lisp/emacs-lisp/easymenu.el

   1 ;;; easymenu.el --- support the easymenu interface for defining a menu
   2
   3 ;; Copyright (C) 1994, 1996, 1998, 1999, 2000, 2001, 2002, 2003,
   4 ;;   2004, 2005, 2006, 2007 Free Software Foundation, Inc.
   5
   6 ;; Keywords: emulations
   7 ;; Author: Richard Stallman <rms@gnu.org>
   8
   9 ;; This file is part of GNU Emacs.
  10
  11 ;; GNU Emacs is free software; you can redistribute it and/or modify
  12 ;; it under the terms of the GNU General Public License as published by
  13 ;; the Free Software Foundation; either version 3, or (at your option)
  14 ;; any later version.
  15
  16 ;; GNU Emacs is distributed in the hope that it will be useful,
  17 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  18 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  19 ;; GNU General Public License for more details.
  20
  21 ;; You should have received a copy of the GNU General Public License
  22 ;; along with GNU Emacs; see the file COPYING.  If not, write to the
  23 ;; Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  24 ;; Boston, MA 02110-1301, USA.
  25
  26 ;;; Commentary:
  27
  28 ;; This is compatible with easymenu.el by Per Abrahamsen
  29 ;; but it is much simpler as it doesn't try to support other Emacs versions.
  30 ;; The code was mostly derived from lmenu.el.
  31
  32 ;;; Code:
  33
  34 (defcustom easy-menu-precalculate-equivalent-keybindings t
  35   "Determine when equivalent key bindings are computed for easy-menu menus.
  36 It can take some time to calculate the equivalent key bindings that are shown
  37 in a menu.  If the variable is on, then this calculation gives a (maybe
  38 noticeable) delay when a mode is first entered.  If the variable is off, then
  39 this delay will come when a menu is displayed the first time.  If you never use
  40 menus, turn this variable off, otherwise it is probably better to keep it on."
  41   :type 'boolean
  42   :group 'menu
  43   :version "20.3")
  44
  45 (defsubst easy-menu-intern (s)
  46   (if (stringp s) (intern s) s))
  47
  48 ;;;###autoload
  49 (put 'easy-menu-define 'lisp-indent-function 'defun)
  50 ;;;###autoload
  51 (defmacro easy-menu-define (symbol maps doc menu)
  52   "Define a menu bar submenu in maps MAPS, according to MENU.
  53
  54 If SYMBOL is non-nil, store the menu keymap in the value of SYMBOL,
  55 and define SYMBOL as a function to pop up the menu, with DOC as its doc string.
  56 If SYMBOL is nil, just store the menu keymap into MAPS.
  57
  58 The first element of MENU must be a string.  It is the menu bar item name.
  59 It may be followed by the following keyword argument pairs
  60
  61    :filter FUNCTION
  62
  63 FUNCTION is a function with one argument, the rest of menu items.
  64 It returns the remaining items of the displayed menu.
  65
  66    :visible INCLUDE
  67
  68 INCLUDE is an expression; this menu is only visible if this
  69 expression has a non-nil value.  `:included' is an alias for `:visible'.
  70
  71    :active ENABLE
  72
  73 ENABLE is an expression; the menu is enabled for selection
  74 whenever this expression's value is non-nil.
  75
  76 The rest of the elements in MENU, are menu items.
  77
  78 A menu item is usually a vector of three elements:  [NAME CALLBACK ENABLE]
  79
  80 NAME is a string--the menu item name.
  81
  82 CALLBACK is a command to run when the item is chosen,
  83 or a list to evaluate when the item is chosen.
  84
  85 ENABLE is an expression; the item is enabled for selection
  86 whenever this expression's value is non-nil.
  87
  88 Alternatively, a menu item may have the form:
  89
  90    [ NAME CALLBACK [ KEYWORD ARG ] ... ]
  91
  92 Where KEYWORD is one of the symbols defined below.
  93
  94    :keys KEYS
  95
  96 KEYS is a string; a complex keyboard equivalent to this menu item.
  97 This is normally not needed because keyboard equivalents are usually
  98 computed automatically.
