bug#10992: error signaled for syntax expression

bug#10992: error signaled for syntax expression

[Stefan Israelsson Tampe]

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Hi,

I wanted to enter meta data where the symbols are important into a syntax
object and tried to be smart
in doing that but stumbled on this because loading (a simplified example)
the attached file I get an annoying error e.g.

ERROR: bad src
$7 = #(a (a b) (a (b c) #f))

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[-- Attachment #2: stx-bug.scm --]
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(eval-when (compile load eval)
  (define (syntax->list x)
    (syntax-case x ()
      ((x . l) (cons #'x (stx->list #'l)))
      (()     '()))))

(eval-when (compile load eval)
  (define (my-datum->syntax stx l)
    (datum->syntax 
     stx
     (map (lambda (x) `(quote ,x)) l))))

(define q 1)

(define-syntax f
  (lambda (x)
    #`(vector #,@(my-datum->syntax #'q
                                   '(a (a b) (a (b c) #f))))))


(f 1)

bug#10992: error signaled for syntax expression

[Mark H Weaver]

Stefan Israelsson Tampe <stefan.itampe@gmail.com> writes:

> Hi,
>
>
> I wanted to enter meta data where the symbols are important into a
> syntax object and tried to be smart
> in doing that but stumbled on this because loading (a simplified
> example) the attached file I get an annoying error e.g.
>
> ERROR: bad src
> $7 = #(a (a b) (a (b c) #f))

Fixed in 30398e94f9cadfaff44117bbff214b0b7ba703ca.

   Thanks!
     Mark

bug#10992: patch and fixed test

[Stefan Israelsson Tampe]

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Racket has two versions of syntax-local-binding, one that does lookup of
syntax parameters and one that don't. So it would be interesting to know
why.

Anyway with this mail, there is a patch that enable syntax-local-value to
lookup syntax-parameters
as well.

Also let's fix the test. With the definitions as in the previous mail use
in stead,

(define-syntax info
  (lambda (x)
    (syntax-case x ()
      ((_ f)
        (let-values (((key ret) (syntax-local-binding #'f)))
          (datum->syntax x (eq? ret %f)))))))

and
(info f)                                                       => #t
(fluid-let-syntax ((f (lambda x #'#t))) (info f))  =>  #f

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[-- Attachment #2: resolve-identifier.patch --]
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From 847991d6424ab99009a632bf7561392c52e7704d Mon Sep 17 00:00:00 2001
From: Stefan Israelsson Tampe <stefan.itampe@gmail.com>
Date: Sun, 18 Mar 2012 22:08:39 +0100
Subject: [PATCH] module/ice-9/psyntax.scm (resolve-identifier): enable
 syntax-local-value to lookup syntax-parameters.

---
 module/ice-9/psyntax.scm |    7 +++++++
 1 files changed, 7 insertions(+), 0 deletions(-)

diff --git a/module/ice-9/psyntax.scm b/module/ice-9/psyntax.scm
index 6015eff..4f71764 100644
--- a/module/ice-9/psyntax.scm
+++ b/module/ice-9/psyntax.scm
@@ -843,6 +843,13 @@
           (values (binding-type b) (binding-value b) mod)))
       (let ((n (id-var-name id w)))
         (cond
+         ((assq n r) => (lambda (pb) 
+                          (let ((b (cdr pb)))
+                            (values (binding-type  b)
+                                    (binding-value b)
+                                    (if (syntax-object? id)
+                                        (syntax-object-module id)
+                                        mod)))))
          ((symbol? n)
           (resolve-global n (if (syntax-object? id)
                                 (syntax-object-module id)
-- 
1.7.9