From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!.POSTED.blaine.gmane.org!not-for-mail From: Andy Moreton Newsgroups: gmane.emacs.devel Subject: Re: 7 logical-xor implementations in source tree Date: Tue, 23 Jul 2019 14:54:12 +0100 Message-ID: References: <87tvbd9a8p.fsf@oremacs.com> <86wog9gn5n.fsf@gmail.com> <7AAB8009-DD68-4EA7-93CC-3B4A89FC8AFD@acm.org> <878ssoevkg.fsf@tcd.ie> Mime-Version: 1.0 Content-Type: text/plain Injection-Info: blaine.gmane.org; posting-host="blaine.gmane.org:195.159.176.226"; logging-data="174450"; mail-complaints-to="usenet@blaine.gmane.org" User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/27.0.50 (windows-nt) To: emacs-devel@gnu.org Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Tue Jul 23 15:54:30 2019 Return-path: Envelope-to: ged-emacs-devel@m.gmane.org Original-Received: from lists.gnu.org ([209.51.188.17]) by blaine.gmane.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.89) (envelope-from ) id 1hpvFO-000jG4-0X for ged-emacs-devel@m.gmane.org; Tue, 23 Jul 2019 15:54:30 +0200 Original-Received: from localhost ([::1]:42676 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1hpvFM-00085j-UC for ged-emacs-devel@m.gmane.org; Tue, 23 Jul 2019 09:54:28 -0400 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]:40494) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1hpvFF-0007fM-N7 for emacs-devel@gnu.org; Tue, 23 Jul 2019 09:54:22 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hpvFE-0006bs-RD for emacs-devel@gnu.org; Tue, 23 Jul 2019 09:54:21 -0400 Original-Received: from 195-159-176-226.customer.powertech.no ([195.159.176.226]:58044 helo=blaine.gmane.org) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1hpvFE-0006aO-Kn for emacs-devel@gnu.org; Tue, 23 Jul 2019 09:54:20 -0400 Original-Received: from list by blaine.gmane.org with local (Exim 4.89) (envelope-from ) id 1hpvFB-000j23-DB for emacs-devel@gnu.org; Tue, 23 Jul 2019 15:54:17 +0200 X-Injected-Via-Gmane: http://gmane.org/ Cancel-Lock: sha1:whrUbO0aqbXLxu7MtUUyrCJRh2w= X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 195.159.176.226 X-BeenThere: emacs-devel@gnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: "Emacs development discussions." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Original-Sender: "Emacs-devel" Xref: news.gmane.org gmane.emacs.devel:238839 Archived-At: On Tue 23 Jul 2019, Basil L. Contovounesios wrote: > Andy Moreton writes: > >> On Tue 23 Jul 2019, Andreas Schwab wrote: >> >>> On Jul 23 2019, Andy Moreton wrote: >>> >>>> Perhaps an `xor' special form in eval.c next to `and' and `or' ? >>> >>> There is no need for a special form since xor needs to evaluate all its >>> arguments anyway. >> >> You are right for a two argument xor. However for a multi-argument xor, >> the remaining arguments can be ignored after a second non-nil argument >> is evaluated. > > No, xor must evaluate all of its arguments in all n-ary interpretations > suggested so far: > > - Odd number of non-nil arguments Agreed. > - Exactly one non-nil argument After two non-nil arguments have been evaluated, there is no need to evaluate the remaining arguments. AndyM