From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!not-for-mail From: Stefan Monnier Newsgroups: gmane.emacs.help Subject: Re: Lexical binding and macros. Date: Wed, 15 Dec 2010 10:40:08 -0500 Organization: A noiseless patient Spider Message-ID: References: <87r5dmkir6.fsf@kuiper.lan.informatimago.com> <96134923-1314-4675-bd77-004945a7159e@y3g2000vbm.googlegroups.com> NNTP-Posting-Host: lo.gmane.org Mime-Version: 1.0 Content-Type: text/plain X-Trace: dough.gmane.org 1292431259 717 80.91.229.12 (15 Dec 2010 16:40:59 GMT) X-Complaints-To: usenet@dough.gmane.org NNTP-Posting-Date: Wed, 15 Dec 2010 16:40:59 +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 Dec 15 17:40:53 2010 Return-path: Envelope-to: geh-help-gnu-emacs@m.gmane.org Original-Received: from lists.gnu.org ([199.232.76.165]) by lo.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1PSuPN-0007sK-Me for geh-help-gnu-emacs@m.gmane.org; Wed, 15 Dec 2010 17:40:53 +0100 Original-Received: from localhost ([127.0.0.1]:55858 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1PSuPN-0006sH-3c for geh-help-gnu-emacs@m.gmane.org; Wed, 15 Dec 2010 11:40:53 -0500 Original-Path: usenet.stanford.edu!news.tele.dk!news.tele.dk!small.news.tele.dk!news-2.dfn.de!news.dfn.de!newsfeed.straub-nv.de!eternal-september.org!feeder.eternal-september.org!.POSTED!not-for-mail Original-Newsgroups: gnu.emacs.help Original-Lines: 21 Injection-Info: mx02.eternal-september.org; posting-host="npc8WwhkFofBeKiRj5F6nA"; logging-data="9768"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX1/0tXOy9ikTeDu8OGV0qD8V" User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/24.0.50 (gnu/linux) Cancel-Lock: sha1:IgbZ67A7A/qJrFR2Fc7U5srYAkI= sha1:4+zWlj0mY9Qg/U5oSH3SXwN1lJk= Original-Xref: usenet.stanford.edu gnu.emacs.help:183303 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 List-Unsubscribe: , List-Archive: List-Post: List-Help: List-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 Xref: news.gmane.org gmane.emacs.help:77553 Archived-At: > Do they still leak memory? From http://c2.com/cgi/wiki?EmacsLisp : > "Note that variables bound with lexical-let are never released, even > if they are never used. Try > (loop for i from 1 to 100000 collect (lexical-let ((x i)) '())) > and watch it eat memory. So making infinity (ZeroOneInfinity) lexical > variables is out of the question except for very small values of > infinity." Additionally to what Pascal already explained, I'll add that, lexical-let, like `loop' are relatively heavy macros, so you definitely don't want to run them interpreted (where the macro is re-expanded each time). If you byte-compile the code above, the memory use will be identical to what you get with (loop for i from 1 to 100000 collect (let ((x i)) '())) Stefan