[gambit-list] Gambit-C macros
Bob McIsaac
bobmc_net at rogers.com
Sun Aug 26 15:58:00 EDT 2012
Hi:
3 questions...
I'm looking for a "when" macro and tried one patterned on "unless". It
behaves like "when-not". How do I write a proper "when" macro?
(define-syntax when-not
(syntax-rules ()
((when-not test body ...)
(if test #t (begin body ...)))))
(define (test-when n)
(when-not (not (< n 50))
(println "line1 " n)
(println "line2 " n)
(println "line3 " n)))
(test-when 0) (test-when 3) (test-when 55)
;-------------------------------------------
Re "define-syntax" the Gambit-C manual says .."Note that this
implementation of syntax-case does not support special forms that are
specific to Gambit." What are the implications of this statement? Is
there a preferred model for writing Gambit-C macros?
;------------------------------------------------------------
Some code has a "##" prefix like..
(##define-macro (err form)
`(let ()
(##declare (safe) (generic))
(err-form (lambda () ,form))))
Why is that?
=bob=
||
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