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: Thu, 16 Dec 2010 16:59:59 -0500 Organization: A noiseless patient Spider Message-ID: References: <87r5dmkir6.fsf@kuiper.lan.informatimago.com> <96134923-1314-4675-bd77-004945a7159e@y3g2000vbm.googlegroups.com> <87vd2v8107.fsf@lola.goethe.zz> NNTP-Posting-Host: lo.gmane.org Mime-Version: 1.0 Content-Type: text/plain X-Trace: dough.gmane.org 1292539263 15548 80.91.229.12 (16 Dec 2010 22:41:03 GMT) X-Complaints-To: usenet@dough.gmane.org NNTP-Posting-Date: Thu, 16 Dec 2010 22:41:03 +0000 (UTC) To: help-gnu-emacs@gnu.org Original-X-From: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane.org@gnu.org Thu Dec 16 23:40:58 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 1PTMVN-0008Ul-Kw for geh-help-gnu-emacs@m.gmane.org; Thu, 16 Dec 2010 23:40:57 +0100 Original-Received: from localhost ([127.0.0.1]:40280 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1PTMVN-00056J-5Z for geh-help-gnu-emacs@m.gmane.org; Thu, 16 Dec 2010 17:40:57 -0500 Original-Path: usenet.stanford.edu!news.tele.dk!news.tele.dk!small.news.tele.dk!newsgate.cistron.nl!newsgate.news.xs4all.nl!194.109.133.84.MISMATCH!newsfeed.xs4all.nl!newsfeed5.news.xs4all.nl!xs4all!feeds.phibee-telecom.net!eternal-september.org!feeder.eternal-september.org!.POSTED!not-for-mail Original-Newsgroups: gnu.emacs.help Original-Lines: 18 Injection-Info: mx02.eternal-september.org; posting-host="npc8WwhkFofBeKiRj5F6nA"; logging-data="7460"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX19TO4CCZYo8bdxnrFX6r1lq" User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/24.0.50 (gnu/linux) Cancel-Lock: sha1:V9kuJiiFGh0WPR87MuQlrkUq9/4= sha1:RxUlfpHSVrQB7arDH2b5ItHKIx8= Original-Xref: usenet.stanford.edu gnu.emacs.help:183355 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:77607 Archived-At: >> 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). > Why would they be reexpanded each time? Because it's easier to implement it that way in a pure interpreter. > They are macros. Their expansion is done once and merely evalled > each time. > Or do I misunderstand something here? Their expansion *can be* done once (which is what happens when you byte-compile), but the interpreter doesn't bother with such optimizations. Stefan