From mboxrd@z Thu Jan 1 00:00:00 1970 Path: main.gmane.org!not-for-mail From: Stefan Monnier Newsgroups: gmane.emacs.devel Subject: Re: printing.el again Date: Thu, 18 Nov 2004 11:30:32 -0500 Message-ID: References: <419779C4.50909@ig.com.br> <871xew44v1.fsf-monnier+emacs@gnu.org> <41990B75.1080603@ig.com.br> <41994FFB.2060308@ig.com.br> <419C00A6.90905@ig.com.br> NNTP-Posting-Host: deer.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Trace: sea.gmane.org 1100795494 29357 80.91.229.6 (18 Nov 2004 16:31:34 GMT) X-Complaints-To: usenet@sea.gmane.org NNTP-Posting-Date: Thu, 18 Nov 2004 16:31:34 +0000 (UTC) Cc: emacs-devel@gnu.org Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Thu Nov 18 17:31:17 2004 Return-path: Original-Received: from lists.gnu.org ([199.232.76.165]) by deer.gmane.org with esmtp (Exim 3.35 #1 (Debian)) id 1CUpBj-0000bj-00 for ; Thu, 18 Nov 2004 17:31:17 +0100 Original-Received: from localhost ([127.0.0.1] helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.33) id 1CUpKa-0006jT-9r for ged-emacs-devel@m.gmane.org; Thu, 18 Nov 2004 11:40:24 -0500 Original-Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.33) id 1CUpKI-0006fJ-Jj for emacs-devel@gnu.org; Thu, 18 Nov 2004 11:40:06 -0500 Original-Received: from exim by lists.gnu.org with spam-scanned (Exim 4.33) id 1CUpKH-0006f7-R2 for emacs-devel@gnu.org; Thu, 18 Nov 2004 11:40:06 -0500 Original-Received: from [199.232.76.173] (helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.33) id 1CUpKH-0006f4-Lx for emacs-devel@gnu.org; Thu, 18 Nov 2004 11:40:05 -0500 Original-Received: from [132.204.24.67] (helo=mercure.iro.umontreal.ca) by monty-python.gnu.org with esmtp (Exim 4.34) id 1CUpBN-0001ON-GV for emacs-devel@gnu.org; Thu, 18 Nov 2004 11:30:53 -0500 Original-Received: from hidalgo.iro.umontreal.ca (hidalgo.iro.umontreal.ca [132.204.27.50]) by mercure.iro.umontreal.ca (Postfix) with ESMTP id 41F6D82828D; Thu, 18 Nov 2004 11:30:53 -0500 (EST) Original-Received: from asado.iro.umontreal.ca (asado.iro.umontreal.ca [132.204.24.84]) by hidalgo.iro.umontreal.ca (Postfix) with ESMTP id 01FE84AC49C; Thu, 18 Nov 2004 11:30:33 -0500 (EST) Original-Received: by asado.iro.umontreal.ca (Postfix, from userid 20848) id B68F28CA69; Thu, 18 Nov 2004 11:30:32 -0500 (EST) Original-To: Vinicius Jose Latorre In-Reply-To: <419C00A6.90905@ig.com.br> (Vinicius Jose Latorre's message of "Wed, 17 Nov 2004 23:53:42 -0200") User-Agent: Gnus/5.11 (Gnus v5.11) Emacs/21.3.50 (gnu/linux) X-DIRO-MailScanner-Information: Please contact the ISP for more information X-DIRO-MailScanner: Found to be clean X-DIRO-MailScanner-SpamCheck: n'est pas un polluriel, SpamAssassin (score=0, requis 5) X-MailScanner-From: monnier@iro.umontreal.ca X-BeenThere: emacs-devel@gnu.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: "Emacs development discussions." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Original-Sender: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Errors-To: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Xref: main.gmane.org gmane.emacs.devel:30026 X-Report-Spam: http://spam.gmane.org/gmane.emacs.devel:30026 > Well, I think it's important to know the optimizations we can use or not > and when. I don't understand. *You* can't use an optimization: the byte-compiler can. > That is, if I have a code which test (featurep 'some-package) and > some-package is not loaded, does the byte-compiler eliminate the code > associated with this test? Think of it this way: any optimization should be "semantics preserving" and should thus only affect the CPU and memory usage but not the beavior. So if you can think of a case where an optimization induces a different behavior, there are 3 possibilities: 1 - this case is really outlandish and can be itself considered a bug (e.g. someone does (provide 'xemacs)). 2 - the case is a real problem and thus the byte-compiler does not use this optimization. 3 - the case is a real problem but the compiler does use the optimization, in which case you have uncovered a byte-compiler bug and you should report it. Stefan