): DynamicTextSpanner, Glissando, Hairpin, HorizontalBracket, LigatureBracket, OttavaBracket, PianoPedalBracket, TextSpanner, TrillSpanner, TupletBracket, VoiceFollower and VoltaBracket.

### 3.2.50 line-spanner-interface

Generic line drawn between two objects, e.g., for use with glissandi.

#### User settable properties:

> `bound-details` (list)

>   An alist of properties for determining attachments of spanners to edges.

> `extra-dy` (number)

>   Slope glissandi this much extra.

> `gap` (dimension, in staff space)

>   Size of a gap in a variable symbol.

> `left-bound-info` (list)

>   An alist of properties for determining attachments of spanners to edges.

> `right-bound-info` (list)

>   An alist of properties for determining attachments of spanners to edges.

> `thickness` (number)

>   Line thickness, generally measured in `line-thickness`.

> `to-barline` (boolean)

>   If true, the spanner will stop at the bar line just before it would otherwise stop.

#### Internal properties:

> `note-columns` (pair)

>   A list of `NoteColumn` grobs.

This grob interface is used in the following graphical object(s): DynamicTextSpanner, Glissando, TextSpanner, TrillSpanner and VoiceFollower.

### 3.2.51 lyric-extender-interface

The extender is a simple line at the baseline of the lyric that helps show the length of a melisma (a tied or slurred note).

#### User settable properties:

> `left-padding` (dimension, in staff space)

>   The amount of space that is put left to an object (e.g., a group of accidentals).

> `next` (layout object)

>   Object that is next relation (e.g., the lyric syllable following an extender).

> `right-padding` (dimension, in staff space)

>   Space to insert on the right side of an object (e.g., between note and its accidentals).

> `thickness` (number)

>   Line thickness, generally measured in `line-thickness`.

#### Internal properties:

> `heads` (unknown)

>   A list of note heads.

This grob interface is used in the following graphical object(s): LyricExtender.

### 3.2.52 lyric-hyphen-interface

A centered hyphen is simply a line between lyrics used to divide syllables.

#### User settable properties:

> `dash-period` (number)

>   The length of one dash together with whitespace. If negative, no line is drawn at all.

> `height` (dimension, in staff space)

>   Height of an object in `staff-space` units.

> `length` (dimension, in staff space)

>   User override for the stem length of unbeamed stems.

> `minimum-distance` (dimension, in staff space)

>   Minimum distance between rest and notes or beam.

> `minimum-length` (dimension, in staff space)

>   Try to make a spanner at least this long, normally in the horizontal direction. This requires an appropriate callback for the `springs-and-rods` property. If added to a `Tie`, this sets the minimum distance between noteheads.

> `padding` (dimension, in staff space)

>   Add this much extra space between objects that are next to each other.

> `thickness` (number)

>   Line thickness, generally measured in `line-thickness`.

This grob interface is used in the following graphical object(s): LyricHyphen and LyricSpace.

### 3.2.53 lyric-interface

Any object that is related to lyrics.

This grob interface is used in the following graphical object(s): LyricExtender and LyricHyphen.

### 3.2.54 lyric-syllable-interface

A single piece of lyrics.

This grob interface is used in the following graphical object(s): LyricText.

### 3.2.55 mark-interface

A rehearsal mark.

This grob interface is used in the following graphical object(s): RehearsalMark.

### 3.2.56 measure-grouping-interface

This object indicates groups of beats. Valid choices for `style` are `bracket` and `triangle`.

#### User settable properties:

> `height` (dimension, in staff space)

>   Height of an object in `staff-space` units.

> `style` (symbol)

>   This setting determines in what style a grob is typeset. Valid choices depend on the `stencil` callback reading this property.

> `thickness` (number)

>   Line thickness, generally measured in `line-thickness`.

This grob interface is used in the following graphical object(s): MeasureGrouping.

### 3.2.57 melody-spanner-interface

Context dependent typesetting decisions.

#### User settable properties:

> `neutral-direction` (direction)

>   Which direction to take in the center of the staff.

#### Internal properties:

> `stems` (unknown)

>   A list of stem objects, corresponding to the notes that the arpeggio has to be before.

This grob interface is used in the following graphical object(s): MelodyItem.

### 3.2.58 mensural-ligature-interface

A mensural ligature.

#### User settable properties:

> `thickness` (number)

>   Line thickness, generally measured in `line-thickness`.

#### Internal properties:

> `delta-position` (number)

>   The vertical position difference.

> `flexa-width` (dimension, in staff space)

>   The width of a flexa shape in a ligature grob in (in `staff-space` units).

> `head-width` (dimension, in staff space)

>   The width of this ligature head.

> `join-right-amount` (number)

>   DOCME

> `primitive` (integer)

>   A pointer to a ligature primitive, i.e., an item similar to a note head that is part of a ligature.

This grob interface is used in the following graphical object(s): MensuralLigature and NoteHead.

### 3.2.59 metronome-mark-interface

A metronome mark.

This grob interface is used in the following graphical object(s): MetronomeMark.

### 3.2.60 multi-measure-interface

Multi measure rest, and the text or number that is printed over it.

#### User settable properties:

> `bound-padding` (number)

>   The amount of padding to insert around spanner bounds.

This grob interface is used in the following graphical object(s): MultiMeasureRest, MultiMeasureRestNumber and MultiMeasureRestText.

### 3.2.61 multi-measure-rest-interface

A rest that spans a whole number of measures.

#### User settable properties:

> `bound-padding` (number)

>   The amount of padding to insert around spanner bounds.

> `expand-limit` (integer)

>   Maximum number of measures expanded in church rests.

> `hair-thickness` (number)

>   Thickness of the thin line in a bar line.

> `measure-count` (integer)

>   The number of measures for a multi-measure rest.

> `minimum-length` (dimension, in staff space)

>   Try to make a spanner at least this long, normally in the horizontal direction. This requires an appropriate callback for the `springs-and-rods` property. If added to a `Tie`, this sets the minimum distance between noteheads.

> `thick-thickness` (number)

>   Bar line thickness, measured in `line-thickness`.

#### Internal properties:

> `use-breve-rest` (boolean)

>   Use breve rests for measures longer than a whole rest.

This grob interface is used in the following graphical object(s): MultiMeasureRest and PercentRepeat.

### 3.2.62 note-collision-interface

An object that handles collisions between notes with different stem directions and horizontal shifts. Most of the interesting properties are to be set in note-column-interface: these are `force-hshift` and `horizontal-shift`.

#### User settable properties:

> `merge-differently-dotted` (boolean)

>   Merge note heads in collisions, even if they have a different number of dots. This is normal notation for some types of polyphonic music.

>   `merge-differently-dotted` only applies to opposing stem directions (i.e., voice 1 & 2).

> `merge-differently-headed` (boolean)

>   Merge note heads in collisions, even if they have different note heads. The smaller of the two heads is rendered invisible. This is used in polyphonic guitar notation. The value of this setting is used by note-collision-interface.

>   `merge-differently-headed` only applies to opposing stem directions (i.e., voice 1 & 2).

> `prefer-dotted-right` (boolean)

>   For note collisions, prefer to shift dotted up-note to the right, rather than shifting just the dot.

#### Internal properties:

> `positioning-done` (boolean)

>   Used to signal that a positioning element did its job. This ensures that a positioning is only done once.

This grob interface is used in the following graphical object(s): NoteCollision.

### 3.2.63 note-column-interface

Stem and noteheads combined.

#### User settable properties:

> `force-hshift` (number)

>   This specifies a manual shift for notes in collisions. The unit is the note head width of the first voice note. This is used by note-collision-interface.

> `horizontal-shift` (integer)

>   An integer that identifies ranking of `NoteColumn`s for horizontal shifting. This is used by note-collision-interface.

> `ignore-collision` (boolean)

>   If set, don’t do note collision resolution on this `NoteColumn`.

#### Internal properties:

> `arpeggio` (layout object)

>   A pointer to an `Arpeggio` object.

> `note-heads` (unknown)

>   A list of note head grobs.

> `rest` (layout object)

>   A pointer to a `Rest` object.

> `rest-collision` (layout object)

>   A rest collision that a rest is in.

> `stem` (layout object)

>   A pointer to a `Stem` object.

This grob interface is used in the following graphical object(s): NoteColumn.

### 3.2.64 note-head-interface

A note head. There are many possible values for `style`. For a complete list, see Note head styles.

#### User settable properties:

> `note-names` (vector)

>   Vector of strings containing names for easy-notation note heads.

> `stem-attachment` (pair of numbers)

>   An `(x . y)` pair where the stem attaches to the notehead.

> `style` (symbol)

>   This setting determines in what style a grob is typeset. Valid choices depend on the `stencil` callback reading this property.

#### Internal properties:

> `accidental-grob` (layout object)

>   The accidental for this note.

> `glyph-name` (string)

>   The glyph name within the font.

This grob interface is used in the following graphical object(s): AmbitusNoteHead, NoteHead, TabNoteHead and TrillPitchGroup.

### 3.2.65 note-name-interface

Note names.

This grob interface is used in the following graphical object(s): NoteName.

### 3.2.66 note-spacing-interface

This object calculates spacing wishes for individual voices.

#### User settable properties:

> `knee-spacing-correction` (number)

>   Factor for the optical correction amount for kneed beams. Set between `0` for no correction and `1` for full correction.

> `same-direction-correction` (number)

>   Optical correction amount for stems that are placed in tight configurations. This amount is used for stems with the same direction to compensate for note head to stem distance.

> `space-to-barline` (boolean)

>   If set, the distance between a note and the following non-musical column will be measured to the bar line instead of to the beginning of the non-musical column. If there is a clef change followed by a bar line, for example, this means that we will try to space the non-musical column as though the clef is not there.

> `stem-spacing-correction` (number)

>   Optical correction amount for stems that are placed in tight configurations. For opposite directions, this amount is the correction for two normal sized stems that overlap completely.

#### Internal properties:

> `left-items` (unknown)

>   DOCME

> `right-items` (unknown)

>   DOCME

This grob interface is used in the following graphical object(s): NoteSpacing.

### 3.2.67 only-prebreak-interface

Kill this grob after the line breaking process.

This grob interface is not used in any graphical object.

### 3.2.68 ottava-bracket-interface

An ottava bracket.

#### User settable properties:

> `bracket-flare` (pair of numbers)

>   A pair of numbers specifying how much edges of brackets should slant outward. Value `0.0` means straight edges.

> `edge-height` (pair)

>   A pair of numbers specifying the heights of the vertical edges: `(left-height . right-height)`.

> `minimum-length` (dimension, in staff space)

>   Try to make a spanner at least this long, normally in the horizontal direction. This requires an appropriate callback for the `springs-and-rods` property. If added to a `Tie`, this sets the minimum distance between noteheads.

> `shorten-pair` (pair of numbers)

>   The lengths to shorten a text-spanner on both sides, for example a pedal bracket. Positive values shorten the text-spanner, while negative values lengthen it.

This grob interface is used in the following graphical object(s): OttavaBracket.

### 3.2.69 paper-column-interface

`Paper_column` objects form the top-most X parents for items. There are two types of columns: musical columns, where are attached to, and non-musical columns, where bar-lines, clefs, etc., are attached to. The spacing engine determines the X positions of these objects.

They are numbered, the first (leftmost) is column 0. Numbering happens before line breaking, and columns are not renumbered after line breaking. Since many columns go unused, you should only use the rank field to get ordering information. Two adjacent columns may have non-adjacent numbers.

#### User settable properties:

> `between-cols` (pair)

>   Where to attach a loose column to.

> `full-measure-extra-space` (number)

>   Extra space that is allocated at the beginning of a measure with only one note. This property is read from the NonMusicalPaperColumn that begins the measure.

> `labels` (list)

>   List of labels (symbols) placed on a column

> `line-break-penalty` (number)

>   Penalty for a line break at this column. This affects the choices of the line breaker; it avoids a line break at a column with a positive penalty and prefers a line break at a column with a negative penalty.

> `line-break-permission` (symbol)

>   Instructs the line breaker on whether to put a line break at this column. Can be `force` or `allow`.

> `line-break-system-details` (list)

>   An alist of properties to use if this column is the start of a system.

> `page-break-penalty` (number)

>   Penalty for page break at this column. This affects the choices of the page breaker; it avoids a page break at a column with a positive penalty and prefers a page break at a column with a negative penalty.

> `page-break-permission` (symbol)

>   Instructs the page breaker on whether to put a page break at this column. Can be `force` or `allow`.

> `page-turn-penalty` (number)

>   Penalty for a page turn at this column. This affects the choices of the page breaker; it avoids a page turn at a column with a positive penalty and prefers a page turn at a column with a negative penalty.

> `page-turn-permission` (symbol)

>   Instructs the page breaker on whether to put a page turn at this column. Can be `force` or `allow`.

> `rhythmic-location` (rhythmic location)

>   Where (bar number, measure position) in the score.

> `shortest-playing-duration` (moment)

>   The duration of the shortest note playing here.

> `shortest-starter-duration` (moment)

>   The duration of the shortest note that starts here.

> `used` (boolean)

>   If set, this spacing column is kept in the spacing problem.

> `when` (moment)

>   Global time step associated with this column happen?

#### Internal properties:

> `bounded-by-me` (unknown)

>   A list of spanners that have this column as start/begin point. Only columns that have grobs or act as bounds are spaced.

> `grace-spacing` (layout object)

>   A run of grace notes.

> `spacing` (layout object)

>   The spacing spanner governing this section.

This grob interface is used in the following graphical object(s): NonMusicalPaperColumn and PaperColumn.

### 3.2.70 parentheses-interface

Parentheses for other objects.

#### User settable properties:

> `padding` (dimension, in staff space)

>   Add this much extra space between objects that are next to each other.

> `stencils` (list)

>   Multiple stencils, used as intermediate value.

This grob interface is used in the following graphical object(s): HarmonicParenthesesItem, ParenthesesItem and TrillPitchGroup.

### 3.2.71 percent-repeat-interface

Beat, Double and single measure repeats.

#### User settable properties:

> `dot-negative-kern` (number)

>   The space to remove between a dot and a slash in percent repeat glyphs. Larger values bring the two elements closer together.

> `slash-negative-kern` (number)

>   The space to remove between slashes in percent repeat glyphs. Larger values bring the two elements closer together.

> `slope` (number)

>   The slope of this object.

> `thickness` (number)

>   Line thickness, generally measured in `line-thickness`.

This grob interface is used in the following graphical object(s): DoublePercentRepeat, DoublePercentRepeatCounter, PercentRepeat, PercentRepeatCounter and RepeatSlash.

### 3.2.72 percent-repeat-item-interface

Repeats that look like percent signs.

#### User settable properties:

> `dot-negative-kern` (number)

>   The space to remove between a dot and a slash in percent repeat glyphs. Larger values bring the two elements closer together.

> `slash-negative-kern` (number)

>   The space to remove between slashes in percent repeat glyphs. Larger values bring the two elements closer together.

> `slope` (number)

>   The slope of this object.

> `thickness` (number)

>   Line thickness, generally measured in `line-thickness`.

This grob interface is used in the following graphical object(s): DoublePercentRepeat, DoublePercentRepeatCounter and RepeatSlash.

### 3.2.73 piano-pedal-bracket-interface

The bracket of the piano pedal. It can be tuned through the regular bracket properties.

#### User settable properties:

> `bound-padding` (number)

>   The amount of padding to insert around spanner bounds.

> `bracket-flare` (pair of numbers)

>   A pair of numbers specifying how much edges of brackets should slant outward. Value `0.0` means straight edges.

> `edge-height` (pair)

>   A pair of numbers specifying the heights of the vertical edges: `(left-height . right-height)`.

> `shorten-pair` (pair of numbers)

>   The lengths to shorten a text-spanner on both sides, for example a pedal bracket. Positive values shorten the text-spanner, while negative values lengthen it.

#### Internal properties:

> `pedal-text` (layout object)

>   A pointer to the text of a mixed-style piano pedal.

This grob interface is used in the following graphical object(s): PianoPedalBracket.

### 3.2.74 piano-pedal-interface

A piano pedal sign.

This grob interface is used in the following graphical object(s): PianoPedalBracket, SostenutoPedalLineSpanner, SustainPedal, SustainPedalLineSpanner and UnaCordaPedalLineSpanner.

### 3.2.75 piano-pedal-script-interface

A piano pedal sign, fixed size.

This grob interface is used in the following graphical object(s): SostenutoPedal, SustainPedal and UnaCordaPedal.

### 3.2.76 pitched-trill-interface

A note head to indicate trill pitches.

#### Internal properties:

> `accidental-grob` (layout object)

>   The accidental for this note.

This grob interface is used in the following graphical object(s): TrillPitchHead.

### 3.2.77 rest-collision-interface

Move around ordinary rests (not multi-measure-rests) to avoid conflicts.

#### User settable properties:

> `minimum-distance` (dimension, in staff space)

>   Minimum distance between rest and notes or beam.

#### Internal properties:

> `elements` (unknown)

>   A list of grobs; the type is depending on the grob where this is set in.

> `positioning-done` (boolean)

>   Used to signal that a positioning element did its job. This ensures that a positioning is only done once.

This grob interface is used in the following graphical object(s): RestCollision.

### 3.2.78 rest-interface

A rest symbol. The property `style` can be `default`, `mensural`, `neomensural` or `classical`.

#### User settable properties:

> `direction` (direction)

>   If `side-axis` is `0` (or `#X`), then this property determines whether the object is placed `#LEFT`, `#CENTER` or `#RIGHT` with respect to the other object. Otherwise, it determines whether the object is placed `#UP`, `#CENTER` or `#DOWN`. Numerical values may also be used: `#UP`=`1`, `#DOWN`=`-1`, `#LEFT`=`-1`, `#RIGHT`=`1`, `#CENTER`=`0`.

> `minimum-distance` (dimension, in staff space)

>   Minimum distance between rest and notes or beam.

> `style` (symbol)

>   This setting determines in what style a grob is typeset. Valid choices depend on the `stencil` callback reading this property.

This grob interface is used in the following graphical object(s): MultiMeasureRest and Rest.

### 3.2.79 rhythmic-grob-interface

Any object with a duration. Used to determine which grobs are interesting enough to maintain a hara-kiri staff.

