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From: Paul Eggert <eggert@cs.ucla.edu>
To: Pip Cet <pipcet@gmail.com>
Cc: Robert Pluim <rpluim@gmail.com>, emacs-devel@gnu.org
Subject: Re: Floating-point constant folding in Emacs byte compiler
Date: Fri, 30 Mar 2018 09:39:05 -0700	[thread overview]
Message-ID: <e246e5d9-a4dc-98cc-d5e8-4991f1244011@cs.ucla.edu> (raw)
In-Reply-To: <CAOqdjBfOSJ+aP4OnEBw2njV2H6_PzC87BVbDjazU+2h2PERbdQ@mail.gmail.com>

On 03/30/2018 09:26 AM, Pip Cet wrote:
> with optimization,
> (lambda () (eq 1024.0 1024.0)) will still be false, but without
> optimization, it will turn into bytecode that always returns true

This problem is endemic to Lisp implementations and I wouldn't worry 
about it too much. In Scheme, for example, it is unspecifed whether (eq? 
2.0 2.0) returns true or false, and Emacs Lisp could do the same. We'll 
have similar problems with bignums if we ever get around to implementing 
them.




  parent reply	other threads:[~2018-03-30 16:39 UTC|newest]

Thread overview: 39+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-03-22 23:04 Floating-point constant folding in Emacs byte compiler Paul Eggert
2018-03-23  1:26 ` Stefan Monnier
2018-03-23  5:22   ` Paul Eggert
2018-03-23  8:24     ` Eli Zaretskii
2018-03-23 20:00       ` Paul Eggert
2018-03-23  8:15   ` Eli Zaretskii
2018-03-23 20:52 ` Pip Cet
2018-03-24  6:25   ` Eli Zaretskii
2018-03-26  9:39     ` Robert Pluim
2018-03-26 15:13       ` Eli Zaretskii
2018-03-26 15:57         ` Robert Pluim
2018-03-26 16:02           ` Eli Zaretskii
2018-03-26 18:23             ` Pip Cet
2018-03-26 18:29               ` Eli Zaretskii
2018-03-27  0:28               ` Paul Eggert
2018-03-27 23:28                 ` Paul Eggert
2018-03-30 16:26                   ` Pip Cet
2018-03-30 16:31                     ` Noam Postavsky
2018-03-30 16:39                     ` Paul Eggert [this message]
2018-04-02 10:56                       ` Pip Cet
2018-04-02 11:22                         ` Eli Zaretskii
2018-04-02 11:42                           ` Pip Cet
2018-04-02 12:50                             ` Eli Zaretskii
2018-04-02 14:50                         ` Stefan Monnier
2018-04-02 15:02                           ` Pip Cet
2018-04-02 12:57                     ` Noam Postavsky
2018-04-02 13:30                       ` Eli Zaretskii
2018-04-02 14:48                         ` Stefan Monnier
2018-04-02 19:20                           ` Paul Eggert
2018-04-02 19:39                             ` Pip Cet
2018-04-02 19:58                               ` Eli Zaretskii
2018-04-02 20:55                                 ` Pip Cet
     [not found]                       ` <<83y3i568i0.fsf@gnu.org>
2018-04-02 13:37                         ` Drew Adams
2018-04-02 14:05                           ` Eli Zaretskii
2018-04-02 14:54                           ` Pip Cet
2018-04-02 15:02                             ` Drew Adams
2018-03-26 17:52         ` Stefan Monnier
2018-03-26 18:30           ` Eli Zaretskii
2018-03-27  0:08           ` Paul Eggert

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