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[PATCH] Fix error messages involving internal definitions
|
From: |
Mark H Weaver |
|
Subject: |
[PATCH] Fix error messages involving internal definitions |
|
Date: |
Fri, 27 Jan 2012 02:26:13 -0500 |
Hi Andy,
I know this is very last minute, but it would be great if you could
include this fix in 2.0.4. Since the release is so close, I was _very_
careful writing it and testing it, and am quite confident that it is
correct. (After regenerating psyntax-pp.scm, I removed all .go files,
recompiled everything, and did a 'make check'. I also did several other
tests by hand targetting the changed code.)
I very nearly pushed this, but I know that you are very opinionated
about psyntax changes, and this fix did require adding another parameter
to 'expand-expr' and another return value to 'syntax-type', so I wanted
to run it by you. Unless you object to the basic strategy here, please
take my word for it that it is correct, and push it.
So, what does this fix? The "definition in expression context" error
message is broken in several ways. First of all, source location
information is _never_ provided, even when compiling a module in the
normal way. Secondly, instead of printing the definition form, it
reports the identifier as the 'subform', and the rhs expression as the
'form'. Thirdly, "definition in expression context" is a confusing
message for Scheme beginners, who are likely to make this mistake.
This came up because Bruce Korb recently posted here, quite confused
(and understandably so) about what could be the cause of this misleading
error message.
For example, if you try to compile a module containing:
(let ((x 1))
#f
(define blah 3))
Currently, you get a message like this:
unknown location: definition in expression context in subform blah of 3
With this patch, you get a message like this:
/home/mhw/guile-modules/foo.scm:5:2: internal definition in a context where
definitions are not allowed in form (define blah 3)
Okay, here's the patch, with the syntax-pp.scm portion removed.
Mark
>From 278aed1c13ba183458a9e4cd6ec66df1dadf98c9 Mon Sep 17 00:00:00 2001
From: Mark H Weaver <address@hidden>
Date: Thu, 26 Jan 2012 23:55:24 -0500
Subject: [PATCH] Fix error messages involving internal definitions
* module/ice-9/psyntax.scm (syntax-type): Return an additional value
that contains the entire form in _all_ cases, including for definition
forms. Previously, the entire form was not returned for definition
forms.
(expand-expr): Add an additional argument that contains the entire
form in _all_ cases, including for definition forms. Use it to
include the entire form in the error message for internal definitions
in contexts where they are not allowed, and improve the error message
to be more comprehensible for Scheme beginners. Also include the
source location information, which was previously missing from the
error message.
(expand-top-sequence, expand, expand-body): Receive the additional
return value from 'syntax-type'.
* module/ice-9/psyntax-pp.scm: Regenerate.
* NEWS: Add news entry.
---
NEWS | 1 +
module/ice-9/psyntax-pp.scm |12980 ++++++++++++++++++++++---------------------
module/ice-9/psyntax.scm | 75 +-
3 files changed, 6587 insertions(+), 6469 deletions(-)
diff --git a/NEWS b/NEWS
index ad0910c..5a74fc9 100644
--- a/NEWS
+++ b/NEWS
@@ -173,6 +173,7 @@ Search the manual for these identifiers and modules, for
more.
** Fix <dynwind> serialization.
** Fix erroneous check in `set-procedure-properties!'.
** Fix generalized-vector-{ref,set!} for slices.
+** Fix error messages involving internal definitions.