This grob interface is used in the following graphical object(s): BassFigure, ChordName, ClusterSpannerBeacon, LyricText, NoteHead, RepeatSlash, Rest and TabNoteHead.

### 3.2.80 rhythmic-head-interface

Note head or rest.

#### User settable properties:

> `duration-log` (integer)

>   The 2-log of the note head duration, i.e., `0` = whole note, `1` = half note, etc.

#### Internal properties:

> `dot` (layout object)

>   A reference to a `Dots` object.

> `stem` (layout object)

>   A pointer to a `Stem` object.

This grob interface is used in the following graphical object(s): AmbitusNoteHead, NoteHead, Rest, TabNoteHead and TrillPitchHead.

### 3.2.81 script-column-interface

An interface that sorts scripts according to their `script-priority`.

This grob interface is used in the following graphical object(s): ScriptColumn and ScriptRow.

### 3.2.82 script-interface

An object that is put above or below a note.

#### User settable properties:

> `add-stem-support` (boolean)

>   If set, the `Stem` object is included in this script’s support.

> `avoid-slur` (symbol)

>   Method of handling slur collisions. Choices are `around`, `inside`, `outside`. If unset, scripts and slurs ignore each other. `around` only moves the script if there is a collision; `outside` always moves the script.

> `script-priority` (number)

>   A sorting key that determines in what order a script is within a stack of scripts.

> `slur-padding` (number)

>   Extra distance between slur and script.

> `toward-stem-shift` (number)

>   Amount by which scripts are shifted toward the stem if their direction coincides with the stem direction. `0.0` means keep the default position (centered on the note head), `1.0` means centered on the stem. Interpolated values are possible.

#### Internal properties:

> `positioning-done` (boolean)

>   Used to signal that a positioning element did its job. This ensures that a positioning is only done once.

> `script-stencil` (pair)

>   A pair `(type . arg)` which acts as an index for looking up a `Stencil` object.

> `slur` (layout object)

>   A pointer to a `Slur` object.

This grob interface is used in the following graphical object(s): AccidentalSuggestion, DynamicText and Script.

### 3.2.83 self-alignment-interface

Position this object on itself and/or on its parent. To this end, the following functions are provided:

`Self_alignment_interface::[xy]_aligned_on_self`

  Align self on reference point, using `self-alignment-X` and `self-alignment-Y`.

`Self_alignment_interface::aligned_on_[xy]_parent`
`Self_alignment_interface::centered_on_[xy]_parent`

  Shift the object so its own reference point is centered on the extent of the parent

#### User settable properties:

> `self-alignment-X` (number)

>   Specify alignment of an object. The value `-1` means left aligned, `0` centered, and `1` right-aligned in X direction. Other numerical values may also be specified.

> `self-alignment-Y` (number)

>   Like `self-alignment-X` but for the Y axis.

This grob interface is used in the following graphical object(s): AccidentalSuggestion, BarNumber, DoublePercentRepeatCounter, DynamicText, Fingering, GridLine, Hairpin, InstrumentName, InstrumentSwitch, LyricText, MultiMeasureRestNumber, MultiMeasureRestText, OctavateEight, PercentRepeatCounter, RehearsalMark, SostenutoPedal, StringNumber, StrokeFinger, SustainPedal, TextScript and UnaCordaPedal.

### 3.2.84 semi-tie-column-interface

The interface for a column of l.v. (laissez vibrer) ties.

#### User settable properties:

> `head-direction` (direction)

>   Are the note heads left or right in a semitie?

> `tie-configuration` (list)

>   List of `(position . dir)` pairs, indicating the desired tie configuration, where position is the offset from the center of the staff in staff space and dir indicates the direction of the tie (`1`=>up, `-1`=>down, `0`=>center). A non-pair entry in the list causes the corresponding tie to be formatted automatically.

#### Internal properties:

> `positioning-done` (boolean)

>   Used to signal that a positioning element did its job. This ensures that a positioning is only done once.

This grob interface is used in the following graphical object(s): LaissezVibrerTieColumn and RepeatTieColumn.

### 3.2.85 semi-tie-interface

A tie which is only on one side connected to a note head.

#### User settable properties:

> `control-points` (list)

>   List of offsets (number pairs) that form control points for the tie, slur, or bracket shape. For Béziers, this should list the control points of a third-order Bézier curve.

> `direction` (direction)

>   If `side-axis` is `0` (or `#X`), then this property determines whether the object is placed `#LEFT`, `#CENTER` or `#RIGHT` with respect to the other object. Otherwise, it determines whether the object is placed `#UP`, `#CENTER` or `#DOWN`. Numerical values may also be used: `#UP`=`1`, `#DOWN`=`-1`, `#LEFT`=`-1`, `#RIGHT`=`1`, `#CENTER`=`0`.

> `head-direction` (direction)

>   Are the note heads left or right in a semitie?

> `thickness` (number)

>   Line thickness, generally measured in `line-thickness`.

#### Internal properties:

> `details` (list)

>   Alist of parameters for detailed grob behavior.

>   More information on the allowed parameters can be found by inspecting ‘`lily/slur-scoring.cc`’, ‘`lily/beam-quanting.cc`’, and ‘`lily/tie-formatting-problem.cc`’. Setting `debug-tie-scoring`, `debug-beam-scoring` or `debug-slur-scoring` also provides useful clues.

> `note-head` (layout object)

>   A single note head.

This grob interface is used in the following graphical object(s): LaissezVibrerTie and RepeatTie.

### 3.2.86 separation-item-interface

Item that computes widths to generate spacing rods.

#### User settable properties:

> `X-extent` (pair of numbers)

>   Hard coded extent in X direction.

> `horizontal-skylines` (unknown)

>   Two skylines, one to the left and one to the right of this grob.

> `padding` (dimension, in staff space)

>   Add this much extra space between objects that are next to each other.

#### Internal properties:

> `conditional-elements` (unknown)

>   Internal use only.

> `elements` (unknown)

>   A list of grobs; the type is depending on the grob where this is set in.

This grob interface is used in the following graphical object(s): NonMusicalPaperColumn, NoteColumn, PaperColumn and SeparationItem.

### 3.2.87 side-position-interface

Position a victim object (this one) next to other objects (the support). The property `direction` signifies where to put the victim object relative to the support (left or right, up or down?)

The routine also takes the size of the staff into account if `staff-padding` is set. If undefined, the staff symbol is ignored.

#### User settable properties:

> `direction` (direction)

>   If `side-axis` is `0` (or `#X`), then this property determines whether the object is placed `#LEFT`, `#CENTER` or `#RIGHT` with respect to the other object. Otherwise, it determines whether the object is placed `#UP`, `#CENTER` or `#DOWN`. Numerical values may also be used: `#UP`=`1`, `#DOWN`=`-1`, `#LEFT`=`-1`, `#RIGHT`=`1`, `#CENTER`=`0`.

> `minimum-space` (dimension, in staff space)

>   Minimum distance that the victim should move (after padding).

> `padding` (dimension, in staff space)

>   Add this much extra space between objects that are next to each other.

> `side-axis` (number)

>   If the value is `#X` (or equivalently `0`), the object is placed horizontally next to the other object. If the value is `#Y` or `1`, it is placed vertically.

> `side-relative-direction` (direction)

>   Multiply direction of `direction-source` with this to get the direction of this object.

> `slur-padding` (number)

>   Extra distance between slur and script.

> `staff-padding` (dimension, in staff space)

>   Maintain this much space between reference points and the staff. Its effect is to align objects of differing sizes (like the dynamics p and f) on their baselines.

#### Internal properties:

> `direction-source` (layout object)

>   In case `side-relative-direction` is set, which grob to get the direction from.

> `quantize-position` (boolean)

>   If set, a vertical alignment is aligned to be within staff spaces.

> `side-support-elements` (unknown)

>   The side support, a list of grobs.

This grob interface is used in the following graphical object(s): AccidentalSuggestion, AmbitusAccidental, Arpeggio, BarNumber, BassFigureAlignmentPositioning, CombineTextScript, DoublePercentRepeatCounter, DynamicLineSpanner, Fingering, HorizontalBracket, InstrumentName, InstrumentSwitch, MeasureGrouping, MetronomeMark, MultiMeasureRestNumber, MultiMeasureRestText, OctavateEight, OttavaBracket, PercentRepeatCounter, RehearsalMark, Script, SostenutoPedalLineSpanner, StanzaNumber, StringNumber, StrokeFinger, SustainPedalLineSpanner, SystemStartBar, SystemStartBrace, SystemStartBracket, SystemStartSquare, TextScript, TextSpanner, TrillPitchAccidental, TrillPitchGroup, TrillSpanner, UnaCordaPedalLineSpanner, VoltaBracket and VoltaBracketSpanner.

### 3.2.88 slur-interface

A slur.

#### User settable properties:

> `annotation` (string)

>   Annotate a grob for debug purposes.

> `avoid-slur` (symbol)

>   Method of handling slur collisions. Choices are `around`, `inside`, `outside`. If unset, scripts and slurs ignore each other. `around` only moves the script if there is a collision; `outside` always moves the script.

> `control-points` (list)

>   List of offsets (number pairs) that form control points for the tie, slur, or bracket shape. For Béziers, this should list the control points of a third-order Bézier curve.

> `dash-fraction` (number)

>   Size of the dashes, relative to `dash-period`. Should be between `0.0` (no line) and `1.0` (continuous line).

> `dash-period` (number)

>   The length of one dash together with whitespace. If negative, no line is drawn at all.

> `direction` (direction)

>   If `side-axis` is `0` (or `#X`), then this property determines whether the object is placed `#LEFT`, `#CENTER` or `#RIGHT` with respect to the other object. Otherwise, it determines whether the object is placed `#UP`, `#CENTER` or `#DOWN`. Numerical values may also be used: `#UP`=`1`, `#DOWN`=`-1`, `#LEFT`=`-1`, `#RIGHT`=`1`, `#CENTER`=`0`.

> `eccentricity` (number)

>   How asymmetrical to make a slur. Positive means move the center to the right.

> `height-limit` (dimension, in staff space)

>   Maximum slur height: The longer the slur, the closer it is to this height.

> `inspect-index` (integer)

>   If debugging is set, set beam and slur configuration to this index, and print the respective scores.

> `inspect-quants` (pair of numbers)

>   If debugging is set, set beam and slur quants to this position, and print the respective scores.

> `line-thickness` (number)

>   The thickness of the tie or slur contour.

> `positions` (pair of numbers)

>   Pair of staff coordinates `(left . right)`, where both left and right are in `staff-space` units of the current staff. For slurs, this value selects which slur candidate to use; if extreme positions are requested, the closest one is taken.

> `ratio` (number)

>   Parameter for slur shape. The higher this number, the quicker the slur attains its `height-limit`.

> `thickness` (number)

>   Line thickness, generally measured in `line-thickness`.

#### Internal properties:

> `details` (list)

>   Alist of parameters for detailed grob behavior.

>   More information on the allowed parameters can be found by inspecting ‘`lily/slur-scoring.cc`’, ‘`lily/beam-quanting.cc`’, and ‘`lily/tie-formatting-problem.cc`’. Setting `debug-tie-scoring`, `debug-beam-scoring` or `debug-slur-scoring` also provides useful clues.

> `encompass-objects` (unknown)

>   Objects that a slur should avoid in addition to notes and stems.

> `note-columns` (pair)

>   A list of `NoteColumn` grobs.

> `quant-score` (string)

>   The beam quanting score; stored for debugging.

This grob interface is used in the following graphical object(s): PhrasingSlur and Slur.

### 3.2.89 spaceable-grob-interface

A layout object that takes part in the spacing problem.

#### User settable properties:

> `allow-loose-spacing` (boolean)

>   If set, column can be detached from main spacing.

> `keep-inside-line` (boolean)

>   If set, this column cannot have objects sticking into the margin.

> `measure-length` (moment)

>   Length of a measure. Used in some spacing situations.

#### Internal properties:

> `ideal-distances` (list)

>   `(obj . (dist . strength))` pairs.

> `left-neighbors` (unknown)

>   A list of `spacing-wishes` grobs that are close to the current column.

>   The closest `spacing-wishes` determine the actual distances between the columns.

> `minimum-distances` (list)

>   A list of rods that have the format `(obj . dist)`.

> `right-neighbors` (unknown)

>   See `left-neighbors`.

> `spacing-wishes` (unknown)

>   List of note spacing or staff spacing objects.

This grob interface is used in the following graphical object(s): NonMusicalPaperColumn and PaperColumn.

### 3.2.90 spacing-interface

This object calculates the desired and minimum distances between two columns.

#### Internal properties:

> `left-items` (unknown)

>   DOCME

> `right-items` (unknown)

>   DOCME

This grob interface is used in the following graphical object(s): NoteSpacing and StaffSpacing.

### 3.2.91 spacing-options-interface

Supports setting of spacing variables.

#### User settable properties:

> `shortest-duration-space` (dimension, in staff space)

>   Start with this much space for the shortest duration. This is expressed in `spacing-increment` as unit. See also spacing-spanner-interface.

> `spacing-increment` (number)

>   Add this much space for a doubled duration. Typically, the width of a note head. See also spacing-spanner-interface.

This grob interface is used in the following graphical object(s): GraceSpacing and SpacingSpanner.

### 3.2.92 spacing-spanner-interface

The space taken by a note is dependent on its duration. Doubling a duration adds `spacing-increment` to the space. The most common shortest note gets `shortest-duration-space`. Notes that are even shorter are spaced proportonial to their duration.

Typically, the increment is the width of a black note head. In a piece with lots of 8th notes, and some 16th notes, the eighth note gets a 2 note heads width (i.e., the space following a note is a 1 note head width). A 16th note is followed by 0.5 note head width. The quarter note is followed by 3 NHW, the half by 4 NHW, etc.

#### User settable properties:

> `average-spacing-wishes` (boolean)

>   If set, the spacing wishes are averaged over staves.

> `base-shortest-duration` (moment)

>   Spacing is based on the shortest notes in a piece. Normally, pieces are spaced as if notes at least as short as this are present.

> `common-shortest-duration` (moment)

>   The most common shortest note length. This is used in spacing. Enlarging this sets the score tighter.

> `packed-spacing` (boolean)

>   If set, the notes are spaced as tightly as possible.

> `shortest-duration-space` (dimension, in staff space)

>   Start with this much space for the shortest duration. This is expressed in `spacing-increment` as unit. See also spacing-spanner-interface.

> `spacing-increment` (number)

>   Add this much space for a doubled duration. Typically, the width of a note head. See also spacing-spanner-interface.

> `strict-grace-spacing` (boolean)

>   If set, main notes are spaced normally, then grace notes are put left of the musical columns fot the main notes.

> `strict-note-spacing` (boolean)

>   If set, unbroken columns with non-musical material (clefs, bar lines, etc.) are not spaced separately, but put before musical columns.

> `uniform-stretching` (boolean)

>   If set, items stretch proportionally to their durations. This looks better in complex polyphonic patterns.

This grob interface is used in the following graphical object(s): SpacingSpanner.

### 3.2.93 span-bar-interface

A bar line that is spanned between other barlines. This interface is used for bar lines that connect different staves.

#### Internal properties:

> `elements` (unknown)

>   A list of grobs; the type is depending on the grob where this is set in.

> `glyph-name` (string)

>   The glyph name within the font.

This grob interface is used in the following graphical object(s): SpanBar.

### 3.2.94 spanner-interface

Some objects are horizontally spanned between objects. For example, slurs, beams, ties, etc. These grobs form a subtype called `Spanner`. All spanners have two span points (these must be `Item` objects), one on the left and one on the right. The left bound is also the X reference point of the spanner.

#### User settable properties:

> `minimum-length` (dimension, in staff space)

>   Try to make a spanner at least this long, normally in the horizontal direction. This requires an appropriate callback for the `springs-and-rods` property. If added to a `Tie`, this sets the minimum distance between noteheads.

> `to-barline` (boolean)

>   If true, the spanner will stop at the bar line just before it would otherwise stop.

This grob interface is used in the following graphical object(s): BassFigureAlignment, BassFigureAlignmentPositioning, BassFigureContinuation, BassFigureLine, Beam, BendAfter, ClusterSpanner, DynamicLineSpanner, DynamicTextSpanner, Glissando, GraceSpacing, Hairpin, HorizontalBracket, InstrumentName, LedgerLineSpanner, LigatureBracket, LyricExtender, LyricHyphen, LyricSpace, MeasureGrouping, MensuralLigature, MultiMeasureRest, MultiMeasureRestNumber, MultiMeasureRestText, OttavaBracket, PercentRepeat, PercentRepeatCounter, PhrasingSlur, PianoPedalBracket, Slur, SostenutoPedalLineSpanner, SpacingSpanner, StaffSymbol, SustainPedalLineSpanner, System, SystemStartBar, SystemStartBrace, SystemStartBracket, SystemStartSquare, TextSpanner, Tie, TieColumn, TrillSpanner, TupletBracket, TupletNumber, UnaCordaPedalLineSpanner, VaticanaLigature, VerticalAlignment, VerticalAxisGroup, VoiceFollower, VoltaBracket and VoltaBracketSpanner.

### 3.2.95 staff-spacing-interface

This object calculates spacing details from a breakable symbol (left) to another object. For example, it takes care of optical spacing from a bar line to a note.

#### User settable properties:

> `stem-spacing-correction` (number)

>   Optical correction amount for stems that are placed in tight configurations. For opposite directions, this amount is the correction for two normal sized stems that overlap completely.

This grob interface is used in the following graphical object(s): StaffSpacing.

### 3.2.96 staff-symbol-interface

This spanner draws the lines of a staff. A staff symbol defines a vertical unit, the staff space. Quantities that go by a half staff space are called positions. The center (i.e., middle line or space) is position 0. The length of the symbol may be set by hand through the `width` property.

#### User settable properties:

> `ledger-line-thickness` (pair of numbers)

>   The thickness of ledger lines. It is the sum of 2 numbers: The first is the factor for line thickness, and the second for staff space. Both contributions are added.

> `line-count` (integer)

>   The number of staff lines.

> `line-positions` (list)

>   Vertical positions of staff lines.

