lisp/wid-edit.el

   1 ;;; wid-edit.el --- Functions for creating and using widgets -*-byte-compile-dynamic: t;-*-
   2 ;;
   3 ;; Copyright (C) 1996,97,1999,2000,01,02,2003, 2004, 2005  Free Software Foundation, Inc.
   4 ;;
   5 ;; Author: Per Abrahamsen <abraham@dina.kvl.dk>
   6 ;; Maintainer: FSF
   7 ;; Keywords: extensions
   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 2, 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., 59 Temple Place - Suite 330,
  24 ;; Boston, MA 02111-1307, USA.
  25
  26 ;;; Wishlist items (from widget.texi):
  27
  28 ;; * The `menu-choice' tag should be prettier, something like the
  29 ;;   abbreviated menus in Open Look.
  30
  31 ;; * Finish `:tab-order'.
  32
  33 ;; * Make indentation work with glyphs and proportional fonts.
  34
  35 ;; * Add commands to show overview of object and class hierarchies to
  36 ;;   the browser.
  37
  38 ;; * Find a way to disable mouse highlight for inactive widgets.
  39
  40 ;; * Find a way to make glyphs look inactive.
  41
  42 ;; * Add `key-binding' widget.
  43
  44 ;; * Add `widget' widget for editing widget specifications.
  45
  46 ;; * Find clean way to implement variable length list.  See
  47 ;;   `TeX-printer-list' for an explanation.
  48
  49 ;; * `C-h' in `widget-prompt-value' should give type specific help.
  50
  51 ;; * A mailto widget. [This should work OK as a url-link if with
  52 ;;   browse-url-browser-function' set up appropriately.]
  53
  54 ;;; Commentary:
  55 ;;
  56 ;; See `widget.el'.
  57
  58 ;;; Code:
  59
  60 ;;; Compatibility.
  61
  62 (defun widget-event-point (event)
  63   "Character position of the end of event if that exists, or nil."
  64   (posn-point (event-end event)))
  65
  66 (defun widget-button-release-event-p (event)
  67   "Non-nil if EVENT is a mouse-button-release event object."
  68   (and (eventp event)
  69        (memq (event-basic-type event) '(mouse-1 mouse-2 mouse-3))
  70        (or (memq 'click (event-modifiers event))
  71            (memq  'drag (event-modifiers event)))))
  72
  73 ;;; Customization.
  74
  75 (defgroup widgets nil
  76   "Customization support for the Widget Library."
  77   :link '(custom-manual "(widget)Top")
  78   :link '(emacs-library-link :tag "Lisp File" "widget.el")
  79   :prefix "widget-"
  80   :group 'extensions
  81   :group 'hypermedia)
  82
  83 (defgroup widget-documentation nil
  84   "Options controling the display of documentation strings."
  85   :group 'widgets)
  86
  87 (defgroup widget-faces nil
  88   "Faces used by the widget library."
  89   :group 'widgets
  90   :group 'faces)
  91
  92 (defvar widget-documentation-face 'widget-documentation
  93   "Face used for documentation strings in widgets.
  94 This exists as a variable so it can be set locally in certain buffers.")
  95
  96 (defface widget-documentation '((((class color)
  97                                   (background dark))
  98                                  (:foreground "lime green"))
  99                                 (((class color)
 100                                   (background light))
 101                                  (:foreground "dark green"))
 102                                 (t nil))
 103   "Face used for documentation text."
 104   :group 'widget-documentation
 105   :group 'widget-faces)
 106 ;; backward compatibility alias
 107 (put 'widget-documentation-face 'face-alias 'widget-documentation)
 108
 109 (defvar widget-button-face 'widget-button
 110   "Face used for buttons in widgets.
 111 This exists as a variable so it can be set locally in certain buffers.")
 112
 113 (defface widget-button '((t (:weight bold)))
 114   "Face used for widget buttons."
 115   :group 'widget-faces)
 116 ;; backward compatibility alias
 117 (put 'widget-button-face 'face-alias 'widget-button)
 118
 119 (defcustom widget-mouse-face 'highlight
 120   "Face used for widget buttons when the mouse is above them."
