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define-syntax
From: |
Ludovic Courtès |
Subject: |
define-syntax |
Date: |
Tue, 15 Jun 2010 22:48:46 +0200 |
User-agent: |
Gnus/5.13 (Gnus v5.13) Emacs/23.2 (gnu/linux) |
Hello,
>From R6RS Section 10:
define-syntax form The expander expands and evaluates the
right-hand-side expression and binds the keyword to the resulting
transformer.
Thus I think the following should work:
(define-syntax +
(let ((plus +)) ;; `+' should resolve to whatever `+' is bound to
;; before this definition
(lambda (stx)
(syntax-case stx ()
((_ args ...)
(apply plus (map syntax->datum #'(args ...))))))))
But it fails when expanding the macro:
scheme@(guile-user)> (+ 2 3)
Throw to key `wrong-type-arg':
ERROR: In procedure vm-debug-engine:
ERROR: Wrong type to apply: #<syntax-transformer +>
Thoughts?
Thanks,
Ludo’.
- define-syntax,
Ludovic Courtès <=