From: Stefan Israelsson Tampe <stefan.itampe@gmail.com>
To: 9567@debbugs.gnu.org, Andy Wingo <wingo@pobox.com>
Subject: bug#9567: curious match bug (?)
Date: Wed, 21 Sep 2011 14:15:53 +0200 [thread overview]
Message-ID: <CAGua6m0hYsApL+u=Z67wx4EWBnkcFe6zoBvuou69Vcy42oXDfQ@mail.gmail.com> (raw)
In-Reply-To: <87fwjqin5f.fsf@pobox.com>
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This is an old bug I spotted before, it can be solved by inserting an extra
let
in the expansion aka
(macroexpand '(match a (par code ...))
-> '(let ((arg a)) ....)
This is missing from atoms in match so I added that there and the
missbehavior dissapears. see the git diffed patch in this post.
On Wed, Sep 21, 2011 at 5:34 AM, Andy Wingo <wingo@pobox.com> wrote:
> Hi,
>
> Try this:
>
> (use-modules (language tree-il) (ice-9 match))
> (define foo (parse-tree-il '(let-values (apply (lambda () (lambda-case
> ((() #f #f #f () ()) (apply (primitive values) (const 1) (const 2))))))
> (lambda-case (((a b) #f #f #f () (#{a 134390}# #{b 134391}#)) (apply
> (primitive list) (lexical a #{a 134390}#) (lexical b #{b 134391}#)))))))
> (match foo
> (($ <let-values> src exp
> ($ <lambda-case> src2 req #f #f #f () gensyms body #f))
> #t)
> (_
> #f))
> => #t
>
> (match foo
> (($ <let-values> src foo ;; <- rename "exp" to "foo"
> ($ <lambda-case> src2 req #f #f #f () gensyms body #f))
> #t)
> (_
> #f))
> => #f
>
> I tried to reduce this case a bit, but didn't succeed directly, and I
> need to move on. But what is the deal here?
>
> Andy
> --
> http://wingolog.org/
>
>
>
>
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[-- Attachment #2: match-bug.patch --]
[-- Type: text/x-patch, Size: 869 bytes --]
diff --git a/module/ice-9/match.scm b/module/ice-9/match.scm
index 686539b..0384f69 100644
--- a/module/ice-9/match.scm
+++ b/module/ice-9/match.scm
@@ -57,3 +57,21 @@
;; Note: Make sure to update `match.test.upstream' when updating this
;; file.
(include-from-path "ice-9/match.upstream.scm")
+
+(define-syntax match
+ (syntax-rules ()
+ ((match)
+ (match-syntax-error "missing match expression"))
+ ((match atom)
+ (match-syntax-error "no match clauses"))
+ ((match (app ...) (pat . body) ...)
+ (let ((v (app ...)))
+ (match-next v ((app ...) (set! (app ...))) (pat . body) ...)))
+ ((match #(vec ...) (pat . body) ...)
+ (let ((v #(vec ...)))
+ (match-next v (v (set! v)) (pat . body) ...)))
+ ((match atom (pat . body) ...)
+ (let ((v atom))
+ (match-next v (atom (set! atom)) (pat . body) ...)))
+ ))
+
next prev parent reply other threads:[~2011-09-21 12:15 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-09-21 3:34 bug#9567: curious match bug (?) Andy Wingo
2011-09-21 12:15 ` Stefan Israelsson Tampe [this message]
2011-09-23 14:45 ` Ludovic Courtès
2011-09-23 16:24 ` Stefan Israelsson Tampe
2011-09-24 14:51 ` Andy Wingo
2011-09-24 15:01 ` bug#9567: `match' bug ? Andy Wingo
2011-09-25 6:59 ` Alex Shinn
2011-10-15 14:07 ` Ludovic Courtès
2011-10-16 7:28 ` Alex Shinn
2011-10-16 16:38 ` Ludovic Courtès
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