3.8 Keywords

Keywords in The Racket Guide introduces keywords.

A keyword is like an interned symbol, but its printed form starts with #:, and a keyword cannot be used as an identifier. Furthermore, a keyword by itself is not a valid expression, though a keyword can be quoted to form an expression that produces the symbol.

Two keywords are eq? if and only if they print the same (i.e., keywords are always interned).

Like symbols, keywords are only weakly held by the internal keyword table; see Symbols for more information.

See Reading Keywords for information on reading keywords and Printing Keywords for information on printing keywords.

procedure
(keyword? v) → boolean?
v : any/c

Returns #t if v is a keyword, #f otherwise.

procedure
(keyword->string keyword) → string?
keyword : keyword?

Returns a string for the displayed form of keyword, not including the leading #:.

procedure
(string->keyword str) → keyword?
str : string?

Returns a keyword whose displayed form is the same as that of str, but with a leading #:.

procedure
(keyword<? a-keyword b-keyword ...+) → boolean?
a-keyword : keyword?
b-keyword : keyword?

Returns #t if the arguments are sorted, where the comparison for each pair of keywords is the same as using keyword->string and string<?.

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1	Language Model
2	Syntactic Forms
3	Datatypes
4	Structures
5	Classes and Objects
6	Units
7	Contracts
8	Pattern Matching
9	Control Flow
10	Concurrency and Parallelism
11	Macros
12	Input and Output
13	Reflection and Security
14	Operating System
15	Memory Management
16	Unsafe Operations
17	Running Racket
	Bibliography
	Index

3.1	Booleans and Equality
3.2	Numbers
3.3	Strings
3.4	Byte Strings
3.5	Characters
3.6	Symbols
3.7	Regular Expressions
3.8	Keywords
3.9	Pairs and Lists
3.10	Mutable Pairs and Lists
3.11	Vectors
3.12	Boxes
3.13	Hash Tables
3.14	Sequences and Streams
3.15	Dictionaries
3.16	Sets
3.17	Procedures
3.18	Void and Undefined