Guile, by default, only recognizes a keyword syntax that is compatible
with R5RS. A token of the form #:NAME, where NAME has the
same syntax as a Scheme symbol (see Extended Read Syntax for Symbols), is the
external representation of the keyword named NAME. Keyword
objects print using this syntax as well, so values containing keyword
objects can be read back into Guile. When used in an expression,
keywords are self-quoting objects.
If the keywords read option is set to 'prefix, Guile also
recognizes the alternative read syntax :NAME. Otherwise, tokens
of the form :NAME are read as symbols, as required by R5RS.
If the keywords read option is set to 'postfix, Guile
recognizes the SRFI-88 read syntax NAME: (see SRFI-88 Keyword Objects).
Otherwise, tokens of this form are read as symbols.
To enable and disable the alternative non-R5RS keyword syntax, you use
the read-set! procedure documented Reading Scheme Code. Note that
the prefix and postfix syntax are mutually exclusive.
(read-set! keywords 'prefix) #:type ⇒ #:type :type ⇒ #:type (read-set! keywords 'postfix) type: ⇒ #:type :type ⇒ :type (read-set! keywords #f) #:type ⇒ #:type :type -| ERROR: In expression :type: ERROR: Unbound variable: :type ABORT: (unbound-variable)