key interception in major mode

key interception in major mode

[Anton V. Belyaev]

I am writing my own major mode. How can I make my own function called
on every key press?
I tried to create a copy of global map, replacing self-insert-command
function with my own, but failed. Maybe there is another way to achieve
key interception in major mode?

Re: key interception in major mode

[Ian Zimmerman]

Anton> I am writing my own major mode. How can I make my own function
Anton> called on every key press?  I tried to create a copy of global
Anton> map, replacing self-insert-command function with my own, but
Anton> failed. Maybe there is another way to achieve key interception in
Anton> major mode?

First of all, it is not clear what you mean by "called on every key
press".  `self-insert-command' certainly isn't called on every key press
from my POV; for example, it isn't called when you press the TAB key.
(unless a major mode overrides its binding in the global map, of
course).

That said, here is one way (though probably not the cleanest way) of
doing something along the lines you did: define an advice (see the
online help for `defadvice') for `self-insert-command'; the adviced
function should first check the major mode (variable `major-mode')
and either do your thing or else the usual thing (`ad-do-it').

-- 
A true pessimist won't be discouraged by a little success.

Re: key interception in major mode

[Stefan Monnier]

> I am writing my own major mode. How can I make my own function called
> on every key press?

(define-key my-major-mode-map [t] 'my-own-special-catch-all-function)

Most likely it's not going to do what you want, tho.  Please give us
more details.


        Stefan

Re: key interception in major mode

[Anton V. Belyaev]

Thank you for your reply.

I want to handle all the aphabetic characters. Of cource I could
(define-key) for all of them, but it is not a clean solution either.

For example, it should be possible to track all the keypresses for
certaiin buffer. Another example: I want to write a mode, where every
word starts with a capital letter. So on every character typed I should
insert upper or lower case letter.

Re: key interception in major mode

[Stefan Monnier]

> Thank you for your reply.
> I want to handle all the aphabetic characters.  Of cource I could
> (define-key) for all of them, but it is not a clean solution either.

> For example, it should be possible to track all the keypresses for
> certaiin buffer. Another example: I want to write a mode, where every
> word starts with a capital letter. So on every character typed I should
> insert upper or lower case letter.

Check autocap.el for an example.  I'm not sure what it uses, tho.
In any case, I guess post-command-hook is one way to do it.
auto-fill-function is another.


        Stefan

Re: key interception in major mode

[Anton V. Belyaev]

Thank you for your solution. Though it doesnt look clean it should work
anyway :)