> `staff-space` (dimension, in staff space)

>   Amount of space between staff lines, expressed in global `staff-space`.

> `thickness` (number)

>   Line thickness, generally measured in `line-thickness`.

> `width` (dimension, in staff space)

>   The width of a grob measured in staff space.

This grob interface is used in the following graphical object(s): StaffSymbol.

### 3.2.97 staff-symbol-referencer-interface

An object whose Y position is meant relative to a staff symbol. These usually have `Staff_symbol_referencer::callback` in their `Y-offset-callbacks`.

#### User settable properties:

> `staff-position` (number)

>   Vertical position, measured in half staff spaces, counted from the middle line.

This grob interface is used in the following graphical object(s): AmbitusLine, AmbitusNoteHead, Arpeggio, Beam, Clef, Custos, Dots, KeyCancellation, KeySignature, MultiMeasureRest, NoteHead, Rest, TabNoteHead and TrillPitchHead.

### 3.2.98 stanza-number-interface

A stanza number, to be put in from of a lyrics line.

This grob interface is used in the following graphical object(s): StanzaNumber.

### 3.2.99 stem-interface

The stem represents the graphical stem. In addition, it internally connects note heads, beams, and tremolos. Rests and whole notes have invisible stems.

The following properties may be set in the `details` list.

`beamed-lengths`

  List of stem lengths given beam multiplicity.

`beamed-minimum-free-lengths`

  List of normal minimum free stem lengths (chord to beams) given beam multiplicity.

`beamed-extreme-minimum-free-lengths`

  List of extreme minimum free stem lengths (chord to beams) given beam multiplicity.

`lengths`

  Default stem lengths. The list gives a length for each flag count.

`stem-shorten`

  How much a stem in a forced direction should be shortened. The list gives an amount depending on the number of flags and beams.

#### User settable properties:

> `avoid-note-head` (boolean)

>   If set, the stem of a chord does not pass through all note heads, but starts at the last note head.

> `beaming` (pair)

>   Pair of number lists. Each number list specifies which beams to make. `0` is the central beam, `1` is the next beam toward the note, etc. This information is used to determine how to connect the beaming patterns from stem to stem inside a beam.

> `beamlet-default-length` (pair)

>   A pair of numbers. The first number specifies the default length of a beamlet that sticks out of the left hand side of this stem; the second number specifies the default length of the beamlet to the right. The actual length of a beamlet is determined by taking either the default length or the length specified by `beamlet-max-length-proportion`, whichever is smaller.

> `beamlet-max-length-proportion` (pair)

>   The maximum length of a beamlet, as a proportion of the distance between two adjacent stems.

> `default-direction` (direction)

>   Direction determined by note head positions.

> `direction` (direction)

>   If `side-axis` is `0` (or `#X`), then this property determines whether the object is placed `#LEFT`, `#CENTER` or `#RIGHT` with respect to the other object. Otherwise, it determines whether the object is placed `#UP`, `#CENTER` or `#DOWN`. Numerical values may also be used: `#UP`=`1`, `#DOWN`=`-1`, `#LEFT`=`-1`, `#RIGHT`=`1`, `#CENTER`=`0`.

> `duration-log` (integer)

>   The 2-log of the note head duration, i.e., `0` = whole note, `1` = half note, etc.

> `flag` (unknown)

>   A function returning the full flag stencil for the `Stem`, which is passed to the function as the only argument. The default ly:stem::calc-stencil function uses the `flag-style` property to determine the correct glyph for the flag. By providing your own function, you can create arbitrary flags.

> `flag-style` (symbol)

>   A symbol determining what style of flag glyph is typeset on a `Stem`. Valid options include `'()` for standard flags, `'mensural` and `'no-flag`, which switches off the flag.

> `french-beaming` (boolean)

>   Use French beaming style for this stem. The stem stops at the innermost beams.

> `length` (dimension, in staff space)

>   User override for the stem length of unbeamed stems.

> `length-fraction` (number)

>   Multiplier for lengths. Used for determining ledger lines and stem lengths.

> `max-beam-connect` (integer)

>   Maximum number of beams to connect to beams from this stem. Further beams are typeset as beamlets.

> `neutral-direction` (direction)

>   Which direction to take in the center of the staff.

> `no-stem-extend` (boolean)

>   If set, notes with ledger lines do not get stems extending to the middle staff line.

> `stem-end-position` (number)

>   Where does the stem end (the end is opposite to the support-head)?

> `stemlet-length` (number)

>   How long should be a stem over a rest?

> `stroke-style` (string)

>   Set to `"grace"` to turn stroke through flag on.

> `thickness` (number)

>   Line thickness, generally measured in `line-thickness`.

#### Internal properties:

> `beam` (layout object)

>   A pointer to the beam, if applicable.

> `details` (list)

>   Alist of parameters for detailed grob behavior.

>   More information on the allowed parameters can be found by inspecting ‘`lily/slur-scoring.cc`’, ‘`lily/beam-quanting.cc`’, and ‘`lily/tie-formatting-problem.cc`’. Setting `debug-tie-scoring`, `debug-beam-scoring` or `debug-slur-scoring` also provides useful clues.

> `note-heads` (unknown)

>   A list of note head grobs.

> `positioning-done` (boolean)

>   Used to signal that a positioning element did its job. This ensures that a positioning is only done once.

> `rests` (unknown)

>   A list of rest objects.

> `stem-info` (pair)

>   A cache of stem parameters.

> `tremolo-flag` (layout object)

>   The tremolo object on a stem.

This grob interface is used in the following graphical object(s): Stem.

### 3.2.100 stem-tremolo-interface

A beam slashing a stem to indicate a tremolo. The property `style` can be `default` or `rectangle`.

#### User settable properties:

> `beam-thickness` (dimension, in staff space)

>   Beam thickness, measured in `staff-space` units.

> `beam-width` (dimension, in staff space)

>   Width of the tremolo sign.

> `flag-count` (number)

>   The number of tremolo beams.

> `length-fraction` (number)

>   Multiplier for lengths. Used for determining ledger lines and stem lengths.

> `slope` (number)

>   The slope of this object.

> `style` (symbol)

>   This setting determines in what style a grob is typeset. Valid choices depend on the `stencil` callback reading this property.

#### Internal properties:

> `stem` (layout object)

>   A pointer to a `Stem` object.

This grob interface is used in the following graphical object(s): StemTremolo.

### 3.2.101 string-number-interface

A string number instruction.

This grob interface is used in the following graphical object(s): StringNumber.

### 3.2.102 stroke-finger-interface

A right hand finger instruction.

#### User settable properties:

> `digit-names` (unknown)

>   Names for string finger digits.

This grob interface is used in the following graphical object(s): StrokeFinger.

### 3.2.103 system-interface

This is the top-level object: Each object in a score ultimately has a `System` object as its X and Y parent.

#### User settable properties:

> `labels` (list)

>   List of labels (symbols) placed on a column

> `skyline-horizontal-padding` (number)

>   For determining the vertical distance between two staves, it is possible to have a configuration which would result in a tight interleaving of grobs from the top staff and the bottom staff. The larger this parameter is, the farther apart the staves are placed in such a configuration.

#### Internal properties:

> `all-elements` (unknown)

>   A list of all grobs in this line. Its function is to protect objects from being garbage collected.

> `columns` (unknown)

>   A list of grobs, typically containing `PaperColumn` or `NoteColumn` objects.

> `pure-Y-extent` (pair of numbers)

>   The estimated height of a system.

> `skyline-distance` (number)

>   The distance between this staff and the next one, as determined by a skyline algorithm.

> `spaceable-staves` (unknown)

>   Objects to be spaced during page layout.

This grob interface is used in the following graphical object(s): System.

### 3.2.104 system-start-delimiter-interface

The brace, bracket or bar in front of the system. The following values for `style` are recognized:

`bracket`

  A thick bracket, normally used to group similar instruments in a score. Default for `StaffGroup`. `SystemStartBracket` uses this style.

`brace`

  A ‘piano style’ brace normally used for an instrument that uses two staves. The default style for `GrandStaff`. `SystemStartBrace` uses this style.

`bar-line`

  A simple line between the staves in a score. Default for staves enclosed in `<<` and `>>`. `SystemStartBar` uses this style.

`line-bracket`

  A simple square, normally used for subgrouping instruments in a score. `SystemStartSquare` uses this style.

See also ‘`input/regression/system-start-nesting.ly`’.

#### User settable properties:

> `collapse-height` (dimension, in staff space)

>   Minimum height of system start delimiter. If equal or smaller, the bracket/brace/line is removed.

> `style` (symbol)

>   This setting determines in what style a grob is typeset. Valid choices depend on the `stencil` callback reading this property.

> `thickness` (number)

>   Line thickness, generally measured in `line-thickness`.

This grob interface is used in the following graphical object(s): SystemStartBar, SystemStartBrace, SystemStartBracket and SystemStartSquare.

### 3.2.105 system-start-text-interface

Text in front of the system.

#### User settable properties:

> `long-text` (markup)

>   Text markup. See Formatting text.

> `self-alignment-X` (number)

>   Specify alignment of an object. The value `-1` means left aligned, `0` centered, and `1` right-aligned in X direction. Other numerical values may also be specified.

> `self-alignment-Y` (number)

>   Like `self-alignment-X` but for the Y axis.

> `text` (markup)

>   Text markup. See Formatting text.

This grob interface is used in the following graphical object(s): InstrumentName.

### 3.2.106 tablature-interface

An interface for any notes set in a tablature staff.

This grob interface is not used in any graphical object.

### 3.2.107 text-interface

A Scheme markup text, see Formatting text and New markup command definition.

There are two important commands: `ly:text-interface::print`, which is a grob callback, and `ly:text-interface::interpret-markup`.

#### User settable properties:

> `baseline-skip` (dimension, in staff space)

>   Distance between base lines of multiple lines of text.

> `text` (markup)

>   Text markup. See Formatting text.

> `text-direction` (direction)

>   This controls the ordering of the words. The default `RIGHT` is for roman text. Arabic or Hebrew should use `LEFT`.

> `word-space` (dimension, in staff space)

>   Space to insert between words in texts.

This grob interface is used in the following graphical object(s): BalloonTextItem, BarNumber, BassFigure, BreathingSign, ChordName, CombineTextScript, DoublePercentRepeatCounter, DynamicText, DynamicTextSpanner, Fingering, InstrumentSwitch, LyricText, MetronomeMark, MultiMeasureRestNumber, MultiMeasureRestText, NoteName, OctavateEight, OttavaBracket, PercentRepeatCounter, RehearsalMark, SostenutoPedal, StanzaNumber, StringNumber, StrokeFinger, SustainPedal, TabNoteHead, TextScript, TupletNumber, UnaCordaPedal and VoltaBracket.

### 3.2.108 text-script-interface

An object that is put above or below a note.

#### User settable properties:

> `add-stem-support` (boolean)

>   If set, the `Stem` object is included in this script’s support.

> `avoid-slur` (symbol)

>   Method of handling slur collisions. Choices are `around`, `inside`, `outside`. If unset, scripts and slurs ignore each other. `around` only moves the script if there is a collision; `outside` always moves the script.

> `script-priority` (number)

>   A sorting key that determines in what order a script is within a stack of scripts.

#### Internal properties:

> `slur` (layout object)

>   A pointer to a `Slur` object.

This grob interface is used in the following graphical object(s): CombineTextScript, Fingering, StringNumber, StrokeFinger and TextScript.

### 3.2.109 tie-column-interface

Object that sets directions of multiple ties in a tied chord.

#### User settable properties:

> `tie-configuration` (list)

>   List of `(position . dir)` pairs, indicating the desired tie configuration, where position is the offset from the center of the staff in staff space and dir indicates the direction of the tie (`1`=>up, `-1`=>down, `0`=>center). A non-pair entry in the list causes the corresponding tie to be formatted automatically.

#### Internal properties:

> `positioning-done` (boolean)

>   Used to signal that a positioning element did its job. This ensures that a positioning is only done once.

This grob interface is used in the following graphical object(s): TieColumn.

### 3.2.110 tie-interface

A horizontal curve connecting two noteheads.

#### User settable properties:

> `annotation` (string)

>   Annotate a grob for debug purposes.

> `avoid-slur` (symbol)

>   Method of handling slur collisions. Choices are `around`, `inside`, `outside`. If unset, scripts and slurs ignore each other. `around` only moves the script if there is a collision; `outside` always moves the script.

> `control-points` (list)

>   List of offsets (number pairs) that form control points for the tie, slur, or bracket shape. For Béziers, this should list the control points of a third-order Bézier curve.

> `dash-fraction` (number)

>   Size of the dashes, relative to `dash-period`. Should be between `0.0` (no line) and `1.0` (continuous line).

> `dash-period` (number)

>   The length of one dash together with whitespace. If negative, no line is drawn at all.

> `direction` (direction)

>   If `side-axis` is `0` (or `#X`), then this property determines whether the object is placed `#LEFT`, `#CENTER` or `#RIGHT` with respect to the other object. Otherwise, it determines whether the object is placed `#UP`, `#CENTER` or `#DOWN`. Numerical values may also be used: `#UP`=`1`, `#DOWN`=`-1`, `#LEFT`=`-1`, `#RIGHT`=`1`, `#CENTER`=`0`.

> `head-direction` (direction)

>   Are the note heads left or right in a semitie?

> `line-thickness` (number)

>   The thickness of the tie or slur contour.

> `neutral-direction` (direction)

>   Which direction to take in the center of the staff.

> `staff-position` (number)

>   Vertical position, measured in half staff spaces, counted from the middle line.

> `thickness` (number)

>   Line thickness, generally measured in `line-thickness`.

#### Internal properties:

> `details` (list)

>   Alist of parameters for detailed grob behavior.

>   More information on the allowed parameters can be found by inspecting ‘`lily/slur-scoring.cc`’, ‘`lily/beam-quanting.cc`’, and ‘`lily/tie-formatting-problem.cc`’. Setting `debug-tie-scoring`, `debug-beam-scoring` or `debug-slur-scoring` also provides useful clues.

> `quant-score` (string)

>   The beam quanting score; stored for debugging.

> `separation-item` (layout object)

>   A separation item.

This grob interface is used in the following graphical object(s): Tie.

### 3.2.111 time-signature-interface

A time signature, in different styles. The following values for `style` are are recognized:

`C`

  4/4 and 2/2 are typeset as C and struck C, respectively. All other time signatures are written with two digits. The value `default` is equivalent to `C`.

`neomensural`

  2/2, 3/2, 2/4, 3/4, 4/4, 6/4, 9/4, 4/8, 6/8, and 9/8 are typeset with neo-mensural style mensuration marks. All other time signatures are written with two digits.

`mensural`

  2/2, 3/2, 2/4, 3/4, 4/4, 6/4, 9/4, 4/8, 6/8, and 9/8 are typeset with mensural style mensuration marks. All other time signatures are written with two digits.

`single-digit`

  All time signatures are typeset with a single digit, e.g., 3/2 is written as 3.

`numbered`

  All time signatures are typeset with two digits.

#### User settable properties:

> `fraction` (pair of numbers)

>   Numerator and denominator of a time signature object.

> `style` (symbol)

>   This setting determines in what style a grob is typeset. Valid choices depend on the `stencil` callback reading this property.

This grob interface is used in the following graphical object(s): TimeSignature.

### 3.2.112 trill-pitch-accidental-interface

An accidental for trill pitch.

This grob interface is used in the following graphical object(s): TrillPitchAccidental.

### 3.2.113 trill-spanner-interface

A trill spanner.

This grob interface is used in the following graphical object(s): TrillSpanner.

### 3.2.114 tuplet-bracket-interface

A bracket with a number in the middle, used for tuplets. When the bracket spans a line break, the value of `break-overshoot` determines how far it extends beyond the staff. At a line break, the markups in the `edge-text` are printed at the edges.

#### User settable properties:

> `bracket-flare` (pair of numbers)

>   A pair of numbers specifying how much edges of brackets should slant outward. Value `0.0` means straight edges.

> `bracket-visibility` (boolean or symbol)

>   This controls the visibility of the tuplet bracket. Setting it to false prevents printing of the bracket. Setting the property to `if-no-beam` makes it print only if there is no beam associated with this tuplet bracket.

> `break-overshoot` (pair of numbers)

>   How much does a broken spanner stick out of its bounds?

> `connect-to-neighbor` (pair)

>   Pair of booleans, indicating whether this grob looks as a continued break.

> `control-points` (list)

>   List of offsets (number pairs) that form control points for the tie, slur, or bracket shape. For Béziers, this should list the control points of a third-order Bézier curve.

> `direction` (direction)

>   If `side-axis` is `0` (or `#X`), then this property determines whether the object is placed `#LEFT`, `#CENTER` or `#RIGHT` with respect to the other object. Otherwise, it determines whether the object is placed `#UP`, `#CENTER` or `#DOWN`. Numerical values may also be used: `#UP`=`1`, `#DOWN`=`-1`, `#LEFT`=`-1`, `#RIGHT`=`1`, `#CENTER`=`0`.

> `edge-height` (pair)

>   A pair of numbers specifying the heights of the vertical edges: `(left-height . right-height)`.

> `edge-text` (pair)

>   A pair specifying the texts to be set at the edges: `(left-text . right-text)`.

> `full-length-padding` (number)

>   How much padding to use at the right side of a full-length tuplet bracket.

> `full-length-to-extent` (boolean)

>   Run to the extent of the column for a full-length tuplet bracket.

> `gap` (dimension, in staff space)

>   Size of a gap in a variable symbol.

> `padding` (dimension, in staff space)

>   Add this much extra space between objects that are next to each other.

> `positions` (pair of numbers)

>   Pair of staff coordinates `(left . right)`, where both left and right are in `staff-space` units of the current staff. For slurs, this value selects which slur candidate to use; if extreme positions are requested, the closest one is taken.

> `shorten-pair` (pair of numbers)

>   The lengths to shorten a text-spanner on both sides, for example a pedal bracket. Positive values shorten the text-spanner, while negative values lengthen it.

> `staff-padding` (dimension, in staff space)

>   Maintain this much space between reference points and the staff. Its effect is to align objects of differing sizes (like the dynamics p and f) on their baselines.

> `thickness` (number)

>   Line thickness, generally measured in `line-thickness`.

