From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 8665 invoked from network); 17 Jun 2008 11:28:29 -0000 X-Spam-Checker-Version: SpamAssassin 3.2.4 (2008-01-01) on f.primenet.com.au X-Spam-Level: X-Spam-Status: No, score=-2.6 required=5.0 tests=AWL,BAYES_00 autolearn=ham version=3.2.4 Received: from news.dotsrc.org (HELO a.mx.sunsite.dk) (130.225.247.88) by ns1.primenet.com.au with SMTP; 17 Jun 2008 11:28:29 -0000 Received-SPF: none (ns1.primenet.com.au: domain at sunsite.dk does not designate permitted sender hosts) Received: (qmail 69800 invoked from network); 17 Jun 2008 11:28:25 -0000 Received: from sunsite.dk (130.225.247.90) by a.mx.sunsite.dk with SMTP; 17 Jun 2008 11:28:25 -0000 Received: (qmail 12643 invoked by alias); 17 Jun 2008 11:28:23 -0000 Mailing-List: contact zsh-workers-help@sunsite.dk; run by ezmlm Precedence: bulk X-No-Archive: yes X-Seq: 25181 Received: (qmail 12631 invoked from network); 17 Jun 2008 11:28:22 -0000 Received: from bifrost.dotsrc.org (130.225.254.106) by sunsite.dk with SMTP; 17 Jun 2008 11:28:22 -0000 Received: from prunille.vinc17.org (vinc17.pck.nerim.net [213.41.242.187]) by bifrost.dotsrc.org (Postfix) with ESMTP id 67CBD8028AC3 for ; Tue, 17 Jun 2008 13:28:16 +0200 (CEST) Received: by prunille.vinc17.org (Postfix, from userid 501) id C2D9323500B7; Tue, 17 Jun 2008 13:28:15 +0200 (CEST) Date: Tue, 17 Jun 2008 13:28:15 +0200 From: Vincent Lefevre To: Zsh hackers list Subject: Re: arithmetic operator precedence Message-ID: <20080617112815.GF10734@prunille.vinc17.org> Mail-Followup-To: Zsh hackers list References: <20080612095723.GF5113@sc.homeunix.net> <20080616080726.GP10734@prunille.vinc17.org> <20080616144211.276fb0e3@pws-pc> <2d460de70806170219k12ff4cadn441b52c48bf8076f@mail.gmail.com> <20080617094509.GC5016@sc.homeunix.net> <2d460de70806170324o5a44609x9383cc2445d67dd6@mail.gmail.com> <20080617103829.GD5016@sc.homeunix.net> <20080617114340.398c731f@news01> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20080617114340.398c731f@news01> X-Mailer-Info: http://www.vinc17.org/mutt/ User-Agent: Mutt/1.5.18-vl-r22984 (2008-06-11) X-Virus-Scanned: ClamAV 0.92.1/7494/Tue Jun 17 06:46:03 2008 on bifrost X-Virus-Status: Clean On 2008-06-17 11:43:40 +0100, Peter Stephenson wrote: > On Tue, 17 Jun 2008 11:38:29 +0100 > Stephane Chazelas wrote: > > Anyway, I was just curious about Peter's statement. I'm most > > probably not as versed in maths as he is, so was curious about > > the rationale behind his statement about -3**2 = 9 not being > > mathematically correct. > > That was Vincent. I'm inclined to leave the shell the way it is since > there seems to be no widespread agreement on having C_PRECEDENCES (which > probably few people will set explicitly) different from other shells (for > which it will automatically be used in the appropriate emulation). Well, the C language doesn't have a power operator (there's a power function, with prefix notation, so no precedence problem with it). Concerning the precedence of & and |, I'd say that zsh should do what POSIX requires in sh emulation mode. Also, when people don't agree about the precedence of operators, a solution could be to require parentheses (but I don't know if this is easy to implement such rules). At least ambiguity is avoided. -- Vincent Lefèvre - Web: 100% accessible validated (X)HTML - Blog: Work: CR INRIA - computer arithmetic / Arenaire project (LIP, ENS-Lyon)