code.delx.au - gnu-emacs/blob - lisp/emacs-lisp/lmenu.el

   1 ;;; lmenu.el --- emulate Lucid's menubar support
   2
   3 ;; Keywords: emulations
   4
   5 ;; Copyright (C) 1992, 1993 Free Software Foundation, Inc.
   6
   7 ;; This file is part of GNU Emacs.
   8
   9 ;; GNU Emacs is free software; you can redistribute it and/or modify
  10 ;; it under the terms of the GNU General Public License as published by
  11 ;; the Free Software Foundation; either version 2, or (at your option)
  12 ;; any later version.
  13
  14 ;; GNU Emacs is distributed in the hope that it will be useful,
  15 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  16 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17 ;; GNU General Public License for more details.
  18
  19 ;; You should have received a copy of the GNU General Public License
  20 ;; along with GNU Emacs; see the file COPYING.  If not, write to
  21 ;; the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
  22
  23 ;;; Code:
  24
  25 \f
  26 ;; First, emulate the Lucid menubar support in GNU Emacs 19.
  27
  28 ;; Arrange to use current-menubar to set up part of the menu bar.
  29
  30 (setq recompute-lucid-menubar 'recompute-lucid-menubar)
  31 (defun recompute-lucid-menubar ()
  32   (define-key lucid-menubar-map [menu-bar]
  33     (condition-case nil
  34         (make-lucid-menu-keymap "menu-bar" current-menubar)
  35       (error (message "Invalid data in current-menubar moved to lucid-failing-menubar")
  36              (sit-for 1)
  37              (setq lucid-failing-menubar current-menubar
  38                    current-menubar nil))))
  39   (setq lucid-menu-bar-dirty-flag nil))
  40
  41 (defvar lucid-menubar-map (make-sparse-keymap))
  42 (or (assq 'current-menubar minor-mode-map-alist)
  43     (setq minor-mode-map-alist
  44           (cons (cons 'current-menubar lucid-menubar-map)
  45                 minor-mode-map-alist)))
  46
  47 (defun set-menubar-dirty-flag ()
  48   (force-mode-line-update)
  49   (setq lucid-menu-bar-dirty-flag t))
  50
  51 (defvar add-menu-item-count 0)
  52
  53 ;; Return a menu keymap corresponding to a Lucid-style menu list
  54 ;; MENU-ITEMS, and with name MENU-NAME.
  55 (defun make-lucid-menu-keymap (menu-name menu-items)
  56   (let ((menu (make-sparse-keymap menu-name)))
  57     ;; Process items in reverse order,
  58     ;; since the define-key loop reverses them again.
  59     (setq menu-items (reverse menu-items))
  60     (while menu-items
  61       (let* ((item (car menu-items))
  62              (callback (if (vectorp item) (aref item 1)))
  63              command enabler name)
  64         (cond ((stringp item)
  65                (setq command nil)
  66                (setq name item))
  67               ((consp item)
  68                (setq command (make-lucid-menu-keymap (car item) (cdr item)))
  69                (setq name (car item)))
  70               ((vectorp item)
  71                (setq command (make-symbol (format "menu-function-%d"
  72                                                   add-menu-item-count)))
  73                (setq enabler (make-symbol (format "menu-function-%d-enabler"
  74                                                   add-menu-item-count)))
  75                (setq add-menu-item-count (1+ add-menu-item-count))
  76                (put command 'menu-enable enabler)
  77                (set enabler (aref item 2))
  78                (setq name (aref item 0))
  79                (if (symbolp callback)
  80                    (fset command callback)
  81                  (fset command (list 'lambda () '(interactive) callback)))))
  82         (if name
  83             (define-key menu (vector (intern name)) (cons name command))))
  84       (setq menu-items (cdr menu-items)))
  85     menu))
  86
  87 (defun popup-menu (menu-desc)
  88   "Pop up the given menu.
  89 A menu is a list of menu items, strings, and submenus.
  90
  91 The first element of a menu must be a string, which is the name of the
  92 menu.  This is the string that will be displayed in the parent menu, if
  93 any.  For toplevel menus, it is ignored.  This string is not displayed
  94 in the menu itself.
  95
  96 A menu item is a vector of three or four elements:
  97
  98  - the name of the menu item (a string);
  99  - the `callback' of that item;
 100  - whether this item is active (selectable);
 101  - and an optional string to append to the name.