** HTTP: Extend handling of "Cache-Control" header.
** HTTP: Fix qstring writing of cache-extension values
** HTTP: Fix validators for various list-style headers.
diff --git a/module/ice-9/psyntax.scm b/module/ice-9/psyntax.scm
index 20ea8eb..9812f3a 100644
--- a/module/ice-9/psyntax.scm
+++ b/module/ice-9/psyntax.scm
@@ -982,7 +982,7 @@
(lambda ()
(let ((e (car body)))
(syntax-type e r w (or (source-annotation e) s) #f
mod #f)))
- (lambda (type value e w s mod)
+ (lambda (type value form e w s mod)
(case type
((begin-form)
(syntax-case e ()
@@ -1079,18 +1079,20 @@
exps)))
((displaced-lexical)
(syntax-violation #f "identifier out of context"
- e (wrap value w mod)))
+ (source-wrap form w s mod)
+ (wrap value w mod)))
(else
(syntax-violation #f "cannot define keyword at
top level"
- e (wrap value w mod))))))
+ (source-wrap form w s mod)
+ (wrap value w mod))))))
(else
(values (cons
(if (eq? m 'c&e)
- (let ((x (expand-expr type value e r w s
mod)))
+ (let ((x (expand-expr type value form e
r w s mod)))
(top-level-eval-hook x mod)
x)
(lambda ()
- (expand-expr type value e r w s mod)))
+ (expand-expr type value form e r w s
mod)))
exps)))))))
(lambda (exps)
(scan (cdr body) r w s m esew mod exps))))))
@@ -1132,8 +1134,8 @@
(syntax-violation 'eval-when "invalid situation" e
(car l))))))))
- ;; syntax-type returns six values: type, value, e, w, s, and mod. The
- ;; first two are described in the table below.
+ ;; syntax-type returns seven values: type, value, form, e, w, s, and
+ ;; mod. The first two are described in the table below.
;;
;; type value explanation
;; -------------------------------------------------------------------
@@ -1162,10 +1164,11 @@
;; constant none self-evaluating datum
;; other none anything else
;;
- ;; For definition forms (define-form, define-syntax-parameter-form,
- ;; and define-syntax-form), e is the rhs expression. For all
- ;; others, e is the entire form. w is the wrap for e. s is the
- ;; source for the entire form. mod is the module for e.
+ ;; form is the entire form. For definition forms (define-form,
+ ;; define-syntax-form, and define-syntax-parameter-form), e is the
+ ;; rhs expression. For all others, e is the entire form. w is the
+ ;; wrap for both form and e. s is the source for the entire form.
+ ;; mod is the module for both form and e.
;;
;; syntax-type expands macros and unwraps as necessary to get to one
;; of the forms above. It also parses definition forms, although
@@ -1179,28 +1182,28 @@
(b (lookup n r mod))
(type (binding-type b)))
(case type
- ((lexical) (values type (binding-value b) e w s mod))
- ((global) (values type n e w s mod))
+ ((lexical) (values type (binding-value b) e e w s mod))
+ ((global) (values type n e e w s mod))
((macro)
(if for-car?
- (values type (binding-value b) e w s mod)
+ (values type (binding-value b) e e w s mod)
(syntax-type (expand-macro (binding-value b) e r w s rib
mod)
r empty-wrap s rib mod #f)))
- (else (values type (binding-value b) e w s mod)))))
+ (else (values type (binding-value b) e e w s mod)))))
((pair? e)
(let ((first (car e)))
(call-with-values
(lambda () (syntax-type first r w s rib mod #t))
- (lambda (ftype fval fe fw fs fmod)
+ (lambda (ftype fval fform fe fw fs fmod)
(case ftype
((lexical)
- (values 'lexical-call fval e w s mod))
+ (values 'lexical-call fval e e w s mod))
((global)
;; If we got here via an (@@ ...) expansion, we need to
;; make sure the fmod information is propagated back
;; correctly -- hence this consing.
(values 'global-call (make-syntax-object fval w fmod)
- e w s mod))
+ e e w s mod))
((macro)
(syntax-type (expand-macro fval e r w s rib mod)
r empty-wrap s rib mod for-car?))
@@ -1209,23 +1212,24 @@
(lambda (e r w s mod)
(syntax-type e r w s rib mod for-car?))))