  99 KEYS is expanded with `substitute-command-keys' before it is used.
 100
 101    :key-sequence KEYS
 102
 103 KEYS is nil, a string or a vector; nil or a keyboard equivalent to this
 104 menu item.
 105 This is a hint that will considerably speed up Emacs' first display of
 106 a menu.  Use `:key-sequence nil' when you know that this menu item has no
 107 keyboard equivalent.
 108
 109    :active ENABLE
 110
 111 ENABLE is an expression; the item is enabled for selection
 112 whenever this expression's value is non-nil.
 113
 114    :visible INCLUDE
 115
 116 INCLUDE is an expression; this item is only visible if this
 117 expression has a non-nil value.  `:included' is an alias for `:visible'.
 118
 119    :suffix FORM
 120
 121 FORM is an expression that will be dynamically evaluated and whose
 122 value will be concatenated to the menu entry's NAME.
 123
 124    :style STYLE
 125
 126 STYLE is a symbol describing the type of menu item.  The following are
 127 defined:
 128
 129 toggle: A checkbox.
 130         Prepend the name with `(*) ' or `( ) ' depending on if selected or not.
 131 radio: A radio button.
 132        Prepend the name with `[X] ' or `[ ] ' depending on if selected or not.
 133 button: Surround the name with `[' and `]'.  Use this for an item in the
 134         menu bar itself.
 135 anything else means an ordinary menu item.
 136
 137    :selected SELECTED
 138
 139 SELECTED is an expression; the checkbox or radio button is selected
 140 whenever this expression's value is non-nil.
 141
 142    :help HELP
 143
 144 HELP is a string, the help to display for the menu item.
 145
 146 A menu item can be a string.  Then that string appears in the menu as
 147 unselectable text.  A string consisting solely of hyphens is displayed
 148 as a solid horizontal line.
 149
 150 A menu item can be a list with the same format as MENU.  This is a submenu."
 151   `(progn
 152      ,(if symbol `(defvar ,symbol nil ,doc))
 153      (easy-menu-do-define (quote ,symbol) ,maps ,doc ,menu)))
 154
 155 (defun easy-menu-binding (menu &optional item-name)
 156   "Return a binding suitable to pass to `define-key'.
 157 This is expected to be bound to a mouse event."
 158   ;; Under Emacs this is almost trivial, whereas under XEmacs this may
 159   ;; involve defining a function that calls popup-menu.
 160   (let ((props (if (symbolp menu)
 161                    (prog1 (get menu 'menu-prop)
 162                      (setq menu (symbol-function menu))))))
 163     (cons 'menu-item
 164           (cons (or item-name
 165                     (if (keymapp menu)
 166                         (keymap-prompt menu))
 167                     "")
 168                 (cons menu props)))))
 169
 170 ;;;###autoload
 171 (defun easy-menu-do-define (symbol maps doc menu)
 172   ;; We can't do anything that might differ between Emacs dialects in
 173   ;; `easy-menu-define' in order to make byte compiled files
 174   ;; compatible.  Therefore everything interesting is done in this
 175   ;; function.
 176   (let ((keymap (easy-menu-create-menu (car menu) (cdr menu))))
 177     (when symbol
 178       (set symbol keymap)
 179       (defalias symbol
 180         `(lambda (event) ,doc (interactive "@e")
 181            ;; FIXME: XEmacs uses popup-menu which calls the binding
 182            ;; while x-popup-menu only returns the selection.
 183            (x-popup-menu event
 184                          (or (and (symbolp ,symbol)
 185                                   (funcall
 186                                    (or (plist-get (get ,symbol 'menu-prop)
 187                                                   :filter)
 188                                        'identity)
 189                                    (symbol-function ,symbol)))
 190                              ,symbol)))))
 191     (dolist (map (if (keymapp maps) (list maps) maps))
 192       (define-key map
 193         (vector 'menu-bar (easy-menu-intern (car menu)))
 194         (easy-menu-binding keymap (car menu))))))
 195
 196 (defun easy-menu-filter-return (menu &optional name)
 197  "Convert MENU to the right thing to return from a menu filter.