#### Internal properties:

> `note-columns` (pair)

>   A list of `NoteColumn` grobs.

> `tuplet-number` (layout object)

>   The number for a bracket.

> `tuplets` (unknown)

>   A list of smaller tuplet brackets.

This grob interface is used in the following graphical object(s): LigatureBracket and TupletBracket.

### 3.2.115 tuplet-number-interface

The number for a bracket.

#### User settable properties:

> `avoid-slur` (symbol)

>   Method of handling slur collisions. Choices are `around`, `inside`, `outside`. If unset, scripts and slurs ignore each other. `around` only moves the script if there is a collision; `outside` always moves the script.

#### Internal properties:

> `bracket` (layout object)

>   The bracket for a number.

This grob interface is used in the following graphical object(s): TupletNumber.

### 3.2.116 unbreakable-spanner-interface

A spanner that should not be broken across line breaks. Override with `breakable=##t`.

#### User settable properties:

> `breakable` (boolean)

>   Allow breaks here.

This grob interface is used in the following graphical object(s): Beam and Glissando.

### 3.2.117 vaticana-ligature-interface

A vaticana style Gregorian ligature.

#### User settable properties:

> `thickness` (number)

>   Line thickness, generally measured in `line-thickness`.

#### Internal properties:

> `add-cauda` (boolean)

>   Does this flexa require an additional cauda on the left side?

> `add-join` (boolean)

>   Is this ligature head-joined with the next one by a vertical line?

> `add-stem` (boolean)

>   Is this ligature head a virga and therefore needs an additional stem on the right side?

> `delta-position` (number)

>   The vertical position difference.

> `flexa-height` (dimension, in staff space)

>   The height of a flexa shape in a ligature grob (in `staff-space` units).

> `flexa-width` (dimension, in staff space)

>   The width of a flexa shape in a ligature grob in (in `staff-space` units).

> `glyph-name` (string)

>   The glyph name within the font.

> `x-offset` (dimension, in staff space)

>   Extra horizontal offset for ligature heads.

This grob interface is used in the following graphical object(s): NoteHead and VaticanaLigature.

### 3.2.118 vertically-spaceable-interface

Objects that should be kept at constant vertical distances. Typically: VerticalAxisGroup objects of Staff contexts.

This grob interface is used in the following graphical object(s): VerticalAxisGroup.

### 3.2.119 volta-bracket-interface

Volta bracket with number.

#### User settable properties:

> `height` (dimension, in staff space)

>   Height of an object in `staff-space` units.

> `thickness` (number)

>   Line thickness, generally measured in `line-thickness`.

#### Internal properties:

> `bars` (unknown)

>   A list of bar line pointers.

This grob interface is used in the following graphical object(s): VoltaBracket.

## 3.3 User backend properties

`X-extent` (pair of numbers)

  Hard coded extent in X direction.

`X-offset` (number)

  The horizontal amount that this object is moved relative to its X-parent.

`Y-extent` (pair of numbers)

  Hard coded extent in Y direction.

`Y-offset` (number)

  The vertical amount that this object is moved relative to its Y-parent.

`add-stem-support` (boolean)

  If set, the `Stem` object is included in this script’s support.

`after-line-breaking` (boolean)

  Dummy property, used to trigger callback for `after-line-breaking`.

`align-dir` (direction)

  Which side to align? `-1`: left side, `0`: around center of width, `1`: right side.

`allow-loose-spacing` (boolean)

  If set, column can be detached from main spacing.

`allow-span-bar` (boolean)

  If false, no inter-staff bar line will be created below this bar line.

`alteration` (number)

  Alteration numbers for accidental.

`alteration-alist` (list)

  List of `(pitch . accidental)` pairs for key signature.

`annotation` (string)

  Annotate a grob for debug purposes.

`arpeggio-direction` (direction)

  If set, put an arrow on the arpeggio squiggly line.

`arrow-length` (number)

  Arrow length.

`arrow-width` (number)

  Arrow width.

`auto-knee-gap` (dimension, in staff space)

  If a gap is found between note heads where a horizontal beam fits that is larger than this number, make a kneed beam.

`average-spacing-wishes` (boolean)

  If set, the spacing wishes are averaged over staves.

`avoid-note-head` (boolean)

  If set, the stem of a chord does not pass through all note heads, but starts at the last note head.

`avoid-slur` (symbol)

  Method of handling slur collisions. Choices are `around`, `inside`, `outside`. If unset, scripts and slurs ignore each other. `around` only moves the script if there is a collision; `outside` always moves the script.

`axes` (list)

  List of axis numbers. In the case of alignment grobs, this should contain only one number.

`bar-size` (dimension, in staff space)

  The size of a bar line.

`base-shortest-duration` (moment)

  Spacing is based on the shortest notes in a piece. Normally, pieces are spaced as if notes at least as short as this are present.

`baseline-skip` (dimension, in staff space)

  Distance between base lines of multiple lines of text.

`beam-thickness` (dimension, in staff space)

  Beam thickness, measured in `staff-space` units.

`beam-width` (dimension, in staff space)

  Width of the tremolo sign.

`beamed-stem-shorten` (list)

  How much to shorten beamed stems, when their direction is forced. It is a list, since the value is different depending on the number of flags and beams.

`beaming` (pair)

  Pair of number lists. Each number list specifies which beams to make. `0` is the central beam, `1` is the next beam toward the note, etc. This information is used to determine how to connect the beaming patterns from stem to stem inside a beam.

`beamlet-default-length` (pair)

  A pair of numbers. The first number specifies the default length of a beamlet that sticks out of the left hand side of this stem; the second number specifies the default length of the beamlet to the right. The actual length of a beamlet is determined by taking either the default length or the length specified by `beamlet-max-length-proportion`, whichever is smaller.

`beamlet-max-length-proportion` (pair)

  The maximum length of a beamlet, as a proportion of the distance between two adjacent stems.

`before-line-breaking` (boolean)

  Dummy property, used to trigger a callback function.

`between-cols` (pair)

  Where to attach a loose column to.

`bound-details` (list)

  An alist of properties for determining attachments of spanners to edges.

`bound-padding` (number)

  The amount of padding to insert around spanner bounds.

`bracket-flare` (pair of numbers)

  A pair of numbers specifying how much edges of brackets should slant outward. Value `0.0` means straight edges.

`bracket-visibility` (boolean or symbol)

  This controls the visibility of the tuplet bracket. Setting it to false prevents printing of the bracket. Setting the property to `if-no-beam` makes it print only if there is no beam associated with this tuplet bracket.

`break-align-anchor` (number)

  Grobs aligned to this break-align grob will have their X-offsets shifted by this number. In bar lines, for example, this is used to position grobs relative to the (visual) center of the bar line.

`break-align-anchor-alignment` (number)

  Read by `ly:break-aligned-interface::calc-extent-aligned-anchor` for aligning an anchor to a grob’s extent

`break-align-orders` (vector)

  Defines the order in which prefatory matter (clefs, key signatures) appears. The format is a vector of length 3, where each element is one order for end-of-line, middle of line, and start-of-line, respectively. An order is a list of symbols.

  For example, clefs are put after key signatures by setting

  >     \override Score.BreakAlignment #'break-align-orders =
  >       #(make-vector 3 '(span-bar
  >                         breathing-sign
  >                         staff-bar
  >                         key
  >                         clef
  >                         time-signature))

`break-align-symbol` (symbol)

  This key is used for aligning and spacing breakable items.

`break-align-symbols` (list)

  A list of symbols that determine which break-aligned grobs to align this to. If the grob selected by the first symbol in the list is invisible due to break-visibility, we will align to the next grob (and so on).

`break-overshoot` (pair of numbers)

  How much does a broken spanner stick out of its bounds?

`break-visibility` (vector)

  A vector of 3 booleans, `#(end-of-line unbroken begin-of-line)`. `#t` means visible, `#f` means killed.

`breakable` (boolean)

  Allow breaks here.

`c0-position` (integer)

  An integer indicating the position of middle C.

`circled-tip` (boolean)

  Put a circle at start/end of hairpins (al/del niente).

`clip-edges` (boolean)

  Allow outward pointing beamlets at the edges of beams?

`collapse-height` (dimension, in staff space)

  Minimum height of system start delimiter. If equal or smaller, the bracket/brace/line is removed.

`color` (list)

  The color of this grob.

`common-shortest-duration` (moment)

  The most common shortest note length. This is used in spacing. Enlarging this sets the score tighter.

`concaveness` (number)

  A beam is concave if its inner stems are closer to the beam than the two outside stems. This number is a measure of the closeness of the inner stems. It is used for damping the slope of the beam.

`connect-to-neighbor` (pair)

  Pair of booleans, indicating whether this grob looks as a continued break.

`control-points` (list)

  List of offsets (number pairs) that form control points for the tie, slur, or bracket shape. For Béziers, this should list the control points of a third-order Bézier curve.

`damping` (number)

  Amount of beam slope damping.

`dash-fraction` (number)

  Size of the dashes, relative to `dash-period`. Should be between `0.0` (no line) and `1.0` (continuous line).

`dash-period` (number)

  The length of one dash together with whitespace. If negative, no line is drawn at all.

`default-direction` (direction)

  Direction determined by note head positions.

`digit-names` (unknown)

  Names for string finger digits.

`direction` (direction)

  If `side-axis` is `0` (or `#X`), then this property determines whether the object is placed `#LEFT`, `#CENTER` or `#RIGHT` with respect to the other object. Otherwise, it determines whether the object is placed `#UP`, `#CENTER` or `#DOWN`. Numerical values may also be used: `#UP`=`1`, `#DOWN`=`-1`, `#LEFT`=`-1`, `#RIGHT`=`1`, `#CENTER`=`0`.

`dot-count` (integer)

  The number of dots.

`dot-negative-kern` (number)

  The space to remove between a dot and a slash in percent repeat glyphs. Larger values bring the two elements closer together.

`dot-placement-list` (list)

  List consisting of `(description string-number fret-number finger-number)` entries used to define fret diagrams.

`duration-log` (integer)

  The 2-log of the note head duration, i.e., `0` = whole note, `1` = half note, etc.

`eccentricity` (number)

  How asymmetrical to make a slur. Positive means move the center to the right.

`edge-height` (pair)

  A pair of numbers specifying the heights of the vertical edges: `(left-height . right-height)`.

`edge-text` (pair)

  A pair specifying the texts to be set at the edges: `(left-text . right-text)`.

`expand-limit` (integer)

  Maximum number of measures expanded in church rests.

`extra-X-extent` (pair of numbers)

  A grob is enlarged in X dimension by this much.

`extra-Y-extent` (pair of numbers)

  A grob is enlarged in Y dimension by this much.

`extra-dy` (number)

  Slope glissandi this much extra.

`extra-offset` (pair of numbers)

  A pair representing an offset. This offset is added just before outputting the symbol, so the typesetting engine is completely oblivious to it. The values are measured in `staff-space` units of the staff’s `StaffSymbol`.

`extra-spacing-height` (pair of numbers)

  In the horizontal spacing problem, we increase the height of each item by this amount (by adding the ‘car’ to the bottom of the item and adding the ‘cdr’ to the top of the item). In order to make a grob infinitely high (to prevent the horizontal spacing problem from placing any other grobs above or below this grob), set this to `(-inf.0 . +inf.0)`.

`extra-spacing-width` (pair of numbers)

  In the horizontal spacing problem, we pad each item by this amount (by adding the ‘car’ on the left side of the item and adding the ‘cdr’ on the right side of the item). In order to make a grob take up no horizontal space at all, set this to `(+inf.0 . -inf.0)`.

`flag` (unknown)

  A function returning the full flag stencil for the `Stem`, which is passed to the function as the only argument. The default ly:stem::calc-stencil function uses the `flag-style` property to determine the correct glyph for the flag. By providing your own function, you can create arbitrary flags.

`flag-count` (number)

  The number of tremolo beams.

`flag-style` (symbol)

  A symbol determining what style of flag glyph is typeset on a `Stem`. Valid options include `'()` for standard flags, `'mensural` and `'no-flag`, which switches off the flag.

`font-encoding` (symbol)

  The font encoding is the broadest category for selecting a font. Currently, only lilypond’s system fonts (Emmentaler and Aybabtu) are using this property. Available values are `fetaMusic` (Emmentaler), `fetaBraces` (Aybabtu), `fetaNumber` (Emmentaler), and `fetaDynamic` (Emmentaler).

`font-family` (symbol)

  The font family is the broadest category for selecting text fonts. Options include: `sans`, `roman`.

`font-name` (string)

  Specifies a file name (without extension) of the font to load. This setting overrides selection using `font-family`, `font-series` and `font-shape`.

`font-series` (symbol)

  Select the series of a font. Choices include `medium`, `bold`, `bold-narrow`, etc.

`font-shape` (symbol)

  Select the shape of a font. Choices include `upright`, `italic`, `caps`.

`font-size` (number)

  The font size, compared to the ‘normal’ size. `0` is style-sheet’s normal size, `-1` is smaller, `+1` is bigger. Each step of 1 is approximately 12% larger; 6 steps are exactly a factor 2 larger. Fractional values are allowed.

`force-hshift` (number)

  This specifies a manual shift for notes in collisions. The unit is the note head width of the first voice note. This is used by note-collision-interface.

`fraction` (pair of numbers)

  Numerator and denominator of a time signature object.

`french-beaming` (boolean)

  Use French beaming style for this stem. The stem stops at the innermost beams.

`fret-diagram-details` (list)

  An alist of detailed grob properties for fret diagrams. Each alist entry consists of a `(property . value)` pair. The properties which can be included in `fret-diagram-details` include the following:

  - `barre-type` – Type of barre indication used. Choices include `curved`, `straight`, and `none`. Default `curved`.
  - `capo-thickness` – Thickness of capo indicator, in multiples of fret-space. Default value 0.5.
  - `dot-color` – Color of dots. Options include `black` and `white`. Default `black`.
  - `dot-label-font-mag` – Magnification for font used to label fret dots. Default value 1.
  - `dot-position` – Location of dot in fret space. Default 0.6 for dots without labels, 0.95-`dot-radius` for dots with labels.
  - `dot-radius` – Radius of dots, in terms of fret spaces. Default value 0.425 for labeled dots, 0.25 for unlabeled dots.
  - `finger-code` – Code for the type of fingering indication used. Options include `none`, `in-dot`, and `below-string`. Default `none` for markup fret diagrams, `below-string` for `FretBoards` fret diagrams.
  - `fret-count` – The number of frets. Default 4.
  - `fret-label-font-mag` – The magnification of the font used to label the lowest fret number. Default 0.5.
  - `fret-label-vertical-offset` – The offset of the fret label from the center of the fret in direction parallel to strings. Default 0.
  - `label-dir` – Side to which the fret label is attached. `-1`, `#LEFT`, or `#DOWN` for left or down; `1`, `#RIGHT`, or `#UP` for right or up. Default `#RIGHT`.
  - `mute-string` – Character string to be used to indicate muted string. Default `"x"`.
  - `number-type` – Type of numbers to use in fret label. Choices include `roman-lower`, `roman-upper`, and `arabic`. Default `roman-lower`.
  - `open-string` – Character string to be used to indicate open string. Default `"o"`.
  - `orientation` – Orientation of fret-diagram. Options include `normal`, `landscape`, and `opposing-landscape`. Default `normal`.
  - `string-count` – The number of strings. Default 6.
  - `string-label-font-mag` – The magnification of the font used to label fingerings at the string, rather than in the dot. Default value 0.6 for `normal` orientation, 0.5 for `landscape` and `opposing-landscape`.
  - `string-thickness-factor` – Factor for changing thickness of each string in the fret diagram. Thickness of string k is given by `thickness` * (1+`string-thickness-factor`) ^ (k-1). Default 0.
  - `top-fret-thickness` – The thickness of the top fret line, as a multiple of the standard thickness. Default value 3.
  - `xo-font-magnification` – Magnification used for mute and open string indicators. Default value 0.5.
  - `xo-padding` – Padding for open and mute indicators from top fret. Default value 0.25.
`full-length-padding` (number)

  How much padding to use at the right side of a full-length tuplet bracket.

`full-length-to-extent` (boolean)

  Run to the extent of the column for a full-length tuplet bracket.

`full-measure-extra-space` (number)

  Extra space that is allocated at the beginning of a measure with only one note. This property is read from the NonMusicalPaperColumn that begins the measure.

`full-size-change` (boolean)

  Don’t make a change clef smaller.

`gap` (dimension, in staff space)

  Size of a gap in a variable symbol.

`gap-count` (integer)

  Number of gapped beams for tremolo.

`glyph` (string)

  A string determining what ‘style’ of glyph is typeset. Valid choices depend on the function that is reading this property.

`glyph-name-alist` (list)

  An alist of key-string pairs.

`grow-direction` (direction)

  Crescendo or decrescendo?

`hair-thickness` (number)

  Thickness of the thin line in a bar line.

`harp-pedal-details` (list)

  An alist of detailed grob properties for harp pedal diagrams. Each alist entry consists of a `(property . value)` pair. The properties which can be included in harp-pedal-details include the following:

  - `box-offset` – Vertical shift of the center of flat/sharp pedal boxes above/below the horizontal line. Default value 0.8.
  - `box-width` – Width of each pedal box. Default value 0.4.
  - `box-height` – Height of each pedal box. Default value 1.0.
  - `space-before-divider` – Space between boxes before the first divider (so that the diagram can be made symmetric). Default value 0.8.
  - `space-after-divider` – Space between boxes after the first divider. Default value 0.8.
  - `circle-thickness` – Thickness (in unit of the line-thickness) of the ellipse around circled pedals. Default value 0.5.
  - `circle-x-padding` – Padding in X direction of the ellipse around circled pedals. Default value 0.15.
  - `circle-y-padding` – Padding in Y direction of the ellipse around circled pedals. Default value 0.2.
`head-direction` (direction)

  Are the note heads left or right in a semitie?

`height` (dimension, in staff space)

  Height of an object in `staff-space` units.

`height-limit` (dimension, in staff space)

  Maximum slur height: The longer the slur, the closer it is to this height.

`horizontal-shift` (integer)

  An integer that identifies ranking of `NoteColumn`s for horizontal shifting. This is used by note-collision-interface.

