From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!.POSTED.blaine.gmane.org!not-for-mail From: "Basil L. Contovounesios" Newsgroups: gmane.emacs.devel Subject: Re: 7 logical-xor implementations in source tree Date: Tue, 23 Jul 2019 14:20:47 +0100 Message-ID: <878ssoevkg.fsf@tcd.ie> References: <87tvbd9a8p.fsf@oremacs.com> <86wog9gn5n.fsf@gmail.com> <7AAB8009-DD68-4EA7-93CC-3B4A89FC8AFD@acm.org> Mime-Version: 1.0 Content-Type: text/plain Injection-Info: blaine.gmane.org; posting-host="blaine.gmane.org:195.159.176.226"; logging-data="26314"; mail-complaints-to="usenet@blaine.gmane.org" User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/27.0.50 (gnu/linux) Cc: emacs-devel@gnu.org To: Andy Moreton Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Tue Jul 23 15:21:13 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 1hpujA-0006fI-8z for ged-emacs-devel@m.gmane.org; Tue, 23 Jul 2019 15:21:12 +0200 Original-Received: from localhost ([::1]:42420 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1hpuj9-0001XR-6T for ged-emacs-devel@m.gmane.org; Tue, 23 Jul 2019 09:21:11 -0400 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]:55901) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1hpuj1-0001X8-Oj for emacs-devel@gnu.org; Tue, 23 Jul 2019 09:21:04 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hpuj0-0007UA-O7 for emacs-devel@gnu.org; Tue, 23 Jul 2019 09:21:03 -0400 Original-Received: from mail-wr1-x435.google.com ([2a00:1450:4864:20::435]:41934) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1hpuj0-0007Ob-9i for emacs-devel@gnu.org; Tue, 23 Jul 2019 09:21:02 -0400 Original-Received: by mail-wr1-x435.google.com with SMTP id c2so39959133wrm.8 for ; Tue, 23 Jul 2019 06:21:01 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=tcd-ie.20150623.gappssmtp.com; s=20150623; h=from:to:cc:subject:references:date:in-reply-to:message-id :user-agent:mime-version; bh=S5icMPFu+Fdz8HU4fNhZmIJzy6Fbow7TqPfD6n9J+tM=; b=hPmXtQhjcQY64l1Z6bhzXLx5urkKBliQn84DVS+Vd0bXklaBmyPs6ilse/Y/8AAu66 JHxa7pgB70qUg5Mb4ImlbY0rH1q/cg/hvsByuj6EQoV/C6vy+hrzDlrAFOcLLkQiJ/a0 2Jr0IaFX6mP93b91hcI5OseKPBjG+GMK+ZiS5kvf674ulmBHS7c7PZTLl4FrpFRoLFqI fDRhsp2hM4NojAtkIJ51OnAOJ3S23JoCsciOQay4ax/qx13i8U+XkGzRey16joErHNX7 kBU6yTB6tVJoq72vr9K+wlur+HcFpbS81bREOdaSx7rXl7nabiOLkvEJTiIQtWmCvPaO aftg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:references:date:in-reply-to :message-id:user-agent:mime-version; bh=S5icMPFu+Fdz8HU4fNhZmIJzy6Fbow7TqPfD6n9J+tM=; b=k7fjQGcMqJa5kY+BVM5gDcUJxTFLq1NkWuW0D5PetnA2Ol6+2GOV31z4oaxzU4ZgrX kSZEObbymVwrZGWbOrRMnoH3vfm+PtAEjNUVAyF4vHHvkMwIaFqwov2ycEvlpWBSiIyu F6zOfX6a735uhKfQyHK1njHI9mjmSgTjLmXosoRTdbcKY3gs0auqCPQMd5jIbRtEh1TW i3tdNToEgV0Gih9ud6KKqz1P3cMxfaZtCExK1rxqOfuZdVJcc6bfsqd4KiC7hZDkgNS0 PZL1l34wR/Lc8zzVZtOU+Wwo3amoFKgS5Ui/MOQfVhljG9hufQkwrZD+HRP0Gm0NsjPx OVKA== X-Gm-Message-State: APjAAAVzfmJyFaLPtlGgQFnkdTUEJUytAg/NZ84ARsFk0xCM1Dgl9kz2 Y8ZITPeNvy+3QIVqmWn6Hl8lfQ== X-Google-Smtp-Source: APXvYqxxQpP/mx1p8PZu+uPQwjbI6BoRHETznXElgLtKx2vKThhPLjFf+oJc4bi+73g5gdixIrkVcw== X-Received: by 2002:a5d:6144:: with SMTP id y4mr82942775wrt.84.1563888060025; Tue, 23 Jul 2019 06:21:00 -0700 (PDT) Original-Received: from localhost ([86.47.56.169]) by smtp.gmail.com with ESMTPSA id u18sm35465837wmd.19.2019.07.23.06.20.57 (version=TLS1_3 cipher=AEAD-AES256-GCM-SHA384 bits=256/256); Tue, 23 Jul 2019 06:20:59 -0700 (PDT) In-Reply-To: (Andy Moreton's message of "Tue, 23 Jul 2019 13:11:56 +0100") X-detected-operating-system: by eggs.gnu.org: Genre and OS details not recognized. X-Received-From: 2a00:1450:4864:20::435 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:238838 Archived-At: 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 - Exactly one non-nil argument Neither of these conditions can be known without examining the entire arglist. -- Basil