 198 MENU is a menu as computed by `easy-menu-define' or `easy-menu-create-menu' or
 199 a symbol whose value is such a menu.
 200 In Emacs a menu filter must return a menu (a keymap), in XEmacs a filter must
 201 return a menu items list (without menu name and keywords).
 202 This function returns the right thing in the two cases.
 203 If NAME is provided, it is used for the keymap."
 204  (cond
 205   ((and (not (keymapp menu)) (consp menu))
 206    ;; If it's a cons but not a keymap, then it can't be right
 207    ;; unless it's an XEmacs menu.
 208    (setq menu (easy-menu-create-menu (or name "") menu)))
 209   ((vectorp menu)
 210    ;; It's just a menu entry.
 211    (setq menu (cdr (easy-menu-convert-item menu)))))
 212  menu)
 213
 214 ;;;###autoload
 215 (defun easy-menu-create-menu (menu-name menu-items)
 216   "Create a menu called MENU-NAME with items described in MENU-ITEMS.
 217 MENU-NAME is a string, the name of the menu.  MENU-ITEMS is a list of items
 218 possibly preceded by keyword pairs as described in `easy-menu-define'."
 219   (let ((menu (make-sparse-keymap menu-name))
 220         prop keyword arg label enable filter visible help)
 221     ;; Look for keywords.
 222     (while (and menu-items
 223                 (cdr menu-items)
 224                 (keywordp (setq keyword (car menu-items))))
 225       (setq arg (cadr menu-items))
 226       (setq menu-items (cddr menu-items))
 227       (cond
 228        ((eq keyword :filter)
 229         (setq filter `(lambda (menu)
 230                         (easy-menu-filter-return (,arg menu) ,menu-name))))
 231        ((eq keyword :active) (setq enable (or arg ''nil)))
 232        ((eq keyword :label) (setq label arg))
 233        ((eq keyword :help) (setq help arg))
 234        ((or (eq keyword :included) (eq keyword :visible))
 235         (setq visible (or arg ''nil)))))
 236     (if (equal visible ''nil)
 237         nil                             ; Invisible menu entry, return nil.
 238       (if (and visible (not (easy-menu-always-true-p visible)))
 239           (setq prop (cons :visible (cons visible prop))))
 240       (if (and enable (not (easy-menu-always-true-p enable)))
 241           (setq prop (cons :enable (cons enable prop))))
 242       (if filter (setq prop (cons :filter (cons filter prop))))
 243       (if help (setq prop (cons :help (cons help prop))))
 244       (if label (setq prop (cons nil (cons label prop))))
 245       (if filter
 246           ;; The filter expects the menu in its XEmacs form and the pre-filter
 247           ;; form will only be passed to the filter anyway, so we'd better
 248           ;; not convert it at all (it will be converted on the fly by
 249           ;; easy-menu-filter-return).
 250           (setq menu menu-items)
 251         (setq menu (append menu (mapcar 'easy-menu-convert-item menu-items))))
 252       (when prop
 253         (setq menu (easy-menu-make-symbol menu 'noexp))
 254         (put menu 'menu-prop prop))
 255       menu)))
 256
 257
 258 ;; Known button types.
 259 (defvar easy-menu-button-prefix
 260   '((radio . :radio) (toggle . :toggle)))
 261
 262 (defvar easy-menu-converted-items-table (make-hash-table :test 'equal))
 263
 264 (defun easy-menu-convert-item (item)
 265   "Memoize the value returned by `easy-menu-convert-item-1' called on ITEM.
 266 This makes key-shortcut-caching work a *lot* better when this
 267 conversion is done from within a filter.