 102
 103 If the `callback' of a menu item is a symbol, then it must name a command.
 104 It will be invoked with `call-interactively'.  If it is a list, then it is
 105 evaluated with `eval'.
 106
 107 The fourth element of a menu item is a convenient way of adding the name
 108 of a command's ``argument'' to the menu, like ``Kill Buffer NAME''.
 109
 110 If an element of a menu is a string, then that string will be presented in
 111 the menu as unselectable text.
 112
 113 If an element of a menu is a string consisting solely of hyphens, then that
 114 item will be presented as a solid horizontal line.
 115
 116 If an element of a menu is a list, it is treated as a submenu.  The name of
 117 that submenu (the first element in the list) will be used as the name of the
 118 item representing this menu on the parent.
 119
 120 The syntax, more precisely:
 121
 122    form         :=  <something to pass to `eval'>
 123    command      :=  <a symbol or string, to pass to `call-interactively'>
 124    callback     :=  command | form
 125    active-p     :=  <t or nil, whether this thing is selectable>
 126    text         :=  <string, non selectable>
 127    name         :=  <string>
 128    argument     :=  <string>
 129    menu-item    :=  '['  name callback active-p [ argument ]  ']'
 130    menu         :=  '(' name [ menu-item | menu | text ]+ ')'
 131 "
 132   (let ((menu (make-lucid-menu-keymap (car menu-desc) (cdr menu-desc)))
 133         (pos (mouse-position))
 134         answer)
 135     (setq answer (x-popup-menu (list (list (nth 1 pos) (nthcdr 2 pos))
 136                                      (car pos))
 137                                menu))
 138     (setq cmd (lookup-key menu (vector answer)))
 139     (if cmd (call-interactively cmd))))
 140 \f
 141 (defconst default-menubar
 142   '(("File"     ["New Frame"            x-new-frame             t]
 143                 ["Open File..."         find-file               t]
 144                 ["Save Buffer"          save-buffer             t  nil]
 145                 ["Save Buffer As..."    write-file              t]
 146                 ["Revert Buffer"        revert-buffer           t  nil]
 147                 "-----"
 148                 ["Print Buffer"         lpr-buffer              t  nil]
 149                 "-----"
 150                 ["Delete Frame"         delete-frame            t]
 151 ;;              ["Kill Buffer..."       kill-buffer             t]
 152                 ["Kill Buffer"          kill-this-buffer        t  nil]
 153                 ["Exit Emacs"           save-buffers-kill-emacs t]
 154                 )
 155     ("Edit"     ["Undo"                 advertised-undo            t]
 156                 ["Cut"                  x-kill-primary-selection   t]
 157                 ["Copy"                 x-copy-primary-selection   t]
 158                 ["Paste"                x-yank-clipboard-selection t]
 159                 ["Clear"                x-delete-primary-selection t]
 160                 )
 161     ("Buffers"  "")
 162
 163     nil         ; the partition: menus after this are flushright
 164
 165     ("Help"     ["Info"                 info                    t]
 166                 ["Describe Mode"        describe-mode           t]
 167                 ["Command Apropos..."   command-apropos         t]
 168                 ["List Keybindings"     describe-bindings       t]
 169                 ["Describe Key..."      describe-key            t]
 170                 ["Describe Function..." describe-function       t]
 171                 ["Describe Variable..." describe-variable       t]
 172                 "-----"
 173                 ["Man..."               manual-entry            t]
 174                 ["Emacs Tutorial"       help-with-tutorial      t]
 175                 ["Emacs News"           view-emacs-news         t]
 176                 )
 177     ))
 178
 179
 180 (defun kill-this-buffer ()      ; for the menubar
 181   "Kills the current buffer."
 182   (interactive)
 183   (kill-buffer (current-buffer)))
 184
 185 (defun x-new-frame (&optional frame-name)
 186   "Creates a new Emacs frame (that is, a new X window.)"
 187   (interactive)
 188   (select-frame (x-create-frame
 189                   (append (if frame-name
 190                               (list (cons 'name frame-name))
 191                             nil)
 192                           frame-default-alist)))
 193   (switch-to-buffer (get-buffer-create "*scratch*"))
 194   )
 195
 196 (defun set-menubar (menubar)
 197   "Set the default menubar to be menubar."