((core)
- (values 'core-form fval e w s mod))
+ (values 'core-form fval e e w s mod))
((local-syntax)
- (values 'local-syntax-form fval e w s mod))
+ (values 'local-syntax-form fval e e w s mod))
((begin)
- (values 'begin-form #f e w s mod))
+ (values 'begin-form #f e e w s mod))
((eval-when)
- (values 'eval-when-form #f e w s mod))
+ (values 'eval-when-form #f e e w s mod))
((define)
(syntax-case e ()
((_ name val)
(id? #'name)
- (values 'define-form #'name #'val w s mod))
+ (values 'define-form #'name e #'val w s mod))
((_ (name . args) e1 e2 ...)
(and (id? #'name)
(valid-bound-ids? (lambda-var-list #'args)))
;; need lambda here...
(values 'define-form (wrap #'name w mod)
+ (wrap e w mod)
(decorate-source
(cons #'lambda (wrap #'(args e1 e2 ...) w mod))
s)
@@ -1233,38 +1237,39 @@
((_ name)
(id? #'name)
(values 'define-form (wrap #'name w mod)
+ (wrap e w mod)
#'(if #f #f)
empty-wrap s mod))))
((define-syntax)
(syntax-case e ()
((_ name val)
(id? #'name)
- (values 'define-syntax-form #'name #'val w s mod))))
+ (values 'define-syntax-form #'name e #'val w s mod))))
((define-syntax-parameter)
(syntax-case e ()
((_ name val)
(id? #'name)
- (values 'define-syntax-parameter-form #'name #'val w s
mod))))
+ (values 'define-syntax-parameter-form #'name e #'val w s
mod))))
(else
- (values 'call #f e w s mod)))))))
+ (values 'call #f e e w s mod)))))))
((syntax-object? e)
(syntax-type (syntax-object-expression e)
r
(join-wraps w (syntax-object-wrap e))
(or (source-annotation e) s) rib
(or (syntax-object-module e) mod) for-car?))
- ((self-evaluating? e) (values 'constant #f e w s mod))
- (else (values 'other #f e w s mod)))))
+ ((self-evaluating? e) (values 'constant #f e e w s mod))
+ (else (values 'other #f e e w s mod)))))
(define expand
(lambda (e r w mod)
(call-with-values
(lambda () (syntax-type e r w (source-annotation e) #f mod #f))
- (lambda (type value e w s mod)
- (expand-expr type value e r w s mod)))))
+ (lambda (type value form e w s mod)
+ (expand-expr type value form e r w s mod)))))
(define expand-expr
- (lambda (type value e r w s mod)
+ (lambda (type value form e r w s mod)
(case type
((lexical)
(build-lexical-reference 'value s e value))
@@ -1318,8 +1323,8 @@
(expand-sequence #'(e1 e2 ...) r w s mod)
(expand-void))))))
((define-form define-syntax-form define-syntax-parameter-form)
- (syntax-violation #f "definition in expression context"
- e (wrap value w mod)))
+ (syntax-violation #f "internal definition in a context where
definitions are not allowed"
+ (source-wrap form w s mod)))
((syntax)
(syntax-violation #f "reference to pattern variable outside syntax
form"
(source-wrap e w s mod)))
@@ -1463,7 +1468,7 @@
(let ((e (cdar body)) (er (caar body)))
(call-with-values
(lambda () (syntax-type e er empty-wrap
(source-annotation er) ribcage mod #f))
- (lambda (type value e w s mod)
+ (lambda (type value form e w s mod)
(case type
((define-form)
(let ((id (wrap value w mod)) (label (gen-label)))
@@ -2222,7 +2227,7 @@
((_ (head tail ...) val)
(call-with-values
(lambda () (syntax-type #'head r empty-wrap
no-source #f mod #t))
- (lambda (type value ee ww ss modmod)
+ (lambda (type value formform ee ww ss modmod)
(case type
((module-ref)
(let ((val (expand #'val r w mod)))
--
1.7.5.4
- [PATCH] Fix error messages involving internal definitions,
Mark H Weaver <=