`horizontal-skylines` (unknown)

  Two skylines, one to the left and one to the right of this grob.

`ignore-collision` (boolean)

  If set, don’t do note collision resolution on this `NoteColumn`.

`implicit` (boolean)

  Is this an implicit bass figure?

`inspect-index` (integer)

  If debugging is set, set beam and slur configuration to this index, and print the respective scores.

`inspect-quants` (pair of numbers)

  If debugging is set, set beam and slur quants to this position, and print the respective scores.

`keep-fixed-while-stretching` (boolean)

  A grob with this property set to true is fixed relative to the staff above it when systems are stretched.

`keep-inside-line` (boolean)

  If set, this column cannot have objects sticking into the margin.

`kern` (dimension, in staff space)

  Amount of extra white space to add. For bar lines, this is the amount of space after a thick line.

`knee` (boolean)

  Is this beam kneed?

`knee-spacing-correction` (number)

  Factor for the optical correction amount for kneed beams. Set between `0` for no correction and `1` for full correction.

`labels` (list)

  List of labels (symbols) placed on a column

`layer` (integer)

  The output layer (a value between 0 and 2): Layers define the order of printing objects. Objects in lower layers are overprinted by objects in higher layers.

`ledger-line-thickness` (pair of numbers)

  The thickness of ledger lines. It is the sum of 2 numbers: The first is the factor for line thickness, and the second for staff space. Both contributions are added.

`left-bound-info` (list)

  An alist of properties for determining attachments of spanners to edges.

`left-padding` (dimension, in staff space)

  The amount of space that is put left to an object (e.g., a group of accidentals).

`length` (dimension, in staff space)

  User override for the stem length of unbeamed stems.

`length-fraction` (number)

  Multiplier for lengths. Used for determining ledger lines and stem lengths.

`line-break-penalty` (number)

  Penalty for a line break at this column. This affects the choices of the line breaker; it avoids a line break at a column with a positive penalty and prefers a line break at a column with a negative penalty.

`line-break-permission` (symbol)

  Instructs the line breaker on whether to put a line break at this column. Can be `force` or `allow`.

`line-break-system-details` (list)

  An alist of properties to use if this column is the start of a system.

`line-count` (integer)

  The number of staff lines.

`line-positions` (list)

  Vertical positions of staff lines.

`line-thickness` (number)

  The thickness of the tie or slur contour.

`long-text` (markup)

  Text markup. See Formatting text.

`max-beam-connect` (integer)

  Maximum number of beams to connect to beams from this stem. Further beams are typeset as beamlets.

`max-stretch` (number)

  The maximum amount that this `VerticalAxisGroup` can be vertically stretched (for example, in order to better fill a page).

`measure-count` (integer)

  The number of measures for a multi-measure rest.

`measure-length` (moment)

  Length of a measure. Used in some spacing situations.

`merge-differently-dotted` (boolean)

  Merge note heads in collisions, even if they have a different number of dots. This is normal notation for some types of polyphonic music.

  `merge-differently-dotted` only applies to opposing stem directions (i.e., voice 1 & 2).

`merge-differently-headed` (boolean)

  Merge note heads in collisions, even if they have different note heads. The smaller of the two heads is rendered invisible. This is used in polyphonic guitar notation. The value of this setting is used by note-collision-interface.

  `merge-differently-headed` only applies to opposing stem directions (i.e., voice 1 & 2).

`minimum-X-extent` (pair of numbers)

  Minimum size of an object in X dimension, measured in `staff-space` units.

`minimum-Y-extent` (pair of numbers)

  Minimum size of an object in Y dimension, measured in `staff-space` units.

`minimum-distance` (dimension, in staff space)

  Minimum distance between rest and notes or beam.

`minimum-length` (dimension, in staff space)

  Try to make a spanner at least this long, normally in the horizontal direction. This requires an appropriate callback for the `springs-and-rods` property. If added to a `Tie`, this sets the minimum distance between noteheads.

`minimum-length-fraction` (number)

  Minimum length of ledger line as fraction of note head size.

`minimum-space` (dimension, in staff space)

  Minimum distance that the victim should move (after padding).

`neutral-direction` (direction)

  Which direction to take in the center of the staff.

`neutral-position` (number)

  Position (in half staff spaces) where to flip the direction of custos stem.

`next` (layout object)

  Object that is next relation (e.g., the lyric syllable following an extender).

`no-alignment` (boolean)

  If set, don’t place this grob in a `VerticalAlignment`; rather, place it using its own `Y-offset` callback.

`no-ledgers` (boolean)

  If set, don’t draw ledger lines on this object.

`no-stem-extend` (boolean)

  If set, notes with ledger lines do not get stems extending to the middle staff line.

`non-default` (boolean)

  Set for manually specified clefs.

`non-musical` (boolean)

  True if the grob belongs to a `NonMusicalPaperColumn`.

`note-names` (vector)

  Vector of strings containing names for easy-notation note heads.

`outside-staff-horizontal-padding` (number)

  By default, an outside-staff-object can be placed so that is it very close to another grob horizontally. If this property is set, the outside-staff-object is raised so that it is not so close to its neighbor.

`outside-staff-padding` (number)

  The padding to place between this grob and the staff when spacing according to `outside-staff-priority`.

`outside-staff-priority` (number)

  If set, the grob is positioned outside the staff in such a way as to avoid all collisions. In case of a potential collision, the grob with the smaller `outside-staff-priority` is closer to the staff.

`packed-spacing` (boolean)

  If set, the notes are spaced as tightly as possible.

`padding` (dimension, in staff space)

  Add this much extra space between objects that are next to each other.

`padding-pairs` (list)

  An alist mapping `(name . name)` to distances.

`page-break-penalty` (number)

  Penalty for page break at this column. This affects the choices of the page breaker; it avoids a page break at a column with a positive penalty and prefers a page break at a column with a negative penalty.

`page-break-permission` (symbol)

  Instructs the page breaker on whether to put a page break at this column. Can be `force` or `allow`.

`page-turn-penalty` (number)

  Penalty for a page turn at this column. This affects the choices of the page breaker; it avoids a page turn at a column with a positive penalty and prefers a page turn at a column with a negative penalty.

`page-turn-permission` (symbol)

  Instructs the page breaker on whether to put a page turn at this column. Can be `force` or `allow`.

`parenthesized` (boolean)

  Parenthesize this grob.

`positions` (pair of numbers)

  Pair of staff coordinates `(left . right)`, where both left and right are in `staff-space` units of the current staff. For slurs, this value selects which slur candidate to use; if extreme positions are requested, the closest one is taken.

`prefer-dotted-right` (boolean)

  For note collisions, prefer to shift dotted up-note to the right, rather than shifting just the dot.

`ratio` (number)

  Parameter for slur shape. The higher this number, the quicker the slur attains its `height-limit`.

`remove-empty` (boolean)

  If set, remove group if it contains no interesting items.

`remove-first` (boolean)

  Remove the first staff of an orchestral score?

`restore-first` (boolean)

  Print a natural before the accidental.

`rhythmic-location` (rhythmic location)

  Where (bar number, measure position) in the score.

`right-bound-info` (list)

  An alist of properties for determining attachments of spanners to edges.

`right-padding` (dimension, in staff space)

  Space to insert on the right side of an object (e.g., between note and its accidentals).

`rotation` (list)

  Number of degrees to rotate this object, and what point to rotate around. For example, `#'(45 0 0)` rotates by 45 degrees around the center of this object.

`same-direction-correction` (number)

  Optical correction amount for stems that are placed in tight configurations. This amount is used for stems with the same direction to compensate for note head to stem distance.

`script-priority` (number)

  A sorting key that determines in what order a script is within a stack of scripts.

`self-alignment-X` (number)

  Specify alignment of an object. The value `-1` means left aligned, `0` centered, and `1` right-aligned in X direction. Other numerical values may also be specified.

`self-alignment-Y` (number)

  Like `self-alignment-X` but for the Y axis.

`shorten-pair` (pair of numbers)

  The lengths to shorten a text-spanner on both sides, for example a pedal bracket. Positive values shorten the text-spanner, while negative values lengthen it.

`shortest-duration-space` (dimension, in staff space)

  Start with this much space for the shortest duration. This is expressed in `spacing-increment` as unit. See also spacing-spanner-interface.

`shortest-playing-duration` (moment)

  The duration of the shortest note playing here.

`shortest-starter-duration` (moment)

  The duration of the shortest note that starts here.

`side-axis` (number)

  If the value is `#X` (or equivalently `0`), the object is placed horizontally next to the other object. If the value is `#Y` or `1`, it is placed vertically.

`side-relative-direction` (direction)

  Multiply direction of `direction-source` with this to get the direction of this object.

`size` (number)

  Size of object, relative to standard size.

`skyline-horizontal-padding` (number)

  For determining the vertical distance between two staves, it is possible to have a configuration which would result in a tight interleaving of grobs from the top staff and the bottom staff. The larger this parameter is, the farther apart the staves are placed in such a configuration.

`slash-negative-kern` (number)

  The space to remove between slashes in percent repeat glyphs. Larger values bring the two elements closer together.

`slope` (number)

  The slope of this object.

`slur-padding` (number)

  Extra distance between slur and script.

`space-alist` (list)

  A table that specifies distances between prefatory items, like clef and time-signature. The format is an alist of spacing tuples: `(break-align-symbol type . distance)`, where type can be the symbols `minimum-space` or `extra-space`.

`space-to-barline` (boolean)

  If set, the distance between a note and the following non-musical column will be measured to the bar line instead of to the beginning of the non-musical column. If there is a clef change followed by a bar line, for example, this means that we will try to space the non-musical column as though the clef is not there.

`spacing-increment` (number)

  Add this much space for a doubled duration. Typically, the width of a note head. See also spacing-spanner-interface.

`springs-and-rods` (boolean)

  Dummy variable for triggering spacing routines.

`stacking-dir` (direction)

  Stack objects in which direction?

`staff-padding` (dimension, in staff space)

  Maintain this much space between reference points and the staff. Its effect is to align objects of differing sizes (like the dynamics p and f) on their baselines.

`staff-position` (number)

  Vertical position, measured in half staff spaces, counted from the middle line.

`staff-space` (dimension, in staff space)

  Amount of space between staff lines, expressed in global `staff-space`.

`stem-attachment` (pair of numbers)

  An `(x . y)` pair where the stem attaches to the notehead.

`stem-end-position` (number)

  Where does the stem end (the end is opposite to the support-head)?

`stem-spacing-correction` (number)

  Optical correction amount for stems that are placed in tight configurations. For opposite directions, this amount is the correction for two normal sized stems that overlap completely.

`stemlet-length` (number)

  How long should be a stem over a rest?

`stencil` (unknown)

  The symbol to print.

`stencils` (list)

  Multiple stencils, used as intermediate value.

`strict-grace-spacing` (boolean)

  If set, main notes are spaced normally, then grace notes are put left of the musical columns fot the main notes.

`strict-note-spacing` (boolean)

  If set, unbroken columns with non-musical material (clefs, bar lines, etc.) are not spaced separately, but put before musical columns.

`stroke-style` (string)

  Set to `"grace"` to turn stroke through flag on.

`style` (symbol)

  This setting determines in what style a grob is typeset. Valid choices depend on the `stencil` callback reading this property.

`text` (markup)

  Text markup. See Formatting text.

`text-direction` (direction)

  This controls the ordering of the words. The default `RIGHT` is for roman text. Arabic or Hebrew should use `LEFT`.

`thick-thickness` (number)

  Bar line thickness, measured in `line-thickness`.

`thickness` (number)

  Line thickness, generally measured in `line-thickness`.

`thin-kern` (number)

  The space after a hair-line in a bar line.

`threshold` (pair of numbers)

  `(min . max)`, where min and max are dimensions in staff space.

`tie-configuration` (list)

  List of `(position . dir)` pairs, indicating the desired tie configuration, where position is the offset from the center of the staff in staff space and dir indicates the direction of the tie (`1`=>up, `-1`=>down, `0`=>center). A non-pair entry in the list causes the corresponding tie to be formatted automatically.

`to-barline` (boolean)

  If true, the spanner will stop at the bar line just before it would otherwise stop.

`toward-stem-shift` (number)

  Amount by which scripts are shifted toward the stem if their direction coincides with the stem direction. `0.0` means keep the default position (centered on the note head), `1.0` means centered on the stem. Interpolated values are possible.

`transparent` (boolean)

  This makes the grob invisible.

`uniform-stretching` (boolean)

  If set, items stretch proportionally to their durations. This looks better in complex polyphonic patterns.

`used` (boolean)

  If set, this spacing column is kept in the spacing problem.

`vertical-skylines` (unknown)

  Two skylines, one above and one below this grob.

`when` (moment)

  Global time step associated with this column happen?

`width` (dimension, in staff space)

  The width of a grob measured in staff space.

`word-space` (dimension, in staff space)

  Space to insert between words in texts.

`zigzag-length` (dimension, in staff space)

  The length of the lines of a zigzag, relative to `zigzag-width`. A value of `1` gives 60-degree zigzags.

`zigzag-width` (dimension, in staff space)

  The width of one zigzag squiggle. This number is adjusted slightly so that the glissando line can be constructed from a whole number of squiggles.

## 3.4 Internal backend properties

`X-common` (layout object)

  Common reference point for axis group.

`Y-common` (layout object)

  See `X-common`.

`accidental-grob` (layout object)

  The accidental for this note.

`accidental-grobs` (list)

  An alist with `(notename . groblist)` entries.

`add-cauda` (boolean)

  Does this flexa require an additional cauda on the left side?

`add-join` (boolean)

  Is this ligature head-joined with the next one by a vertical line?

`add-stem` (boolean)

  Is this ligature head a virga and therefore needs an additional stem on the right side?

`adjacent-hairpins` (unknown)

  A list of directly neighboring hairpins.

`adjacent-pure-heights` (vector)

  Used by a `VerticalAxisGroup` to cache the `Y-extent`s of different column ranges.

`all-elements` (unknown)

  A list of all grobs in this line. Its function is to protect objects from being garbage collected.

`arpeggio` (layout object)

  A pointer to an `Arpeggio` object.

`ascendens` (boolean)

  Is this neume of ascending type?

`auctum` (boolean)

  Is this neume liquescentically augmented?

`axis-group-parent-X` (layout object)

  Containing X axis group.

`axis-group-parent-Y` (layout object)

  Containing Y axis group.

`bar-extent` (pair of numbers)

  The Y-extent of the actual bar line. This may differ from `Y-extent` because it does not include the dots in a repeat bar line.

`bars` (unknown)

  A list of bar line pointers.

`beam` (layout object)

  A pointer to the beam, if applicable.

`begin-of-line-visible` (boolean)

  Used for marking `ChordNames` that should only show changes.

`bounded-by-me` (unknown)

  A list of spanners that have this column as start/begin point. Only columns that have grobs or act as bounds are spaced.

`bracket` (layout object)

  The bracket for a number.

`cause` (any type)

  Any kind of causation objects (i.e., music, or perhaps translator) that was the cause for this grob.

`cavum` (boolean)

  Is this neume outlined?

`columns` (unknown)

  A list of grobs, typically containing `PaperColumn` or `NoteColumn` objects.

`conditional-elements` (unknown)

  Internal use only.

`context-info` (integer)

  Within a ligature, the final glyph or shape of a head may be affected by the left and/or right neighbour head. `context-info` holds for each head such information about the left and right neighbour, encoded as a bit mask.

`cross-staff` (boolean)

  For a beam or a stem, this is true if we depend on inter-staff spacing.

`delta-position` (number)

  The vertical position difference.

`deminutum` (boolean)

  Is this neume deminished?

`descendens` (boolean)

  Is this neume of descendent type?

`details` (list)

  Alist of parameters for detailed grob behavior.

  More information on the allowed parameters can be found by inspecting ‘`lily/slur-scoring.cc`’, ‘`lily/beam-quanting.cc`’, and ‘`lily/tie-formatting-problem.cc`’. Setting `debug-tie-scoring`, `debug-beam-scoring` or `debug-slur-scoring` also provides useful clues.

`direction-source` (layout object)

  In case `side-relative-direction` is set, which grob to get the direction from.

`dot` (layout object)

  A reference to a `Dots` object.

`dots` (unknown)

  Multiple `Dots` objects.

`elements` (unknown)

  A list of grobs; the type is depending on the grob where this is set in.

`encompass-objects` (unknown)

  Objects that a slur should avoid in addition to notes and stems.

`figures` (unknown)

  Figured bass objects for continuation line.

`flexa-height` (dimension, in staff space)

  The height of a flexa shape in a ligature grob (in `staff-space` units).

`flexa-width` (dimension, in staff space)

  The width of a flexa shape in a ligature grob in (in `staff-space` units).

`font` (font metric)

  A cached font metric object.

`forced` (boolean)

  Manually forced accidental.

`glyph-name` (string)

  The glyph name within the font.

`grace-spacing` (layout object)

  A run of grace notes.

`head-width` (dimension, in staff space)

  The width of this ligature head.

`heads` (unknown)

  A list of note heads.

`ideal-distances` (list)

  `(obj . (dist . strength))` pairs.

`important-column-ranks` (vector)

  A cache of columns that contain `items-worth-living` data.

`inclinatum` (boolean)

  Is this neume an inclinatum?

`interfaces` (list)

  A list of symbols indicating the interfaces supported by this object. It is initialized from the `meta` field.

`items-worth-living` (unknown)

  A list of interesting items. If empty in a particular staff, then that staff is erased.

`join-heads` (boolean)

  Whether to join the note heads of an ambitus grob with a vertical line.

`join-right-amount` (number)

  DOCME

`least-squares-dy` (number)

  The ideal beam slope, without damping.

`left-items` (unknown)

  DOCME

`left-neighbors` (unknown)

  A list of `spacing-wishes` grobs that are close to the current column.

  The closest `spacing-wishes` determine the actual distances between the columns.

`linea` (boolean)

  Attach vertical lines to this neume?

`meta` (list)

  Provide meta information. It is an alist with the entries `name` and `interfaces`.

`minimum-distances` (list)

  A list of rods that have the format `(obj . dist)`.

`normal-stems` (unknown)

  An array of visible stems.

`note-columns` (pair)

  A list of `NoteColumn` grobs.

