Batteries user guide : Batteries.ParserCo

# Module Batteries.ParserCo

    module ParserCo: BatParserCo

###### Base definitions

    type 'a state =

`|` | `Eof` | `(*` | The end of the source has been reached. | `*)`
`|` | `State of `'a``

The current state of the parser.

The actual set of states is defined by the user. States are typically used to convey informations, such as position in the file (i.e. line number and character).

    type 'a report =

`|` | `Report of `('a state * string * 'a report) list`` | `(*` | The final result of parsing | `*)`

    module Source: sig .. end

A source for parsing.

###### Primitives

    type ('a, 'b, 'c) t

A parser for elements of type `'a`, producing elements of type `'b`, with user-defined states of type `'c`.

    val eof : ('a, unit, 'b) t

Accept the end of an enumeration.

    val either : ('a, 'b, 'c) t list -> ('a, 'b, 'c) t

Accept one of several parsers.

    val (<|>) : ('a, 'b, 'c) t ->
           ('a, 'b, 'c) t -> ('a, 'b, 'c) t

Accept one of two parsers

    val maybe : ('a, 'b, 'c) t -> ('a, 'b option, 'c) t

Accept an optional argument.

    val (~?) : ('a, 'b, 'c) t -> ('a, 'b option, 'c) t

As `maybe`

    val bind : ('a, 'b, 'c) t ->
           ('b -> ('a, 'd, 'c) t) -> ('a, 'd, 'c) t

Monadic-style combination:

`bind p f` results in a new parser which behaves as `p` then, in case of success, applies `f` to the result.

    val (>>=) : ('a, 'b, 'c) t ->
           ('b -> ('a, 'd, 'c) t) -> ('a, 'd, 'c) t

As `bind`

    val (>>>) : ('a, 'b, 'c) t ->
           ('a, 'd, 'c) t -> ('a, 'd, 'c) t

As `bind`, but ignoring the result

    val cons : ('a, 'b, 'c) t ->
           ('a, 'b list, 'c) t -> ('a, 'b list, 'c) t

`cons p q` applies parser `p` then parser `q` and conses the results into a list.

    val (>::) : ('a, 'b, 'c) t ->
           ('a, 'b list, 'c) t -> ('a, 'b list, 'c) t

As `cons`

    val label : string -> ('a, 'b, 'c) t -> ('a, 'b, 'c) t

Give a name to a parser, for debugging purposes.

    val state : ('a, 'b state, 'b) t

Succeed and return the state of the parser

    val any : ('a, 'a, 'b) t

Accept any singleton value.

    val return : 'b -> ('a, 'b, 'c) t

A parser which always succeds

    val satisfy : ('a -> bool) -> ('a, 'a, 'b) t

`satisfy p` accepts one value `p x` such that `p x = true`

    val filter : ('b -> bool) -> ('a, 'b, 'c) t -> ('a, 'b, 'c) t

`filter f p` is only accepts values `x` such that `p` accepts `x` and `f (p x)` is `true`

    val suspend : ('a, 'b, 'c) t ->
           ('a, unit -> ('b, 'c report) BatPervasives.result, 'c)
           t

`suspend s` returns the state of the parser in a form that can be resumed by calling the returned function. evaluation will resume from parser s

    val run : ('a, 'b, 'c) t ->
           ('a, 'c) Source.t ->
           ('b, 'c report) BatPervasives.result

`run p s` executes parser `p` on source `s`. In case of success, returns `Ok v`, where `v` is the return value of `p`. In case of failure, returns `Bad f`, with `f` containing details on the parsing error.

    val fail : ('a, 'b, 'c) t

Always fail, without consuming anything.

    val fatal : ('a, 'b, 'c) t

    val lookahead : ('a, 'b, 'c) t -> ('a, 'b option, 'c) t

`lookahead p` behaves as `maybe p` but without consuming anything

###### Utilities

Singletons

    val exactly : 'a -> ('a, 'a, 'c) t

Accept exactly one singleton.

    val one_of : 'a list -> ('a, 'a, 'c) t

Accept one of several values. Faster and more convenient than combining `satisfy` and `either`.

    val none_of : 'a list -> ('a, 'a, 'c) t

Accept any value not in a list Faster and more convenient than combining `satisfy` and `either`.

    val range : 'a -> 'a -> ('a, 'a, 'c) t

Accept any element from a given range.
Repetitions

    val zero_plus : ?sep:('a, 'd, 'c) t ->
           ('a, 'b, 'c) t -> ('a, 'b list, 'c) t

Accept a (possibly empty) list of expressions.

    val ignore_zero_plus : ?sep:('a, 'b, 'c) t ->
           ('a, 'd, 'c) t -> ('a, unit, 'c) t

Ignore a (possibly empty) list of expressions. Optimized version of `zero_plus`, for use when the list of expressions is unimportant.

    val ( ~* ) : ('a, 'b, 'c) t -> ('a, 'b list, 'c) t

As `zero_plus` without arguments.

    val one_plus : ?sep:('a, 'd, 'c) t ->
           ('a, 'b, 'c) t -> ('a, 'b list, 'c) t

Accept a (non-empty) list of expressions

    val ignore_one_plus : ?sep:('a, 'b, 'c) t ->
           ('a, 'd, 'c) t -> ('a, unit, 'c) t

Ignore a (non-empty) list of expressions. Optimized version of `one_plus`, for use when the list of expressions is unimportant.

    val (~+) : ('a, 'b, 'c) t -> ('a, 'b list, 'c) t

As `one_plus`

    val times : int -> ('a, 'b, 'c) t -> ('a, 'b list, 'c) t

`times n p` accepts a list of `n` expressions accepted by `p`

    val (^^) : ('a, 'b, 'c) t -> int -> ('a, 'b list, 'c) t

`p ^^ n` is the same thing as `times n p`

    val must : ('a, 'b, 'c) t -> ('a, 'b, 'c) t

Prevent backtracking.

    val should : ('a, 'b, 'c) t -> ('a, 'b, 'c) t

Prevent backtracking.
Maps

    val post_map : ('b -> 'c) -> ('a, 'b, 'd) t -> ('a, 'c, 'd) t

Pass the (successful) result of some parser through a map.

    val source_map : ('a, 'b, 'c) t ->
           ('a, 'c) Source.t -> ('b, 'c) Source.t

    val scan : ('a, 'b, 'c) t -> ('a, 'a list, 'c) t

Use a parser to extract list of tokens, but return that list of tokens instead of whatever the original parser returned.
Others

    val sat : ('a -> bool) -> ('a, unit, 'b) t

`satisfy p` accepts one value `p x` such that `p x = true`

    val debug_mode : bool Pervasives.ref

If set to `true`, debugging information will be printed to the standard error.

    module Infix: sig .. end

Infix submodule regrouping all infix operators