Add button with dynamic menu to emacs's modeline?

I'm making my own minor mode for emacs. Now I want to add button to modeline. Click on this button must сause pop-up menu appear. The items of this menu depend on user's actions. I know that there is a way to add a function button to modeline with `minor-mode-alist', but I have no idea how to make dynamic menu.

Solution

I found more proper way: When you define minor mode, you can specify :lighter param

(define-minor-mode my-minor-mode
  "docstring"
  nil
  :lighter (:eval (format "%s%.5s" "#" "some code if you want dynamic label"))
  ;or just string :lighter "static string"
  :keymap my-minor-mode-map
... ... ... rest of code ....

then you can use easymenu:

(require 'easymenu)

(easy-menu-define my-minor-mode-menu
  my-minor-mode-map
  "Menu for my-minor-mode"
   '("some text"
      "-")) ;separator

; and then add menu items with easy-menu-add-item and remove with easy-menu-remove-item
; it's nothing hard. Read the docs ;)

This menu will be added to global menu-bar and it will pop up if you click on auto added(cause you specified :lighter param) minor-mode button on modeline.