 121   :type 'face
 122   :group 'widget-faces)
 123
 124 ;; TTY gets special definitions here and in the next defface, because
 125 ;; the gray colors defined for other displays cause black text on a black
 126 ;; background, at least on light-background TTYs.
 127 (defface widget-field '((((type tty))
 128                          :background "yellow3"
 129                          :foreground "black")
 130                         (((class grayscale color)
 131                           (background light))
 132                          :background "gray85")
 133                         (((class grayscale color)
 134                           (background dark))
 135                          :background "dim gray")
 136                         (t
 137                          :slant italic))
 138   "Face used for editable fields."
 139   :group 'widget-faces)
 140 ;; backward-compatibility alias
 141 (put 'widget-field-face 'face-alias 'widget-field)
 142
 143 (defface widget-single-line-field '((((type tty))
 144                                      :background "green3"
 145                                      :foreground "black")
 146                                     (((class grayscale color)
 147                                       (background light))
 148                                      :background "gray85")
 149                                     (((class grayscale color)
 150                                       (background dark))
 151                                      :background "dim gray")
 152                                     (t
 153                                      :slant italic))
 154   "Face used for editable fields spanning only a single line."
 155   :group 'widget-faces)
 156 ;; backward-compatibility alias
 157 (put 'widget-single-line-field-face 'face-alias 'widget-single-line-field)
 158
 159 ;;; This causes display-table to be loaded, and not usefully.
 160 ;;;(defvar widget-single-line-display-table
 161 ;;;  (let ((table (make-display-table)))
 162 ;;;    (aset table 9  "^I")
 163 ;;;    (aset table 10 "^J")
 164 ;;;    table)
 165 ;;;  "Display table used for single-line editable fields.")
 166
 167 ;;;(when (fboundp 'set-face-display-table)
 168 ;;;  (set-face-display-table 'widget-single-line-field-face
 169 ;;;                       widget-single-line-display-table))
 170
 171 ;;; Utility functions.
 172 ;;
 173 ;; These are not really widget specific.
 174
 175 (defun widget-princ-to-string (object)
 176   "Return string representation of OBJECT, any Lisp object.
 177 No quoting characters are used; no delimiters are printed around
 178 the contents of strings."
 179   (with-output-to-string
 180       (princ object)))
 181
 182 (defun widget-clear-undo ()
 183   "Clear all undo information."
 184   (buffer-disable-undo (current-buffer))
 185   (buffer-enable-undo))
 186
 187 (defcustom widget-menu-max-size 40
 188   "Largest number of items allowed in a popup-menu.
 189 Larger menus are read through the minibuffer."
 190   :group 'widgets
 191   :type 'integer)
 192
 193 (defcustom widget-menu-max-shortcuts 40
 194   "Largest number of items for which it works to choose one with a character.
 195 For a larger number of items, the minibuffer is used."
 196   :group 'widgets
 197   :type 'integer)
 198
 199 (defcustom widget-menu-minibuffer-flag nil
 200   "*Control how to ask for a choice from the keyboard.
 201 Non-nil means use the minibuffer;
 202 nil means read a single character."
 203   :group 'widgets
 204   :type 'boolean)
 205
 206 (defun widget-choose (title items &optional event)
 207   "Choose an item from a list.
 208
 209 First argument TITLE is the name of the list.
 210 Second argument ITEMS is a list whose members are either
 211  (NAME . VALUE), to indicate selectable items, or just strings to
 212  indicate unselectable items.
 213 Optional third argument EVENT is an input event.
 214
 215 The user is asked to choose between each NAME from the items alist,
 216 and the VALUE of the chosen element will be returned.  If EVENT is a
 217 mouse event, and the number of elements in items is less than
 218 `widget-menu-max-size', a popup menu will be used, otherwise the
 219 minibuffer."
 220   (cond ((and (< (length items) widget-menu-max-size)
 221               event (display-popup-menus-p))
 222          ;; Mouse click.
 223          (x-popup-menu event
 224                        (list title (cons "" items))))
 225         ((or widget-menu-minibuffer-flag
 226              (> (length items) widget-menu-max-shortcuts))
 227          ;; Read the choice of name from the minibuffer.
