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Re: cond clause does not allow definitions
From: |
Damien Mattei |
Subject: |
Re: cond clause does not allow definitions |
Date: |
Thu, 23 May 2024 00:09:53 +0200 |
in the version below it seems that else in cond with definition works alone
but not when there is other conditions before:
GNU Guile 3.0.8.99-f3ea8
Copyright (C) 1995-2022 Free Software Foundation, Inc.
Guile comes with ABSOLUTELY NO WARRANTY; for details type `,show w'.
This program is free software, and you are welcome to redistribute it
under certain conditions; type `,show c' for details.
Enter `,help' for help.
scheme@(guile-user)> (cond (else (define x 7) x))
$1 = 7
scheme@(guile-user)> (cond (#f 'never) (else (define x 7) x))
While compiling expression:
Syntax error:
unknown file:2:24: definition in expression context, where definitions are
not allowed, in form (define x 7)
i understand that because in my code, that i can not write all here, i
had to change:
#`(cond (#,test (let ()
#,@L-then))
(else
#,@L-else)))
#`(cond (#,test (let ()
#,@L-then))
(else
(let ()
#,@L-else))))
add a (let () in the else of cond too to encapsulate the possible
definitions in #,@L-else
now i understand that and it is late here...
good night
On Wed, May 22, 2024 at 11:08 PM Pierpaolo Bernardi <olopierpa@gmail.com>
wrote:
> On Wed, May 22, 2024 at 10:08 PM Jeronimo Pellegrini <j_p@aleph0.info>
> wrote:
>
> > A: (cond (#t (define x 7) x))
> > B: (cond (else (define x 7) x))
> >
> > | system | A | B |
> > |-------------|-------|-------|
> > | Bigloo | 7 | 7 |
> > | Biwa | 7 | 7 |
> > | Chez | error | 7 |
> > | Chibi | error | 7 |
>
> In chez:
>
> > (cond (else (define x 7) x))
> 7
> > x
> 7
>
> which looks like a bug to me. You may check if x is defined outside of
> the cond expression in the other implementations which do not raise an
> error too?
>
RE: cond clause does not allow definitions, Maxime Devos, 2024/05/22
Re: cond clause does not allow definitions, Linus Björnstam, 2024/05/24