From: David Kastrup <dak@gnu.org>
To: guile-devel@gnu.org
Subject: Re: Dotted pair call argument
Date: Tue, 21 Feb 2012 16:59:18 +0100 [thread overview]
Message-ID: <87vcn0ch49.fsf@fencepost.gnu.org> (raw)
In-Reply-To: 87d39819mp.fsf@netris.org
Mark H Weaver <mhw@netris.org> writes:
> David Kastrup <dak@gnu.org> writes:
>> I guess my "real" problem is that I'd like to do call wrapping by writing
>>
>> (lambda ( . x) (fun . x))
>>
>> instead of having to write
>>
>> (lambda ( . x) (apply fun x))
>>
>> I assume eval is not supposed to try dealing with dotted lists?
>
> The problem is that (f . (g x y)) is equivalent to (f g x y).
> Therefore, while Scheme could in theory support procedure calls with a
> dotted tail that happened to be an atom, it would do something rather
> different and confusing if the dotted tail was itself a procedure/macro
> call.
A list in dotted tail position is evaluated via (map ... eval) rather
than (eval ...). I don't see much of a problem with that.
It works fine for () as one can see:
guile> (+ . ())
0
guile>
So why not for others?
--
David Kastrup
next prev parent reply other threads:[~2012-02-21 15:59 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-02-21 14:03 Dotted pair call argument David Kastrup
2012-02-21 15:36 ` Mark H Weaver
2012-02-21 15:59 ` David Kastrup [this message]
2012-02-21 16:05 ` David Kastrup
2012-02-21 17:23 ` Mark H Weaver
2012-02-21 18:05 ` David Kastrup
2012-02-22 0:41 ` Mark H Weaver
2012-02-22 9:06 ` David Kastrup
2012-02-21 20:31 ` Neil Jerram
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