emacs/lisp/menu-bar.el

(define-key global-map [menu-bar] (make-sparse-keymap "menu-bar"))
(setq menu-bar-help-menu (make-sparse-keymap "Help"))
(define-key global-map [menu-bar help] (cons "Help" menu-bar-help-menu))
(setq menu-bar-edit-menu (make-sparse-keymap "Edit"))
(define-key global-map [menu-bar edit] (cons "Edit" menu-bar-edit-menu))
(setq menu-bar-file-menu (make-sparse-keymap "File"))
(define-key global-map [menu-bar file] (cons "File" menu-bar-file-menu))

(define-key menu-bar-file-menu [exit-emacs]
  '("Exit Emacs" . save-buffers-kill-emacs))
(define-key menu-bar-file-menu [kill-buffer]
  '("Kill Buffer" . kill-this-buffer))
(define-key menu-bar-file-menu [delete-frame] '("Delete Frame" . delete-frame))
(define-key menu-bar-file-menu [print-buffer] '("Print Buffer" . print-buffer))
(define-key menu-bar-file-menu [revert-buffer]
  '("Revert Buffer" . revert-buffer))
(define-key menu-bar-file-menu [write-file]
  '("Save Buffer As..." . write-file))
(define-key menu-bar-file-menu [save-buffer] '("Save Buffer" . save-buffer))
(define-key menu-bar-file-menu [open-file] '("Open File..." . find-file))
(define-key menu-bar-file-menu [new-frame] '("New Frame" . new-frame))

(define-key menu-bar-edit-menu [clear] '("Clear" . x-delete-primary-selection))
(define-key menu-bar-edit-menu [paste] '("Paste" . x-yank-clipboard-selection))
(define-key menu-bar-edit-menu [copy] '("Copy" . x-copy-primary-selection))
(define-key menu-bar-edit-menu [cut] '("Cut" . x-kill-primary-selection))
(define-key menu-bar-edit-menu [undo] '("Undo" . advertised-undo))

(define-key menu-bar-help-menu [emacs-tutorial]
  '("Emacs Tutorial" . help-with-tutorial))
(define-key menu-bar-help-menu [man] '("Man..." . manual-entry))
(define-key menu-bar-help-menu [describe-variable]
  '("Describe Variable..." . describe-variable))
(define-key menu-bar-help-menu [describe-function]
  '("Describe Function..." . describe-function))
(define-key menu-bar-help-menu [describe-key]
  '("Describe Key..." . describe-key))
(define-key menu-bar-help-menu [list-keybindings]
  '("List Keybindings" . describe-bindings))
(define-key menu-bar-help-menu [command-apropos]
  '("Command Apropos..." . command-apropos))
(define-key menu-bar-help-menu [describe-mode]
  '("Describe Mode" . describe-mode))
(define-key menu-bar-help-menu [info] '("Info" . info))

(define-key menu-bar-help-menu [emacs-news] '("Emacs News" . view-emacs-news))
(defun kill-this-buffer ()	; for the menubar
  "Kills the current buffer."
  (interactive)
  (kill-buffer (current-buffer)))

(defun kill-this-buffer-enabled-p ()
  (let ((count 0)
	(buffers (buffer-list)))
    (while buffers
      (or (string-match "^ " (buffer-name (car buffers)))
	  (setq count (1+ count)))
      (setq buffers (cdr buffers)))
    (> count 1)))

(put 'save-buffer 'menu-enable '(buffer-modified-p))
(put 'revert-buffer 'menu-enable '(and (buffer-modified-p) (buffer-file-name)))
(put 'delete-frame 'menu-enable '(cdr (visible-frame-list)))
(put 'kill-this-buffer 'menu-enable '(kill-this-buffer-enabled-p))

(put 'x-kill-primary-selection 'menu-enable '(x-selection-owner-p))
(put 'x-copy-primary-selection 'menu-enable '(x-selection-owner-p))
(put 'x-yank-clipboard-selection 'menu-enable '(x-selection-owner-p))
(put 'x-delete-primary-selection 'menu-enable
     '(x-selection-exists-p 'CLIPBOARD))

(put 'advertised-undo 'menu-enable
     '(and (not (eq t buffer-undo-list))
	   (if (eq last-command 'undo)
	       (and (boundp 'pending-undo-list)
		    pending-undo-list)
	     buffer-undo-list)))

(define-key global-map [menu-bar buffer] '("Buffers" . mouse-buffer-menu))

(defvar complex-buffers-menu-p nil
  "*Non-nil says, offer a choice of actions after you pick a buffer.
This applies to the Buffers menu from the menu bar.")

