From: Lars Ingebrigtsen <larsi@gnus.org>
To: Daniel Mendler <mail@daniel-mendler.de>
Cc: 47992@debbugs.gnu.org, monnier@iro.umontreal.ca,
jakanakaevangeli@chiru.no
Subject: bug#47992: 27; 28; Phase out use of `equal` in `add-hook`, `remove-hook`
Date: Sun, 02 May 2021 11:09:48 +0200 [thread overview]
Message-ID: <87mttdh57n.fsf@gnus.org> (raw)
In-Reply-To: <a9335e6c-e261-59a0-d59a-7dbb70d6dba6@daniel-mendler.de> (Daniel Mendler's message of "Sat, 24 Apr 2021 14:11:48 +0200")
Daniel Mendler <mail@daniel-mendler.de> writes:
> It would be good to change `add/remove-hook` such that it only relies
> on `eq` to test hook equality. Then the symbol indirection workarounds
> can be avoided.
>
> However making such a change directly can lead to subtle
> breakage. Perhaps one could introduce some deprecation behavior first,
> before making the final change to `eq`. If a hook is added/removed
> and the added/removed object is not found via `eq` but found via
> `equal`, show a deprecation warning?
There are two issues here:
1) Should `add/remove-hook' even attempt to do uniqueness checks when
adding/removing things that aren't symbols (or more generally, eq-able
things), and
2) Should `add-hook' disallow adding such things?
Today, it's super common for people to say
(add-hook 'some-hook (lambda () ...))
in their .emacs files. This isn't because they have any expectation
that add-hook does this uniquely, or that remove-hook will work, but
because that's just what they think they should do.
So I think 2) is out of the question -- we can't deprecate this, and we
can't issue any warnings about doing it this way. (Even if it's
"wrong" -- it's just not feasible to disallow this.)
And since 2) isn't possible, I don't really think 1) is possible
either. People do `M-x eval-buffer' their .emacs files, and since we're
using `equal' here, this happens to work -- almost by accident.
(If they change the lambda, then they get two instances of the lambda in
the hook, so it's "wrong", but it's so common.)
So I'm not sure I see any way forward with this. Would adding a new
pair of functions (that are `eq' only) help in any way?
--
(domestic pets only, the antidote for overdose, milk.)
bloggy blog: http://lars.ingebrigtsen.no
next prev parent reply other threads:[~2021-05-02 9:09 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-24 12:11 bug#47992: 27; 28; Phase out use of `equal` in `add-hook`, `remove-hook` Daniel Mendler
2021-04-24 20:12 ` bug#47992: [External] : " Drew Adams
2021-04-24 20:23 ` Daniel Mendler
2021-04-24 21:20 ` Drew Adams
2021-04-24 21:34 ` Daniel Mendler
2021-04-24 22:30 ` Stefan Monnier
2021-04-24 22:38 ` Daniel Mendler
2021-04-24 23:04 ` Stefan Monnier
2021-04-24 23:38 ` Daniel Mendler
2021-04-25 1:16 ` Drew Adams
2021-04-25 3:08 ` Stefan Monnier
2021-04-25 4:57 ` Drew Adams
2021-04-25 13:52 ` Stefan Monnier
2021-04-25 1:16 ` Drew Adams
2021-04-25 1:23 ` Drew Adams
2021-04-25 3:10 ` Stefan Monnier
2021-04-25 4:57 ` Drew Adams
2021-04-25 10:33 ` Daniel Mendler
2021-04-25 13:56 ` Stefan Monnier
2021-05-02 9:09 ` Lars Ingebrigtsen [this message]
2021-05-02 10:37 ` Daniel Mendler
2021-05-03 8:50 ` Lars Ingebrigtsen
2021-07-06 14:44 ` Olivier Certner
[not found] ` <877di6udfy.fsf@web.de>
2021-07-04 1:09 ` Lars Ingebrigtsen
2021-07-04 2:35 ` Michael Heerdegen
2021-07-04 2:56 ` Lars Ingebrigtsen
2021-07-04 4:28 ` Michael Heerdegen
2021-07-04 13:36 ` Lars Ingebrigtsen
2021-07-04 17:08 ` bug#47992: [External] : " Drew Adams
2021-07-04 22:45 ` Michael Heerdegen
2021-07-05 12:39 ` Lars Ingebrigtsen
2021-07-06 1:48 ` Richard Stallman
2021-07-06 2:37 ` bug#47992: [External] : " Drew Adams
2021-07-06 3:21 ` Michael Heerdegen
2021-07-07 23:57 ` Richard Stallman
2021-07-06 9:46 ` Arthur Miller
2021-07-07 23:57 ` Richard Stallman
2021-07-08 2:11 ` Arthur Miller
2021-07-04 23:15 ` Michael Heerdegen
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