`note-head` (layout object)

  A single note head.

`note-heads` (unknown)

  A list of note head grobs.

`oriscus` (boolean)

  Is this neume an oriscus?

`pedal-text` (layout object)

  A pointer to the text of a mixed-style piano pedal.

`pes-or-flexa` (boolean)

  Shall this neume be joined with the previous head?

`positioning-done` (boolean)

  Used to signal that a positioning element did its job. This ensures that a positioning is only done once.

`prefix-set` (number)

  A bit mask that holds all Gregorian head prefixes, such as `\virga` or `\quilisma`.

`primitive` (integer)

  A pointer to a ligature primitive, i.e., an item similar to a note head that is part of a ligature.

`pure-Y-common` (layout object)

  A cache of the `common_refpoint_of_array` of the `elements` grob set.

`pure-Y-extent` (pair of numbers)

  The estimated height of a system.

`pure-Y-offset-in-progress` (boolean)

  A debugging aid for catching cyclic dependencies.

`pure-relevant-items` (unknown)

  A subset of elements that are relevant for finding the `pure-Y-extent`.

`pure-relevant-spanners` (unknown)

  A subset of elements that are relevant for finding the `pure-Y-extent`.

`quant-score` (string)

  The beam quanting score; stored for debugging.

`quantize-position` (boolean)

  If set, a vertical alignment is aligned to be within staff spaces.

`quantized-positions` (pair of numbers)

  The beam positions after quanting.

`quilisma` (boolean)

  Is this neume a quilisma?

`rest` (layout object)

  A pointer to a `Rest` object.

`rest-collision` (layout object)

  A rest collision that a rest is in.

`rests` (unknown)

  A list of rest objects.

`right-items` (unknown)

  DOCME

`right-neighbors` (unknown)

  See `left-neighbors`.

`script-stencil` (pair)

  A pair `(type . arg)` which acts as an index for looking up a `Stencil` object.

`separation-item` (layout object)

  A separation item.

`shorten` (dimension, in staff space)

  The amount of space that a stem is shortened. Internally used to distribute beam shortening over stems.

`side-support-elements` (unknown)

  The side support, a list of grobs.

`skyline-distance` (number)

  The distance between this staff and the next one, as determined by a skyline algorithm.

`slur` (layout object)

  A pointer to a `Slur` object.

`spaceable-staves` (unknown)

  Objects to be spaced during page layout.

`spacing` (layout object)

  The spacing spanner governing this section.

`spacing-wishes` (unknown)

  List of note spacing or staff spacing objects.

`staff-symbol` (layout object)

  The staff symbol grob that we are in.

`stem` (layout object)

  A pointer to a `Stem` object.

`stem-info` (pair)

  A cache of stem parameters.

`stems` (unknown)

  A list of stem objects, corresponding to the notes that the arpeggio has to be before.

`stropha` (boolean)

  Is this neume a stropha?

`tie` (layout object)

  A pointer to a `Tie` object.

`tremolo-flag` (layout object)

  The tremolo object on a stem.

`tuplet-number` (layout object)

  The number for a bracket.

`tuplets` (unknown)

  A list of smaller tuplet brackets.

`use-breve-rest` (boolean)

  Use breve rests for measures longer than a whole rest.

`virga` (boolean)

  Is this neume a virga?

`x-offset` (dimension, in staff space)

  Extra horizontal offset for ligature heads.

# 4. Scheme functions

Function: dispatcher x

  Is x a `Dispatcher` object?

Function: listener x

  Is x a `Listener` object?

Function: ly:add-file-name-alist alist

  Add mappings for error messages from alist.

Function: ly:add-interface a b c

  Add an interface description.

Function: ly:add-listener list disp cl

  Add the listener list to the dispatcher disp. Whenever disp hears an event of class cl, it is forwarded to list.

Function: ly:add-option sym val description

  Add a program option sym with default val.

Function: ly:all-grob-interfaces

  Get a hash table with all interface descriptions.

Function: ly:all-options

  Get all option settings in an alist.

Function: ly:all-stencil-expressions

  Return all symbols recognized as stencil expressions.

Function: ly:assoc-get key alist default-value

  Return value if key in alist, else `default-value` (or `#f` if not specified).

Function: ly:book-add-bookpart! book-smob book-part

  Add book_part to book-smob book part list.

Function: ly:book-add-score! book-smob score

  Add score to book-smob score list.

Function: ly:book-process book-smob default-paper default-layout output

  Print book. output is passed to the backend unchanged. For example, it may be a string (for file based outputs) or a socket (for network based output).

Function: ly:book-process-to-systems book-smob default-paper default-layout output

  Print book. output is passed to the backend unchanged. For example, it may be a string (for file based outputs) or a socket (for network based output).

Function: ly:box? x

  Is x a `Box` object?

Function: ly:bp num

  num bigpoints (1/72th inch).

Function: ly:bracket a iv t p

  Make a bracket in direction a. The extent of the bracket is given by iv. The wings protrude by an amount of p, which may be negative. The thickness is given by t.

Function: ly:broadcast disp ev

  Send the stream event ev to the dispatcher disp.

Function: ly:camel-case->lisp-identifier name-sym

  Convert `FooBar_Bla` to `foo-bar-bla` style symbol.

Function: ly:chain-assoc-get key achain dfault

  Return value for key from a list of alists achain. If no entry is found, return dfault or `#f` if no dfault is specified.

Function: ly:clear-anonymous-modules

  Plug a GUILE 1.6 and 1.7 memory leak by breaking a weak reference pointer cycle explicitly.

Function: ly:cm num

  num cm.

Function: ly:command-line-code

  The Scheme code specified on command-line with ‘`-e`’.

Function: ly:command-line-options

  The Scheme options specified on command-line with ‘`-d`’.

Function: ly:command-line-verbose?

  Was `be_verbose_global` set?

Function: ly:connect-dispatchers to from

  Make the dispatcher to listen to events from from.

Function: ly:context-event-source context

  Return `event-source` of context context.

Function: ly:context-events-below context

  Return a `stream-distributor` that distributes all events from context and all its subcontexts.

Function: ly:context-find context name

  Find a parent of context that has name or alias name. Return `#f` if not found.

Function: ly:context-grob-definition context name

  Return the definition of name (a symbol) within context as an alist.

Function: ly:context-id context

  Return the ID string of context, i.e., for `\context Voice = one …` return the string `one`.

Function: ly:context-name context

  Return the name of context, i.e., for `\context Voice = one …` return the symbol `Voice`.

Function: ly:context-now context

  Return `now-moment` of context context.

Function: ly:context-parent context

  Return the parent of context, `#f` if none.

Function: ly:context-property c name

  Return the value of name from context c.

Function: ly:context-property-where-defined context name

  Return the context above context where name is defined.

Function: ly:context-pushpop-property context grob eltprop val

  Do a single `\override` or `\revert` operation in context. The grob definition grob is extended with eltprop (if val is specified) or reverted (if unspecified).

Function: ly:context-set-property! context name val

  Set value of property name in context context to val.

Function: ly:context-unset-property context name

  Unset value of property name in context context.

Function: ly:context? x

  Is x a `Context` object?

Function: ly:default-scale

  Get the global default scale.

Function: ly:dimension? d

  Return d as a number. Used to distinguish length variables from normal numbers.

Function: ly:dir? s

  A type predicate. The direction `s` is `-1`, `0` or `1`, where `-1` represents left or down and `1` represents right or up.

Function: ly:duration->string dur

  Convert dur to a string.

Function: ly:duration-dot-count dur

  Extract the dot count from dur.

Function: ly:duration-factor dur

  Extract the compression factor from dur. Return it as a pair.

Function: ly:duration-length dur

  The length of the duration as a `moment`.

Function: ly:duration-log dur

  Extract the duration log from dur.

Function: ly:duration<? p1 p2

  Is p1 shorter than p2?

Function: ly:duration? x

  Is x a `Duration` object?

Function: ly:effective-prefix

  Return effective prefix.

Function: ly:error str rest

  A Scheme callable function to issue the error str. The error is formatted with `format` and rest.

Function: ly:eval-simple-closure delayed closure scm-start scm-end

  Evaluate a simple closure with the given delayed argument. If scm-start and scm-end are defined, evaluate it purely with those start and end points.

Function: ly:event-deep-copy m

  Copy m and all sub expressions of m.

Function: ly:event-property sev sym

  Get the property sym of stream event mus. If sym is undefined, return `'()`.

Function: ly:event-set-property! ev sym val

  Set property sym in event ev to val.

Function: ly:expand-environment str

  Expand `$VAR` and `${VAR}` in str.

Function: ly:export arg

  Export a Scheme object to the parser so it is treated as an identifier.

Function: ly:find-file name

  Return the absolute file name of name, or `#f` if not found.

Function: ly:font-config-add-directory dir

  Add directory dir to FontConfig.

Function: ly:font-config-add-font font

  Add font font to FontConfig.

Function: ly:font-config-display-fonts

  Dump a list of all fonts visible to FontConfig.

Function: ly:font-config-get-font-file name

  Get the file for font name.

Function: ly:font-design-size font

  Given the font metric font, return the design size, relative to the current output-scale.

Function: ly:font-file-name font

  Given the font metric font, return the corresponding file name.

Function: ly:font-get-glyph font name

  Return a stencil from font for the glyph named name. If the glyph is not available, return an empty stencil.

  Note that this command can only be used to access glyphs from fonts loaded with `ly:system-font-load`; currently, this means either the Emmentaler or Aybabtu fonts, corresponding to the font encodings `fetaMusic` and `fetaBraces`, respectively.

Function: ly:font-glyph-name-to-charcode font name

  Return the character code for glyph name in font.

  Note that this command can only be used to access glyphs from fonts loaded with `ly:system-font-load`; currently, this means either the Emmentaler or Aybabtu fonts, corresponding to the font encodings `fetaMusic` and `fetaBraces`, respectively.

Function: ly:font-glyph-name-to-index font name

  Return the index for name in font.

  Note that this command can only be used to access glyphs from fonts loaded with `ly:system-font-load`; currently, this means either the Emmentaler or Aybabtu fonts, corresponding to the font encodings `fetaMusic` and `fetaBraces`, respectively.

Function: ly:font-index-to-charcode font index

  Return the character code for index in font.

  Note that this command can only be used to access glyphs from fonts loaded with `ly:system-font-load`; currently, this means either the Emmentaler or Aybabtu fonts, corresponding to the font encodings `fetaMusic` and `fetaBraces`, respectively.

Function: ly:font-magnification font

  Given the font metric font, return the magnification, relative to the current output-scale.

Function: ly:font-metric? x

  Is x a `Font_metric` object?

Function: ly:font-name font

  Given the font metric font, return the corresponding name.

Function: ly:font-sub-fonts font

  Given the font metric font of an OpenType font, return the names of the subfonts within font.

Function: ly:format str rest

  LilyPond specific format, supporting `~a` and `~[0-9]f`.

Function: ly:format-output context

  Given a global context in its final state, process it and return the `Music_output` object in its final state.

Function: ly:get-all-function-documentation

  Get a hash table with all LilyPond Scheme extension functions.

Function: ly:get-all-translators

  Return a list of all translator objects that may be instantiated.

Function: ly:get-glyph font index

  Retrieve a stencil for the glyph numbered index in font.

  Note that this command can only be used to access glyphs from fonts loaded with `ly:system-font-load`; currently, this means either the Emmentaler or Aybabtu fonts, corresponding to the font encodings `fetaMusic` and `fetaBraces`, respectively.

Function: ly:get-listened-event-classes

  Return a list of all event classes that some translator listens to.

Function: ly:get-option var

  Get a global option setting.

Function: ly:gettext original

  A Scheme wrapper function for `gettext`.

Function: ly:grob-alist-chain grob global

  Get an alist chain for grob grob, with global as the global default. If unspecified, `font-defaults` from the layout block is taken.

Function: ly:grob-array-length grob-arr

  Return the length of grob-arr.

Function: ly:grob-array-ref grob-arr index

  Retrieve the indexth element of grob-arr.

Function: ly:grob-array? x

  Is x a `Grob_array` object?

Function: ly:grob-basic-properties grob

  Get the immutable properties of grob.

Function: ly:grob-common-refpoint grob other axis

  Find the common refpoint of grob and other for axis.

Function: ly:grob-common-refpoint-of-array grob others axis

  Find the common refpoint of grob and others (a grob-array) for axis.

Function: ly:grob-default-font grob

  Return the default font for grob gr.

Function: ly:grob-extent grob refp axis

  Get the extent in axis direction of grob relative to the grob refp.

Function: ly:grob-interfaces grob

  Return the interfaces list of grob grob.

Function: ly:grob-layout grob

  Get `\layout` definition from grob grob.

Function: ly:grob-object grob sym

  Return the value of a pointer in grob g of property sym. It returns `'()` (end-of-list) if sym is undefined in g.

Function: ly:grob-original grob

  Return the unbroken original grob of grob.

Function: ly:grob-parent grob axis

  Get the parent of grob. axis is 0 for the X-axis, 1 for the Y-axis.

Function: ly:grob-pq<? a b

  Compare two grob priority queue entries. This is an internal function.

Function: ly:grob-properties grob

  Get the mutable properties of grob.

Function: ly:grob-property grob sym deflt

  Return the value of a value in grob g of property sym. It returns `'()` (end-of-list) or deflt (if specified) if sym is undefined in g.

Function: ly:grob-property-data grob sym

  Retrieve sym for grob but don’t process callbacks.

Function: ly:grob-relative-coordinate grob refp axis

  Get the coordinate in axis direction of grob relative to the grob refp.

Function: ly:grob-robust-relative-extent grob refp axis

  Get the extent in axis direction of grob relative to the grob refp, or `(0,0)` if empty.

Function: ly:grob-script-priority-less a b

  Compare two grobs by script priority. For internal use.

Function: ly:grob-set-property! grob sym val

  Set sym in grob grob to value val.

Function: ly:grob-staff-position sg

  Return the Y-position of sg relative to the staff.

Function: ly:grob-suicide! grob

  Kill grob.

Function: ly:grob-system grob

  Return the system grob of grob.

Function: ly:grob-translate-axis! grob d a

  Translate g on axis a over distance d.

Function: ly:grob? x

  Is x a `Grob` object?

Function: ly:gulp-file name size

  Read the file name, and return its contents in a string. The file is looked up using the search path.

Function: ly:hash-table-keys tab

  Return a list of keys in tab.

Function: ly:inch num

  num inches.

Function: ly:input-both-locations sip

  Return input location in sip as `(file-name first-line first-column last-line last-column)`.

Function: ly:input-file-line-char-column sip

  Return input location in sip as `(file-name line char column)`.

Function: ly:input-location? x

  Is x an `input-location`?

Function: ly:input-message sip msg rest

  Print msg as a GNU compliant error message, pointing to the location in sip. msg is interpreted similar to `format`’s argument, using rest.

Function: ly:interpret-music-expression mus ctx

  Interpret the music expression mus in the global context ctx. The context is returned in its final state.

Function: ly:interpret-stencil-expression expr func arg1 offset

  Parse expr, feed bits to func with first arg arg1 having offset offset.

Function: ly:intlog2 d

  The 2-logarithm of 1/d.

Function: ly:is-listened-event-class sym

  Is sym a listened event class?

Function: ly:item-break-dir it

  The break status direction of item it. `-1` means end of line, `0` unbroken, and `1` beginning of line.

Function: ly:item? g

  Is g an `Item` object?

Function: ly:iterator? x

  Is x a `Music_iterator` object?

Function: ly:lexer-keywords lexer

  Return a list of `(KEY . CODE)` pairs, signifying the LilyPond reserved words list.

Function: ly:lily-lexer? x

  Is x a `Lily_lexer` object?

Function: ly:lily-parser? x

  Is x a `Lily_parser` object?

Function: ly:make-book paper header scores

  Make a `\book` of paper and header (which may be `#f` as well) containing `\scores`.

Function: ly:make-book-part scores

  Make a `\bookpart` containing `\scores`.

Function: ly:make-dispatcher

  Return a newly created dispatcher.

Function: ly:make-duration length dotcount num den

  length is the negative logarithm (base 2) of the duration: 1 is a half note, 2 is a quarter note, 3 is an eighth note, etc. The number of dots after the note is given by the optional argument dotcount.

  The duration factor is optionally given by num and den.

  A duration is a musical duration, i.e., a length of time described by a power of two (whole, half, quarter, etc.) and a number of augmentation dots.

Function: ly:make-global-context output-def

  Set up a global interpretation context, using the output block output_def. The context is returned.

Function: ly:make-global-translator global

  Create a translator group and connect it to the global context global. The translator group is returned.

Function: ly:make-listener callback

  Create a listener. Any time the listener hears an object, it will call callback with that object.

  callback should take exactly one argument.

Function: ly:make-moment n d gn gd

  Create the rational number with main timing n/d, and optional grace timing gn/gd.

  A moment is a point in musical time. It consists of a pair of rationals (m, g), where m is the timing for the main notes, and g the timing for grace notes. In absence of grace notes, g is zero.

Function: ly:make-music props

  Make a C++ `Music` object and initialize it with props.

  This function is for internal use and is only called by `make-music`, which is the preferred interface for creating music objects.

Function: ly:make-music-function signature func

  Make a function to process music, to be used for the parser. `func` is the function, and `signature` describes its arguments. `signature` is a list containing either `ly:music?` predicates or other type predicates.

Function: ly:make-output-def

  Make an output definition.

Function: ly:make-page-label-marker label

  Return page marker with label.

Function: ly:make-page-permission-marker symbol permission

  Return page marker with page breaking and turning permissions.

Function: ly:make-pango-description-string chain size

  Make a `PangoFontDescription` string for the property alist chain at size size.

Function: ly:make-paper-outputter port format

  Create an outputter that evaluates within `output-`format, writing to port.

Function: ly:make-pitch octave note alter

  octave is specified by an integer, zero for the octave containing middle C. note is a number indexing the global default scale, with 0 corresponding to pitch C and 6 usually corresponding to pitch B. alter is a rational number of 200-cent whole tones for alteration.

Function: ly:make-prob type init rest

  Create a `Prob` object.