 228          (setq items (widget-remove-if 'stringp items))
 229          (let ((val (completing-read (concat title ": ") items nil t)))
 230            (if (stringp val)
 231                (let ((try (try-completion val items)))
 232                  (when (stringp try)
 233                    (setq val try))
 234                  (cdr (assoc val items))))))
 235         (t
 236          ;; Construct a menu of the choices
 237          ;; and then use it for prompting for a single character.
 238          (let* ((overriding-terminal-local-map (make-sparse-keymap))
 239                 (next-digit ?0)
 240                 map choice some-choice-enabled value)
 241            ;; Define SPC as a prefix char to get to this menu.
 242            (define-key overriding-terminal-local-map " "
 243              (setq map (make-sparse-keymap title)))
 244            (with-current-buffer (get-buffer-create " widget-choose")
 245              (erase-buffer)
 246              (insert "Available choices:\n\n")
 247              (while items
 248                (setq choice (car items) items (cdr items))
 249                (if (consp choice)
 250                    (let* ((name (car choice))
 251                          (function (cdr choice)))
 252                      (insert (format "%c = %s\n" next-digit name))
 253                      (define-key map (vector next-digit) function)
 254                      (setq some-choice-enabled t)))
 255                ;; Allocate digits to disabled alternatives
 256                ;; so that the digit of a given alternative never varies.
 257                (setq next-digit (1+ next-digit)))
 258              (insert "\nC-g = Quit"))
 259            (or some-choice-enabled
 260                (error "None of the choices is currently meaningful"))
 261            (define-key map [?\C-g] 'keyboard-quit)
 262            (define-key map [t] 'keyboard-quit)
 263            (define-key map [?\M-\C-v] 'scroll-other-window)
 264            (define-key map [?\M--] 'negative-argument)
 265            (setcdr map (nreverse (cdr map)))
 266            ;; Read a char with the menu, and return the result
 267            ;; that corresponds to it.
 268            (save-window-excursion
 269              (let ((buf (get-buffer " widget-choose")))
 270                (fit-window-to-buffer (display-buffer buf))
 271                (let ((cursor-in-echo-area t)
 272                      keys
 273                      (char 0)
 274                      (arg 1))
 275                  (while (not (or (and (>= char ?0) (< char next-digit))
 276                                  (eq value 'keyboard-quit)))
 277                    ;; Unread a SPC to lead to our new menu.
 278                    (setq unread-command-events (cons ?\  unread-command-events))
 279                    (setq keys (read-key-sequence title))
 280                    (setq value
 281                          (lookup-key overriding-terminal-local-map keys t)
 282                          char (string-to-char (substring keys 1)))
 283                    (cond ((eq value 'scroll-other-window)
 284                           (let ((minibuffer-scroll-window
 285                                  (get-buffer-window buf)))
 286                             (if (> 0 arg)
 287                                 (scroll-other-window-down
 288                                  (window-height minibuffer-scroll-window))
 289                               (scroll-other-window))
 290                             (setq arg 1)))
 291                          ((eq value 'negative-argument)
 292                           (setq arg -1))
 293                          (t
 294                           (setq arg 1)))))))
 295            (when (eq value 'keyboard-quit)
 296              (error "Canceled"))
 297            value))))
 298
 299 (defun widget-remove-if (predictate list)
 300   (let (result (tail list))
 301     (while tail
 302       (or (funcall predictate (car tail))
 303           (setq result (cons (car tail) result)))
 304       (setq tail (cdr tail)))
 305     (nreverse result)))
 306
 307 ;;; Widget text specifications.
 308 ;;
 309 ;; These functions are for specifying text properties.
 310
 311 ;; We can set it to nil now that get_local_map uses get_pos_property.
 312 (defconst widget-field-add-space nil
 313   "Non-nil means add extra space at the end of editable text fields.
 314 If you don't add the space, it will become impossible to edit a zero
 315 size field.")
 316
 317 (defvar widget-field-use-before-change t
 318   "Non-nil means use `before-change-functions' to track editable fields.
 319 This enables the use of undo, but doesn't work on Emacs 19.34 and earlier.
 320 Using before hooks also means that the :notify function can't know the
 321 new value.")
 322
 323 (defun widget-specify-field (widget from to)
 324   "Specify editable button for WIDGET between FROM and TO."
