Keywords are similar to symbols. They are used mainly for specifying keyword arguments.

Historically keywords have been self-evaluating (you did not need to quote them). This is changing: you should quote a keyword if you want a literal keyword value, and not quote it if it is used with a keyword argument. (This change is a work-in-progress.)

keyword ::= identifier:

A keyword is a single token; therefore no whitespace is allowed between the identifier and the colon (which is not considered part of the name of the keyword).

Procedure: keyword? obj

Return #t if obj is a keyword, and otherwise returns #f.

Procedure: keyword->string keyword

Returns the name of keyword as a string. The name does not include the final #\:.

Procedure: string->keyword string

Returns the keyword whose name is string. (The string does not include a final #\:.)