How to define backslash as keybinding in AUCTeX

Question

I have inserted the following code in my init file. This code insert a space+\ (ie, " \") when typing \ in a buffer.

Despite the fact that the function ddd works without problem in any buffer, the shortcut \ doesn't work when the file is in LaTeX mode (AUCTeX).

Is there any solution to solve this problem, i.e. typing \ executes the function ddd? The function ddd is just an example, the same problem occurs for any function I bind to the backslash.

(defun ddd ()
  "Insert a dollar sign with a space in front."
  (interactive)
  (insert " \\"))

(global-set-key (kbd "\\") 'ddd)

Answer 1

When using AUCTeX, \ is bound to TeX-insert-backslash by default, which you can discover by entering C-h k \ (ie, describe-key) when in a buffer in latex-mode.

If you really want to override TeX-insert-backslash with ddd, define the key in the LaTeX-mode-map as such:

(define-key LaTeX-mode-map (kbd "\\") #'ddd)

You need to bind this key after loading AUCTeX so that Emacs knows about the keymap -- you could, for example, do an eval-after-load to achieve this:

(eval-after-load "latex"
  '(define-key LaTeX-mode-map (kbd "\\") #'ddd))