From: Hans Aberg <haberg-1@telia.com>
To: Mark H Weaver <mhw@netris.org>
Cc: bug-guile <bug-guile@gnu.org>
Subject: Re: (+ (values 1 2)) should be 1
Date: Wed, 25 May 2011 10:41:23 +0200 [thread overview]
Message-ID: <1BCD41C1-8A89-4202-B8E2-761790E2A0A0@telia.com> (raw)
In-Reply-To: <87ei3nk4mg.fsf@netris.org>
On 25 May 2011, at 02:25, Mark H Weaver wrote:
>> Right, but as the result is unspecified according to the standard, the
>> Guile manual suggests that the value SCM_UNSPECIFIED as an
>> interpretation of that. I merely say that I think it would be a good
>> idea.
...
> Having said all this, one could still make the case that we should
> attempt to return SCM_UNSPECIFIED from expressions whose values are
> unspecified by the standards whenever _practical_. However, doing this
> would prevent us from implementing extensions to many aspects of the
> standard.
Then sec. 10.2.5.2 of the manual needs to be clarified. It should say if a returned value is SCM_UNSPECIFIED then the standard says it is unspecified, but not the other way around.
> Let's always keep in mind these two common rationales for unspecified
> behavior in language specifications:
>
> * to allow more efficient implementation
> * to allow extensions to the standard
Then it agrees with this for unspecified values.
Hans
next prev parent reply other threads:[~2011-05-25 8:41 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-05-22 14:02 (+ (values 1 2)) should be 1 Andy Wingo
2011-05-23 13:34 ` Hans Aberg
2011-05-23 13:49 ` Andy Wingo
2011-05-23 13:58 ` Hans Aberg
2011-05-24 10:35 ` Hans Aberg
2011-05-24 13:11 ` Andy Wingo
2011-05-24 13:48 ` Hans Aberg
2011-05-24 15:07 ` Andy Wingo
2011-05-24 16:13 ` Hans Aberg
2011-05-25 0:25 ` Mark H Weaver
2011-05-25 8:41 ` Hans Aberg [this message]
2011-05-25 16:54 ` Mark H Weaver
2011-05-25 17:10 ` Hans Aberg
2011-06-17 17:43 ` Andy Wingo
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