 268 This also helps when the NAME of the entry is recreated each time:
 269 since the menu is built and traversed separately, the lookup
 270 would always fail because the key is `equal' but not `eq'."
 271   (or (gethash item easy-menu-converted-items-table)
 272       (puthash item (easy-menu-convert-item-1 item)
 273                easy-menu-converted-items-table)))
 274
 275 (defun easy-menu-convert-item-1 (item)
 276   "Parse an item description and convert it to a menu keymap element.
 277 ITEM defines an item as in `easy-menu-define'."
 278   (let (name command label prop remove)
 279     (cond
 280      ((stringp item)                    ; An item or separator.
 281       (setq label item))
 282      ((consp item)                      ; A sub-menu
 283       (setq label (setq name (car item)))
 284       (setq command (cdr item))
 285       (if (not (keymapp command))
 286           (setq command (easy-menu-create-menu name command)))
 287       (if (null command)
 288           ;; Invisible menu item. Don't insert into keymap.
 289           (setq remove t)
 290         (when (and (symbolp command) (setq prop (get command 'menu-prop)))
 291           (when (null (car prop))
 292             (setq label (cadr prop))
 293             (setq prop (cddr prop)))
 294           (setq command (symbol-function command)))))
 295      ((vectorp item)                    ; An item.
 296       (let* ((ilen (length item))
 297              (active (if (> ilen 2) (or (aref item 2) ''nil) t))
 298              (no-name (not (symbolp (setq command (aref item 1)))))
 299              cache cache-specified)
 300         (setq label (setq name (aref item 0)))
 301         (if no-name (setq command (easy-menu-make-symbol command)))
 302         (if (keywordp active)
 303             (let ((count 2)
 304                   keyword arg suffix visible style selected keys)
 305               (setq active nil)
 306               (while (> ilen count)
 307                 (setq keyword (aref item count))
 308                 (setq arg (aref item (1+ count)))
 309                 (setq count (+ 2 count))
 310                 (cond
 311                  ((or (eq keyword :included) (eq keyword :visible))
 312                   (setq visible (or arg ''nil)))
 313                  ((eq keyword :key-sequence)
 314                   (setq cache arg cache-specified t))
 315                  ((eq keyword :keys) (setq keys arg no-name nil))
 316                  ((eq keyword :label) (setq label arg))
 317                  ((eq keyword :active) (setq active (or arg ''nil)))
 318                  ((eq keyword :help) (setq prop (cons :help (cons arg prop))))
 319                  ((eq keyword :suffix) (setq suffix arg))
 320                  ((eq keyword :style) (setq style arg))
 321                  ((eq keyword :selected) (setq selected (or arg ''nil)))))
 322               (if suffix
 323                   (setq label
 324                         (if (stringp suffix)
 325                             (if (stringp label) (concat label " " suffix)
 326                               (list 'concat label (concat " " suffix)))
 327                           (if (stringp label)
 328                               (list 'concat (concat label " ") suffix)
 329                             (list 'concat label " " suffix)))))
 330               (cond
 331                ((eq style 'button)
 332                 (setq label (if (stringp label) (concat "[" label "]")
 333                               (list 'concat "[" label "]"))))
 334                ((and selected
 335                      (setq style (assq style easy-menu-button-prefix)))
 336                 (setq prop (cons :button
 337                                  (cons (cons (cdr style) selected) prop)))))
 338               (when (stringp keys)
 339                  (if (string-match "^[^\\]*\\(\\\\\\[\\([^]]+\\)]\\)[^\\]*$"
 340                                    keys)
 341                      (let ((prefix
 342                             (if (< (match-beginning 0) (match-beginning 1))
 343                                 (substring keys 0 (match-beginning 1))))
 344                            (postfix
 345                             (if (< (match-end 1) (match-end 0))
 346                                 (substring keys (match-end 1))))
 347                            (cmd (intern (match-string 2 keys))))
 348                        (setq keys (and (or prefix postfix)
 349                                        (cons prefix postfix)))
 350                        (setq keys
 351                              (and (or keys (not (eq command cmd)))
 352                                   (cons cmd keys))))
 353                    (setq cache-specified nil))
 354                  (if keys (setq prop (cons :keys (cons keys prop)))))
 355               (if (and visible (not (easy-menu-always-true-p visible)))
 356                   (if (equal visible ''nil)
 357                       ;; Invisible menu item. Don't insert into keymap.
