How to steal another mode keybindings when you define your minor mode.
I was just trying out org-transclusion, a fantastic little mode that I really needed. Only little problem? When you enable the org-transclusion minor-mode, you would lose Org Mode keybindings. So I decided to fix it (at least for myself).
The secret is in the manual: keymaps inheritance. If you are setting up a new keymap for your minor-mode (so associating keys to your new commands), you can enrich it with an existing keymap by just extending it.
So for org-transclusion we have:
(defvar org-transclusion-map
(let ((map (make-sparse-keymap)))
(define-key map (kbd "e") #'org-transclusion-live-sync-start)
(define-key map (kbd "g") #'org-transclusion-refresh)
(define-key map (kbd "d") #'org-transclusion-remove)
(define-key map (kbd "P") #'org-transclusion-promote-subtree)
(define-key map (kbd "D") #'org-transclusion-demote-subtree)
(define-key map (kbd "o") #'org-transclusion-open-source)
(define-key map (kbd "O") #'org-transclusion-move-to-source)
(define-key map (kbd "TAB") #'org-cycle)
(define-key map (kbd "C-c C-c") #'org-ctrl-c-ctrl-c)
map)
"It is the local-map used within a transclusion.
As the transcluded text content is read-only, these keybindings
are meant to be a sort of contextual menu to trigger different
functions on the transclusion.")
And with inheritance it becomes:
(defvar org-transclusion-map
(let ((map (make-sparse-keymap)))
(set-keymap-parent map org-mode-map)
(define-key map (kbd "e") #'org-transclusion-live-sync-start)
(define-key map (kbd "g") #'org-transclusion-refresh)
(define-key map (kbd "d") #'org-transclusion-remove)
(define-key map (kbd "P") #'org-transclusion-promote-subtree)
(define-key map (kbd "D") #'org-transclusion-demote-subtree)
(define-key map (kbd "o") #'org-transclusion-open-source)
(define-key map (kbd "O") #'org-transclusion-move-to-source)
map)
"It is the local-map used within a transclusion.
As the transcluded text content is read-only, these keybindings
are meant to be a sort of contextual menu to trigger different
functions on the transclusion.")
The trick is (set-keymap-parent map org-mode-map) that does the inheritance.
Happy key-pressing!