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bug#47992: [External] : bug#47992: 27; 28; Phase out use of `equal` in `
From: |
Drew Adams |
Subject: |
bug#47992: [External] : bug#47992: 27; 28; Phase out use of `equal` in `add-hook`, `remove-hook` |
Date: |
Sat, 24 Apr 2021 21:20:08 +0000 |
> In order to improve the support for closures as hooks,
> this change is necessary.
Necessary? Why? There's no other way to do that?
> It is not reasonable to require every `add-hook` user,
> who wants to add a closure, to introduce a symbol
> indirection.
Why not? "Symbol indirection" just means setting a
symbol's `symbol-function' to the closure, then using
the symbol. Why is doing that a big deal?
It's what anyone should do when using `add|remove-hook',
at least interpreted, and interactively.
I ask again: If closure equality is inherently a
problem, why limit the "solution" to `add|remove-hook'?
Shouldn't your argument be that closure equality should
_always_ be tested (testable) using just `eq'? Is this
really about `add|remove-hook'? Why would they be
special in this regard?
> 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`.
M-: (add-hook 'foo-hook (lambda () (whatever)))
Of course that's generally not advisable, because if
you then want to remove it interactively you'll have
to provide a lambda that's `equal' (with `M-: M-p',
for example). But it's common enough, I think.
It's better, e.g., to defun or fset the lambda form,
and then use the symbol. But I'm guessing that many
users don't always bother, and they're just careful
to respect `equal' (or they soon learn to be).
Emacs's use of Lisp is also interactive, and often ad
hoc. If we lose sight of that we lose sight of Emacs.
> This is more than enough motivation for a change to `eq`.
It's your motivation; understood. Thx.
- bug#47992: 27; 28; Phase out use of `equal` in `add-hook`, `remove-hook`, Daniel Mendler, 2021/04/24
- bug#47992: [External] : bug#47992: 27; 28; Phase out use of `equal` in `add-hook`, `remove-hook`, Drew Adams, 2021/04/24
- bug#47992: [External] : bug#47992: 27; 28; Phase out use of `equal` in `add-hook`, `remove-hook`, Stefan Monnier, 2021/04/24
- bug#47992: [External] : bug#47992: 27; 28; Phase out use of `equal` in `add-hook`, `remove-hook`, Daniel Mendler, 2021/04/24
- bug#47992: [External] : bug#47992: 27; 28; Phase out use of `equal` in `add-hook`, `remove-hook`, Stefan Monnier, 2021/04/24
- bug#47992: [External] : bug#47992: 27; 28; Phase out use of `equal` in `add-hook`, `remove-hook`, Daniel Mendler, 2021/04/24
- bug#47992: [External] : bug#47992: 27; 28; Phase out use of `equal` in `add-hook`, `remove-hook`, Drew Adams, 2021/04/24
- bug#47992: [External] : bug#47992: 27; 28; Phase out use of `equal` in `add-hook`, `remove-hook`, Stefan Monnier, 2021/04/24
- bug#47992: [External] : bug#47992: 27; 28; Phase out use of `equal` in `add-hook`, `remove-hook`, Drew Adams, 2021/04/25
- bug#47992: [External] : bug#47992: 27; 28; Phase out use of `equal` in `add-hook`, `remove-hook`, Stefan Monnier, 2021/04/25
- bug#47992: [External] : bug#47992: 27; 28; Phase out use of `equal` in `add-hook`, `remove-hook`, Drew Adams, 2021/04/24