* begin oddities
@ 2008-09-24 13:32 Bill Schottstaedt
2008-09-24 23:54 ` Marijn Schouten (hkBst)
0 siblings, 1 reply; 9+ messages in thread
From: Bill Schottstaedt @ 2008-09-24 13:32 UTC (permalink / raw)
To: bug-guile
Is this a bug?
guile> (begin (define x 0) (+ x 1))
1
guile> (lambda () (begin (define x 0) (+ x 1)))
#<procedure #f ()>
guile> (let ((f (lambda () (begin (define x 0) (+ x 1))))) (f))
Backtrace:
In standard input:
3: 0* (let* ((f (lambda () #))) (f))
3: 1 [#<procedure #f ()>]
standard input:3:53: In procedure memoization in expression (f):
standard input:3:53: In file "standard input", line 2: Mixed definitions and expressio
ns in (begin (define x 0) (+ x 1)).
ABORT: (syntax-error)
Also,
guile> (let () (begin . 1))
Segmentation fault (core dumped)
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: begin oddities
2008-09-24 13:32 begin oddities Bill Schottstaedt
@ 2008-09-24 23:54 ` Marijn Schouten (hkBst)
2008-09-25 21:30 ` Neil Jerram
0 siblings, 1 reply; 9+ messages in thread
From: Marijn Schouten (hkBst) @ 2008-09-24 23:54 UTC (permalink / raw)
To: Bill Schottstaedt; +Cc: bug-guile
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Hash: SHA1
Bill Schottstaedt wrote:
> Is this a bug?
>
> guile> (begin (define x 0) (+ x 1))
> 1
>
> guile> (lambda () (begin (define x 0) (+ x 1)))
> #<procedure #f ()>
>
> guile> (let ((f (lambda () (begin (define x 0) (+ x 1))))) (f))
Weird thing is it seems to have no problem with
(let ((f (lambda () (define x 0) (+ x 1)))) (f))
> Backtrace:
> In standard input:
> 3: 0* (let* ((f (lambda () #))) (f))
> 3: 1 [#<procedure #f ()>]
>
> standard input:3:53: In procedure memoization in expression (f):
> standard input:3:53: In file "standard input", line 2: Mixed definitions and expressio
> ns in (begin (define x 0) (+ x 1)).
> ABORT: (syntax-error)
- --
Marijn Schouten (hkBst), Gentoo Lisp project, Gentoo ML
<http://www.gentoo.org/proj/en/lisp/>, #gentoo-{lisp,ml} on FreeNode
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^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: begin oddities
2008-09-24 23:54 ` Marijn Schouten (hkBst)
@ 2008-09-25 21:30 ` Neil Jerram
2008-09-25 22:14 ` Bill Schottstaedt
2008-09-25 22:16 ` Bill Schottstaedt
0 siblings, 2 replies; 9+ messages in thread
From: Neil Jerram @ 2008-09-25 21:30 UTC (permalink / raw)
To: Marijn Schouten (hkBst); +Cc: Bill Schottstaedt, bug-guile
2008/9/25 Marijn Schouten (hkBst) <hkBst@gentoo.org>:
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> Hash: SHA1
>
> Bill Schottstaedt wrote:
>> Is this a bug?
No. See the R5RS formal syntax. Different things are allowed for
(begin ...) at top level and (begin ...) inside a definition.
> Weird thing is it seems to have no problem with
> (let ((f (lambda () (define x 0) (+ x 1)))) (f))
Right, because there's no begin there.
Regards,
Neil
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: begin oddities
2008-09-25 21:30 ` Neil Jerram
@ 2008-09-25 22:14 ` Bill Schottstaedt
2008-09-25 22:16 ` Bill Schottstaedt
1 sibling, 0 replies; 9+ messages in thread
From: Bill Schottstaedt @ 2008-09-25 22:14 UTC (permalink / raw)
To: Neil Jerram, Marijn Schouten (hkBst); +Cc: bug-guile
Sorry, I don't see what you're referring to -- if the preceding
(lambda () (begin ...)) doesn't get an error, then there's no
difference that I can see in the formal syntax between it and
the same thing sitting in a let.
