From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!not-for-mail From: Luc Teirlinck Newsgroups: gmane.emacs.devel Subject: Re: Calc: `*' binds more strongly than `/' Date: Wed, 20 Jun 2007 14:28:45 -0500 (CDT) Message-ID: <200706201928.l5KJSjA7025362@jane.dms.auburn.edu> References: <87y7kvxj6p.fsf@arcor.de> <87odlrkn74.fsf@truman.edu> <87tzvhcul9.fsf@stupidchicken.com> <863b2z2mma.fsf@blue.stonehenge.com> <55350.128.165.123.18.1176926533.squirrel@webmail.lanl.gov> <86ps5zuwmi.fsf@blue.stonehenge.com> <87ps5zi1h2.fsf@truman.edu> <87abuu8xaz.fsf@gmail.com> <877ipy8vhd.fsf@kfs-lx.testafd.dk> <200706201729.l5KHTG24023360@jane.dms.auburn.edu> <87fy4mzf3z.fsf@gmail.com> NNTP-Posting-Host: lo.gmane.org X-Trace: sea.gmane.org 1182367971 18007 80.91.229.12 (20 Jun 2007 19:32:51 GMT) X-Complaints-To: usenet@sea.gmane.org NNTP-Posting-Date: Wed, 20 Jun 2007 19:32:51 +0000 (UTC) Cc: jay.p.belanger@gmail.com, emacs-devel@gnu.org To: jay.p.belanger@gmail.com Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Wed Jun 20 21:32:49 2007 Return-path: Envelope-to: ged-emacs-devel@m.gmane.org Original-Received: from lists.gnu.org ([199.232.76.165]) by lo.gmane.org with esmtp (Exim 4.50) id 1I15v7-0001mi-Hw for ged-emacs-devel@m.gmane.org; Wed, 20 Jun 2007 21:32:49 +0200 Original-Received: from localhost ([127.0.0.1] helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1I15v7-0005TW-18 for ged-emacs-devel@m.gmane.org; Wed, 20 Jun 2007 15:32:49 -0400 Original-Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1I15uz-0005Nl-Pe for emacs-devel@gnu.org; Wed, 20 Jun 2007 15:32:41 -0400 Original-Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43) id 1I15ux-0005LE-Ca for emacs-devel@gnu.org; Wed, 20 Jun 2007 15:32:40 -0400 Original-Received: from [199.232.76.173] (helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1I15ux-0005L1-0q for emacs-devel@gnu.org; Wed, 20 Jun 2007 15:32:39 -0400 Original-Received: from manatee.dms.auburn.edu ([131.204.53.104]) by monty-python.gnu.org with esmtps (TLS-1.0:DHE_RSA_3DES_EDE_CBC_SHA1:24) (Exim 4.60) (envelope-from ) id 1I15uw-0003do-LX for emacs-devel@gnu.org; Wed, 20 Jun 2007 15:32:38 -0400 Original-Received: from jane.dms.auburn.edu (jane.dms.auburn.edu [131.204.53.201]) by manatee.dms.auburn.edu (8.13.7+Sun/8.13.7) with ESMTP id l5KJWbRT017939; Wed, 20 Jun 2007 14:32:37 -0500 (CDT) Original-Received: from jane.dms.auburn.edu (localhost [127.0.0.1]) by jane.dms.auburn.edu (8.13.4+Sun/8.13.4) with ESMTP id l5KJSkT7025365; Wed, 20 Jun 2007 14:28:46 -0500 (CDT) Original-Received: (from teirllm@localhost) by jane.dms.auburn.edu (8.13.4+Sun/8.13.3/Submit) id l5KJSjA7025362; Wed, 20 Jun 2007 14:28:45 -0500 (CDT) X-Authentication-Warning: jane.dms.auburn.edu: teirllm set sender to teirllm@dms.auburn.edu using -f In-reply-to: <87fy4mzf3z.fsf@gmail.com> (message from Jay Belanger on Wed, 20 Jun 2007 12:54:08 -0500) X-detected-kernel: Solaris 10 (beta) 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: news.gmane.org gmane.emacs.devel:73467 Archived-At: Jay Belanger wrote: I can't offhand; that's what I asked about. It can never make any difference in an expression containing only * and /. Indeed, what happens with equal precedence and left associativity in an expression without parentheses containing only * and / is that any `* a' (`/ a'. resp.) anywhere in the expression results in the final result being bigger by (smaller by, resp.) a factor of a. Giving / higher precedence results in exactly the same. Things do make a difference if a third "multiplicative type operator", say mod, is involved. If you give / and * equal precedence, then you can be consistent and give these other ones exactly the same precedence, and use left associativity (this is exactly what most mathematical software I know of does with `mod', _unless_ they _require_, as many do, explicit parentheses do disambiguate and throw an error if these parentheses are missing). But if you give / higher precedence than *. then you have to decide which relative precedence these other operators get. Of course, that same problem occurs just as much if you give * higher precedence than /, as Calc did up to know and still does by default now (unless I misunderstood). I do not know what preference Calc gives to mod, relative to / and *, for either value of `calc-multiplication-has-precedence'. Sincerely, Luc.