From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!.POSTED!not-for-mail From: Achim Gratz Newsgroups: gmane.emacs.devel Subject: Re: bignum branch Date: Fri, 20 Jul 2018 22:02:56 +0200 Organization: Linux Private Site Message-ID: <87muuly8sv.fsf@Rainer.invalid> References: <87o9fbbw1t.fsf@tromey.com> <83wotu7fcj.fsf@gnu.org> <83k1pt7q1e.fsf@gnu.org> <83h8kx7oeu.fsf@gnu.org> <83fu0h7nr6.fsf@gnu.org> <83d0vl7kg2.fsf@gnu.org> <4bc2a6ba-bc73-c4a9-f7a6-20303955bc7f@cs.ucla.edu> <838t696zb2.fsf@gnu.org> <5095f6d2-c8c1-8d9b-4f4f-ccb74a68d58e@cs.ucla.edu> <8547e501-a41f-68eb-6e00-5fed6c593da4@gmail.com> <73e5dd79-d7d5-3bec-f991-04ceb5d3472d@gmail.com> <87o9f45ot8.fsf@Rainer.invalid> <447774de-c305-5478-1438-7794344456d4@cs.ucla.edu> NNTP-Posting-Host: blaine.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit X-Trace: blaine.gmane.org 1532116876 2778 195.159.176.226 (20 Jul 2018 20:01:16 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Fri, 20 Jul 2018 20:01:16 +0000 (UTC) User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/26.1 (gnu/linux) To: emacs-devel@gnu.org Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Fri Jul 20 22:01:12 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 1fgbaR-0000cs-Rm for ged-emacs-devel@m.gmane.org; Fri, 20 Jul 2018 22:01:11 +0200 Original-Received: from localhost ([::1]:49602 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fgbcY-00044P-RT for ged-emacs-devel@m.gmane.org; Fri, 20 Jul 2018 16:03:22 -0400 Original-Received: from eggs.gnu.org ([2001:4830:134:3::10]:51074) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fgbcM-000448-Jy for emacs-devel@gnu.org; Fri, 20 Jul 2018 16:03:11 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1fgbcH-0007Bo-KL for emacs-devel@gnu.org; Fri, 20 Jul 2018 16:03:10 -0400 Original-Received: from [195.159.176.226] (port=40128 helo=blaine.gmane.org) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1fgbcH-00076h-DA for emacs-devel@gnu.org; Fri, 20 Jul 2018 16:03:05 -0400 Original-Received: from list by blaine.gmane.org with local (Exim 4.84_2) (envelope-from ) id 1fgba7-0000Eu-Bl for emacs-devel@gnu.org; Fri, 20 Jul 2018 22:00:51 +0200 X-Injected-Via-Gmane: http://gmane.org/ Original-Lines: 39 Original-X-Complaints-To: usenet@blaine.gmane.org Cancel-Lock: sha1:kEAzLt0kAvEpm2NMjQxBLFRS5p8= X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] 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:227594 Archived-At: Paul Eggert writes: > On 07/18/2018 12:25 PM, Achim Gratz wrote: >> the established FP math says these >> two values should not compare equal anyway. > > Sure, and = still does that. = is about numeric comparison; eql is > about value comparison. Neither dominates the other: for example, they > disagree about 0.0 vs -0.0 (= says they're equal, but eql says they're > distinguishable values and so are not equal), and conversely they > disagree about 0.0e+NaN versus 0.0e+NaN (= says they're not equal, > whereas eql says they're indistinguishable values are so are equal). I was obliquely hinting at this part of the documentation: --8<---------------cut here---------------start------------->8--- eql is a built-in function in ‘C source code’. (eql OBJ1 OBJ2) Return t if the two args are the same Lisp object. Floating-point numbers of equal value are ‘eql’, but they may not be ‘eq’. --8<---------------cut here---------------end--------------->8--- This seems to say that eql returns a predicate for same-objectness, except for FP numbers where it compares values instead. Your documentation clarification (I think) is about different ways of comparing FP numeric values, so maybe the doc string for eql should directly indicate that the representations of the FP numbers are compared bit-wise, which is distinct from their numerical values as prescribed by IEEE754 (and that comparison is done via =)? Regards, Achim. -- +<[Q+ Matrix-12 WAVE#46+305 Neuron microQkb Andromeda XTk Blofeld]>+ SD adaptations for KORG EX-800 and Poly-800MkII V0.9: http://Synth.Stromeko.net/Downloads.html#KorgSDada