 325   ;; Terminating space is not part of the field, but necessary in
 326   ;; order for local-map to work.  Remove next sexp if local-map works
 327   ;; at the end of the overlay.
 328   (save-excursion
 329     (goto-char to)
 330     (cond ((null (widget-get widget :size))
 331            (forward-char 1))
 332           (widget-field-add-space
 333            (insert-and-inherit " ")))
 334     (setq to (point)))
 335   (let ((keymap (widget-get widget :keymap))
 336         (face (or (widget-get widget :value-face) 'widget-field))
 337         (help-echo (widget-get widget :help-echo))
 338         (follow-link (widget-get widget :follow-link))
 339         (rear-sticky
 340          (or (not widget-field-add-space) (widget-get widget :size))))
 341     (if (functionp help-echo)
 342       (setq help-echo 'widget-mouse-help))
 343     (when (= (char-before to) ?\n)
 344       ;; When the last character in the field is a newline, we want to
 345       ;; give it a `field' char-property of `boundary', which helps the
 346       ;; C-n/C-p act more naturally when entering/leaving the field.  We
 347      ;; do this by making a small secondary overlay to contain just that
 348       ;; one character.
 349       (let ((overlay (make-overlay (1- to) to nil t nil)))
 350         (overlay-put overlay 'field 'boundary)
 351         ;; We need the real field for tabbing.
 352         (overlay-put overlay 'real-field widget)
 353         ;; Use `local-map' here, not `keymap', so that normal editing
 354         ;; works in the field when, say, Custom uses `suppress-keymap'.
 355         (overlay-put overlay 'local-map keymap)
 356         (overlay-put overlay 'face face)
 357         (overlay-put overlay 'follow-link follow-link)
 358         (overlay-put overlay 'help-echo help-echo))
 359       (setq to (1- to))
 360       (setq rear-sticky t))
 361     (let ((overlay (make-overlay from to nil nil rear-sticky)))
 362       (widget-put widget :field-overlay overlay)
 363       ;;(overlay-put overlay 'detachable nil)
 364       (overlay-put overlay 'field widget)
 365       (overlay-put overlay 'local-map keymap)
 366       (overlay-put overlay 'face face)
 367       (overlay-put overlay 'follow-link follow-link)
 368       (overlay-put overlay 'help-echo help-echo)))
 369   (widget-specify-secret widget))
 370
 371 (defun widget-specify-secret (field)
 372   "Replace text in FIELD with value of `:secret', if non-nil."
 373   (let ((secret (widget-get field :secret))
 374         (size (widget-get field :size)))
 375     (when secret
 376       (let ((begin (widget-field-start field))
 377             (end (widget-field-end field)))
 378         (when size
 379           (while (and (> end begin)
 380                       (eq (char-after (1- end)) ?\ ))
 381             (setq end (1- end))))
 382         (while (< begin end)
 383           (let ((old (char-after begin)))
 384             (unless (eq old secret)
 385               (subst-char-in-region begin (1+ begin) old secret)
 386               (put-text-property begin (1+ begin) 'secret old))
 387             (setq begin (1+ begin))))))))
 388
 389 (defun widget-specify-button (widget from to)
 390   "Specify button for WIDGET between FROM and TO."
 391   (let ((overlay (make-overlay from to nil t nil))
 392         (follow-link (widget-get widget :follow-link))
 393         (help-echo (widget-get widget :help-echo)))
 394     (widget-put widget :button-overlay overlay)
 395     (if (functionp help-echo)
 396       (setq help-echo 'widget-mouse-help))
 397     (overlay-put overlay 'button widget)
 398     (overlay-put overlay 'keymap (widget-get widget :keymap))
 399     (overlay-put overlay 'evaporate t)
 400     ;; We want to avoid the face with image buttons.
 401     (unless (widget-get widget :suppress-face)
 402       (overlay-put overlay 'face (widget-apply widget :button-face-get))
 403       ; Text terminals cannot change mouse pointer shape, so use mouse
 404       ; face instead.