 358                       (setq remove t)
 359                     (setq prop (cons :visible (cons visible prop)))))))
 360         (if (and active (not (easy-menu-always-true-p active)))
 361             (setq prop (cons :enable (cons active prop))))
 362         (if (and (or no-name cache-specified)
 363                  (or (null cache) (stringp cache) (vectorp cache)))
 364             (setq prop (cons :key-sequence (cons cache prop))))))
 365      (t (error "Invalid menu item in easymenu")))
 366     ;; `intern' the name so as to merge multiple entries with the same name.
 367     ;; It also makes it easier/possible to lookup/change menu bindings
 368     ;; via keymap functions.
 369     (cons (easy-menu-intern name)
 370           (and (not remove)
 371                (cons 'menu-item
 372                      (cons label
 373                            (and name
 374                                 (cons command prop))))))))
 375
 376 (defun easy-menu-define-key (menu key item &optional before)
 377   "Add binding in MENU for KEY => ITEM.  Similar to `define-key-after'.
 378 If KEY is not nil then delete any duplications.
 379 If ITEM is nil, then delete the definition of KEY.
 380
 381 Optional argument BEFORE is nil or a key in MENU.  If BEFORE is not nil,
 382 put binding before the item in MENU named BEFORE; otherwise,
 383 if a binding for KEY is already present in MENU, just change it;
 384 otherwise put the new binding last in MENU.
 385 BEFORE can be either a string (menu item name) or a symbol
 386 \(the fake function key for the menu item).
 387 KEY does not have to be a symbol, and comparison is done with equal."
 388   (if (symbolp menu) (setq menu (indirect-function menu)))
 389   (let ((inserted (null item))          ; Fake already inserted.
 390         tail done)
 391     (while (not done)
 392       (cond
 393        ((or (setq done (or (null (cdr menu)) (keymapp (cdr menu))))
 394             (and before (easy-menu-name-match before (cadr menu))))
 395         ;; If key is nil, stop here, otherwise keep going past the
 396         ;; inserted element so we can delete any duplications that come
 397         ;; later.
 398         (if (null key) (setq done t))
 399         (unless inserted                ; Don't insert more than once.
 400           (setcdr menu (cons (cons key item) (cdr menu)))
 401           (setq inserted t)
 402           (setq menu (cdr menu)))
 403         (setq menu (cdr menu)))
 404        ((and key (equal (car-safe (cadr menu)) key))
 405         (if (or inserted                ; Already inserted or
 406                 (and before             ;  wanted elsewhere and
 407                      (setq tail (cddr menu)) ; not last item and not
 408                      (not (keymapp tail))
 409                      (not (easy-menu-name-match
 410                            before (car tail))))) ; in position
 411             (setcdr menu (cddr menu))   ; Remove item.
 412           (setcdr (cadr menu) item)     ; Change item.
 413           (setq inserted t)
 414           (setq menu (cdr menu))))
 415        (t (setq menu (cdr menu)))))))
 416
 417 (defun easy-menu-name-match (name item)
 418   "Return t if NAME is the name of menu item ITEM.
 419 NAME can be either a string, or a symbol.
 420 ITEM should be a keymap binding of the form (KEY . MENU-ITEM)."
 421   (if (consp item)
 422       (if (symbolp name)
 423           (eq (car-safe item) name)
 424         (if (stringp name)
 425             ;; Match against the text that is displayed to the user.
 426             (or (condition-case nil (member-ignore-case name item)
 427                   (error nil))          ;`item' might not be a proper list.