 198   (setq-default current-menubar (copy-sequence menubar))
 199   (set-menubar-dirty-flag))
 200
 201 (defun set-buffer-menubar (menubar)
 202   "Set the buffer-local menubar to be menubar."
 203   (make-local-variable 'current-menubar)
 204   (setq current-menubar (copy-sequence menubar))
 205   (set-menubar-dirty-flag))
 206
 207 \f
 208 ;;; menu manipulation functions
 209
 210 (defun find-menu-item (menubar item-path-list &optional parent)
 211   "Searches MENUBAR for item given by ITEM-PATH-LIST.
 212 Returns (ITEM . PARENT), where PARENT is the immediate parent of
 213  the item found.
 214 Signals an error if the item is not found."
 215   (or parent (setq item-path-list (mapcar 'downcase item-path-list)))
 216   (if (not (consp menubar))
 217       nil
 218     (let ((rest menubar)
 219           result)
 220       (while rest
 221         (if (and (car rest)
 222                  (equal (car item-path-list)
 223                         (downcase (if (vectorp (car rest))
 224                                       (aref (car rest) 0)
 225                                     (if (stringp (car rest))
 226                                         (car rest)
 227                                       (car (car rest)))))))
 228             (setq result (car rest) rest nil)
 229           (setq rest (cdr rest))))
 230       (if (cdr item-path-list)
 231           (if (consp result)
 232               (find-menu-item (cdr result) (cdr item-path-list) result)
 233             (if result
 234                 (signal 'error (list "not a submenu" result))
 235               (signal 'error (list "no such submenu" (car item-path-list)))))
 236         (cons result parent)))))
 237
 238
 239 (defun disable-menu-item (path)
 240   "Make the named menu item be unselectable.
 241 PATH is a list of strings which identify the position of the menu item in
 242 the menu hierarchy.  (\"File\" \"Save\") means the menu item called \"Save\"
 243 under the toplevel \"File\" menu.  (\"Menu\" \"Foo\" \"Item\") means the
 244 menu item called \"Item\" under the \"Foo\" submenu of \"Menu\"."
 245   (let* ((menubar current-menubar)
 246          (pair (find-menu-item menubar path))
 247          (item (car pair))
 248          (menu (cdr pair)))
 249     (or item
 250         (signal 'error (list (if menu "No such menu item" "No such menu")
 251                              path)))
 252     (if (consp item) (error "can't disable menus, only menu items"))
 253     (aset item 2 nil)
 254     (set-menubar-dirty-flag)
 255     item))
 256
 257
 258 (defun enable-menu-item (path)
 259   "Make the named menu item be selectable.
 260 PATH is a list of strings which identify the position of the menu item in
 261 the menu hierarchy.  (\"File\" \"Save\") means the menu item called \"Save\"
 262 under the toplevel \"File\" menu.  (\"Menu\" \"Foo\" \"Item\") means the
 263 menu item called \"Item\" under the \"Foo\" submenu of \"Menu\"."
 264   (let* ((menubar current-menubar)
 265          (pair (find-menu-item menubar path))
 266          (item (car pair))
 267          (menu (cdr pair)))
 268     (or item
 269         (signal 'error (list (if menu "No such menu item" "No such menu")
 270                              path)))
 271     (if (consp item) (error "%S is a menu, not a menu item" path))
 272     (aset item 2 t)
 273     (set-menubar-dirty-flag)
 274     item))
 275
 276
 277 (defun add-menu-item-1 (item-p menu-path item-name item-data enabled-p before)
 278   (if before (setq before (downcase before)))
 279   (let* ((menubar current-menubar)
 280          (menu (condition-case ()
 281                    (car (find-menu-item menubar menu-path))
 282                  (error nil)))
 283          (item (if (listp menu)
 284                    (car (find-menu-item (cdr menu) (list item-name)))
 285                  (signal 'error (list "not a submenu" menu-path)))))
 286     (or menu
 287         (let ((rest menu-path)
 288               (so-far menubar))
 289           (while rest
 290 ;;;         (setq menu (car (find-menu-item (cdr so-far) (list (car rest)))))
 291             (setq menu
 292                   (if (eq so-far menubar)
 293                       (car (find-menu-item so-far (list (car rest))))
 294                     (car (find-menu-item (cdr so-far) (list (car rest))))))
 295             (or menu
 296                 (let ((rest2 so-far))
 297                   (while (and (cdr rest2) (car (cdr rest2)))
 298                     (setq rest2 (cdr rest2)))
 299                   (setcdr rest2
 300                   (nconc (list (setq menu (list (car rest))))
 301                          (cdr rest2)))))
 302             (setq so-far menu)
 303             (setq rest (cdr rest)))))
 304     (or menu (setq menu menubar))
 305     (if item
 306         nil     ; it's already there
 307       (if item-p
 308           (setq item (vector item-name item-data enabled-p))
 309         (setq item (cons item-name item-data)))
 310       ;; if BEFORE is specified, try to add it there.