Function: ly:make-scale steps

  Create a scale. The argument is a vector of rational numbers, each of which represents the number of 200 cent tones of a pitch above the tonic.

Function: ly:make-score music

  Return score with music encapsulated in score.

Function: ly:make-simple-closure expr

  Make a simple closure. expr should be form of `(func a1 A2 …)`, and will be invoked as `(func delayed-arg a1 a2 …)`.

Function: ly:make-stencil expr xext yext

  Stencils are device independent output expressions. They carry two pieces of information:

  1. A specification of how to print this object. This specification is processed by the output backends, for example ‘`scm/output-ps.scm`’.
  2. The vertical and horizontal extents of the object, given as pairs. If an extent is unspecified (or if you use `(1000 . -1000)` as its value), it is taken to be empty.

Function: ly:make-stream-event cl proplist

  Create a stream event of class cl with the given mutable property list.

Function: ly:message str rest

  A Scheme callable function to issue the message str. The message is formatted with `format` and rest.

Function: ly:minimal-breaking pb

  Break (pages and lines) the `Paper_book` object pb without looking for optimal spacing: stack as many lines on a page before moving to the next one.

Function: ly:mm num

  num mm.

Function: ly:module->alist mod

  Dump the contents of module mod as an alist.

Function: ly:module-copy dest src

  Copy all bindings from module src into dest.

Function: ly:modules-lookup modules sym def

  Look up sym in the list modules, returning the first occurence. If not found, return def or `#f` if def isn’t specified.

Function: ly:moment-add a b

  Add two moments.

Function: ly:moment-div a b

  Divide two moments.

Function: ly:moment-grace-denominator mom

  Extract denominator from grace timing.

Function: ly:moment-grace-numerator mom

  Extract numerator from grace timing.

Function: ly:moment-main-denominator mom

  Extract denominator from main timing.

Function: ly:moment-main-numerator mom

  Extract numerator from main timing.

Function: ly:moment-mod a b

  Modulo of two moments.

Function: ly:moment-mul a b

  Multiply two moments.

Function: ly:moment-sub a b

  Subtract two moments.

Function: ly:moment<? a b

  Compare two moments.

Function: ly:moment? x

  Is x a `Moment` object?

Function: ly:music-compress m factor

  Compress music object m by moment factor.

Function: ly:music-deep-copy m

  Copy m and all sub expressions of m.

Function: ly:music-duration-compress mus fact

  Compress mus by factor fact, which is a `Moment`.

Function: ly:music-duration-length mus

  Extract the duration field from mus and return the length.

Function: ly:music-function-extract x

  Return the Scheme function inside x.

Function: ly:music-function? x

  Is x a `music-function`?

Function: ly:music-length mus

  Get the length of music expression mus and return it as a `Moment` object.

Function: ly:music-list? lst

  Type predicate: Return true if lst is a list of music objects.

Function: ly:music-mutable-properties mus

  Return an alist containing the mutable properties of mus. The immutable properties are not available, since they are constant and initialized by the `make-music` function.

Function: ly:music-output? x

  Is x a `Music_output` object?

Function: ly:music-property mus sym dfault

  Get the property sym of music expression mus. If sym is undefined, return `'()`.

Function: ly:music-set-property! mus sym val

  Set property sym in music expression mus to val.

Function: ly:music-transpose m p

  Transpose m such that central C is mapped to p. Return m.

Function: ly:music? obj

  Type predicate.

Function: ly:note-head::stem-attachment font-metric glyph-name

  Get attachment in font-metric for attaching a stem to notehead glyph-name.

Function: ly:number->string s

  Convert num to a string without generating many decimals.

Function: ly:optimal-breaking pb

  Optimally break (pages and lines) the `Paper_book` object pb to minimize badness in bother vertical and horizontal spacing.

Function: ly:option-usage

  Print `ly:set-option` usage.

Function: ly:otf->cff otf-file-name

  Convert the contents of an OTF file to a CFF file, returning it as a string.

Function: ly:otf-font-glyph-info font glyph

  Given the font metric font of an OpenType font, return the information about named glyph glyph (a string).

Function: ly:otf-font-table-data font tag

  Extract a table tag from font. Return empty string for non-existent tag.

Function: ly:otf-font? font

  Is font an OpenType font?

Function: ly:otf-glyph-list font

  Return a list of glyph names for font.

Function: ly:output-def-clone def

  Clone output definition def.

Function: ly:output-def-lookup pap sym def

  Look up sym in the pap output definition (e.g., `\paper`). Return the value or def (which defaults to `'()`) if undefined.

Function: ly:output-def-parent def

  Get the parent output definition of def.

Function: ly:output-def-scope def

  Get the variable scope inside def.

Function: ly:output-def-set-variable! def sym val

  Set an output definition def variable sym to val.

Function: ly:output-def? def

  Is def a layout definition?

Function: ly:output-description output-def

  Return the description of translators in output-def.

Function: ly:output-formats

  Formats passed to ‘`--format`’ as a list of strings, used for the output.

Function: ly:outputter-close outputter

  Close port of outputter.

Function: ly:outputter-dump-stencil outputter stencil

  Dump stencil expr onto outputter.

Function: ly:outputter-dump-string outputter str

  Dump str onto outputter.

Function: ly:outputter-output-scheme outputter expr

  Eval expr in module of outputter.

Function: ly:outputter-port outputter

  Return output port for outputter.

Function: ly:page-marker? x

  Is x a `Page_marker` object?

Function: ly:page-turn-breaking pb

  Optimally break (pages and lines) the `Paper_book` object pb such that page turns only happen in specified places, returning its pages.

Function: ly:pango-font-physical-fonts f

  Return alist of `(ps-name file-name font-index)` lists for Pango font f.

Function: ly:pango-font? f

  Is f a pango font?

Function: ly:paper-book-pages pb

  Return pages in book pb.

Function: ly:paper-book-paper pb

  Return pages in book pb.

Function: ly:paper-book-performances paper-book

  Return performances in book paper-book.

Function: ly:paper-book-scopes book

  Return scopes in layout book book.

Function: ly:paper-book-systems pb

  Return systems in book pb.

Function: ly:paper-book? x

  Is x a `Paper_book` object?

Function: ly:paper-fonts bp

  Return fonts from the `\paper` block bp.

Function: ly:paper-get-font paper-smob chain

  Return a font metric satisfying the font-qualifiers in the alist chain chain. (An alist chain is a list of alists, containing grob properties.)

Function: ly:paper-get-number layout-smob name

  Return the layout variable name.

Function: ly:paper-outputscale bp

  Get output-scale for bp.

Function: ly:paper-score-paper-systems paper-score

  Return vector of `paper_system` objects from paper-score.

Function: ly:paper-system-minimum-distance sys1 sys2

  Measure the minimum distance between these two paper-systems, using their stored skylines if possible and falling back to their extents otherwise.

Function: ly:paper-system? obj

  Type predicate.

Function: ly:parse-file name

  Parse a single `.ly` file. Upon failure, throw `ly-file-failed` key.

Function: ly:parser-clear-error parser

  Clear the error flag for the parser.

Function: ly:parser-clone parser-smob

  Return a clone of parser-smob.

Function: ly:parser-define! parser-smob symbol val

  Bind symbol to val in parser-smob’s module.

Function: ly:parser-error parser msg input

  Display an error message and make the parser fail.

Function: ly:parser-has-error? parser

  Does parser have an error flag?

Function: ly:parser-lexer parser-smob

  Return the lexer for parser-smob.

Function: ly:parser-lookup parser-smob symbol

  Look up symbol in parser-smob’s module. Return `'()` if not defined.

Function: ly:parser-output-name parser

  Return the base name of the output file.

Function: ly:parser-parse-string parser-smob ly-code

  Parse the string ly-code with parser-smob. Upon failure, throw `ly-file-failed` key.

Function: ly:parser-set-note-names parser names

  Replace current note names in parser. names is an alist of symbols. This only has effect if the current mode is notes.

Function: ly:performance-write performance filename

  Write performance to filename.

Function: ly:pfb->pfa pfb-file-name

  Convert the contents of a PFB file to PFA.

Function: ly:pitch-alteration pp

  Extract the alteration from pitch pp.

Function: ly:pitch-diff pitch root

  Return pitch delta such that pitch transposed by delta equals root.

Function: ly:pitch-negate p

  Negate p.

Function: ly:pitch-notename pp

  Extract the note name from pitch pp.

Function: ly:pitch-octave pp

  Extract the octave from pitch pp.

Function: ly:pitch-quartertones pp

  Calculate the number of quarter tones of pp from middle C.

Function: ly:pitch-semitones pp

  Calculate the number of semitones of pp from middle C.

Function: ly:pitch-steps p

  Number of steps counted from middle C of the pitch p.

Function: ly:pitch-transpose p delta

  Transpose p by the amount delta, where delta is relative to middle C.

Function: ly:pitch<? p1 p2

  Is p1 lexicographically smaller than p2?

Function: ly:pitch? x

  Is x a `Pitch` object?

Function: ly:position-on-line? sg spos

  Return whether pos is on a line of the staff associated with the the grob sg (even on an extender line).

Function: ly:prob-immutable-properties prob

  Retrieve an alist of mutable properties.

Function: ly:prob-mutable-properties prob

  Retrieve an alist of mutable properties.

Function: ly:prob-property obj sym dfault

  Return the value for sym.

Function: ly:prob-property? obj sym

  Is boolean prop sym set?

Function: ly:prob-set-property! obj sym value

  Set property sym of obj to value.

Function: ly:prob-type? obj type

  Is obj the specified prob-type?

Function: ly:prob? x

  Is x a `Prob` object?

Function: ly:programming-error str rest

  A Scheme callable function to issue the internal warning str. The message is formatted with `format` and rest.

Function: ly:progress str rest

  A Scheme callable function to print progress str. The message is formatted with `format` and rest.

Function: ly:property-lookup-stats sym

  Return hash table with a property access corresponding to sym. Choices are `prob`, `grob`, and `context`.

Function: ly:protects

  Return hash of protected objects.

Function: ly:pt num

  num printer points.

Function: ly:register-stencil-expression symbol

  Add symbol as head of a stencil expression.

Function: ly:relative-group-extent elements common axis

  Determine the extent of elements relative to common in the axis direction.

Function: ly:reset-all-fonts

  Forget all about previously loaded fonts.

Function: ly:round-filled-box xext yext blot

  Make a `Stencil` object that prints a black box of dimensions xext, yext and roundness blot.

Function: ly:round-filled-polygon points blot

  Make a `Stencil` object that prints a black polygon with corners at the points defined by points (list of coordinate pairs) and roundness blot.

Function: ly:run-translator mus output-def

  Process mus according to output-def. An interpretation context is set up, and mus is interpreted with it. The context is returned in its final state.

  Optionally, this routine takes an object-key to to uniquely identify the score block containing it.

Function: ly:score-add-output-def! score def

  Add an output definition def to score.

Function: ly:score-embedded-format score layout

  Run score through layout (an output definition) scaled to correct output-scale already, returning a list of layout-lines. This function takes an optional `Object_key` argument.

Function: ly:score-error? score

  Was there an error in the score?

Function: ly:score-header score

  Return score header.

Function: ly:score-music score

  Return score music.

Function: ly:score-output-defs score

  All output definitions in a score.

Function: ly:score-set-header! score module

  Set the score header.

Function: ly:score? x

  Is x a `Score` object?

Function: ly:set-default-scale scale

  Set the global default scale. This determines the tuning of pitches with no accidentals or key signatures. The first pitch is C. Alterations are calculated relative to this scale. The number of pitches in this scale determines the number of scale steps that make up an octave. Usually the 7-note major scale.

Function: ly:set-grob-modification-callback cb

  Specify a procedure that will be called every time LilyPond modifies a grob property. The callback will receive as arguments the grob that is being modified, the name of the C++ file in which the modification was requested, the line number in the C++ file in which the modification was requested, the name of the function in which the modification was requested, the property to be changed, and the new value for the property.

Function: ly:set-middle-C! context

  Set the `middleCPosition` variable in context based on the variables `middleCClefPosition` and middleCOffset.

Function: ly:set-option var val

  Set a program option.

Function: ly:set-property-cache-callback cb

  Specify a procedure that will be called whenever lilypond calculates a callback function and caches the result. The callback will receive as arguments the grob whose property it is, the name of the property, the name of the callback that calculated the property, and the new (cached) value of the property.

Function: ly:simple-closure? clos

  Type predicate.

Function: ly:skyline-pair? x

  Is x a `Skyline_pair` object?

Function: ly:skyline? x

  Is x a `Skyline` object?

Function: ly:smob-protects

  Return LilyPond’s internal smob protection list.

Function: ly:solve-spring-rod-problem springs rods length ragged

  Solve a spring and rod problem for count objects, that are connected by count-1 springs, and an arbitrary number of rods. count is implicitly given by springs and rods. The springs argument has the format `(ideal, inverse_hook)` and rods is of the form `(idx1, idx2, distance)`.

  length is a number, ragged a boolean.

  The function returns a list containing the force (positive for stretching, negative for compressing and `#f` for non-satisfied constraints) followed by spring-count+1 positions of the objects.

Function: ly:source-file? x

  Is x a `Source_file` object?

Function: ly:spanner-bound spanner dir

  Get one of the bounds of spanner. dir is `-1` for left, and `1` for right.

Function: ly:spanner-broken-into spanner

  Return broken-into list for spanner.

Function: ly:spanner? g

  Is g a spanner object?

Function: ly:staff-symbol-line-thickness grob

  Returns the line-thickness of the staff associated with grob.

Function: ly:start-environment

  Return the environment (a list of strings) that was in effect at program start.

Function: ly:stderr-redirect file-name mode

  Redirect stderr to file-name, opened with mode.

Function: ly:stencil-add args

  Combine stencils. Takes any number of arguments.

Function: ly:stencil-aligned-to stil axis dir

  Align stil using its own extents. dir is a number. `-1` and `1` are left and right, respectively. Other values are interpolated (so `0` means the center).

Function: ly:stencil-combine-at-edge first axis direction second padding minimum

  Construct a stencil by putting second next to first. axis can be 0 (x-axis) or 1 (y-axis). direction can be -1 (left or down) or 1 (right or up). The stencils are juxtaposed with padding as extra space. If this puts the reference points closer than minimum, they are moved by the latter amount. first and second may also be `'()` or `#f`.

Function: ly:stencil-empty? stil

  Return whether stil is empty.

Function: ly:stencil-expr stil

  Return the expression of stil.

Function: ly:stencil-extent stil axis

  Return a pair of numbers signifying the extent of stil in axis direction (`0` or `1` for x and y axis, respectively).

Function: ly:stencil-fonts s

  Analyze s, and return a list of fonts used in s.

Function: ly:stencil-in-color stc r g b

  Put stc in a different color.

Function: ly:stencil-rotate stil angle x y

  Return a stencil stil rotated angle degrees around the relative offset (x, y). E.g. an offset of (-1, 1) will rotate the stencil around the left upper corner.

Function: ly:stencil-rotate-absolute stil angle x y

  Return a stencil stil rotated angle degrees around point (x, y), given in absolute coordinates.

Function: ly:stencil-translate stil offset

  Return a stil, but translated by offset (a pair of numbers).

Function: ly:stencil-translate-axis stil amount axis

  Return a copy of stil but translated by amount in axis direction.

Function: ly:stencil? x

  Is x a `Stencil` object?

Function: ly:stream-event? x

  Is x a `Stream_event` object?

Function: ly:string-substitute a b s

  Replace string a by string b in string s.

Function: ly:system-font-load name

  Load the OpenType system font ‘`name.otf`’. Fonts loaded with this command must contain three additional SFNT font tables called `LILC`, `LILF`, and `LILY`, needed for typesetting musical elements. Currently, only the Emmentaler and the Aybabtu fonts fulfill these requirements.

  Note that only `ly:font-get-glyph` and derived code (like `\lookup`) can access glyphs from the system fonts; text strings are handled exclusively via the Pango interface.

Function: ly:system-print system

  Draw the system and return the prob containing its stencil.

Function: ly:system-stretch system amount-scm

  Stretch the system vertically by the given amount. This must be called before the system is drawn (for example with `ly:system-print`).

Function: ly:text-dimension font text

  Given the font metric in font and the string text, compute the extents of that text in that font. The return value is a pair of number-pairs.

Function: ly:text-interface::interpret-markup

  Convert a text markup into a stencil. Takes three arguments, layout, props, and markup.

  layout is a `\layout` block; it may be obtained from a grob with `ly:grob-layout`. props is an alist chain, i.e. a list of alists. This is typically obtained with `(ly:grob-alist-chain grob (ly:output-def-lookup layout 'text-font-defaults))`. markup is the markup text to be processed.

Function: ly:translator-description me

  Return an alist of properties of translator me.

Function: ly:translator-group? x

  Is x a `Translator_group` object?

Function: ly:translator-name trans

  Return the type name of the translator object trans. The name is a symbol.

Function: ly:translator? x

  Is x a `Translator` object?

Function: ly:transpose-key-alist l pit

  Make a new key alist of l transposed by pitch pit.

Function: ly:truncate-list! lst i

  Take at most the first i of list lst.

Function: ly:ttf->pfa ttf-file-name idx

  Convert the contents of a TrueType font file to PostScript Type 42 font, returning it as a string. The optional idx argument is useful for TrueType collections (TTC) only; it specifies the font index within the TTC. The default value of idx is 0.

Function: ly:ttf-ps-name ttf-file-name idx

  Extract the PostScript name from a TrueType font. The optional idx argument is useful for TrueType collections (TTC) only; it specifies the font index within the TTC. The default value of idx is 0.

Function: ly:unit

  Return the unit used for lengths as a string.

Function: ly:usage

  Print usage message.

Function: ly:version

  Return the current lilypond version as a list, e.g., `(1 3 127 uu1)`.

Function: ly:warning str rest

  A Scheme callable function to issue the warning `str`. The message is formatted with `format` and `rest`.

Function: ly:wide-char->utf-8 wc

  Encode the Unicode codepoint wc, an integer, as UTF-8.

