This SRFI defines keyword objects, a
data type similar to Scheme symbols. Keyword objects have the same
lexical syntax as symbols but they must end in a colon. Moreover keyword
objects are self-evaluating. Procedures for converting between strings
and keyword objects (string->keyword and
keyword->string) and a type predicate (keyword?) are
defined. Finally this SRFI specifies the changes to the Scheme lexical
syntax required to accomodate keywords.