How add specifc string(ex: TODO) along with a comment character for a specifc mode?

Question

Based on specific mode, by using a keybinding I want to add a TODO string that is preceded by an unique comment character. For example, (org-mode is exception since ** does not stands for comment and TODO shouldn't followed by :)

• python-mode: => # TODO:
• for script-mode: => # TODO:
• for latex mode: => % TODO:
• for org-mode: => ** TODO

Basically comment character of the current mode on the buffer followed by TODO: .

Answer 1

This function should cover the first cases (comment delimiter followed by " TODO: ")

(defun insert-todo ()
  (interactive "*")
  (insert comment-start " TODO: "))

This one covers the org-mode case:

(defun org-insert-todo ()
  (interactive "*")
  (insert "** TODO "))

You could bind them to a key combination with something like this

(define-key prog-mode-map (kbd "C-c t") #'insert-todo)
(define-key org-mode-map (kbd "C-c t") #'org-insert-todo)

In case you're wondering, the * in the interactive form serves to signal an error when the user invokes the function in a read-only buffer (see the manual).