How to get the function by the keymap?

[Adam Jiang]

Hi,

I am working on a minor mode in which I want to remap [backspace] key to different functions in different situation. The lisp code looks like

(defun smart-operator-backspace ()
  (interactive)
  (cond ((looking-back "hello"))
     (save-excursion
        (replace-regexp-in-string ".*hello" "" (match-string 1))))
     (t
        (delete-char 1))))


However, (delete-char) never works for me. The reason is another minor mode remapped the backspace key to function 'autopair-backspace'. Then, I realized that I need a method to fetch the function by given keymap and get it called rather thant have hardcoded deletion executed.

How can I do that with elisp code?

/Adam

[Eli Zaretskii]

> Date: Sun, 11 Nov 2012 01:09:02 +0900
> From: Adam Jiang <jiang...@gmail.com>

>
> (defun smart-operator-backspace ()
> (interactive)
> (cond ((looking-back "hello"))
> (save-excursion
> (replace-regexp-in-string ".*hello" "" (match-string 1))))
> (t
> (delete-char 1))))
>
>
> However, (delete-char) never works for me. The reason is another minor mode
> remapped the backspace key to function 'autopair-backspace'. Then, I
> realized that I need a method to fetch the function by given keymap and get
> it called rather thant have hardcoded deletion executed.
>
> How can I do that with elisp code?

I think you want lookup-key or local-key-binding.

[Adam Jiang]

2012/11/11 Le Wang <l26...@gmail.com>

On Sun, Nov 11, 2012 at 12:09 AM, Adam Jiang <jiang...@gmail.com> wrote:
> However, (delete-char) never works for me. The reason is another minor mode
> remapped the backspace key to function 'autopair-backspace'. Then, I
> realized that I need a method to fetch the function by given keymap and get
> it called rather thant have hardcoded deletion executed.
>
> How can I do that with elisp code?

You don't want to dig through the keymaps yourself.  Just take your
minor-mode out of the lookup chain and use `key-binding'.

This is what I do here:

https://github.com/lewang/rebox2/blob/master/rebox2.el#L2363

The code works like a charm. Thank you, Le.
 

The deeper problem is that I have a chain of 3 functions from
different minor-modes all bound to backspace.  They share the key
happily, but Emacs lacks the mechanism to document this calling chain
when I ask about <BACKSPACE> with C-h k.  I described the need to
solve this as a feature request
http://lists.gnu.org/archive/html/help-gnu-emacs/2012-10/msg00465.html
, but there wasn't much interest.  :(

 
It seems this is a good idea. I'd like to help but I am pretty new to elisp. I'll try to get some experience about the keybinding-chain thing first.

Best regards,
/Adam

--
Le