From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!not-for-mail From: Emanuel Berg Newsgroups: gmane.emacs.help Subject: Re: cl-dolist, dolist, cl-return, Date: Wed, 08 Jul 2015 12:25:08 +0200 Message-ID: <87k2ub2bgb.fsf@nl106-137-147.student.uu.se> References: <87fv4za4jo.fsf@nl106-137-147.student.uu.se> NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: text/plain X-Trace: ger.gmane.org 1436351434 811 80.91.229.3 (8 Jul 2015 10:30:34 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Wed, 8 Jul 2015 10:30:34 +0000 (UTC) To: help-gnu-emacs@gnu.org Original-X-From: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane.org@gnu.org Wed Jul 08 12:30:25 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 1ZCmcS-0001lu-Vp for geh-help-gnu-emacs@m.gmane.org; Wed, 08 Jul 2015 12:30:25 +0200 Original-Received: from localhost ([::1]:34246 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZCmcS-0004CJ-DM for geh-help-gnu-emacs@m.gmane.org; Wed, 08 Jul 2015 06:30:24 -0400 Original-Received: from eggs.gnu.org ([2001:4830:134:3::10]:43798) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZCmcE-0004Bh-TW for help-gnu-emacs@gnu.org; Wed, 08 Jul 2015 06:30:11 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ZCmcA-0000Xb-9D for help-gnu-emacs@gnu.org; Wed, 08 Jul 2015 06:30:10 -0400 Original-Received: from plane.gmane.org ([80.91.229.3]:34043) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZCmcA-0000VC-35 for help-gnu-emacs@gnu.org; Wed, 08 Jul 2015 06:30:06 -0400 Original-Received: from list by plane.gmane.org with local (Exim 4.69) (envelope-from ) id 1ZCmc8-0001Z6-W4 for help-gnu-emacs@gnu.org; Wed, 08 Jul 2015 12:30:05 +0200 Original-Received: from nl106-137-246.student.uu.se ([130.243.137.246]) by main.gmane.org with esmtp (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Wed, 08 Jul 2015 12:30:04 +0200 Original-Received: from embe8573 by nl106-137-246.student.uu.se with local (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Wed, 08 Jul 2015 12:30:04 +0200 X-Injected-Via-Gmane: http://gmane.org/ Mail-Followup-To: help-gnu-emacs@gnu.org Original-Lines: 21 Original-X-Complaints-To: usenet@ger.gmane.org X-Gmane-NNTP-Posting-Host: nl106-137-246.student.uu.se Mail-Copies-To: never User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/24.4 (gnu/linux) Cancel-Lock: sha1:M4e7cMMlXSloodIx3kYsJ8GvmzU= X-detected-operating-system: by eggs.gnu.org: Genre and OS details not recognized. X-Received-From: 80.91.229.3 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:105518 Archived-At: Stefan Monnier writes: >> Just once. Besides inefficiency, evaluating it >> every time would lead to wrong results. > > Right, the question often makes sense for loop > boundary computations, but for this specific case, > if you think enough about it, it makes no sense to > re-evaluate it: you'd have to use an index into the > list, and at each iteration, increment the index, > recompute the list, and do an (nth ), > which would overall be *really* inefficient. No, of course I don't want to re-evaluate it! I didn't think it did re-evaluate, but I wasn't sure so I thought about putting it in a `let' before asking here. It is good I don't have to. -- underground experts united http://user.it.uu.se/~embe8573