Warning: This is the manual of the legacy Guile 2.2 series. You may want to read the manual of the current stable series instead.
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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 Symbol Read Syntax), 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).
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 Scheme Read. 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)