Marco Maggi <marco.maggi-i...@poste.it> writes:
> #!r6rs
> (import (rnrs))
> (define (alpha)
> (define-syntax define-special
> (syntax-rules ()
> ((_ ?who ?val)
> (define ?who ?val))))
> (define-special beta #t)
> #f)
> (alpha)
>
> should succeed, but instead it fails with:
[...]
> /home/marco/var/tmp/proof.sps:12:2: definition in expression context,
> where definitions are not allowed, in form (define beta #t)
I've attached two patches for stable-2.0. The second patch fixes this
bug. The first patch is for an unrelated bug that I discovered during
my investigation.
Reviews solicited, otherwise I'll commit these in a week or so.
Mark
>From 2b8587d090d13f044f3cc4d221e832a655dcc1cd Mon Sep 17 00:00:00 2001
From: Mark H Weaver <m...@netris.org>
Date: Wed, 23 Jan 2013 17:27:50 -0500
Subject: [PATCH 1/2] Fix source annotation bug in psyntax 'expand-body'.
* module/ice-9/psyntax.scm (expand-body): Apply source-annotation to an
expression, not to the expression's compile-time environment.
* module/ice-9/psyntax-pp.scm: Regenerate.
---
module/ice-9/psyntax-pp.scm | 2 +-
module/ice-9/psyntax.scm | 2 +-
2 files changed, 2 insertions(+), 2 deletions(-)
diff --git a/module/ice-9/psyntax-pp.scm b/module/ice-9/psyntax-pp.scm
index 5dfa8c0..139c02b 100644
--- a/module/ice-9/psyntax-pp.scm
+++ b/module/ice-9/psyntax-pp.scm
@@ -976,7 +976,7 @@
(let ((e (cdar body)) (er (caar body)))
(call-with-values
(lambda ()
- (syntax-type e er '(()) (source-annotation er) ribcage mod #f))
+ (syntax-type e er '(()) (source-annotation e) ribcage mod #f))
(lambda (type value form e w s mod)
(let ((key type))
(cond ((memv key '(define-form))
diff --git a/module/ice-9/psyntax.scm b/module/ice-9/psyntax.scm
index d41a0eb..4abd3c9 100644
--- a/module/ice-9/psyntax.scm
+++ b/module/ice-9/psyntax.scm
@@ -1457,7 +1457,7 @@
(syntax-violation #f "no expressions in body" outer-form)
(let ((e (cdar body)) (er (caar body)))
(call-with-values
- (lambda () (syntax-type e er empty-wrap (source-annotation er) ribcage mod #f))
+ (lambda () (syntax-type e er empty-wrap (source-annotation e) ribcage mod #f))
(lambda (type value form e w s mod)
(case type
((define-form)
--
1.7.10.4
>From 20e2db39b23dfd27c92cfbdd831e91eb3e2880a5 Mon Sep 17 00:00:00 2001
From: Mark H Weaver <m...@netris.org>
Date: Wed, 23 Jan 2013 17:49:38 -0500
Subject: [PATCH 2/2] Do not defer expansion of internal define-syntax forms.
* module/ice-9/psyntax.scm (expand-body): As required by R6RS, expand
the right-hand-sides of internal 'define-syntax' forms and add their
transformers to the compile-time environment immediately, so that the
newly-defined keywords may be used in definition context within the
same lexical contour. Fixes #13509.
---
module/ice-9/psyntax-pp.scm | 29 ++++++++++-------------------
module/ice-9/psyntax.scm | 36 +++++++++++++++---------------------
2 files changed, 25 insertions(+), 40 deletions(-)
diff --git a/module/ice-9/psyntax-pp.scm b/module/ice-9/psyntax-pp.scm
index 139c02b..a0d338c 100644
--- a/module/ice-9/psyntax-pp.scm
+++ b/module/ice-9/psyntax-pp.scm
@@ -991,15 +991,17 @@
(cons (cons er (wrap e w mod)) vals)
(cons (cons 'lexical var) bindings)))))
((memv key '(define-syntax-form define-syntax-parameter-form))
- (let ((id (wrap value w mod)) (label (gen-label)))
+ (let ((id (wrap value w mod))
+ (label (gen-label))
+ (trans-r (macros-only-env er)))
(extend-ribcage! ribcage id label)
- (parse (cdr body)
- (cons id ids)
- (cons label labels)
- var-ids
- vars
- vals
- (cons (cons 'macro (cons er (wrap e w mod))) bindings))))
+ (set-cdr!
