Question

I wanted to change the behaviour of Ctrl–d key. So it will delete a word backward. I created a function:

(defun backward-delete-word (arg)
      "Delete characters backward until encountering the beginning of a word.
With argument ARG, do this that many times."
      (interactive "p")
      (delete-region (point) (progn (backward-word arg) (point))))

Then inserted this into emacs.d:

(global-set-key (kbd "\C-d") 'backward-delete-word)

It works in fundamental-mode, but in php-mode it just removes the next character. When I click

Ctrl-h k Ctrl-d

Emacs gives this:

C-d runs the command c-electric-delete-forward, which is an
interactive compiled Lisp function in `cc-cmds.el'.

It is bound to C-d.

(c-electric-delete-forward ARG)

Somehow, it was reset to another function. How to find out, where it was reset and make it work with my function instead?

Answer 1

I don’t have php-mode so I can’t say for sure, but the binding is likely overriden in php-mode-map (which, as a major mode map, has higher precedence than the global map).

You can check by using C-h b to list all available key bindings and look for C-d or c-electric-delete-forward in the output buffer to see in which keymap the binding is defined.

Assuming php-mode-map overrides the C-d binding, you can disable it using

(define-key php-mode-map (kbd "C-d") nil)