I'm trying to write a custom tab completion implementation which tries a bunch of different completions depending on where the point is. However, if none of the conditions for completions are met I would like tab to do what ever the current mode originally intended it to do.
Something like this:
(defun my-custom-tab-completion ()
(interactive)
(cond
(some-condition
(do-something))
(some-other-condition
(do-something-else))
(t
(do-whatever-tab-is-supposed-to-do-in-the-current-mode))) ;; How do I do this?
Currently I'm checking for specific modes and doing the right thing for that mode, but I really would like a solution that just does the right thing without me having to explicitly add a condition for that specific mode.
Any ideas of how to do this?
Thanks! /Erik
You could use functions such as key-binding (or its more specific variants global-key-binding, minor-mode-key-binding and local-key-binding) to probe active keymaps for bindings.
For example:
(call-interactively (key-binding (kbd "TAB")))
;; in an emacs-lisp-mode buffer:
;; --> indent-for-tab-command
;;
;; in a c++-mode buffer with yas/minor-mode:
;; --> yas/expand
One way to avoid infinite loops if your command is bound to TAB could be to put your binding in a minor mode, and temporarily disable its keymap while looking for the TAB binding:
(define-minor-mode my-complete-mode
"Smart completion"
:keymap (let ((map (make-sparse-keymap)))
(define-key map (kbd "TAB") 'my-complete)
map))
(defun my-complete ()
(interactive)
(if (my-condition)
(message "my-complete")
(let ((my-complete-mode nil))
(call-interactively (key-binding (kbd "TAB"))))))