2.3 Literals: quote and #%datum

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▼ | 2 | Syntactic Forms

2.1 | Modules: module, module*, ...
2.2 | Importing and Exporting: require and provide
2.3 | Literals: quote and #%datum
2.4 | Expression Wrapper: #%expression
2.5 | Variable References and #%top
2.6 | Locations: #%variable-reference
2.7 | Procedure Applications and #%app
2.8 | Procedure Expressions: lambda and case-lambda
2.9 | Local Binding: let, let*, letrec, ...
2.10 | Local Definitions: local
2.11 | Constructing Graphs: shared
2.12 | Conditionals: if, cond, and, and or
2.13 | Dispatch: case
2.14 | Definitions: define, define-syntax, ...
2.15 | Sequencing: begin, begin0, and begin-for-syntax
2.16 | Guarded Evaluation: when and unless
2.17 | Assignment: set! and set!-values
2.18 | Iterations and Comprehensions: for, for/ list, ...
2.19 | Continuation Marks: with-continuation-mark
2.20 | Quasiquoting: quasiquote, unquote, and unquote-splicing
2.21 | Syntax Quoting: quote-syntax
2.22 | Interaction Wrapper: #%top-interaction
2.23 | Blocks: block
2.24 | Internal-Definition Limiting: #%stratified-body
2.25 | Performance Hints: begin-encourage-inline
2.26 | Importing Modules Lazily: lazy-require

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quote
#%datum

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#### 2.3`` Literals: quote and #%datum

Many forms are implicitly quoted (via #%datum) as literals. See Expansion Steps for more information.

> > > Quoting: quote and ' in The Racket Guide introduces quote.

> syntax (quote datum)

Produces a constant value corresponding to datum (i.e., the representation of the program fragment) without its lexical information, source location, etc. Quoted pairs, vectors, and boxes are immutable.

Examples:
> > (quote x)
> 'x
> > (quote (+ 1 2))
> '(+ 1 2)
> > (+ 1 2)
> 3

> syntax (#%datum . datum)

Expands to (quote datum), as long as datum is not a keyword. If datum is a keyword, a syntax error is reported.

See also Expansion Steps for information on how the expander introduces #%datum identifiers.

Examples:
> > (#%datum . 10)
> 10
> > (#%datum . x)
> 'x
> > (#%datum . #:x)
> eval:6:0: #%datum: keyword used as an expression
> in: #:x

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