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Re: [Emacs-diffs] master 37940b3: min and max now return one of their ar

From: Eli Zaretskii
Subject: Re: [Emacs-diffs] master 37940b3: min and max now return one of their arguments
Date: Thu, 09 Mar 2017 20:34:29 +0200

> Cc: address@hidden, address@hidden
> From: Paul Eggert <address@hidden>
> 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.

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