From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!.POSTED.blaine.gmane.org!not-for-mail From: Marcin Borkowski Newsgroups: gmane.emacs.devel Subject: Re: 7 logical-xor implementations in source tree Date: Wed, 31 Jul 2019 19:12:34 +0200 Message-ID: <87y30eqgal.fsf@mbork.pl> References: <87tvbd9a8p.fsf@oremacs.com> <87pnm14u95.fsf@tcd.ie> <87sgqvoz5c.fsf@tcd.ie> <87d0hz2e11.fsf@tcd.ie> <5B633129-B795-4BFA-AE81-FE9FD0A24CE9@acm.org> <0edfffbb-6f5a-a6b2-334a-9000e8f2eb3e@gmail.com> <20190728080417.GA5072@ACM> <875znm3q19.fsf@mbork.pl> <20190730093651.GA5427@ACM> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Injection-Info: blaine.gmane.org; posting-host="blaine.gmane.org:195.159.176.226"; logging-data="77089"; mail-complaints-to="usenet@blaine.gmane.org" User-Agent: mu4e 1.1.0; emacs 27.0.50 Cc: emacs-devel@gnu.org To: Alan Mackenzie Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Wed Jul 31 19:12:51 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 1hss9i-000Jvj-QK for ged-emacs-devel@m.gmane.org; Wed, 31 Jul 2019 19:12:50 +0200 Original-Received: from localhost ([::1]:43104 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1hss9h-0003WJ-8s for ged-emacs-devel@m.gmane.org; Wed, 31 Jul 2019 13:12:49 -0400 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]:59431) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1hss9c-0003W1-6V for emacs-devel@gnu.org; Wed, 31 Jul 2019 13:12:45 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hss9b-0000pF-59 for emacs-devel@gnu.org; Wed, 31 Jul 2019 13:12:44 -0400 Original-Received: from mail.mojserwer.eu ([195.110.48.8]:37840) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1hss9a-0000nZ-U1 for emacs-devel@gnu.org; Wed, 31 Jul 2019 13:12:43 -0400 Original-Received: from localhost (localhost [127.0.0.1]) by mail.mojserwer.eu (Postfix) with ESMTP id 4375AE6CB4; Wed, 31 Jul 2019 19:12:40 +0200 (CEST) X-Virus-Scanned: Debian amavisd-new at mail.mojserwer.eu Original-Received: from mail.mojserwer.eu ([127.0.0.1]) by localhost (mail.mojserwer.eu [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id XnK65twNGIrn; Wed, 31 Jul 2019 19:12:36 +0200 (CEST) Original-Received: from localhost (jeden09-dwa27.echostar.pl [213.156.109.227]) by mail.mojserwer.eu (Postfix) with ESMTPSA id A4301E639A; Wed, 31 Jul 2019 19:12:35 +0200 (CEST) In-reply-to: <20190730093651.GA5427@ACM> X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 195.110.48.8 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:239052 Archived-At: On 2019-07-30, at 11:36, Alan Mackenzie wrote: > Hello, Marcin. > > On Sun, Jul 28, 2019 at 21:43:19 +0200, Marcin Borkowski wrote: > >> On 2019-07-28, at 10:04, Alan Mackenzie wrote: > >> > Hello, Philippe. > >> > On Sun, Jul 28, 2019 at 09:09:01 +0200, Philippe Schnoebelen wrote: >> >> On 2019/07/25 14:07, Mattias Engdeg=C3=A5rd wrote: >> >> > 25 juli 2019 kl. 01.44 skrev Basil L. Contovounesios : > > >> >> > bool-equal, bool-equiv, bool=3D, bool-eq are all fine as far as I'm= concerned. `xnor' and `nxor', not so much. >> >> > Racket has `boolean=3D?', but presumably it only copes with #t/#f. >> >> > I'll be using `equiv' as placeholder below for brevity. > >> >> I like the name `iff' for this function. > >> > No, please don't use the name `iff' here. In mathematical circles, iff >> > means "if and only if", and has done for many decades/several centurie= s. >> > Introducing it into Emacs with a radically different meaning will be >> > jarring in the extreme to anybody with a maths background. > >> Out of curiosity: how is that a "radically different meaning"? I assume >> that we are talking about a function `iff' such that >> (iff nil nil) evaluates to t >> (iff nil ) evaluates to nil >> (iff nil) evaluates to nil >> (iff ) evaluates to t (or perhaps the latter >> ) > > Er, it's not radically different. My brain seems to have been switched > off when I wrote my last post. Apologies. No worry. > Less importantly, I don't like iff being used in this way. I'm not sure > why. Maybe it's because I've been used to iff applying solely to TRUE > and FALSE. Maybe it's that I've been used to iff declaring a > proposition, rather than being something to be calculated. Well, these are subjective points, but there are much stronger arguments against `iff' raised by others... Best, --=20 Marcin Borkowski http://mbork.pl