From mboxrd@z Thu Jan  1 00:00:00 1970
Path: news.gmane.org!not-for-mail
From: Thien-Thi Nguyen <ttn@glug.org>
Newsgroups: gmane.emacs.help
Subject: Re: sharing list structure
Date: Fri, 25 Mar 2005 02:21:00 +0100
Organization: sometimes
Message-ID: <7eacosh66b.fsf@ada2.unipv.it>
References: <E1DEc4P-0002bS-00@lab45.ma.utexas.edu>
	<6dbd4d00050324161731ef0f51@mail.gmail.com>
	<mailman.176.1111711460.28103.help-gnu-emacs@gnu.org>
NNTP-Posting-Host: main.gmane.org
Mime-Version: 1.0
Content-Type: text/plain; charset=us-ascii
X-Trace: sea.gmane.org 1111714465 18261 80.91.229.2 (25 Mar 2005 01:34:25 GMT)
X-Complaints-To: usenet@sea.gmane.org
NNTP-Posting-Date: Fri, 25 Mar 2005 01:34:25 +0000 (UTC)
Original-X-From: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane.org@gnu.org Fri Mar 25 02:34:25 2005
Original-Received: from lists.gnu.org ([199.232.76.165])
	by ciao.gmane.org with esmtp (Exim 4.43)
	id 1DEdiS-00062U-2g
	for geh-help-gnu-emacs@m.gmane.org; Fri, 25 Mar 2005 02:34:24 +0100
Original-Received: from localhost ([127.0.0.1] helo=lists.gnu.org)
	by lists.gnu.org with esmtp (Exim 4.43)
	id 1DEdxq-0003sE-BF
	for geh-help-gnu-emacs@m.gmane.org; Thu, 24 Mar 2005 20:50:18 -0500
Original-Path: shelby.stanford.edu!newsfeed.stanford.edu!postnews.google.com!news4.google.com!news.glorb.com!blackbush.cw.net!cw.net!feed.news.tiscali.de!news.belwue.de!LF.net!quimby.gnus.org!not-for-mail
Original-Newsgroups: gnu.emacs.help
Original-Lines: 19
Original-NNTP-Posting-Host: ada2.unipv.it
Original-X-Trace: quimby.gnus.org 1111713658 3363 193.204.44.145 (25 Mar 2005 01:20:58
	GMT)
Original-X-Complaints-To: usenet@quimby.gnus.org
Original-NNTP-Posting-Date: Fri, 25 Mar 2005 01:20:58 +0000 (UTC)
User-Agent: Gnus/5.11 (Gnus v5.11) Emacs/22.0.50 (gnu/linux)
Cancel-Lock: sha1:Y66vSDT5c6r87oB4l5ZybL6w9QI=
Original-Xref: shelby.stanford.edu gnu.emacs.help:129582
Original-To: help-gnu-emacs@gnu.org
X-BeenThere: help-gnu-emacs@gnu.org
X-Mailman-Version: 2.1.5
Precedence: list
List-Id: Users list for the GNU Emacs text editor <help-gnu-emacs.gnu.org>
List-Unsubscribe: <http://lists.gnu.org/mailman/listinfo/help-gnu-emacs>,
	<mailto:help-gnu-emacs-request@gnu.org?subject=unsubscribe>
List-Archive: <http://lists.gnu.org/pipermail/help-gnu-emacs>
List-Post: <mailto:help-gnu-emacs@gnu.org>
List-Help: <mailto:help-gnu-emacs-request@gnu.org?subject=help>
List-Subscribe: <http://lists.gnu.org/mailman/listinfo/help-gnu-emacs>,
	<mailto:help-gnu-emacs-request@gnu.org?subject=subscribe>
Original-Sender: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane.org@gnu.org
Errors-To: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane.org@gnu.org
X-MailScanner-To: geh-help-gnu-emacs@m.gmane.org
Xref: news.gmane.org gmane.emacs.help:25133
X-Report-Spam: http://spam.gmane.org/gmane.emacs.help:25133

Joe Corneli <jcorneli@math.utexas.edu> writes:

> OK, I think I've got the idea now.  But still, I'm
> surprised that `setq' is not among the list of
> "destructive functions".  What's that about?

setq changes a symbol's value to a new value.

a symbol and its value are two different concepts.

the "destructiveness" of a function does not refer
to the binding between a symbol and its value, but
rather how the cdr of a pair is treated.

check out gnugo.el, which uses tail-pointer style
extensively.  also: reverse:nreverse::append:nconc
(more or less, pedants be damned).

thi