 428                 ;; Also check the string version of the symbol name,
 429                 ;; for backwards compatibility.
 430                 (eq (car-safe item) (intern name)))))))
 431
 432 (defun easy-menu-always-true-p (x)
 433   "Return true if form X never evaluates to nil."
 434   (if (consp x) (and (eq (car x) 'quote) (cadr x))
 435     (or (eq x t) (not (symbolp x)))))
 436
 437 (defvar easy-menu-item-count 0)
 438
 439 (defun easy-menu-make-symbol (callback &optional noexp)
 440   "Return a unique symbol with CALLBACK as function value.
 441 When non-nil, NOEXP indicates that CALLBACK cannot be an expression
 442 \(i.e. does not need to be turned into a function)."
 443   (let ((command
 444          (make-symbol (format "menu-function-%d" easy-menu-item-count))))
 445     (setq easy-menu-item-count (1+ easy-menu-item-count))
 446     (fset command
 447           (if (or (keymapp callback) (functionp callback) noexp) callback
 448             `(lambda () (interactive) ,callback)))
 449     command))
 450
 451 ;;;###autoload
 452 (defun easy-menu-change (path name items &optional before map)
 453   "Change menu found at PATH as item NAME to contain ITEMS.
 454 PATH is a list of strings for locating the menu that
 455 should contain a submenu named NAME.
 456 ITEMS is a list of menu items, as in `easy-menu-define'.
 457 These items entirely replace the previous items in that submenu.
 458
 459 If MAP is specified, it should normally be a keymap; nil stands for the local
 460 menu-bar keymap.  It can also be a symbol, which has earlier been used as the
 461 first argument in a call to `easy-menu-define', or the value of such a symbol.
 462
 463 If the menu located by PATH has no submenu named NAME, add one.
 464 If the optional argument BEFORE is present, add it just before
 465 the submenu named BEFORE, otherwise add it at the end of the menu.
 466
 467 To implement dynamic menus, either call this from
 468 `menu-bar-update-hook' or use a menu filter."
 469   (easy-menu-add-item map path (easy-menu-create-menu name items) before))
 470
 471 ;; XEmacs needs the following two functions to add and remove menus.
 472 ;; In Emacs this is done automatically when switching keymaps, so
 473 ;; here easy-menu-remove is a noop and easy-menu-add only precalculates
 474 ;; equivalent keybindings (if easy-menu-precalculate-equivalent-keybindings
 475 ;; is on).
 476 (defalias 'easy-menu-remove 'ignore
 477   "Remove MENU from the current menu bar.
 478 Contrary to XEmacs, this is a nop on Emacs since menus are automatically
 479 \(de)activated when the corresponding keymap is (de)activated.
 480
 481 \(fn MENU)")
 482
 483 (defun easy-menu-add (menu &optional map)
 484   "Add the menu to the menubar.
 485 On Emacs, menus are already automatically activated when the
 486 corresponding keymap is activated.  On XEmacs this is needed to
 487 actually add the menu to the current menubar.
 488
 489 This also precalculates equivalent key bindings when
 490 `easy-menu-precalculate-equivalent-keybindings' is on.
 491
 492 You should call this once the menu and keybindings are set up
 493 completely and menu filter functions can be expected to work."
 494   (when easy-menu-precalculate-equivalent-keybindings
 495     (if (and (symbolp menu) (not (keymapp menu)) (boundp menu))
 496         (setq menu (symbol-value menu)))
 497     (and (keymapp menu) (fboundp 'x-popup-menu)
 498          (x-popup-menu nil menu))
 499     ))
 500
 501 (defun add-submenu (menu-path submenu &optional before in-menu)
 502   "Add submenu SUBMENU in the menu at MENU-PATH.