 311       (if before
 312           (setq before (car (find-menu-item menu (list before)))))
 313       (let ((rest menu)
 314             (added-before nil))
 315         (while rest
 316           (if (eq before (car (cdr rest)))
 317               (progn
 318                 (setcdr rest (cons item (cdr rest)))
 319                 (setq rest nil added-before t))
 320             (setq rest (cdr rest))))
 321         (if (not added-before)
 322             ;; adding before the first item on the menubar itself is harder
 323             (if (and (eq menu menubar) (eq before (car menu)))
 324                 (setq menu (cons item menu)
 325                       current-menubar menu)
 326               ;; otherwise, add the item to the end.
 327               (nconc menu (list item))))))
 328     (if item-p
 329         (progn
 330           (aset item 1 item-data)
 331           (aset item 2 (not (null enabled-p))))
 332       (setcar item item-name)
 333       (setcdr item item-data))
 334     (set-menubar-dirty-flag)
 335     item))
 336
 337 (defun add-menu-item (menu-path item-name function enabled-p &optional before)
 338   "Add a menu item to some menu, creating the menu first if necessary.
 339 If the named item exists already, it is changed.
 340 MENU-PATH identifies the menu under which the new menu item should be inserted.
 341  It is a list of strings; for example, (\"File\") names the top-level \"File\"
 342  menu.  (\"File\" \"Foo\") names a hypothetical submenu of \"File\".
 343 ITEM-NAME is the string naming the menu item to be added.
 344 FUNCTION is the command to invoke when this menu item is selected.
 345  If it is a symbol, then it is invoked with `call-interactively', in the same
 346  way that functions bound to keys are invoked.  If it is a list, then the
 347  list is simply evaluated.
 348 ENABLED-P controls whether the item is selectable or not.
 349 BEFORE, if provided, is the name of a menu item before which this item should
 350  be added, if this item is not on the menu already.  If the item is already
 351  present, it will not be moved."
 352   (or menu-path (error "must specify a menu path"))
 353   (or item-name (error "must specify an item name"))
 354   (add-menu-item-1 t menu-path item-name function enabled-p before))
 355
 356
 357 (defun delete-menu-item (path)
 358   "Remove the named menu item from the menu hierarchy.
 359 PATH is a list of strings which identify the position of the menu item in
 360 the menu hierarchy.  (\"File\" \"Save\") means the menu item called \"Save\"
 361 under the toplevel \"File\" menu.  (\"Menu\" \"Foo\" \"Item\") means the
 362 menu item called \"Item\" under the \"Foo\" submenu of \"Menu\"."
 363   (let* ((menubar current-menubar)
 364          (pair (find-menu-item menubar path))
 365          (item (car pair))
 366          (menu (or (cdr pair) menubar)))
 367     (if (not item)
 368         nil
 369       ;; the menubar is the only special case, because other menus begin
 370       ;; with their name.
 371       (if (eq menu current-menubar)
 372           (setq current-menubar (delq item menu))
 373         (delq item menu))
 374       (set-menubar-dirty-flag)
 375       item)))
 376
 377
 378 (defun relabel-menu-item (path new-name)
 379   "Change the string of the specified menu item.
 380 PATH is a list of strings which identify the position of the menu item in
 381 the menu hierarchy.  (\"File\" \"Save\") means the menu item called \"Save\"
 382 under the toplevel \"File\" menu.  (\"Menu\" \"Foo\" \"Item\") means the
 383 menu item called \"Item\" under the \"Foo\" submenu of \"Menu\".
