;;; easymenu.el --- support the easymenu interface for defining a menu.

;; Copyright (C) 1994 Free Software Foundation, Inc.

;; Keywords: emulations
;; Author: rms

;; This file is part of GNU Emacs.

;; GNU Emacs is free software; you can redistribute it and/or modify
;; it under the terms of the GNU General Public License as published by
;; the Free Software Foundation; either version 2, or (at your option)
;; any later version.

;; GNU Emacs is distributed in the hope that it will be useful,
;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
;; GNU General Public License for more details.

;; You should have received a copy of the GNU General Public License
;; along with GNU Emacs; see the file COPYING.  If not, write to
;; the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.

;;; This is compatible with easymenu.el by Per Abrahamsen
;;; but it is much simpler as it doesn't try to support other Emacs versions.
;;; The code was mostly derived from lmenu.el.

;;; Code:

;;;###autoload
(defmacro easy-menu-define (symbol maps doc menu)
  "Define a menu bar submenu in maps MAPS, according to MENU.
SYMBOL is used as a variable to hold the menu data.  It is not evaluated.
DOC is a doc string for that variable.

The first element of MENU must be a string.  It is the menu bar item name.
The rest of the elements are menu items.

A menu item is usually a vector of three elements:  [NAME CALLBACK ENABLE]

NAME is a string--the menu item name.

CALLBACK is a command to run when the item is chosen,
or a list to evaluate when the item is chosen.

ENABLE is an expression; the item is enabled for selection
whenever this expression's value is non-nil.

Alternatively, a menu item may have the form: 

   [ NAME CALLBACK [ KEYWORD ARG ] ... ]

Where KEYWORD is one of the symbol defined below.

   :keys KEYS

KEYS is a string; a complex keyboard equivalent to this menu item.
This is normally not needed because keyboard equivalents are usually
computed automatically.

   :active ENABLE

ENABLE is an expression; the item is enabled for selection
whenever this expression's value is non-nil.

   :suffix NAME

NAME is a string; the name of an argument to CALLBACK.

   :style 
   
STYLE is a symbol describing the type of menu item.  The following are
defined:  

toggle: A checkbox.  
        Currently just prepend the name with the string \"Toggle \".
radio: A radio button. 
nil: An ordinary menu item.

   :selected SELECTED

SELECTED is an expression; the checkbox or radio button is selected
whenever this expression's value is non-nil.
Currently just disable radio buttons, no effect on checkboxes.

A menu item can be a string.  Then that string appears in the menu as
unselectable text.  A string consisting solely of hyphens is displayed
as a solid horizontal line.

A menu item can be a list.  It is treated as a submenu.
The first element should be the submenu name.  That's used as the
menu item in the top-level menu.  The cdr of the submenu list
is a list of menu items, as above."
  (` (progn
       (defvar (, symbol) nil (, doc))
       (easy-menu-do-define (quote (, symbol)) (, maps) (, doc) (, menu)))))

(defun easy-menu-do-define (symbol maps doc menu)
  ;; We can't do anything that might differ between Emacs dialects in
  ;; `easy-menu-define' in order to make byte compiled files
  ;; compatible.  Therefore everything interesting is done in this
  ;; function. 
  (set symbol (easy-menu-create-keymaps (car menu) (cdr menu)))
  (fset symbol (` (lambda (event) (, doc) (interactive "@e")
		    (easy-popup-menu event (, symbol)))))
  (mapcar (function (lambda (map) 
	    (define-key map (vector 'menu-bar (intern (car menu)))
	      (cons (car menu) (symbol-value symbol)))))
	  (if (keymapp maps) (list maps) maps)))

(defvar easy-menu-item-count 0)

;; Return a menu keymap corresponding to a Lucid-style menu list
;; MENU-ITEMS, and with name MENU-NAME.
;;;###autoload
(defun easy-menu-create-keymaps (menu-name menu-items)
  (let ((menu (make-sparse-keymap menu-name)))
    ;; Process items in reverse order,
    ;; since the define-key loop reverses them again.
    (setq menu-items (reverse menu-items))
    (while menu-items
      (let* ((item (car menu-items))
	     (callback (if (vectorp item) (aref item 1)))
	     command enabler name)
	(cond ((stringp item)
	       (setq command nil)
	       (setq name (if (string-match "^-+$" item) "" item)))
	      ((consp item)
	       (setq command (easy-menu-create-keymaps (car item) (cdr item)))
	       (setq name (car item)))
	      ((vectorp item)
	       (setq command (make-symbol (format "menu-function-%d"
						  easy-menu-item-count)))
	       (setq easy-menu-item-count (1+ easy-menu-item-count))
	       (setq name (aref item 0))
	       (let ((keyword (aref item 2)))
		 (if (and (symbolp keyword)
			  (= ?: (aref (symbol-name keyword) 0)))
		     (let ((count 2)
			   style selected active keys
			   arg)
		       (while (> (length item) count)
			 (setq keyword (aref item count))
			 (setq arg (aref item (1+ count)))
			 (setq count (+ 2 count))
			 (cond ((eq keyword ':keys)
				(setq keys arg))
			       ((eq keyword ':active)
				(setq active arg))
			       ((eq keyword ':suffix)
				(setq name (concat name " " arg)))
			       ((eq keyword ':style)
				(setq style arg))
			       ((eq keyword ':selected)
				(setq selected arg))))
		       (if keys
			   (setq name (concat name "  (" keys ")")))
		       (if (eq style 'toggle)
			   ;; Simulate checkboxes.
			   (setq name (concat "Toggle " name)))
		       (if active 
			   (put command 'menu-enable active)
			 (and (eq style 'radio)
			      selected
			      ;; Simulate radio buttons with menu-enable.
			      (put command 'menu-enable
				   (list 'not selected)))))))	       
	       (if (keymapp callback)
		   (setq name (concat name " ...")))
	       (if (symbolp callback)
		   (fset command callback)
		 (fset command (list 'lambda () '(interactive) callback)))))
	(if (null command)
	    ;; Handle inactive strings specially--allow any number
	    ;; of identical ones.
	    (setcdr menu (cons (list nil name) (cdr menu)))
	  (if name 
	      (define-key menu (vector (intern name)) (cons name command)))))
      (setq menu-items (cdr menu-items)))
    menu))

(defun easy-menu-change (path name items)
  "Change menu found at PATH as item NAME to contain ITEMS.
PATH is a list of strings for locating the menu containing NAME in the
menu bar.  ITEMS is a list of menu items, as in `easy-menu-define'.
These items entirely replace the previous items in that map.

Call this from `activate-menubar-hook' to implement dynamic menus."
  (let ((map (key-binding (apply 'vector
				 'menu-bar
				 (mapcar 'intern (append path (list name)))))))
    (if (keymapp map)
	(setcdr map (cdr (easy-menu-create-keymaps name items)))
      (error "Malformed menu in `easy-menu-change'"))))

(defun easy-menu-remove (menu))

(defun easy-menu-add (menu &optional map))

(provide 'easymenu)

;;; easymenu.el ends here