 405       (or (display-graphic-p)
 406           (overlay-put overlay 'mouse-face widget-mouse-face)))
 407     (overlay-put overlay 'pointer 'hand)
 408     (overlay-put overlay 'follow-link follow-link)
 409     (overlay-put overlay 'help-echo help-echo)))
 410
 411 (defun widget-mouse-help (window overlay point)
 412   "Help-echo callback for widgets whose :help-echo is a function."
 413   (with-current-buffer (overlay-buffer overlay)
 414     (let* ((widget (widget-at (overlay-start overlay)))
 415            (help-echo (if widget (widget-get widget :help-echo))))
 416       (if (functionp help-echo)
 417           (funcall help-echo widget)
 418         help-echo))))
 419
 420 (defun widget-specify-sample (widget from to)
 421   "Specify sample for WIDGET between FROM and TO."
 422   (let ((overlay (make-overlay from to nil t nil)))
 423     (overlay-put overlay 'face (widget-apply widget :sample-face-get))
 424     (overlay-put overlay 'evaporate t)
 425     (widget-put widget :sample-overlay overlay)))
 426
 427 (defun widget-specify-doc (widget from to)
 428   "Specify documentation for WIDGET between FROM and TO."
 429   (let ((overlay (make-overlay from to nil t nil)))
 430     (overlay-put overlay 'widget-doc widget)
 431     (overlay-put overlay 'face widget-documentation-face)
 432     (overlay-put overlay 'evaporate t)
 433     (widget-put widget :doc-overlay overlay)))
 434
 435 (defmacro widget-specify-insert (&rest form)
 436   "Execute FORM without inheriting any text properties."
 437   `(save-restriction
 438     (let ((inhibit-read-only t)
 439           (inhibit-modification-hooks t))
 440       (narrow-to-region (point) (point))
 441       (prog1 (progn ,@form)
 442         (goto-char (point-max))))))
 443
 444 (defface widget-inactive '((((class grayscale color)
 445                              (background dark))
 446                             (:foreground "light gray"))
 447                            (((class grayscale color)
 448                              (background light))
 449                             (:foreground "dim gray"))
 450                            (t
 451                             (:slant italic)))
 452   "Face used for inactive widgets."
 453   :group 'widget-faces)
 454 ;; backward-compatibility alias
 455 (put 'widget-inactive-face 'face-alias 'widget-inactive)
 456
 457 (defun widget-specify-inactive (widget from to)
 458   "Make WIDGET inactive for user modifications."
 459   (unless (widget-get widget :inactive)
 460     (let ((overlay (make-overlay from to nil t nil)))
 461       (overlay-put overlay 'face 'widget-inactive)
 462       ;; This is disabled, as it makes the mouse cursor change shape.
 463       ;; (overlay-put overlay 'mouse-face 'widget-inactive)
 464       (overlay-put overlay 'evaporate t)
 465       (overlay-put overlay 'priority 100)
 466       (overlay-put overlay 'modification-hooks '(widget-overlay-inactive))
 467       (widget-put widget :inactive overlay))))
 468
 469 (defun widget-overlay-inactive (&rest junk)
 470   "Ignoring the arguments, signal an error."
 471   (unless inhibit-read-only
 472     (error "The widget here is not active")))
 473
 474
 475 (defun widget-specify-active (widget)
 476   "Make WIDGET active for user modifications."
 477   (let ((inactive (widget-get widget :inactive)))
 478     (when inactive
 479       (delete-overlay inactive)
 480       (widget-put widget :inactive nil))))
 481
 482 ;;; Widget Properties.
 483
 484 (defsubst widget-type (widget)
 485   "Return the type of WIDGET, a symbol."
 486   (car widget))
 487
 488 ;;;###autoload
 489 (defun widgetp (widget)
 490   "Return non-nil iff WIDGET is a widget."
 491   (if (symbolp widget)
 492       (get widget 'widget-type)
 493     (and (consp widget)
 494          (symbolp (car widget))
 495          (get (car widget) 'widget-type))))
 496
 497 (defun widget-get-indirect (widget property)
 498   "In WIDGET, get the value of PROPERTY.
 499 If the value is a symbol, return its binding.
 500 Otherwise, just return the value."
 501   (let ((value (widget-get widget property)))
 502     (if (symbolp value)
 503         (symbol-value value)
 504       value)))
 505
 506 (defun widget-member (widget property)
 507   "Non-nil iff there is a definition in WIDGET for PROPERTY."