 384 NEW-NAME is the string that the menu item will be printed as from now on."
 385   (or (stringp new-name)
 386       (setq new-name (signal 'wrong-type-argument (list 'stringp new-name))))
 387   (let* ((menubar current-menubar)
 388          (pair (find-menu-item menubar path))
 389          (item (car pair))
 390          (menu (cdr pair)))
 391     (or item
 392         (signal 'error (list (if menu "No such menu item" "No such menu")
 393                              path)))
 394     (if (and (consp item)
 395              (stringp (car item)))
 396         (setcar item new-name)
 397       (aset item 0 new-name))
 398     (set-menubar-dirty-flag)
 399     item))
 400
 401 (defun add-menu (menu-path menu-name menu-items &optional before)
 402   "Add a menu to the menubar or one of its submenus.
 403 If the named menu exists already, it is changed.
 404 MENU-PATH identifies the menu under which the new menu should be inserted.
 405  It is a list of strings; for example, (\"File\") names the top-level \"File\"
 406  menu.  (\"File\" \"Foo\") names a hypothetical submenu of \"File\".
 407  If MENU-PATH is nil, then the menu will be added to the menubar itself.
 408 MENU-NAME is the string naming the menu to be added.
 409 MENU-ITEMS is a list of menu item descriptions.
 410  Each menu item should be a vector of three elements:
 411    - a string, the name of the menu item;
 412    - a symbol naming a command, or a form to evaluate;
 413    - and t or nil, whether this item is selectable.
 414 BEFORE, if provided, is the name of a menu before which this menu should
 415  be added, if this menu is not on its parent already.  If the menu is already
 416  present, it will not be moved."
 417   (or menu-name (error "must specify a menu name"))
 418   (or menu-items (error "must specify some menu items"))
 419   (add-menu-item-1 nil menu-path menu-name menu-items t before))
 420
 421 \f
 422
 423 (defvar put-buffer-names-in-file-menu t)
 424
 425 (defun sensitize-file-and-edit-menus-hook ()
 426   "For use as a value of activate-menubar-hook.
 427 This function changes the sensitivity of these File and Edit menu items:
 428
 429   Cut    sensitive only when emacs owns the primary X Selection.
 430   Copy   sensitive only when emacs owns the primary X Selection.
 431   Clear  sensitive only when emacs owns the primary X Selection.
 432   Paste  sensitive only when there is an owner for the X Clipboard Selection.
 433   Undo   sensitive only when there is undo information.
 434          While in the midst of an undo, this is changed to \"Undo More\".
 435
 436   Kill Buffer    has the name of the current buffer appended to it.
 437   Print Buffer   has the name of the current buffer appended to it.
 438   Save Buffer    has the name of the current buffer appended to it, and is
 439                  sensitive only when the current buffer is modified.
 440   Revert Buffer  has the name of the current buffer appended to it, and is
 441                  sensitive only when the current buffer has a file.
 442   Delete Frame   sensitive only when there is more than one visible frame."
 443   ;;
 444   ;; the hair in here to not update the menubar unless something has changed
 445   ;; isn't really necessary (the menubar code is fast enough) but it makes
 446   ;; me feel better (and creates marginally less list garbage.)
