From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!.POSTED!not-for-mail From: Eli Zaretskii Newsgroups: gmane.emacs.devel Subject: Re: [Emacs-diffs] master 37940b3: min and max now return one of their arguments Date: Thu, 09 Mar 2017 20:34:29 +0200 Message-ID: <83innifgei.fsf@gnu.org> References: <20170307012700.3354.30219@vcs0.savannah.gnu.org> <20170307012701.1C05D23F1F@vcs0.savannah.gnu.org> <83efy7hih9.fsf@gnu.org> <3530106c-241e-c7e5-f01a-7462b98db737@cs.ucla.edu> <83shmmfn21.fsf@gnu.org> Reply-To: Eli Zaretskii NNTP-Posting-Host: blaine.gmane.org X-Trace: blaine.gmane.org 1489084549 4365 195.159.176.226 (9 Mar 2017 18:35:49 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Thu, 9 Mar 2017 18:35:49 +0000 (UTC) Cc: monnier@iro.umontreal.ca, emacs-devel@gnu.org To: Paul Eggert Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Thu Mar 09 19:35:45 2017 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 1cm2ua-0000Vy-RA for ged-emacs-devel@m.gmane.org; Thu, 09 Mar 2017 19:35:40 +0100 Original-Received: from localhost ([::1]:35746 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1cm2ug-0000r7-Qn for ged-emacs-devel@m.gmane.org; Thu, 09 Mar 2017 13:35:46 -0500 Original-Received: from eggs.gnu.org ([2001:4830:134:3::10]:43659) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1cm2tt-0000hV-Fw for emacs-devel@gnu.org; Thu, 09 Mar 2017 13:35:02 -0500 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1cm2to-0001CQ-7j for emacs-devel@gnu.org; Thu, 09 Mar 2017 13:34:57 -0500 Original-Received: from fencepost.gnu.org ([2001:4830:134:3::e]:51770) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1cm2to-0001CM-5J; Thu, 09 Mar 2017 13:34:52 -0500 Original-Received: from 84.94.185.246.cable.012.net.il ([84.94.185.246]:3463 helo=home-c4e4a596f7) by fencepost.gnu.org with esmtpsa (TLS1.2:RSA_AES_256_CBC_SHA1:256) (Exim 4.82) (envelope-from ) id 1cm2tn-0007oZ-9H; Thu, 09 Mar 2017 13:34:51 -0500 In-reply-to: (message from Paul Eggert on Thu, 9 Mar 2017 09:45:47 -0800) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 2001:4830:134:3::e 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:212864 Archived-At: > Cc: monnier@iro.umontreal.ca, emacs-devel@gnu.org > From: Paul Eggert > Date: Thu, 9 Mar 2017 09:45:47 -0800 > > > I get > > > > (<= 10000000000000001 1e16) => t > > > > in Emacs 25.1 on a 64-bit GNU/Linux host. > > > Yes, and that's an example of the opposite. Emacs 25 is inconsistent, It doesn't look like inconsistency to me, because I expect these two numbers to be indistinguishable. It's basically the same as getting unstable results from qsort -- this should be expected. > and this inconsistency leads to weirdnesses, e.g., it's possible for (<= > A C) to be nil even though (<= A B C) is t, because the implementation > of <= does not compare consistently. Programmers generally do not expect > these weirdnesses, and the patches in master remove them by having Emacs > use consistent comparisons. Programmers who know something about FP calculations do expect that, and won't be surprised.