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From: Daniel Mendler <mail@daniel-mendler.de>
To: Drew Adams <drew.adams@oracle.com>,
	"47992@debbugs.gnu.org" <47992@debbugs.gnu.org>
Cc: "monnier@iro.umontreal.ca" <monnier@iro.umontreal.ca>,
	"jakanakaevangeli@chiru.no" <jakanakaevangeli@chiru.no>
Subject: bug#47992: [External] : bug#47992: 27; 28; Phase out use of `equal` in `add-hook`, `remove-hook`
Date: Sat, 24 Apr 2021 22:23:50 +0200	[thread overview]
Message-ID: <95dee1b3-10c4-24fb-e483-ec3f36bdf5f0@daniel-mendler.de> (raw)
In-Reply-To: <SA2PR10MB4474A35FF2DE9386A0F3F6E3F3449@SA2PR10MB4474.namprd10.prod.outlook.com>

On 4/24/21 10:12 PM, Drew Adams wrote:
> So instead of just advising users not to use lambda forms
> (which makes sense), you'd make it no longer work at all
> for interpreted lambda forms (except rare cases where
> they might actually be `eq' - e.g., same list structure)?

I agree that it makes sense to use symbols in case you want to add a 
plain function as hook. However often you want to add closures; 
`minibuffer-with-setup-hook`, `set-transient-map` and `eval-after-load` 
are examples where this happens. In order to improve the support for 
closures as hooks, this change is necessary.

It is not reasonable to require every `add-hook` user, who wants to add 
a closure, to introduce a symbol indirection. This is neither obvious 
nor easy. Even a very commonly used macro like 
`minibuffer-with-setup-hook` got this wrong.

Furthermore I would argue there are no plausible scenarios where you 
want to add a closure or lambda as hook and then remove or add it again 
afterwards, but not using the identical object, but only an object which 
is `equal`.

This is more than enough motivation for a change to `eq`.

Daniel





  reply	other threads:[~2021-04-24 20:23 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 [this message]
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
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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