 508   (cond ((plist-member (cdr widget) property)
 509          t)
 510         ((car widget)
 511          (widget-member (get (car widget) 'widget-type) property))
 512         (t nil)))
 513
 514 (defun widget-value (widget)
 515   "Extract the current value of WIDGET."
 516   (widget-apply widget
 517                 :value-to-external (widget-apply widget :value-get)))
 518
 519 (defun widget-value-set (widget value)
 520   "Set the current value of WIDGET to VALUE."
 521   (widget-apply widget
 522                 :value-set (widget-apply widget
 523                                          :value-to-internal value)))
 524
 525 (defun widget-default-get (widget)
 526   "Extract the default external value of WIDGET."
 527   (widget-apply widget :value-to-external
 528                 (or (widget-get widget :value)
 529                     (widget-apply widget :default-get))))
 530
 531 (defun widget-match-inline (widget vals)
 532   "In WIDGET, match the start of VALS."
 533   (cond ((widget-get widget :inline)
 534          (widget-apply widget :match-inline vals))
 535         ((and (listp vals)
 536               (widget-apply widget :match (car vals)))
 537          (cons (list (car vals)) (cdr vals)))
 538         (t nil)))
 539
 540 (defun widget-apply-action (widget &optional event)
 541   "Apply :action in WIDGET in response to EVENT."
 542   (if (widget-apply widget :active)
 543       (widget-apply widget :action event)
 544     (error "Attempt to perform action on inactive widget")))
 545
 546 ;;; Helper functions.
 547 ;;
 548 ;; These are widget specific.
 549
 550 ;;;###autoload
 551 (defun widget-prompt-value (widget prompt &optional value unbound)
 552   "Prompt for a value matching WIDGET, using PROMPT.
 553 The current value is assumed to be VALUE, unless UNBOUND is non-nil."
 554   (unless (listp widget)
 555     (setq widget (list widget)))
 556   (setq prompt (format "[%s] %s" (widget-type widget) prompt))
 557   (setq widget (widget-convert widget))
 558   (let ((answer (widget-apply widget :prompt-value prompt value unbound)))
 559     (unless (widget-apply widget :match answer)
 560       (error "Value does not match %S type" (car widget)))
 561     answer))
 562
 563 (defun widget-get-sibling (widget)
 564   "Get the item WIDGET is assumed to toggle.
 565 This is only meaningful for radio buttons or checkboxes in a list."
 566   (let* ((children (widget-get (widget-get widget :parent) :children))
 567          child)
 568     (catch 'child
 569       (while children
 570         (setq child (car children)
 571               children (cdr children))
 572         (when (eq (widget-get child :button) widget)
 573           (throw 'child child)))
 574       nil)))
 575
 576 (defun widget-map-buttons (function &optional buffer maparg)
 577   "Map FUNCTION over the buttons in BUFFER.
 578 FUNCTION is called with the arguments WIDGET and MAPARG.
 579
 580 If FUNCTION returns non-nil, the walk is cancelled.
 581
 582 The arguments MAPARG, and BUFFER default to nil and (current-buffer),
 583 respectively."
 584   (let ((cur (point-min))
 585         (widget nil)
 586         (overlays (if buffer
 587                       (with-current-buffer buffer (overlay-lists))
 588                     (overlay-lists))))
 589     (setq overlays (append (car overlays) (cdr overlays)))
 590     (while (setq cur (pop overlays))
 591       (setq widget (overlay-get cur 'button))
 592       (if (and widget (funcall function widget maparg))
 593           (setq overlays nil)))))
 594
 595 ;;; Images.
 596
 597 (defcustom widget-image-directory (file-name-as-directory
 598                                    (expand-file-name "custom" data-directory))
 599   "Where widget button images are located.
 600 If this variable is nil, widget will try to locate the directory
 601 automatically."
 602   :group 'widgets
 603   :type 'directory)
 604
 605 (defcustom widget-image-enable t
 606   "If non nil, use image buttons in widgets when available."