 503 If BEFORE is non-nil, add before the item named BEFORE.
 504 If IN-MENU is non-nil, follow MENU-PATH in IN-MENU.
 505 This is a compatibility function; use `easy-menu-add-item'."
 506   (easy-menu-add-item (or in-menu (current-global-map))
 507                       (cons "menu-bar" menu-path)
 508                       submenu before))
 509
 510 (defun easy-menu-add-item (map path item &optional before)
 511   "To the submenu of MAP with path PATH, add ITEM.
 512
 513 If an item with the same name is already present in this submenu,
 514 then ITEM replaces it.  Otherwise, ITEM is added to this submenu.
 515 In the latter case, ITEM is normally added at the end of the submenu.
 516 However, if BEFORE is a string and there is an item in the submenu
 517 with that name, then ITEM is added before that item.
 518
 519 MAP should normally be a keymap; nil stands for the local menu-bar keymap.
 520 It can also be a symbol, which has earlier been used as the first
 521 argument in a call to `easy-menu-define', or the value of such a symbol.
 522
 523 PATH is a list of strings for locating the submenu where ITEM is to be
 524 added.  If PATH is nil, MAP itself is used.  Otherwise, the first
 525 element should be the name of a submenu directly under MAP.  This
 526 submenu is then traversed recursively with the remaining elements of PATH.
 527
 528 ITEM is either defined as in `easy-menu-define' or a non-nil value returned
 529 by `easy-menu-item-present-p' or `easy-menu-remove-item' or a menu defined
 530 earlier by `easy-menu-define' or `easy-menu-create-menu'."
 531   (setq map (easy-menu-get-map map path
 532                                (and (null map) (null path)
 533                                     (stringp (car-safe item))
 534                                     (car item))))
 535   (if (and (consp item) (consp (cdr item)) (eq (cadr item) 'menu-item))
 536       ;; This is a value returned by `easy-menu-item-present-p' or
 537       ;; `easy-menu-remove-item'.
 538       (easy-menu-define-key map (easy-menu-intern (car item))
 539                             (cdr item) before)
 540     (if (or (keymapp item)
 541             (and (symbolp item) (keymapp (symbol-value item))
 542                  (setq item (symbol-value item))))
 543         ;; Item is a keymap, find the prompt string and use as item name.
 544         (setq item (cons (keymap-prompt item) item)))
 545     (setq item (easy-menu-convert-item item))
 546     (easy-menu-define-key map (easy-menu-intern (car item)) (cdr item) before)))
 547
 548 (defun easy-menu-item-present-p (map path name)
 549   "In submenu of MAP with path PATH, return non-nil if item NAME is present.
 550 MAP and PATH are defined as in `easy-menu-add-item'.
 551 NAME should be a string, the name of the element to be looked for."
 552   (easy-menu-return-item (easy-menu-get-map map path) name))
 553
 554 (defun easy-menu-remove-item (map path name)
 555   "From submenu of MAP with path PATH remove item NAME.
 556 MAP and PATH are defined as in `easy-menu-add-item'.
 557 NAME should be a string, the name of the element to be removed."
 558   (setq map (easy-menu-get-map map path))
 559   (let ((ret (easy-menu-return-item map name)))
 560     (if ret (easy-menu-define-key map (easy-menu-intern name) nil))
 561     ret))
 562
 563 (defun easy-menu-return-item (menu name)
 564   "In menu MENU try to look for menu item with name NAME.
 565 If a menu item is found, return (NAME . item), otherwise return nil.
 566 If item is an old format item, a new format item is returned."
 567   ;; The call to `lookup-key' also calls the C function `get_keyelt' which
 568   ;; looks inside a menu-item to only return the actual command.  This is
 569   ;; not what we want here.  We should either add an arg to lookup-key to be
 570   ;; able to turn off this "feature", or else we could use map-keymap here.
 571   ;; In the mean time, I just use `assq' which is an OK approximation since
 572   ;; menus are rarely built from vectors or char-tables.
 573   (let ((item (or (cdr (assq name menu))
 574                   (lookup-key menu (vector (easy-menu-intern name)))))
 575         ret enable cache label)
 576     (cond
 577      ((stringp (car-safe item))
 578       ;; This is the old menu format. Convert it to new format.
