3.8 Keywords

Keywords in Guide: PLT Scheme 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.

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

(keyword? v) → boolean?

v : any/c

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

(keyword->string keyword) → string?

keyword : keyword?

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

(string->keyword str) → keyword

str : string?

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

(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<?.