I'd like to advise a /keybinding/, how do I do it?

I'd like to advise a /keybinding/, how do I do it?

[Marcin Borkowski]

Hello everyone,

what I'd like to do is to "advise a keybinding", IOW, advise whatever
command a given key is bound to.  How do I get the name of the command
given a key, and taking into account the current major mode, minor modes
etc.?

I tried to look at the source code of `describe-key-briefly', but it is
pretty dense, and maybe there's a better way than diving into that
rabbit hole.

The rationale is that I'm thinking about writing a minor mode which
could prevent a "finishing" action until the buffer is ready.
A "finishing" action is often bound to C-c C-c (sending an email and
commiting something to Git come to mind), so I'd like to advise whatever
C-c C-c calls to check the buffer for occurrences of a string like TODO.

Of course, a more robust way would be to have a list of various major
modes and their "finishing" commands, but I think the idea with just
looking up C-c C-c is cute (even if not very robust), and I was
wondering if it can be done in a simple way, even as a toy.

Any ideas?

-- 
Marcin Borkowski
http://mbork.pl

Re: I'd like to advise a /keybinding/, how do I do it?

[Omar Polo]

Marcin Borkowski <mbork@mbork.pl> writes:

> Hello everyone,
>
> what I'd like to do is to "advise a keybinding", IOW, advise whatever
> command a given key is bound to.  How do I get the name of the command
> given a key, and taking into account the current major mode, minor modes
> etc.?
>
> I tried to look at the source code of `describe-key-briefly', but it is
> pretty dense, and maybe there's a better way than diving into that
> rabbit hole.
>
> The rationale is that I'm thinking about writing a minor mode which
> could prevent a "finishing" action until the buffer is ready.
> A "finishing" action is often bound to C-c C-c (sending an email and
> commiting something to Git come to mind), so I'd like to advise whatever
> C-c C-c calls to check the buffer for occurrences of a string like TODO.
>
> Of course, a more robust way would be to have a list of various major
> modes and their "finishing" commands, but I think the idea with just
> looking up C-c C-c is cute (even if not very robust), and I was
> wondering if it can be done in a simple way, even as a toy.
>
> Any ideas?

Probably post-command-hook?  I don't know how to read the current
keybinding, but if it's possible then you can run code in the
post-command-hook and check there

HTH

Re: I'd like to advise a /keybinding/, how do I do it?

[Philip Kaludercic]

Omar Polo <op@omarpolo.com> writes:

> Marcin Borkowski <mbork@mbork.pl> writes:
>
>> Hello everyone,
>>
>> what I'd like to do is to "advise a keybinding", IOW, advise whatever
>> command a given key is bound to.  How do I get the name of the command
>> given a key, and taking into account the current major mode, minor modes
>> etc.?
>>
>> I tried to look at the source code of `describe-key-briefly', but it is
>> pretty dense, and maybe there's a better way than diving into that
>> rabbit hole.
>>
>> The rationale is that I'm thinking about writing a minor mode which
>> could prevent a "finishing" action until the buffer is ready.
>> A "finishing" action is often bound to C-c C-c (sending an email and
>> commiting something to Git come to mind), so I'd like to advise whatever
>> C-c C-c calls to check the buffer for occurrences of a string like TODO.
>>
>> Of course, a more robust way would be to have a list of various major
>> modes and their "finishing" commands, but I think the idea with just
>> looking up C-c C-c is cute (even if not very robust), and I was
>> wondering if it can be done in a simple way, even as a toy.
>>
>> Any ideas?
>
> Probably post-command-hook?  I don't know how to read the current
> keybinding, but if it's possible then you can run code in the
> post-command-hook and check there

Do you mean something like (this-command-keys)? But yes, an advice
system could be built that checks an alist or hash-table in
pre/post-command-hook on what to execute.

> HTH
>
>

-- 
	Philip K.

Re: I'd like to advise a /keybinding/, how do I do it?

[Eli Zaretskii]

> From: Marcin Borkowski <mbork@mbork.pl>
> Date: Wed, 28 Apr 2021 07:25:14 +0200
> 
> what I'd like to do is to "advise a keybinding", IOW, advise whatever
> command a given key is bound to.  How do I get the name of the command
> given a key, and taking into account the current major mode, minor modes
> etc.?

Is key-binding (the function) what you want?

Re: I'd like to advise a /keybinding/, how do I do it?

[Stefan Monnier]

> The rationale is that I'm thinking about writing a minor mode which
> could prevent a "finishing" action until the buffer is ready.
> A "finishing" action is often bound to C-c C-c (sending an email and
> commiting something to Git come to mind), so I'd like to advise whatever
> C-c C-c calls to check the buffer for occurrences of a string like TODO.

"advising the key-binding" would imply changing by side-effect the
underlying major mode's keymap (BTW: yes, it can be done, by defining
`lookup-key` as an lvalue (e.g. with gv-define-setter) after which you
can use `add-function` to modify a key binding).

Or you could do it by advising the command bound to the particular key
(in which case it'll also affect invocations of that command that don't
go through this key binding, e.g. via `M-x`).

Or you could do it with a minor-mode map (i.e. without modifying any
major mode keymap or command), where you bind `C-c C-c` to a command
that either beeps or delegates to the command that it hid (e.g. which
you could find for example with (let ((my-new-minor-mode nil))
(key-binding (this-command-keys))))

Or you could do it with a `pre-command-hook` which checks
`this-command-keys`.

Or the minor-mode map could use a "filtered menu-item" conditional
key-binding.

Or ...


        Stefan

Re: I'd like to advise a /keybinding/, how do I do it?

[Bob Newell]

>> A "finishing" action is often bound to C-c C-c (sending an email and
>> commiting something to Git come to mind), so I'd like to advise whatever
>> C-c C-c calls to check the buffer for occurrences of a string like TODO.

> Or you could do it by advising the command bound to the particular key

I've done this when I want the underlying command to be
affected in all cases. For instance I don't wish send out an
email until I've verified that I have a network connection, so
I advise "message-send" and "message-send-and-exit" rather
than the associated keystrokes.

But be at least a little wary. Sometimes the keystrokes fool
you about the underlying function. In my Gnus reply buffer
right now, C-h k on C-c C-c shows 'orgtbl-ctrl-c-ctrl-c'.

> Or you could do it with a minor-mode map (i.e. without modifying any

I've done this on several occasions when I don't want to mess
with the use of a command outside of a particular minor
mode. That's a less common case, I think, but still very
useful for certain things.

-- 
Bob Newell
Honolulu, Hawai`i

- Via GNU/Linux/Emacs/Gnus/BBDB