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: begin oddities
2008-09-25 21:30 ` Neil Jerram
2008-09-25 22:14 ` Bill Schottstaedt
@ 2008-09-25 22:16 ` Bill Schottstaedt
2008-09-25 22:24 ` Neil Jerram
1 sibling, 1 reply; 9+ messages in thread
From: Bill Schottstaedt @ 2008-09-25 22:16 UTC (permalink / raw)
To: Neil Jerram, Marijn Schouten (hkBst); +Cc: bug-guile
oh -- it's the (f) that triggers the silly error, not the preceding stuff.
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: begin oddities
2008-09-25 22:16 ` Bill Schottstaedt
@ 2008-09-25 22:24 ` Neil Jerram
2008-09-25 22:40 ` Bill Schottstaedt
` (2 more replies)
0 siblings, 3 replies; 9+ messages in thread
From: Neil Jerram @ 2008-09-25 22:24 UTC (permalink / raw)
To: Bill Schottstaedt; +Cc: bug-guile
2008/9/25 Bill Schottstaedt <bil@ccrma.stanford.edu>:
> oh -- it's the (f) that triggers the silly error, not the preceding stuff.
Yes. This particular error isn't picked up until the code is actually executed.
Neil
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: begin oddities
2008-09-25 22:24 ` Neil Jerram
@ 2008-09-25 22:40 ` Bill Schottstaedt
2008-09-25 22:56 ` Bill Schottstaedt
2008-09-25 23:12 ` Bill Schottstaedt
2 siblings, 0 replies; 9+ messages in thread
From: Bill Schottstaedt @ 2008-09-25 22:40 UTC (permalink / raw)
To: Neil Jerram; +Cc: bug-guile
Hmm -- gauche and stklos are happy with the first version,
and guile is happy with this version:
guile> (let ((f (lambda () (begin (define x 0)) (+ x 1)))) (f))
1
This is basically taken from Jaffer's r4rstest.html.
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: begin oddities
2008-09-25 22:24 ` Neil Jerram
2008-09-25 22:40 ` Bill Schottstaedt
@ 2008-09-25 22:56 ` Bill Schottstaedt
2008-09-25 23:12 ` Bill Schottstaedt
2 siblings, 0 replies; 9+ messages in thread
From: Bill Schottstaedt @ 2008-09-25 22:56 UTC (permalink / raw)
To: Neil Jerram; +Cc: bug-guile
I've stared at the formal syntax, and read it as:
lambda is (lambda <formals> <body>)
<body> is <definition>* <sequence>
<definition>* is
(define <variable> <expression>)
| (define (<variable> <def formals>) <body>)
| (begin <definition>*)
so (lambda () (begin (define ...) ... in both forms looks legal to me.
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: begin oddities
2008-09-25 22:24 ` Neil Jerram
2008-09-25 22:40 ` Bill Schottstaedt
2008-09-25 22:56 ` Bill Schottstaedt
@ 2008-09-25 23:12 ` Bill Schottstaedt
2 siblings, 0 replies; 9+ messages in thread
From: Bill Schottstaedt @ 2008-09-25 23:12 UTC (permalink / raw)
To: Neil Jerram; +Cc: bug-guile
These things are hard to read! I think there are 2 kinds of
begin, and if it's the definition kind, the spec wants just
definitions, so I think now that Guile is technically correct,
but the whole thing is way too subtle.
^ permalink raw reply [flat|nested] 9+ messages in thread
end of thread, other threads:[~2008-09-25 23:12 UTC | newest]
Thread overview: 9+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2008-09-24 13:32 begin oddities Bill Schottstaedt
2008-09-24 23:54 ` Marijn Schouten (hkBst)
2008-09-25 21:30 ` Neil Jerram
2008-09-25 22:14 ` Bill Schottstaedt
2008-09-25 22:16 ` Bill Schottstaedt
2008-09-25 22:24 ` Neil Jerram
2008-09-25 22:40 ` Bill Schottstaedt
2008-09-25 22:56 ` Bill Schottstaedt
2008-09-25 23:12 ` Bill Schottstaedt
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