From: Matt Wette <matt.wette@gmail.com>
To: Guile User <guile-user@gnu.org>
Subject: problems with syntax-case and with-syntax
Date: Sun, 27 Aug 2017 13:18:20 -0700 [thread overview]
Message-ID: <B474A728-F731-44FF-8CD0-A1BF5AFAF43B@gmail.com> (raw)
Q1) The code below creates two macros. One called `define-foo' which generates a new identifier and
then defines that to #t. The other, `define-foo/p', generates the same identifier (lexical issue?)
and another identifier, then "calls" define-foo and then uses both identifiers in a `define'. When
executed I get this error:
scheme@(guile-user)> (define-foo/p abc)
;;; <stdin>:2:0: warning: possibly unbound variable `wrap-abc'
<unnamed port>:2:0: <unnamed port>:2:0: In procedure module-lookup: Unbound variable: wrap-abc
What am I doing wrong here?
Q2) Also with respect to the code below. Is there any way to pull the definitions for stx->str
and gen-id out of the define-syntax body to make them general purpose?
This code being developed under guile-2.2.2.
The code:
(define-syntax define-foo
(lambda (x)
(define (stx->str stx)
(symbol->string (syntax->datum stx)))
(define (gen-id tmpl-id . args)
(datum->syntax
tmpl-id
(string->symbol
(apply string-append
(map (lambda (ss) (if (string? ss) ss (stx->str ss))) args)))))
(syntax-case x ()
((_ name)
(with-syntax ((wrap (gen-id x "wrap-" #'name)))
#'(begin
(define wrap #t)))))))
(define-syntax define-foo/p
(lambda (x)
(define (stx->str stx)
(symbol->string (syntax->datum stx)))
(define (gen-id tmpl-id . args)
(datum->syntax
tmpl-id
(string->symbol
(apply string-append
(map (lambda (ss) (if (string? ss) ss (stx->str ss))) args)))))
(syntax-case x ()
((_ name)
(with-syntax ((wrap (gen-id x "wrap-" #'name))
(rewrap (gen-id x "rewrap-" #'name)))
#'(begin
(define-foo name)
(define rewrap wrap)))))))
;;(define-foo/p abc)
;; expect:
;; (define wrap-abc #t)
;; (define rewrap-abc wrap-abc)
;;(define-foo abc) ;; works (but does not define rewrap-abc
;; expect:
;; (define wrap-abc #t)
Thanks for the help,
Matt
next reply other threads:[~2017-08-27 20:18 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-08-27 20:18 Matt Wette [this message]
2017-08-28 0:36 ` problems with syntax-case and with-syntax Mark H Weaver
2017-08-28 1:35 ` Mark H Weaver
2017-09-18 13:16 ` Matt Wette
2017-09-20 12:50 ` Matt Wette
2017-08-28 3:48 ` Matt Wette
2017-08-28 3:50 ` Matt Wette
2017-08-28 11:38 ` Chris Vine
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