How to bind a key locally to a buffer (not mode!)

How to bind a key locally to a buffer (not mode!)

[Marcin Borkowski]

Hi all,

(global-set-key ...)

binds a key globally.

(local-set-key ...)

binds a key locally, i.e., in the current major mode.

I'd like to bind a key in /one buffer/ only, so that the rebinding does
not affect other buffers in this mode.  I could probably do it by
defining a minor mode, which rebinds this key to a function, which runs
a function set by a buffer-local variable, but this seems rather
convoluted.  Is there a simpler way to achieve this?

The rationale is that I'd like to have a command which makes an indirect
buffer of the current buffer and sets it into another mode; I'd like to
have then a command (bound to some key) which would kill that buffer
and select the base one back.  I /could/ also make this command
determine the base buffer based on the indirect buffer name (which I
derive from the bas buffer name by means of something like

(concat (buffer-name (current-buffer)) "-some-postfix")

but this doesn't seem too elegant.

Any hints?

-- 
Marcin Borkowski
http://octd.wmi.amu.edu.pl/en/Marcin_Borkowski
Adam Mickiewicz University

Re: How to bind a key locally to a buffer (not mode!)

[John Mastro]

> Marcin Borkowski <mbork@wmi.amu.edu.pl> wrote:
> I'd like to bind a key in /one buffer/ only, so that the rebinding does
> not affect other buffers in this mode.  I could probably do it by
> defining a minor mode, which rebinds this key to a function, which runs
> a function set by a buffer-local variable, but this seems rather
> convoluted.  Is there a simpler way to achieve this?

Why not define a minor mode but, instead of the buffer-local
variable thing, only activate this mode in the buffer where you
want the binding?

-- 
john

Re: How to bind a key locally to a buffer (not mode!)

[Artur Malabarba]

> Hi all,
>
> (global-set-key ...)
>
> binds a key globally.
>
> (local-set-key ...)
>
> binds a key locally, i.e., in the current major mode.
>
> I'd like to bind a key in /one buffer/ only, so that the rebinding does
> not affect other buffers in this mode.  I could probably do it by
> defining a minor mode, which rebinds this key to a function, which runs
> a function set by a buffer-local variable, but this seems rather
> convoluted.  Is there a simpler way to achieve this?

There is, I used to do this in one of my org buffers. I forget the exact
code now, but I'll look for it.

You essentially split the current buffer's keymap from its major mode, and
then call local set key.

Re: How to bind a key locally to a buffer (not mode!)

[Artur Malabarba]

Here it is:

(use-local-map (copy-keymap (current-local-map)))
(local-set-key "x" #'some-function)

This will bind x to some-function only on the current buffer.

Re: How to bind a key locally to a buffer (not mode!)

[Marcin Borkowski]

On 2014-10-20, at 14:16, Artur Malabarba wrote:

> Here it is:
>
> (use-local-map (copy-keymap (current-local-map)))
> (local-set-key "x" #'some-function)
>
> This will bind x to some-function only on the current buffer.

Cool, thanks!  Though I ended up defining a minor mode (which has its
advantages, too, like the "lighter").

Best,

-- 
Marcin Borkowski
http://octd.wmi.amu.edu.pl/en/Marcin_Borkowski
Adam Mickiewicz University

Re: How to bind a key locally to a buffer (not mode!)

[Pascal J. Bourguignon]

Artur Malabarba <bruce.connor.am@gmail.com> writes:

>> Hi all,
>>
>> (global-set-key ...)
>>
>> binds a key globally.
>>
>> (local-set-key ...)
>>
>> binds a key locally, i.e., in the current major mode.
>>
>> I'd like to bind a key in /one buffer/ only, so that the rebinding does
>> not affect other buffers in this mode.  I could probably do it by
>> defining a minor mode, which rebinds this key to a function, which runs
>> a function set by a buffer-local variable, but this seems rather
>> convoluted.  Is there a simpler way to achieve this?
>
> There is, I used to do this in one of my org buffers. I forget the exact
> code now, but I'll look for it.
>
> You essentially split the current buffer's keymap from its major mode, and
> then call local set key.

1. C-h f local-set-key RET

2. the documentation of local-set-key tells you how to do it:

       The binding goes in the current buffer's local map,
       which in most cases is shared with all other buffers in the same major mode.

   Therefore you should create a buffer local map distinct from the major
   mode map.

3. M-x apropos RET local map RET

4. find a command that lets you create a local keymap.

5. use local-set-key with the new buffer local map.


-- 
__Pascal Bourguignon__                 http://www.informatimago.com/
“The factory of the future will have only two employees, a man and a
dog. The man will be there to feed the dog. The dog will be there to
keep the man from touching the equipment.” -- Carl Bass CEO Autodesk

Re: How to bind a key locally to a buffer (not mode!)

[Stefan Monnier]

> I'd like to bind a key in /one buffer/ only, so that the rebinding does
> not affect other buffers in this mode.

As mentioned, you can use a minor mode for that (and only enable it in
the current buffer).  If you want this binding to have lower precedence
than the minor mode, you can use something like:

    (use-local-map (make-composed-keymap nil (current-local-map)))
    (local-set-key ...)

Where the first line changes the local map in the current buffer to use
a fresh new keymap which inherits from the previous one (the previous
one is assumed to be the one set by the major mode).


        Stefan

Re: How to bind a key locally to a buffer (not mode!)

[Joost Kremers]

Marcin Borkowski wrote:
> I'd like to bind a key in /one buffer/ only, so that the rebinding does
> not affect other buffers in this mode.  I could probably do it by
> defining a minor mode, which rebinds this key to a function, which runs
> a function set by a buffer-local variable, but this seems rather
> convoluted.  Is there a simpler way to achieve this?

Define a minor mode that binds that key and only activate it in the
buffer you want it in.

> The rationale is that I'd like to have a command which makes an indirect
> buffer of the current buffer and sets it into another mode; I'd like to
> have then a command (bound to some key) which would kill that buffer
> and select the base one back.  I /could/ also make this command
> determine the base buffer based on the indirect buffer name (which I
> derive from the bas buffer name by means of something like
>
> (concat (buffer-name (current-buffer)) "-some-postfix")
>
> but this doesn't seem too elegant.

I don't see why that wouldn't be elegant. IMHO it's more elegant than
defining a special minor mode for the sole purpose of being able to
return to the correct base buffer.

BTW, are you aware of the function `buffer-base-buffer'? It tells you
what the base buffer of an indirect buffer is. No need to mess with
buffer-local key bindings or buffer names or what have you... :-)


-- 
Joost Kremers                                   joostkremers@fastmail.fm
Selbst in die Unterwelt dringt durch Spalten Licht
EN:SiS(9)