# A. Indices

## A.1 Concept index

## A.2 Function index

Jump to: | D L

| Index Entry | Section
D |  |
| `dispatcher` | 4. Scheme functions
L |  |
| `listener` | 4. Scheme functions
| `ly:add-file-name-alist` | 4. Scheme functions
| `ly:add-interface` | 4. Scheme functions
| `ly:add-listener` | 4. Scheme functions
| `ly:add-option` | 4. Scheme functions
| `ly:all-grob-interfaces` | 4. Scheme functions
| `ly:all-options` | 4. Scheme functions
| `ly:all-stencil-expressions` | 4. Scheme functions
| `ly:assoc-get` | 4. Scheme functions
| `ly:book-add-bookpart!` | 4. Scheme functions
| `ly:book-add-score!` | 4. Scheme functions
| `ly:book-process` | 4. Scheme functions
| `ly:book-process-to-systems` | 4. Scheme functions
| `ly:box?` | 4. Scheme functions
| `ly:bp` | 4. Scheme functions
| `ly:bracket` | 4. Scheme functions
| `ly:broadcast` | 4. Scheme functions
| `ly:camel-case->lisp-identifier` | 4. Scheme functions
| `ly:chain-assoc-get` | 4. Scheme functions
| `ly:clear-anonymous-modules` | 4. Scheme functions
| `ly:cm` | 4. Scheme functions
| `ly:command-line-code` | 4. Scheme functions
| `ly:command-line-options` | 4. Scheme functions
| `ly:command-line-verbose?` | 4. Scheme functions
| `ly:connect-dispatchers` | 4. Scheme functions
| `ly:context-event-source` | 4. Scheme functions
| `ly:context-events-below` | 4. Scheme functions
| `ly:context-find` | 4. Scheme functions
| `ly:context-grob-definition` | 4. Scheme functions
| `ly:context-id` | 4. Scheme functions
| `ly:context-name` | 4. Scheme functions
| `ly:context-now` | 4. Scheme functions
| `ly:context-parent` | 4. Scheme functions
| `ly:context-property` | 4. Scheme functions
| `ly:context-property-where-defined` | 4. Scheme functions
| `ly:context-pushpop-property` | 4. Scheme functions
| `ly:context-set-property!` | 4. Scheme functions
| `ly:context-unset-property` | 4. Scheme functions
| `ly:context?` | 4. Scheme functions
| `ly:default-scale` | 4. Scheme functions
| `ly:dimension?` | 4. Scheme functions
| `ly:dir?` | 4. Scheme functions
| `ly:duration->string` | 4. Scheme functions
| `ly:duration-dot-count` | 4. Scheme functions
| `ly:duration-factor` | 4. Scheme functions
| `ly:duration-length` | 4. Scheme functions
| `ly:duration-log` | 4. Scheme functions
| `ly:duration<?` | 4. Scheme functions
| `ly:duration?` | 4. Scheme functions
| `ly:effective-prefix` | 4. Scheme functions
| `ly:error` | 4. Scheme functions
| `ly:eval-simple-closure` | 4. Scheme functions
| `ly:event-deep-copy` | 4. Scheme functions
| `ly:event-property` | 4. Scheme functions
| `ly:event-set-property!` | 4. Scheme functions
| `ly:expand-environment` | 4. Scheme functions
| `ly:export` | 4. Scheme functions
| `ly:find-file` | 4. Scheme functions
| `ly:font-config-add-directory` | 4. Scheme functions
| `ly:font-config-add-font` | 4. Scheme functions
| `ly:font-config-display-fonts` | 4. Scheme functions
| `ly:font-config-get-font-file` | 4. Scheme functions
| `ly:font-design-size` | 4. Scheme functions
| `ly:font-file-name` | 4. Scheme functions
| `ly:font-get-glyph` | 4. Scheme functions
| `ly:font-glyph-name-to-charcode` | 4. Scheme functions
| `ly:font-glyph-name-to-index` | 4. Scheme functions
| `ly:font-index-to-charcode` | 4. Scheme functions
| `ly:font-magnification` | 4. Scheme functions
| `ly:font-metric?` | 4. Scheme functions
| `ly:font-name` | 4. Scheme functions
| `ly:font-sub-fonts` | 4. Scheme functions
| `ly:format` | 4. Scheme functions
| `ly:format-output` | 4. Scheme functions
| `ly:get-all-function-documentation` | 4. Scheme functions
| `ly:get-all-translators` | 4. Scheme functions
| `ly:get-glyph` | 4. Scheme functions
| `ly:get-listened-event-classes` | 4. Scheme functions
| `ly:get-option` | 4. Scheme functions
| `ly:gettext` | 4. Scheme functions
| `ly:grob-alist-chain` | 4. Scheme functions
| `ly:grob-array-length` | 4. Scheme functions
| `ly:grob-array-ref` | 4. Scheme functions
| `ly:grob-array?` | 4. Scheme functions
| `ly:grob-basic-properties` | 4. Scheme functions
| `ly:grob-common-refpoint` | 4. Scheme functions
| `ly:grob-common-refpoint-of-array` | 4. Scheme functions
| `ly:grob-default-font` | 4. Scheme functions
| `ly:grob-extent` | 4. Scheme functions
| `ly:grob-interfaces` | 4. Scheme functions
| `ly:grob-layout` | 4. Scheme functions
| `ly:grob-object` | 4. Scheme functions
| `ly:grob-original` | 4. Scheme functions
| `ly:grob-parent` | 4. Scheme functions
| `ly:grob-pq<?` | 4. Scheme functions
| `ly:grob-properties` | 4. Scheme functions
| `ly:grob-property` | 4. Scheme functions
| `ly:grob-property-data` | 4. Scheme functions
| `ly:grob-relative-coordinate` | 4. Scheme functions
| `ly:grob-robust-relative-extent` | 4. Scheme functions
| `ly:grob-script-priority-less` | 4. Scheme functions
| `ly:grob-set-property!` | 4. Scheme functions
| `ly:grob-staff-position` | 4. Scheme functions
| `ly:grob-suicide!` | 4. Scheme functions
| `ly:grob-system` | 4. Scheme functions
| `ly:grob-translate-axis!` | 4. Scheme functions
| `ly:grob?` | 4. Scheme functions
| `ly:gulp-file` | 4. Scheme functions
| `ly:hash-table-keys` | 4. Scheme functions
| `ly:inch` | 4. Scheme functions
| `ly:input-both-locations` | 4. Scheme functions
| `ly:input-file-line-char-column` | 4. Scheme functions
| `ly:input-location?` | 4. Scheme functions
| `ly:input-message` | 4. Scheme functions
| `ly:interpret-music-expression` | 4. Scheme functions
| `ly:interpret-stencil-expression` | 4. Scheme functions
| `ly:intlog2` | 4. Scheme functions
| `ly:is-listened-event-class` | 4. Scheme functions
| `ly:item-break-dir` | 4. Scheme functions
| `ly:item?` | 4. Scheme functions
| `ly:iterator?` | 4. Scheme functions
| `ly:lexer-keywords` | 4. Scheme functions
| `ly:lily-lexer?` | 4. Scheme functions
| `ly:lily-parser?` | 4. Scheme functions
| `ly:make-book` | 4. Scheme functions
| `ly:make-book-part` | 4. Scheme functions
| `ly:make-dispatcher` | 4. Scheme functions
| `ly:make-duration` | 4. Scheme functions
| `ly:make-global-context` | 4. Scheme functions
| `ly:make-global-translator` | 4. Scheme functions
| `ly:make-listener` | 4. Scheme functions
| `ly:make-moment` | 4. Scheme functions
| `ly:make-music` | 4. Scheme functions
| `ly:make-music-function` | 4. Scheme functions
| `ly:make-output-def` | 4. Scheme functions
| `ly:make-page-label-marker` | 4. Scheme functions
| `ly:make-page-permission-marker` | 4. Scheme functions
| `ly:make-pango-description-string` | 4. Scheme functions
| `ly:make-paper-outputter` | 4. Scheme functions
| `ly:make-pitch` | 4. Scheme functions
| `ly:make-prob` | 4. Scheme functions
| `ly:make-scale` | 4. Scheme functions
| `ly:make-score` | 4. Scheme functions
| `ly:make-simple-closure` | 4. Scheme functions
| `ly:make-stencil` | 4. Scheme functions
| `ly:make-stream-event` | 4. Scheme functions
| `ly:message` | 4. Scheme functions
| `ly:minimal-breaking` | 4. Scheme functions
| `ly:mm` | 4. Scheme functions
| `ly:module->alist` | 4. Scheme functions
| `ly:module-copy` | 4. Scheme functions
| `ly:modules-lookup` | 4. Scheme functions
| `ly:moment-add` | 4. Scheme functions
| `ly:moment-div` | 4. Scheme functions
| `ly:moment-grace-denominator` | 4. Scheme functions
| `ly:moment-grace-numerator` | 4. Scheme functions
| `ly:moment-main-denominator` | 4. Scheme functions
| `ly:moment-main-numerator` | 4. Scheme functions
| `ly:moment-mod` | 4. Scheme functions
| `ly:moment-mul` | 4. Scheme functions
| `ly:moment-sub` | 4. Scheme functions
| `ly:moment<?` | 4. Scheme functions
| `ly:moment?` | 4. Scheme functions
| `ly:music-compress` | 4. Scheme functions
| `ly:music-deep-copy` | 4. Scheme functions
| `ly:music-duration-compress` | 4. Scheme functions
| `ly:music-duration-length` | 4. Scheme functions
| `ly:music-function-extract` | 4. Scheme functions
| `ly:music-function?` | 4. Scheme functions
| `ly:music-length` | 4. Scheme functions
| `ly:music-list?` | 4. Scheme functions
| `ly:music-mutable-properties` | 4. Scheme functions
| `ly:music-output?` | 4. Scheme functions
| `ly:music-property` | 4. Scheme functions
| `ly:music-set-property!` | 4. Scheme functions
| `ly:music-transpose` | 4. Scheme functions
| `ly:music?` | 4. Scheme functions
| `ly:note-head::stem-attachment` | 4. Scheme functions
| `ly:number->string` | 4. Scheme functions
| `ly:optimal-breaking` | 4. Scheme functions
| `ly:option-usage` | 4. Scheme functions
| `ly:otf->cff` | 4. Scheme functions
| `ly:otf-font-glyph-info` | 4. Scheme functions
| `ly:otf-font-table-data` | 4. Scheme functions
| `ly:otf-font?` | 4. Scheme functions
| `ly:otf-glyph-list` | 4. Scheme functions
| `ly:output-def-clone` | 4. Scheme functions
| `ly:output-def-lookup` | 4. Scheme functions
| `ly:output-def-parent` | 4. Scheme functions
| `ly:output-def-scope` | 4. Scheme functions
| `ly:output-def-set-variable!` | 4. Scheme functions
| `ly:output-def?` | 4. Scheme functions
| `ly:output-description` | 4. Scheme functions
| `ly:output-formats` | 4. Scheme functions
| `ly:outputter-close` | 4. Scheme functions
| `ly:outputter-dump-stencil` | 4. Scheme functions
| `ly:outputter-dump-string` | 4. Scheme functions
| `ly:outputter-output-scheme` | 4. Scheme functions
| `ly:outputter-port` | 4. Scheme functions
| `ly:page-marker?` | 4. Scheme functions
| `ly:page-turn-breaking` | 4. Scheme functions
| `ly:pango-font-physical-fonts` | 4. Scheme functions
| `ly:pango-font?` | 4. Scheme functions
| `ly:paper-book-pages` | 4. Scheme functions
| `ly:paper-book-paper` | 4. Scheme functions
| `ly:paper-book-performances` | 4. Scheme functions
| `ly:paper-book-scopes` | 4. Scheme functions
| `ly:paper-book-systems` | 4. Scheme functions
| `ly:paper-book?` | 4. Scheme functions
| `ly:paper-fonts` | 4. Scheme functions
| `ly:paper-get-font` | 4. Scheme functions
| `ly:paper-get-number` | 4. Scheme functions
| `ly:paper-outputscale` | 4. Scheme functions
| `ly:paper-score-paper-systems` | 4. Scheme functions
| `ly:paper-system-minimum-distance` | 4. Scheme functions
| `ly:paper-system?` | 4. Scheme functions
| `ly:parse-file` | 4. Scheme functions
| `ly:parser-clear-error` | 4. Scheme functions
| `ly:parser-clone` | 4. Scheme functions
| `ly:parser-define!` | 4. Scheme functions
| `ly:parser-error` | 4. Scheme functions
| `ly:parser-has-error?` | 4. Scheme functions
| `ly:parser-lexer` | 4. Scheme functions
| `ly:parser-lookup` | 4. Scheme functions
| `ly:parser-output-name` | 4. Scheme functions
| `ly:parser-parse-string` | 4. Scheme functions
| `ly:parser-set-note-names` | 4. Scheme functions
| `ly:performance-write` | 4. Scheme functions
| `ly:pfb->pfa` | 4. Scheme functions
| `ly:pitch-alteration` | 4. Scheme functions
| `ly:pitch-diff` | 4. Scheme functions
| `ly:pitch-negate` | 4. Scheme functions
| `ly:pitch-notename` | 4. Scheme functions
| `ly:pitch-octave` | 4. Scheme functions
| `ly:pitch-quartertones` | 4. Scheme functions
| `ly:pitch-semitones` | 4. Scheme functions
| `ly:pitch-steps` | 4. Scheme functions
| `ly:pitch-transpose` | 4. Scheme functions
| `ly:pitch<?` | 4. Scheme functions
| `ly:pitch?` | 4. Scheme functions
| `ly:position-on-line?` | 4. Scheme functions
| `ly:prob-immutable-properties` | 4. Scheme functions
| `ly:prob-mutable-properties` | 4. Scheme functions
| `ly:prob-property` | 4. Scheme functions
| `ly:prob-property?` | 4. Scheme functions
| `ly:prob-set-property!` | 4. Scheme functions
| `ly:prob-type?` | 4. Scheme functions
| `ly:prob?` | 4. Scheme functions
| `ly:programming-error` | 4. Scheme functions
| `ly:progress` | 4. Scheme functions
| `ly:property-lookup-stats` | 4. Scheme functions
| `ly:protects` | 4. Scheme functions
| `ly:pt` | 4. Scheme functions
| `ly:register-stencil-expression` | 4. Scheme functions
| `ly:relative-group-extent` | 4. Scheme functions
| `ly:reset-all-fonts` | 4. Scheme functions
| `ly:round-filled-box` | 4. Scheme functions
| `ly:round-filled-polygon` | 4. Scheme functions
| `ly:run-translator` | 4. Scheme functions
| `ly:score-add-output-def!` | 4. Scheme functions
| `ly:score-embedded-format` | 4. Scheme functions
| `ly:score-error?` | 4. Scheme functions
| `ly:score-header` | 4. Scheme functions
| `ly:score-music` | 4. Scheme functions
| `ly:score-output-defs` | 4. Scheme functions
| `ly:score-set-header!` | 4. Scheme functions
| `ly:score?` | 4. Scheme functions
| `ly:set-default-scale` | 4. Scheme functions
| `ly:set-grob-modification-callback` | 4. Scheme functions
| `ly:set-middle-C!` | 4. Scheme functions
| `ly:set-option` | 4. Scheme functions
| `ly:set-property-cache-callback` | 4. Scheme functions
| `ly:simple-closure?` | 4. Scheme functions
| `ly:skyline-pair?` | 4. Scheme functions
| `ly:skyline?` | 4. Scheme functions
| `ly:smob-protects` | 4. Scheme functions
| `ly:solve-spring-rod-problem` | 4. Scheme functions
| `ly:source-file?` | 4. Scheme functions
| `ly:spanner-bound` | 4. Scheme functions
| `ly:spanner-broken-into` | 4. Scheme functions
| `ly:spanner?` | 4. Scheme functions
| `ly:staff-symbol-line-thickness` | 4. Scheme functions
| `ly:start-environment` | 4. Scheme functions
| `ly:stderr-redirect` | 4. Scheme functions
| `ly:stencil-add` | 4. Scheme functions
| `ly:stencil-aligned-to` | 4. Scheme functions
| `ly:stencil-combine-at-edge` | 4. Scheme functions
| `ly:stencil-empty?` | 4. Scheme functions
| `ly:stencil-expr` | 4. Scheme functions
| `ly:stencil-extent` | 4. Scheme functions
| `ly:stencil-fonts` | 4. Scheme functions
| `ly:stencil-in-color` | 4. Scheme functions
| `ly:stencil-rotate` | 4. Scheme functions
| `ly:stencil-rotate-absolute` | 4. Scheme functions
| `ly:stencil-translate` | 4. Scheme functions
| `ly:stencil-translate-axis` | 4. Scheme functions
| `ly:stencil?` | 4. Scheme functions
| `ly:stream-event?` | 4. Scheme functions
| `ly:string-substitute` | 4. Scheme functions
| `ly:system-font-load` | 4. Scheme functions
| `ly:system-print` | 4. Scheme functions
| `ly:system-stretch` | 4. Scheme functions
| `ly:text-dimension` | 4. Scheme functions
| `ly:text-interface::interpret-markup` | 4. Scheme functions
| `ly:translator-description` | 4. Scheme functions
| `ly:translator-group?` | 4. Scheme functions
| `ly:translator-name` | 4. Scheme functions
| `ly:translator?` | 4. Scheme functions
| `ly:transpose-key-alist` | 4. Scheme functions
| `ly:truncate-list!` | 4. Scheme functions
| `ly:ttf->pfa` | 4. Scheme functions
| `ly:ttf-ps-name` | 4. Scheme functions
| `ly:unit` | 4. Scheme functions
| `ly:usage` | 4. Scheme functions
| `ly:version` | 4. Scheme functions
| `ly:warning` | 4. Scheme functions
| `ly:wide-char->utf-8` | 4. Scheme functions

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where the Example assumes that the current position is at Subsubsection One-Two-Three of a document of the following structure:

- 1. Section One
  - 1.1 Subsection One-One
    - ...
  - 1.2 Subsection One-Two
    - 1.2.1 Subsubsection One-Two-One
    - 1.2.2 Subsubsection One-Two-Two
    - 1.2.3 Subsubsection One-Two-Three <== Current Position
    - 1.2.4 Subsubsection One-Two-Four
  - 1.3 Subsection One-Three
    - ...
  - 1.4 Subsection One-Four

#### Internals Reference