 607   :version "21.1"
 608   :group 'widgets
 609   :type 'boolean)
 610
 611 (defcustom widget-image-conversion
 612   '((xpm ".xpm") (gif ".gif") (png ".png") (jpeg ".jpg" ".jpeg")
 613     (xbm ".xbm"))
 614   "Conversion alist from image formats to file name suffixes."
 615   :group 'widgets
 616   :type '(repeat (cons :format "%v"
 617                        (symbol :tag "Image Format" unknown)
 618                        (repeat :tag "Suffixes"
 619                                (string :format "%v")))))
 620
 621 (defun widget-image-find (image)
 622   "Create a graphical button from IMAGE.
 623 IMAGE should either already be an image, or be a file name sans
 624 extension (xpm, xbm, gif, jpg, or png) located in
 625 `widget-image-directory' or otherwise where `find-image' will find it."
 626   (cond ((not (and image widget-image-enable (display-graphic-p)))
 627          ;; We don't want or can't use images.
 628          nil)
 629         ((and (consp image)
 630               (eq 'image (car image)))
 631          ;; Already an image spec.  Use it.
 632          image)
 633         ((stringp image)
 634          ;; A string.  Look it up in relevant directories.
 635          (let* ((load-path (cons widget-image-directory load-path))
 636                 specs)
 637            (dolist (elt widget-image-conversion)
 638              (dolist (ext (cdr elt))
 639                (push (list :type (car elt) :file (concat image ext)) specs)))
 640            (setq specs (nreverse specs))
 641            (find-image specs)))
 642         (t
 643          ;; Oh well.
 644          nil)))
 645
 646 (defvar widget-button-pressed-face 'widget-button-pressed
 647   "Face used for pressed buttons in widgets.
 648 This exists as a variable so it can be set locally in certain
 649 buffers.")
 650
 651 (defun widget-image-insert (widget tag image &optional down inactive)
 652   "In WIDGET, insert the text TAG or, if supported, IMAGE.
 653 IMAGE should either be an image or an image file name sans extension
 654 \(xpm, xbm, gif, jpg, or png) located in `widget-image-directory'.
 655
 656 Optional arguments DOWN and INACTIVE are used instead of IMAGE when the
 657 button is pressed or inactive, respectively.  These are currently ignored."
 658   (if (and (display-graphic-p)
 659            (setq image (widget-image-find image)))
 660       (progn (widget-put widget :suppress-face t)
 661              (insert-image image
 662                            (propertize
 663                             tag 'mouse-face widget-button-pressed-face)))
 664     (insert tag)))
 665
 666 ;;; Buttons.
 667
 668 (defgroup widget-button nil
 669   "The look of various kinds of buttons."
 670   :group 'widgets)
 671
 672 (defcustom widget-button-prefix ""
 673   "String used as prefix for buttons."
 674   :type 'string
 675   :group 'widget-button)
 676
 677 (defcustom widget-button-suffix ""
 678   "String used as suffix for buttons."
 679   :type 'string
 680   :group 'widget-button)
 681
 682 ;;; Creating Widgets.
 683
 684 ;;;###autoload
 685 (defun widget-create (type &rest args)
 686   "Create widget of TYPE.
 687 The optional ARGS are additional keyword arguments."
 688   (let ((widget (apply 'widget-convert type args)))
 689     (widget-apply widget :create)
 690     widget))
 691
 692 (defun widget-create-child-and-convert (parent type &rest args)
 693   "As part of the widget PARENT, create a child widget TYPE.
 694 The child is converted, using the keyword arguments ARGS."
 695   (let ((widget (apply 'widget-convert type args)))
 696     (widget-put widget :parent parent)
 697     (unless (widget-get widget :indent)
 698       (widget-put widget :indent (+ (or (widget-get parent :indent) 0)
 699                                     (or (widget-get widget :extra-offset) 0)
 700                                     (widget-get parent :offset))))
 701     (widget-apply widget :create)
 702     widget))
 703
 704 (defun widget-create-child (parent type)
 705   "Create widget of TYPE."