 447   (let* ((file-menu (cdr (car (find-menu-item current-menubar '("File")))))
 448          (edit-menu (cdr (car (find-menu-item current-menubar '("Edit")))))
 449          (save  (car (find-menu-item file-menu '("Save Buffer"))))
 450          (rvt   (car (find-menu-item file-menu '("Revert Buffer"))))
 451          (del   (car (find-menu-item file-menu '("Delete Frame"))))
 452          (print (car (find-menu-item file-menu '("Print Buffer"))))
 453          (kill  (car (find-menu-item file-menu '("Kill Buffer"))))
 454          (cut   (car (find-menu-item edit-menu '("Cut"))))
 455          (copy  (car (find-menu-item edit-menu '("Copy"))))
 456          (paste (car (find-menu-item edit-menu '("Paste"))))
 457          (clear (car (find-menu-item edit-menu '("Clear"))))
 458          (undo  (or (car (find-menu-item edit-menu '("Undo")))
 459                     (car (find-menu-item edit-menu '("Undo More")))))
 460          (name (buffer-name))
 461          (emacs-owns-selection-p (x-selection-owner-p))
 462          (clipboard-exists-p (x-selection-exists-p 'CLIPBOARD))
 463          undo-available undoing-more
 464          (undo-info-available (not (null (and (not (eq t buffer-undo-list))
 465                                    (if (eq last-command 'undo)
 466                                        (setq undoing-more
 467                                              (and (boundp 'pending-undo-list)
 468                                             pending-undo-list)
 469                                      buffer-undo-list))))))
 470          undo-name undo-state
 471          (change-p
 472           (or (and cut   (not (eq emacs-owns-selection-p (aref cut 2))))
 473               (and copy  (not (eq emacs-owns-selection-p (aref copy 2))))
 474               (and clear (not (eq emacs-owns-selection-p (aref clear 2))))
 475               (and paste (not (eq clipboard-exists-p (aref paste 2))))
 476               (and save  (not (eq (buffer-modified-p) (aref save 2))))
 477               (and rvt   (not (eq (not (not buffer-file-name)) (aref rvt 2))))
 478               (and del   (not (eq (null (cdr (visible-frame-list))) (aref del 2))))
 479               )))
 480     (if (not put-buffer-names-in-file-menu)
 481         nil
 482       (if (= (length save)  4) (progn (aset save  3 name) (setq change-p t)))
 483       (if (= (length rvt)   4) (progn (aset rvt   3 name) (setq change-p t)))
 484       (if (= (length print) 4) (progn (aset print 3 name) (setq change-p t)))
 485       (if (= (length kill)  4) (progn (aset kill  3 name) (setq change-p t))))
 486     (if save  (aset save  2 (buffer-modified-p)))
 487     (if rvt   (aset rvt   2 (not (not buffer-file-name))))
 488     (if del   (aset del   2 (null (cdr (visible-frame-list)))))
 489     (if cut   (aset cut   2 emacs-owns-selection-p))
 490     (if copy  (aset copy  2 emacs-owns-selection-p))
 491     (if clear (aset clear 2 emacs-owns-selection-p))
 492     (if paste (aset paste 2 clipboard-exists-p))
 493
 494     ;; we could also do this with the third field of the item.
 495     (if (eq last-command 'undo)
 496         (setq undo-name "Undo More"
 497               undo-state (not (null (and (boundp 'pending-undo-list)
 498                                          pending-undo-list))))
 499       (setq undo-name "Undo"
 500             undo-state (and (not (eq buffer-undo-list t))
 501                             (not (null
 502                                   (or buffer-undo-list
 503                                       (and (boundp 'pending-undo-list)
 504                                            pending-undo-list)))))))
 505     (if buffer-read-only (setq undo-state nil))
 506     (if (and undo
 507              (or (not (equal undo-name (aref undo 0)))
 508                  (not (eq undo-state (aref undo 2)))))
 509         (progn (aset undo 0 undo-name)
 510                (aset undo 2 undo-state)
 511                (setq change-p t)))
 512     ;; if we made any changes, return nil
 513     ;; otherwise return t to indicate that we haven't done anything.
 514     (not change-p)))
 515
 516 ;; this version is too slow
 517 (defun format-buffers-menu-line (buffer)
 518   "Returns a string to represent the given buffer in the Buffer menu.
 519 nil means the buffer shouldn't be listed.  You can redefine this."
 520   (if (string-match "\\` " (buffer-name buffer))
 521       nil
 522     (save-excursion
 523      (set-buffer buffer)
 524      (let ((size (buffer-size)))
 525        (format "%s%s %-19s %6s %-15s %s"
 526                (if (buffer-modified-p) "*" " ")
 527                (if buffer-read-only "%" " ")
 528                (buffer-name)
 529                size
 530                mode-name
 531                (or (buffer-file-name) ""))))))
 532
 533 (defun format-buffers-menu-line (buffer)
 534   (if (string-match "\\` " (setq buffer (buffer-name buffer)))
 535       nil
 536     buffer))
 537
 538 (defvar buffers-menu-max-size 10
 539   "*Maximum number of entries which may appear on the \"Buffers\" menu.
 540 If this is 10, then only the ten most-recently-selected buffers will be
 541 shown.  If this is nil, then all buffers will be shown.  Setting this to
 542 a large number or nil will slow down menu responsiveness.")
