From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!not-for-mail From: pjb@informatimago.com (Pascal J. Bourguignon) Newsgroups: gmane.emacs.help Subject: Re: Adding many elements to a list Date: Tue, 22 Sep 2009 14:37:15 +0200 Organization: Anevia SAS Message-ID: <7cskefp344.fsf@pbourguignon.lefevre.anevia.com> References: <979e809f-0b95-46bf-afa4-1a25cda5bae0@j9g2000vbp.googlegroups.com> <7chbv0fjuj.fsf@informatimago.com> <87vdjgxrga.fsf@lola.goethe.zz> <7ceiq4s405.fsf@pbourguignon.lefevre.informatimago.com> <87my4sxpzv.fsf@lola.goethe.zz> <7cab0ss2ud.fsf@pbourguignon.lefevre.informatimago.com> <87ws3rtq2b.fsf@lola.goethe.zz> <7cws3rp54a.fsf@pbourguignon.lefevre.informatimago.com> <87vdjbrx7n.fsf@lola.goethe.zz> NNTP-Posting-Host: lo.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Trace: ger.gmane.org 1253623497 20113 80.91.229.12 (22 Sep 2009 12:44:57 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Tue, 22 Sep 2009 12:44:57 +0000 (UTC) To: help-gnu-emacs@gnu.org Original-X-From: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane.org@gnu.org Tue Sep 22 14:44:50 2009 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 4.50) id 1Mq4jg-0001Fb-28 for geh-help-gnu-emacs@m.gmane.org; Tue, 22 Sep 2009 14:44:48 +0200 Original-Received: from localhost ([127.0.0.1]:41340 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1Mq4jf-0003VO-FP for geh-help-gnu-emacs@m.gmane.org; Tue, 22 Sep 2009 08:44:47 -0400 Original-Path: news.stanford.edu!usenet.stanford.edu!news.tele.dk!news.tele.dk!small.news.tele.dk!proxad.net!feeder1-2.proxad.net!cleanfeed2-b.proxad.net!nnrp17-1.free.fr!not-for-mail Original-Newsgroups: gnu.emacs.help Face: iVBORw0KGgoAAAANSUhEUgAAADAAAAAwAQMAAABtzGvEAAAABlBMVEUAAAD///+l2Z/dAAAA oElEQVR4nK3OsRHCMAwF0O8YQufUNIQRGIAja9CxSA55AxZgFO4coMgYrEDDQZWPIlNAjwq9 033pbOBPtbXuB6PKNBn5gZkhGa86Z4x2wE67O+06WxGD/HCOGR0deY3f9Ijwwt7rNGNf6Oac l/GuZTF1wFGKiYYHKSFAkjIo1b6sCYS1sVmFhhhahKQssRjRT90ITWUk6vvK3RsPGs+M1RuR mV+hO/VvFAAAAABJRU5ErkJggg== X-Accept-Language: fr, es, en X-Disabled: X-No-Archive: no User-Agent: Gnus/5.101 (Gnus v5.10.10) Emacs/22.2 (gnu/linux) Cancel-Lock: sha1:abZRMW1j7BZEvlGsKe0A+/xYHvQ= Original-Lines: 28 Original-NNTP-Posting-Date: 22 Sep 2009 14:37:15 MEST Original-NNTP-Posting-Host: 88.170.236.224 Original-X-Trace: 1253623035 news-1.free.fr 419 88.170.236.224:49470 Original-X-Complaints-To: abuse@proxad.net Original-Xref: news.stanford.edu gnu.emacs.help:173257 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:68379 Archived-At: David Kastrup writes: > Well, consult its doc string for what it does and doesn't. It's > basically the same issue as with setf/setq: the cl version of push does > a number of different things depending on a vague concept "location". > But you almost never need this sort of flexibility at runtime, and at > compile time, it obfuscates what actually happens, including the > possible performance impacts. You should write in assembler (what do I say, in binary!), because you almost never need the flexibility that the bare push provide at run-time, and at compilation time, it obfuscate what really happens, including the possible performance impacts. (disassemble (byte-compile (lambda (x) (push x *a*)))) --> byte code: args: (x) 0 varref x 1 varref *a* 2 cons 3 dup 4 varset *a* 5 return See? There's a dup that's most often not used. Performance IMPACT! -- __Pascal Bourguignon__