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Using environment-bound? in macro definitions
- From: Duncan Mak <duncanmak at gmail dot com>
- To: kawa mailing list <kawa at sourceware dot org>
- Date: Mon, 2 Jan 2017 18:29:59 -0500
- Subject: Using environment-bound? in macro definitions
- Authentication-results: sourceware.org; auth=none
Hello,
Here's a stripped down version of two define-form macros that I'm working on:
(require 'syntax-utils)
(define-for-syntax known (list))
(define-syntax define-foo
(lambda (stx)
(syntax-case stx ()
((define-foo a)
(begin
(set! known (cons #'a known))
#'(define a (list)))))))
(define-syntax define-bar
(lambda (stx)
(syntax-case stx ()
((define-bar a n)
(if (environment-bound? (apply environment known) #'a)
#'(set! a (cons n a))
#'(begin
(define-foo a)
(set! a (cons n a))))))))
;; (1) should expand to (define x (list)) and store x in known
(define-foo x)
;; (2) should expand to (set! x (cons 1 x)) since x was previously
;; defined (i.e. can be found in known)
(define-bar x 1)
;; (3) should expand to (begin (define-foo y) (set! y (cons 2 y)))
;; because y is not previous defined
(define-bar y 2)
When I try to run it, I get
test.scm:29:1: evaluating syntax transformer 'define-bar' threw
gnu.text.SyntaxException: <unknown>: unknown library (x)
I must be doing something wrong, is this the right approach?
Thanks!
--
Duncan.