 543
 544 (defvar complex-buffers-menu-p nil
 545   "*If true, the buffers menu will contain several commands, as submenus
 546 of each buffer line.  If this is false, then there will be only one command:
 547 select that buffer.")
 548
 549 (defvar buffers-menu-switch-to-buffer-function 'switch-to-buffer
 550   "*The function to call to select a buffer from the buffers menu.
 551 `switch-to-buffer' is a good choice, as is `pop-to-buffer'.")
 552
 553
 554 (defun buffer-menu-save-buffer (buffer)
 555   (save-excursion
 556     (set-buffer buffer)
 557     (save-buffer)))
 558
 559 (defun buffer-menu-write-file (buffer)
 560   (save-excursion
 561     (set-buffer buffer)
 562     (write-file (read-file-name
 563                  (concat "Write " (buffer-name (current-buffer))
 564                          " to file: ")))))
 565
 566
 567 (defsubst build-buffers-menu-internal (buffers)
 568   (let (name line)
 569     (mapcar
 570      (if complex-buffers-menu-p
 571          (function
 572           (lambda (buffer)
 573             (if (setq line (format-buffers-menu-line buffer))
 574                 (list line
 575                       (vector "Switch to Buffer"
 576                               (list buffers-menu-switch-to-buffer-function
 577                                     (setq name (buffer-name buffer)))
 578                               t)
 579                       (if (and (buffer-modified-p buffer)
 580                                (buffer-file-name buffer))
 581                           (vector "Save Buffer"
 582                                   (list 'buffer-menu-save-buffer name) t)
 583                         ["Save Buffer" nil nil])
 584                       (vector "Save Buffer As..."
 585                               (list 'buffer-menu-write-file name) t)
 586                       (vector "Kill Buffer" (list 'kill-buffer name) t)))))
 587        (function (lambda (buffer)
 588                    (if (setq line (format-buffers-menu-line buffer))
 589                        (vector line
 590                                (list buffers-menu-switch-to-buffer-function
 591                                      (buffer-name buffer))
 592                                t)))))
 593      buffers)))
 594
 595 (defun build-buffers-menu-hook ()
 596   "For use as a value of activate-menubar-hook.
 597 This function changes the contents of the \"Buffers\" menu to correspond
 598 to the current set of buffers.  Only the most-recently-used few buffers
 599 will be listed on the menu, for efficiency reasons.  You can control how
 600 many buffers will be shown by setting `buffers-menu-max-size'.
 601 You can control the text of the menu items by redefining the function
 602 `format-buffers-menu-line'."
 603   (let ((buffer-menu (car (find-menu-item current-menubar '("Buffers"))))
 604         name
 605         buffers)
 606     (if (not buffer-menu)
 607         nil
 608       (setq buffers (buffer-list))
 609
 610       (if (and (integerp buffers-menu-max-size)
 611                (> buffers-menu-max-size 1))
 612           (if (> (length buffers) buffers-menu-max-size)
 613               (setcdr (nthcdr buffers-menu-max-size buffers) nil)))
 614
 615       (setq buffers (build-buffers-menu-internal buffers))
 616       (setq buffers (nconc (delq nil buffers)
 617                            '("----" ["List All Buffers" list-buffers t])))
 618       ;; slightly (only slightly) more efficient to not install the menubar
 619       ;; if it hasn't visibly changed.
 620       (if (equal buffers (cdr buffer-menu))
 621           t  ; return t meaning "no change"
 622         (setcdr buffer-menu buffers)
 623         (set-menubar-dirty-flag)
 624         nil))))
 625
 626 (add-hook 'activate-menubar-hook 'build-buffers-menu-hook)
 627 (add-hook 'activate-menubar-hook 'sensitize-file-and-edit-menus-hook)
 628
 629 (let ((frames (frame-list)))
 630   (while frames
 631     (modify-frame-parameters (car frames) '((menu-bar-lines . 1)))
 632     (setq frames (cdr frames))))
 633 (or (assq 'menu-bar-lines default-frame-alist)
 634     (setq default-frame-alist
 635           (cons '(menu-bar-lines . 1) default-frame-alist)))
 636
 637 (set-menubar default-menubar)
 638 \f
 639 (provide 'menubar)
 640
 641 ;;; lmenu.el ends here