From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!.POSTED!not-for-mail From: Helmut Eller Newsgroups: gmane.emacs.devel Subject: Re: Making 'eq' == 'eql' in bignum branch Date: Wed, 29 Aug 2018 07:40:56 +0200 Message-ID: References: <29f933ac-a6bf-8742-66a7-0a9d6d3e5a88@disroot.org> <09153aed-361d-4f82-d9ac-b502314769ae@cs.ucla.edu> <83lg91dqd4.fsf@gnu.org> <0F8F6E54-176C-48EE-9E7C-7CAC424D0D55@raeburn.org> <352c998a64c646b983a131039e9c732b@lanl.gov> NNTP-Posting-Host: blaine.gmane.org Mime-Version: 1.0 Content-Type: text/plain X-Trace: blaine.gmane.org 1535521153 18012 195.159.176.226 (29 Aug 2018 05:39:13 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Wed, 29 Aug 2018 05:39:13 +0000 (UTC) User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/27.0.50 (gnu/linux) To: emacs-devel@gnu.org Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Wed Aug 29 07:39:08 2018 Return-path: Envelope-to: ged-emacs-devel@m.gmane.org Original-Received: from lists.gnu.org ([208.118.235.17]) by blaine.gmane.org with esmtp (Exim 4.84_2) (envelope-from ) id 1futC8-0004Z7-3Y for ged-emacs-devel@m.gmane.org; Wed, 29 Aug 2018 07:39:08 +0200 Original-Received: from localhost ([::1]:41240 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1futEE-0004Ll-C4 for ged-emacs-devel@m.gmane.org; Wed, 29 Aug 2018 01:41:18 -0400 Original-Received: from eggs.gnu.org ([2001:4830:134:3::10]:60565) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1futE7-0004Lc-TO for emacs-devel@gnu.org; Wed, 29 Aug 2018 01:41:12 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1futE4-0002Kv-NW for emacs-devel@gnu.org; Wed, 29 Aug 2018 01:41:11 -0400 Original-Received: from [195.159.176.226] (port=44450 helo=blaine.gmane.org) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1futE4-0002KN-Fb for emacs-devel@gnu.org; Wed, 29 Aug 2018 01:41:08 -0400 Original-Received: from list by blaine.gmane.org with local (Exim 4.84_2) (envelope-from ) id 1futBu-0004Ig-PM for emacs-devel@gnu.org; Wed, 29 Aug 2018 07:38:54 +0200 X-Injected-Via-Gmane: http://gmane.org/ Original-Lines: 25 Original-X-Complaints-To: usenet@blaine.gmane.org Cancel-Lock: sha1:qlpsDYrHVaf8u5BJBoSxIdRnLbE= 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: 2.1.21 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:229042 Archived-At: On Wed, Aug 29 2018, Herring, Davis wrote: > Of course +/-inf are numbers. They're not real numbers, but neither > are complex numbers, split-complex numbers, dual numbers, p-adic > numbers, quaternions, octonions, sedenions, hyperreal numbers, or > (please no) surreal numbers. With all due respect to your > mathematician friend, she has no exclusive claim over the definition > (such as it is) of "number" (and I'm a bit surprised if she hadn't > heard of at least one of the extended real lines I linked). Also, it seems quite common to define max/min so that +/-inf are the neutral elements . In Lisp, many associative operations return the neutral element if called with zero arguments, e.g. (*) => 1. So I think it's quite nice that (max) returns -infinity. In Scheme, the syntax +inf.0 and -inf.0 is used for infinities. Emacs Lisp could use the same as +inf.0 is just an ordinary symbol. At least Schemers could remember that. One could also write (/ 1 0.0) for +infinity; the easiest to remember IMO. Helmut