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: Sun, 28 Jul 2019 21:43:19 +0200 Message-ID: <875znm3q19.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> 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="107087"; 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 Sun Jul 28 21:43:44 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 1hrp54-000Rgv-Fa for ged-emacs-devel@m.gmane.org; Sun, 28 Jul 2019 21:43:42 +0200 Original-Received: from localhost ([::1]:46552 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1hrp52-0006mL-UN for ged-emacs-devel@m.gmane.org; Sun, 28 Jul 2019 15:43:40 -0400 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]:46209) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1hrp4y-0006mC-Mr for emacs-devel@gnu.org; Sun, 28 Jul 2019 15:43:37 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hrp4x-0005GN-J7 for emacs-devel@gnu.org; Sun, 28 Jul 2019 15:43:36 -0400 Original-Received: from mail.mojserwer.eu ([195.110.48.8]:39688) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1hrp4x-0005EX-CR for emacs-devel@gnu.org; Sun, 28 Jul 2019 15:43:35 -0400 Original-Received: from localhost (localhost [127.0.0.1]) by mail.mojserwer.eu (Postfix) with ESMTP id EBA76E658B; Sun, 28 Jul 2019 21:43:26 +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 Pv5dakPdKwcR; Sun, 28 Jul 2019 21:43:23 +0200 (CEST) Original-Received: from localhost (jeden09-dwa27.echostar.pl [213.156.109.227]) by mail.mojserwer.eu (Postfix) with ESMTPSA id A847DE6302; Sun, 28 Jul 2019 21:43:23 +0200 (CEST) In-reply-to: <20190728080417.GA5072@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:238981 Archived-At: 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 co= ncerned. `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 centuries. > 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 ) This could of course be generalized to n arguments, though I'm not sure whether anyone would want that (as with xor, there is more than one "natural" way to do that). If so, this is precisely the meaning we are talking about, no? Also, Wikipedia claims that "iff" is relatively new (the fifties), btw. Best, -- Marcin Borkowski http://mbork.pl