unofficial mirror of guile-devel@gnu.org 
 help / color / mirror / Atom feed
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




  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

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

  List information: https://www.gnu.org/software/guile/

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=87vcn0ch49.fsf@fencepost.gnu.org \
    --to=dak@gnu.org \
    --cc=guile-devel@gnu.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).