(defvar buffers-menu-max-size 10
  "*Maximum number of entries which may appear on the Buffers menu.
If this is 10, then only the ten most-recently-selected buffers are shown.
If this is nil, then all buffers are shown.
A large number or nil slows down menu responsiveness.")

(defun mouse-buffer-menu (event)
  "Pop up a menu of buffers for selection with the mouse.
This switches buffers in the window that you clicked on,
and selects that window."
  (interactive "e")
  (let ((buffers (buffer-list))
	menu)
    ;; If requested, list only the N most recently selected buffers.
    (if (and (integerp buffers-menu-max-size)
	     (> buffers-menu-max-size 1))
	(if (> (length buffers) buffers-menu-max-size)
	    (setcdr (nthcdr buffers-menu-max-size buffers) nil)))
    (setq menu
	  (list "Buffer Menu"
		(cons "Select Buffer"
		      (let ((tail buffers)
			    (maxlen 0)
			    head)
			(while tail
			  (let ((elt (car tail)))
			    (if (not (string-match "^ "
						   (buffer-name elt)))
				(setq head (cons
					    (cons
					     (format
					      "%14s   %s"
					      (buffer-name elt)
					      (or (buffer-file-name elt) ""))
					     elt)
					    head)))
			    (and head (> (length (car (car head))) maxlen)
				 (setq maxlen (length (car (car head))))))
			  (setq tail (cdr tail)))
			(nconc (reverse head)
			       (list (cons (concat (make-string (- (/ maxlen 2) 8) ?\ )
						   "List All Buffers")
					   'list-buffers)))))))


    (let ((buf (x-popup-menu (if (listp event) event
			       (cons '(0 0) (selected-frame)))
			     menu))
	  (window (and (listp event) (posn-window (event-start event)))))
      (if (eq buf 'list-buffers)
	  (list-buffers)
	(if buf
	    (if complex-buffers-menu-p
		(let ((action (x-popup-menu (if (listp event) event
					      (cons '(0 0) (selected-frame)))
					    '("Buffer Action"
					      (""
					       ("Save Buffer" . save-buffer)
					       ("Kill Buffer" . kill-buffer)
					       ("Select Buffer" . switch-to-buffer))))))
		  (if (eq action 'save-buffer)
		      (save-excursion
			(set-buffer buf)
			(save-buffer))
		    (funcall action buf)))
	      (and (windowp window)
		   (select-window window))
	      (switch-to-buffer buf)))))))

;; this version is too slow
;;;(defun format-buffers-menu-line (buffer)
;;;  "Returns a string to represent the given buffer in the Buffer menu.
;;;nil means the buffer shouldn't be listed.  You can redefine this."
;;;  (if (string-match "\\` " (buffer-name buffer))
;;;      nil
;;;    (save-excursion
;;;     (set-buffer buffer)
;;;     (let ((size (buffer-size)))
;;;       (format "%s%s %-19s %6s %-15s %s"
;;;	       (if (buffer-modified-p) "*" " ")
;;;	       (if buffer-read-only "%" " ")
;;;	       (buffer-name)
;;;	       size
;;;	       mode-name
;;;	       (or (buffer-file-name) ""))))))

(let ((frames (frame-list)))
  (while frames
    (modify-frame-parameters (car frames) '((menu-bar-lines . 1)))
    (setq frames (cdr frames))))
(or (assq 'menu-bar-lines default-frame-alist)
    (setq default-frame-alist
	  (cons '(menu-bar-lines . 1) default-frame-alist)))