From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!not-for-mail From: Eli Zaretskii Newsgroups: gmane.emacs.help Subject: Re: Are two symbols `equal' iff they are `eq'? Date: Sun, 09 Aug 2015 21:19:53 +0300 Message-ID: <83si7spbna.fsf@gnu.org> References: <20150809051452.23051.3919A296@ahiker.mooo.com> <87a8u07wce.fsf@mbork.pl> <871tfctv49.fsf@web.de> <87si7s5whd.fsf@mbork.pl> <83tws8pk0g.fsf@gnu.org> <87pp2w5uuc.fsf@mbork.pl> NNTP-Posting-Host: plane.gmane.org X-Trace: ger.gmane.org 1439144498 4881 80.91.229.3 (9 Aug 2015 18:21:38 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Sun, 9 Aug 2015 18:21:38 +0000 (UTC) To: help-gnu-emacs@gnu.org Original-X-From: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane.org@gnu.org Sun Aug 09 20:21:29 2015 Return-path: Envelope-to: geh-help-gnu-emacs@m.gmane.org Original-Received: from lists.gnu.org ([208.118.235.17]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1ZOVDs-000140-9W for geh-help-gnu-emacs@m.gmane.org; Sun, 09 Aug 2015 20:21:28 +0200 Original-Received: from localhost ([::1]:55951 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZOVDr-00058D-DR for geh-help-gnu-emacs@m.gmane.org; Sun, 09 Aug 2015 14:21:27 -0400 Original-Received: from eggs.gnu.org ([2001:4830:134:3::10]:34817) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZOVDh-00056g-8B for help-gnu-emacs@gnu.org; Sun, 09 Aug 2015 14:21:18 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ZOVDb-0006rH-1X for help-gnu-emacs@gnu.org; Sun, 09 Aug 2015 14:21:17 -0400 Original-Received: from mtaout20.012.net.il ([80.179.55.166]:39341) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZOVDa-0006ol-QG for help-gnu-emacs@gnu.org; Sun, 09 Aug 2015 14:21:10 -0400 Original-Received: from conversion-daemon.a-mtaout20.012.net.il by a-mtaout20.012.net.il (HyperSendmail v2007.08) id <0NST00J00UM2QV00@a-mtaout20.012.net.il> for help-gnu-emacs@gnu.org; Sun, 09 Aug 2015 21:20:05 +0300 (IDT) Original-Received: from HOME-C4E4A596F7 ([87.69.4.28]) by a-mtaout20.012.net.il (HyperSendmail v2007.08) with ESMTPA id <0NST00J53UXHL980@a-mtaout20.012.net.il> for help-gnu-emacs@gnu.org; Sun, 09 Aug 2015 21:20:05 +0300 (IDT) In-reply-to: <87pp2w5uuc.fsf@mbork.pl> X-012-Sender: halo1@inter.net.il X-detected-operating-system: by eggs.gnu.org: Solaris 10 X-Received-From: 80.179.55.166 X-BeenThere: help-gnu-emacs@gnu.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: Users list for the GNU Emacs text editor List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane.org@gnu.org Original-Sender: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane.org@gnu.org Xref: news.gmane.org gmane.emacs.help:106416 Archived-At: > From: Marcin Borkowski > Date: Sun, 09 Aug 2015 17:45:31 +0200 > > >> >From the capitalization I would guess that QUIT is a C macro. From its > >> name I would guess that anything after it is irrelevant;-). Well, > >> joking aside, I found its definition in the source; do I get it right > >> that it quits if something like C-g happens? > > > > Yes. > > > >> If yes, I'd be curious why it is here. > > > > To allow the user to interrupt a (potentially) long operation. > > That's obvious, I just wondered why at this point. Because that point is traversed every recursion, so we check for C-g on each "iteration", so to say. > >> Apart from that, it seems that I was right: `equal' for > >> symbols just calls `eq' (C EQ, not Lisp eq, to be more precise). > > > > What else could it possibly do? > > It could e.g. compare the string representation, so two symbols with the > same name but in different obarrays, or one interned and the other not, > could be equal but not eq. I'm sure you understand how all of those would make no sense as "equality" of any kind. > (I'm not sure whether this would be useful, though - just a > thought.) If it won't be useful, why would someone do it?