+ r
+ (extend-env
+ (list label)
+ (list (cons 'macro (eval-local-transformer (expand e trans-r w mod) mod)))
+ (cdr r)))
+ (parse (cdr body) (cons id ids) labels var-ids vars vals bindings)))
((memv key '(begin-form))
(let* ((tmp-1 e) (tmp ($sc-dispatch tmp-1 '(_ . each-any))))
(if tmp
@@ -1049,17 +1051,6 @@
#f
"invalid or duplicate identifier in definition"
outer-form))
- (let loop ((bs bindings) (er-cache #f) (r-cache #f))
- (if (not (null? bs))
- (let ((b (car bs)))
- (if (eq? (car b) 'macro)
- (let* ((er (cadr b))
- (r-cache (if (eq? er er-cache) r-cache (macros-only-env er))))
- (set-cdr!
- b
- (eval-local-transformer (expand (cddr b) r-cache '(()) mod) mod))
- (loop (cdr bs) er r-cache))
- (loop (cdr bs) er-cache r-cache)))))
(set-cdr! r (extend-env labels bindings (cdr r)))
(build-letrec
#f
diff --git a/module/ice-9/psyntax.scm b/module/ice-9/psyntax.scm
index 4abd3c9..980db80 100644
--- a/module/ice-9/psyntax.scm
+++ b/module/ice-9/psyntax.scm
@@ -1470,13 +1470,22 @@
(cons var vars) (cons (cons er (wrap e w mod)) vals)
(cons (make-binding 'lexical var) bindings)))))
((define-syntax-form define-syntax-parameter-form)
- (let ((id (wrap value w mod)) (label (gen-label)))
+ (let ((id (wrap value w mod))
+ (label (gen-label))
+ (trans-r (macros-only-env er)))
(extend-ribcage! ribcage id label)
- (parse (cdr body)
- (cons id ids) (cons label labels)
- var-ids vars vals
- (cons (make-binding 'macro (cons er (wrap e w mod)))
- bindings))))
+ ;; As required by R6RS, expand the right-hand-sides of internal
+ ;; syntax definition forms and add their transformers to the
+ ;; compile-time environment immediately, so that the newly-defined
+ ;; keywords may be used in definition context within the same
+ ;; lexical contour.
+ (set-cdr! r (extend-env (list label)
+ (list (make-binding 'macro
+ (eval-local-transformer
+ (expand e trans-r w mod)
+ mod)))
+ (cdr r)))
+ (parse (cdr body) (cons id ids) labels var-ids vars vals bindings)))
((begin-form)
(syntax-case e ()
((_ e1 ...)
@@ -1507,21 +1516,6 @@
(syntax-violation
#f "invalid or duplicate identifier in definition"
outer-form))
- (let loop ((bs bindings) (er-cache #f) (r-cache #f))
- (if (not (null? bs))
- (let* ((b (car bs)))
- (if (eq? (car b) 'macro)
- (let* ((er (cadr b))
- (r-cache
- (if (eq? er er-cache)
- r-cache
- (macros-only-env er))))
- (set-cdr! b
- (eval-local-transformer
- (expand (cddr b) r-cache empty-wrap mod)
- mod))
- (loop (cdr bs) er r-cache))
- (loop (cdr bs) er-cache r-cache)))))
(set-cdr! r (extend-env labels bindings (cdr r)))
(build-letrec no-source #t
(reverse (map syntax->datum var-ids))
--
1.7.10.4