 579       (setq label (car item))
 580       (when (stringp (car (setq item (cdr item)))) ; Got help string
 581         (setq ret (list :help (car item)))
 582         (setq item (cdr item)))
 583       (when (and (consp item) (consp (car item))
 584                  (or (null (caar item)) (numberp (caar item))))
 585         (setq cache (car item))         ; Got cache
 586         (setq item (cdr item)))
 587       (and (symbolp item) (setq enable (get item 'menu-enable)) ; Got enable
 588            (setq ret (cons :enable (cons enable ret))))
 589       (if cache (setq ret (cons cache ret)))
 590       (cons name (cons 'menu-enable (cons label (cons item ret)))))
 591      (item ; (or (symbolp item) (keymapp item) (eq (car-safe item) 'menu-item))
 592       (cons name item))                 ; Keymap or new menu format
 593      )))
 594
 595 (defun easy-menu-lookup-name (map name)
 596   "Lookup menu item NAME in keymap MAP.
 597 Like `lookup-key' except that NAME is not an array but just a single key
 598 and that NAME can be a string representing the menu item's name."
 599   (or (lookup-key map (vector (easy-menu-intern name)))
 600       (when (stringp name)
 601         ;; `lookup-key' failed and we have a menu item name: look at the
 602         ;; actual menu entries's names.
 603         (catch 'found
 604           (map-keymap (lambda (key item)
 605                         (if (condition-case nil (member name item)
 606                               (error nil))
 607                             ;; Found it!!  Look for it again with
 608                             ;; `lookup-key' so as to handle inheritance and
 609                             ;; to extract the actual command/keymap bound to
 610                             ;; `name' from the item (via get_keyelt).
 611                             (throw 'found (lookup-key map (vector key)))))
 612                       map)))))
 613
 614 (defun easy-menu-get-map (map path &optional to-modify)
 615   "Return a sparse keymap in which to add or remove an item.
 616 MAP and PATH are as defined in `easy-menu-add-item'.
 617
 618 TO-MODIFY, if non-nil, is the name of the item the caller
 619 wants to modify in the map that we return.
 620 In some cases we use that to select between the local and global maps."
 621   (setq map
 622         (catch 'found
 623           (if (and map (symbolp map) (not (keymapp map)))
 624               (setq map (symbol-value map)))
 625           (let ((maps (if map (if (keymapp map) (list map) map)
 626                         (current-active-maps))))
 627             ;; Look for PATH in each map.
 628             (unless map (push 'menu-bar path))
 629             (dolist (name path)
 630               (setq maps
 631                     (delq nil (mapcar (lambda (map)
 632                                         (setq map (easy-menu-lookup-name
 633                                                    map name))
 634                                         (and (keymapp map) map))
 635                                       maps))))
 636
 637             ;; Prefer a map that already contains the to-be-modified entry.
 638             (when to-modify
 639               (dolist (map maps)
 640                 (when (easy-menu-lookup-name map to-modify)
 641                   (throw 'found map))))
 642             ;; Use the first valid map.
 643             (when maps (throw 'found (car maps)))
 644
 645             ;; Otherwise, make one up.
 646             ;; Hardcoding current-local-map is lame, but it's difficult
 647             ;; to know what the caller intended for us to do ;-(
 648             (let* ((name (if path (format "%s" (car (reverse path)))))
 649                    (newmap (make-sparse-keymap name)))
 650               (define-key (or map (current-local-map))
 651                 (apply 'vector (mapcar 'easy-menu-intern path))
 652                 (if name (cons name newmap) newmap))
 653               newmap))))
 654   (or (keymapp map) (error "Malformed menu in easy-menu: (%s)" map))
 655   map)
 656
 657 (provide 'easymenu)
 658
 659 ;; arch-tag: 2a04020d-90d2-476d-a7c6-71e072007a4a
 660 ;;; easymenu.el ends here