From: Eli Zaretskii <eliz@gnu.org>
To: joaotavora@gmail.com (João Távora)
Cc: 28390@debbugs.gnu.org, monnier@iro.umontreal.ca
Subject: bug#28390: 26.0.50; overlays-at actually sorts by increating priority
Date: Fri, 08 Sep 2017 12:47:02 +0300 [thread overview]
Message-ID: <83lglpy12h.fsf@gnu.org> (raw)
In-Reply-To: <87r2vhin47.fsf@lolita> (joaotavora@gmail.com)
> From: joaotavora@gmail.com (João Távora)
> Cc: 28390@debbugs.gnu.org, monnier@iro.umontreal.ca
> Date: Fri, 08 Sep 2017 09:57:28 +0100
>
> Eli Zaretskii <eliz@gnu.org> writes:
>
> > I think the doc string says what the implementation was supposed to
> > do, so we need to change the implementation instead.
>
> Really? Won't that ripple very paintuflly across the elisp ecosphere?
I don't think so. I believe this optional argument is used very
rarely.
> > If you look at the changeset where the SORTED argument was introduced,
> > you will see that the old code sorted the list returned by overlays-at
> > in descending order of priorities, i.e. overlays with the largest
> > priority first. It used 'sort' like this:
> >
> > (sort (mapcar #'overlay-properties (overlays-at p))
> > (lambda (A B) (> (or (cadr (memq 'priority A)) 0)
> > (or (cadr (memq 'priority B)) 0)))))
>
> I don't follow, where is the code that did this, or is this just an
> illustration?
This is the code which was replaced when overlays-at got its optional
argument in that Stefan's change.
> > The doc string of 'sort' says that its PREDICATE function should
> > return non-nil if the first element passed to PREDICATE should sort
> > _before_ the second. And the predicate above uses '>'.
>
> But where was sort() ever used before Stefan's 2014 change? Did
> overlays-at make any sort guarantee back then?
Look at the changeset of commit 20fa59a0, you will see that the uses
if 'sort' were replaced with calls to overlays-at with the new
optional argument.
> I do agree that it should sort the other way, though. But it's too late
> for that, bugs will be features :-).
I'm not sure it's too late.
next prev parent reply other threads:[~2017-09-08 9:47 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-09-07 22:21 bug#28390: 26.0.50; overlays-at actually sorts by increating priority João Távora
2017-09-08 8:39 ` Eli Zaretskii
2017-09-08 8:57 ` João Távora
2017-09-08 9:47 ` Eli Zaretskii [this message]
[not found] ` <CALDnm5103cjV6TNKiGiaVEcJRLMfnM+wCuW3LrySh8dEur7uwg@mail.gmail.com>
2017-09-08 19:30 ` bug#28390: Fwd: " João Távora
2017-09-10 13:53 ` Stefan Monnier
2017-09-16 10:04 ` Eli Zaretskii
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