Re: [CM] funny scheme code (fwd)

Re: [CM] funny scheme code (fwd)

[Kjetil S. Matheussen]

---------- Forwarded message ----------
Date: Mon, 20 Jul 2009 21:02:38 +0200 (CEST)
From: Kjetil S. Matheussen <k.s.matheussen@notam02.no>
To: Bill Schottstaedt <bil@ccrma.Stanford.EDU>
Cc: cmdist@ccrma.Stanford.EDU, guile-devel-request@gnu.org
Subject: Re: [CM] funny scheme code



On Mon, 20 Jul 2009, Bill Schottstaedt wrote:

> For some reason, this code strikes me as funny:
>
> (let ((j (lambda () 0))
> 	(k 0))
>  (do ((i (j) (j))
> 	  (j (lambda () 1) (lambda () (+ i 1))))
>          ((= i 3) k)
>     (set! k (+ k i))))
>
> would you believe 6?  Maybe I need a vacation.
>

A slight modifications makes Guile (the one included
with fedora 11) crash:


[kjetil@ttleon bin]$ guile
guile> (let ((j (lambda () 0))
...       (k 0))
...   (do ((i (j)
...           (j))
...        (l (lambda ()
...             1)
...           (lambda ()
...             (+ i 1))))
...       ((= i 3) k)
...     (set! k (+ k i))))
Segmentation fault
[kjetil@ttleon bin]$
[kjetil@ttleon bin]$
[kjetil@ttleon bin]$ guile --version
Guile 1.8.6
Copyright (c) 1995, 1996, 1997, 2000, 2001, 2002, 2003, 2004, 2005, 2006,
2007, 2008 Free Software Foundation
Guile may be distributed under the terms of the GNU General Public
Licence;
certain other uses are permitted as well.  For details, see the file
`COPYING', which is included in the Guile distribution.
There is no warranty, to the extent permitted by law.
[kjetil@ttleon bin]$


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Segfault with do (Re: [CM] funny scheme code (fwd))

[Kjetil S. Matheussen]

On Mon, 20 Jul 2009, Kjetil S. Matheussen wrote:
> A slight modifications makes Guile (the one included
> with fedora 11) crash:
>
>
> [kjetil@ttleon bin]$ guile
> guile> (let ((j (lambda () 0))
> ...       (k 0))
> ...   (do ((i (j)
> ...           (j))
> ...        (l (lambda ()
> ...             1)
> ...           (lambda ()
> ...             (+ i 1))))
> ...       ((= i 3) k)
> ...     (set! k (+ k i))))
> Segmentation fault
> [kjetil@ttleon bin]$
> [kjetil@ttleon bin]$
> [kjetil@ttleon bin]$ guile --version
> Guile 1.8.6

Guile 1.8.0 segfaults as well.

Here's the code ready for pasting:

(let ((j (lambda () 0))
         (k 0))
   (do ((i (j) (j))
           (l (lambda () 1) (lambda () (+ i 1))))
           ((= i 3) k)
      (set! k (+ k i))))

Sorry for not having time debugging it myself right now.

Re: Segfault with do (Re: [CM] funny scheme code (fwd))

[Ludovic Courtès]

Hello Kjetil,

"Kjetil S. Matheussen" <k.s.matheussen@notam02.no> writes:

> Guile 1.8.0 segfaults as well.
>
> Here's the code ready for pasting:
>
> (let ((j (lambda () 0))
>         (k 0))
>   (do ((i (j) (j))
>           (l (lambda () 1) (lambda () (+ i 1))))
>           ((= i 3) k)
>      (set! k (+ k i))))
>
> Sorry for not having time debugging it myself right now.

I added it to the bug tracker: http://savannah.gnu.org/bugs/?27062 .
Please follow-up there (changes are reported to anyone involved and to
`bug-guile').

Also, next time you find a bug, it will be even better if you submit it
to the bug tracker directly.  :-)

Thanks,
Ludo'.

Re: Segfault with do (Re: [CM] funny scheme code (fwd))

[Kjetil S. Matheussen]

Ludovic Court?s:
>
> Hello Kjetil,
>
> "Kjetil S. Matheussen" <k.s.matheussen@notam02.no> writes:
>
>> Guile 1.8.0 segfaults as well.
>>
>> Here's the code ready for pasting:
>>
>> (let ((j (lambda () 0))
>>         (k 0))
>>   (do ((i (j) (j))
>>           (l (lambda () 1) (lambda () (+ i 1))))
>>           ((= i 3) k)
>>      (set! k (+ k i))))
>>
>> Sorry for not having time debugging it myself right now.
>
> I added it to the bug tracker: http://savannah.gnu.org/bugs/?27062 .
> Please follow-up there (changes are reported to anyone involved and to
> `bug-guile').
>
> Also, next time you find a bug, it will be even better if you submit it
> to the bug tracker directly.  :-)
>

Didn't know about the bug tracker. Thanks for the tip. :-)

Re: [CM] funny scheme code (fwd)

[Andy Wingo]

On Mon 20 Jul 2009 21:09, "Kjetil S. Matheussen" <k.s.matheussen@notam02.no> writes:

> On Mon, 20 Jul 2009, Bill Schottstaedt wrote:
>
>> For some reason, this code strikes me as funny:
>>
>> (let ((j (lambda () 0))
>> 	(k 0))
>>  (do ((i (j) (j))
>> 	  (j (lambda () 1) (lambda () (+ i 1))))
>>          ((= i 3) k)
>>     (set! k (+ k i))))

I get an endless loop here, at least with the VM. But I will have to
admit that I never did understand `do' ;-)

Andy
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