Emacs Lisp: Create a Hook
You can create a Hook to your major mode, so user can use
add-hook to add functions to call when your mode is activated.
To create a hook, declare a variable like this:
(defvar my-f-hook nil "Hook for function `my-f-hook'.")
(run-hooks 'my-f-hook )
to the function definition
my-f is called, it'll run hook.
(defvar xah-html-browse-url-of-buffer-hook nil "Hook for `xah-html-browse-url-of-buffer'. Hook functions are called before switching to browser.")
(defun xah-html-browse-url-of-buffer () "View current buffer in default browser, but save first. Hook `xah-html-browse-url-of-buffer-hook' is run before saving and before opening in browser. Version 2020-06-26 2021-06-26" (interactive) (let (($url (buffer-file-name))) (run-hooks 'xah-html-browse-url-of-buffer-hook ) (when (buffer-modified-p ) (save-buffer)) (browse-url $url )))
Then, user might add:
(add-hook 'xah-html-browse-url-of-buffer-hook 'xah-clean-whitespace)