[PATCH] Make remove-hook interactive

[PATCH] Make remove-hook interactive

[Thibault Polge]

This makes `remove-hook` interactive.  A common use case for
remove-hook is to fix your own mistakes when programming Emacs:
renaming a hook function for something more expressive, moving a
function to a different hook or from global to local, and so on.  For
these cases, it seems more natural to use the function interactively
than to have to write throwaway lisp one-liners.

A limitation of this approach is that since completion requires a text
representation of the function to remove, if two hooks have the same
representation under `princ` it will be impossible to distinguish
between them.  In this case, which is probably *extremely* rare (and
only concerns anonymous functions), only the first one will be
removed.
---
 lisp/subr.el | 25 ++++++++++++++++++++++++-
 1 file changed, 24 insertions(+), 1 deletion(-)

diff --git a/lisp/subr.el b/lisp/subr.el
index 6e9f66fe97b..ac59ae15465 100644
--- a/lisp/subr.el
+++ b/lisp/subr.el
@@ -1742,7 +1742,30 @@ remove-hook
 list of hooks to run in HOOK, then nothing is done.  See `add-hook'.

 The optional third argument, LOCAL, if non-nil, says to modify
-the hook's buffer-local value rather than its default value."
+the hook's buffer-local value rather than its default value.
+
+Interactively, prompt for the various arguments (skipping local
+unless HOOK has both local and global functions).  If multiple
+functions have the same representation under `princ', the first
+one will be removed."
+  (interactive
+   (let* ((hook (intern (completing-read "Hook variable: " obarray #'boundp t)))
+          (local
+           (and
+            (local-variable-p hook)
+            (symbol-value hook)
+            (or (not (default-value hook)) ; No need to prompt if there's nothing global
+                (y-or-n-p (format "%s has a buffer-local binding, use that? " hook)))))
+          (fn-alist (mapcar
+                     (lambda (x) (cons (with-output-to-string (prin1 x)) x))
+                     (if local (symbol-value hook) (default-value hook))))
+          (function (alist-get (completing-read
+                                (format "%s hook to remove:"
+                                        (if local "Buffer-local" "Global"))
+                                fn-alist
+                                nil t)
+                               fn-alist nil nil 'string=)))
+     (list hook function local)))
   (or (boundp hook) (set hook nil))
   (or (default-boundp hook) (set-default hook nil))
   ;; Do nothing if LOCAL is t but this hook has no local binding.
--
2.29.0

Re: [PATCH] Make remove-hook interactive

[Lars Ingebrigtsen]

Thibault Polge <thibault@thb.lt> writes:

> This makes `remove-hook` interactive.  A common use case for
> remove-hook is to fix your own mistakes when programming Emacs:
> renaming a hook function for something more expressive, moving a
> function to a different hook or from global to local, and so on.  For
> these cases, it seems more natural to use the function interactively
> than to have to write throwaway lisp one-liners.

I think this makes sense, so I'd like to add it to Emacs 28.  However,
it's more code than we can apply without having a copyright assignment
for the FSF.  Would you be willing to sign such paperwork?

-- 
(domestic pets only, the antidote for overdose, milk.)
   bloggy blog: http://lars.ingebrigtsen.no

Re: [PATCH] Make remove-hook interactive

[Thibault Polge]

> I think this makes sense, so I'd like to add it to Emacs 28.  However,
> it's more code than we can apply without having a copyright assignment
> for the FSF.  Would you be willing to sign such paperwork?

Sure, could you please send me the forms?

Regards,

--
Thibault

Re: [PATCH] Make remove-hook interactive

[Lars Ingebrigtsen]

Thibault Polge <thibault@thb.lt> writes:

> Sure, could you please send me the forms?

(Sent off-list.)

-- 
(domestic pets only, the antidote for overdose, milk.)
   bloggy blog: http://lars.ingebrigtsen.no

Re: [PATCH] Make remove-hook interactive

[Thibault Polge]

> Would you be willing to sign such paperwork?

Request sent.  Should I let you know when the process is finished, or
will you be notified?

Best regards,

-- 
Thibault

Re: [PATCH] Make remove-hook interactive

[Lars Ingebrigtsen]

Thibault Polge <thibault@thb.lt> writes:

>> Would you be willing to sign such paperwork?
>
> Request sent.  Should I let you know when the process is finished, or
> will you be notified?

We'll be notified when the process is finished, it'd be good if you
poked us, too, because it's easy to forget these things.

It's probably also a good idea to open a bug report for this, and post
the patch there.  That way we're sure not to lose track of the issue.

-- 
(domestic pets only, the antidote for overdose, milk.)
   bloggy blog: http://lars.ingebrigtsen.no