 706   (let ((widget (widget-copy type)))
 707     (widget-put widget :parent parent)
 708     (unless (widget-get widget :indent)
 709       (widget-put widget :indent (+ (or (widget-get parent :indent) 0)
 710                                     (or (widget-get widget :extra-offset) 0)
 711                                     (widget-get parent :offset))))
 712     (widget-apply widget :create)
 713     widget))
 714
 715 (defun widget-create-child-value (parent type value)
 716   "Create widget of TYPE with value VALUE."
 717   (let ((widget (widget-copy type)))
 718     (widget-put widget :value (widget-apply widget :value-to-internal value))
 719     (widget-put widget :parent parent)
 720     (unless (widget-get widget :indent)
 721       (widget-put widget :indent (+ (or (widget-get parent :indent) 0)
 722                                     (or (widget-get widget :extra-offset) 0)
 723                                     (widget-get parent :offset))))
 724     (widget-apply widget :create)
 725     widget))
 726
 727 ;;;###autoload
 728 (defun widget-delete (widget)
 729   "Delete WIDGET."
 730   (widget-apply widget :delete))
 731
 732 (defun widget-copy (widget)
 733   "Make a deep copy of WIDGET."
 734   (widget-apply (copy-sequence widget) :copy))
 735
 736 (defun widget-convert (type &rest args)
 737   "Convert TYPE to a widget without inserting it in the buffer.
 738 The optional ARGS are additional keyword arguments."
 739   ;; Don't touch the type.
 740   (let* ((widget (if (symbolp type)
 741                      (list type)
 742                    (copy-sequence type)))
 743          (current widget)
 744          done
 745          (keys args))
 746     ;; First set the :args keyword.
 747     (while (cdr current)                ;Look in the type.
 748       (if (and (keywordp (cadr current))
 749                ;; If the last element is a keyword,
 750                ;; it is still the :args element,
 751                ;; even though it is a keyword.
 752                (cddr current))
 753           (if (eq (cadr current) :args)
 754               ;; If :args is explicitly specified, obey it.
 755               (setq current nil)
 756             ;; Some other irrelevant keyword.
 757             (setq current (cdr (cdr current))))
 758         (setcdr current (list :args (cdr current)))
 759         (setq current nil)))
 760     (while (and args (not done))        ;Look in ARGS.
 761       (cond ((eq (car args) :args)
 762              ;; Handle explicit specification of :args.
 763              (setq args (cadr args)
 764                    done t))
 765             ((keywordp (car args))
 766              (setq args (cddr args)))
 767             (t (setq done t))))
 768     (when done
 769       (widget-put widget :args args))
 770     ;; Then Convert the widget.
 771     (setq type widget)
 772     (while type
 773       (let ((convert-widget (plist-get (cdr type) :convert-widget)))
 774         (if convert-widget
 775             (setq widget (funcall convert-widget widget))))
 776       (setq type (get (car type) 'widget-type)))
 777     ;; Finally set the keyword args.
 778     (while keys
 779       (let ((next (nth 0 keys)))
 780         (if (keywordp next)
 781             (progn
 782               (widget-put widget next (nth 1 keys))
 783               (setq keys (nthcdr 2 keys)))
 784           (setq keys nil))))
 785     ;; Convert the :value to internal format.
 786     (if (widget-member widget :value)
 787         (widget-put widget
 788                     :value (widget-apply widget
 789                                          :value-to-internal
 790                                          (widget-get widget :value))))
 791     ;; Return the newly create widget.
 792     widget))
 793
 794 ;;;###autoload
 795 (defun widget-insert (&rest args)
 796   "Call `insert' with ARGS even if surrounding text is read only."
 797   (let ((inhibit-read-only t)
 798         (inhibit-modification-hooks t))
 799     (apply 'insert args)))
 800
 801 (defun widget-convert-text (type from to
 802                                  &optional button-from button-to
 803                                  &rest args)
 804   "Return a widget of type TYPE with endpoint FROM TO.
 805 Optional ARGS are extra keyword arguments for TYPE.
 806 and TO will be used as the widgets end points. If optional arguments
 807 BUTTON-FROM and BUTTON-TO are given, these will be used as the widgets
 808 button end points.
 809 Optional ARGS are extra keyword arguments for TYPE."
 810   (let ((widget (apply 'widget-convert type :delete 'widget-leave-text args))
 811         (from (copy-marker from))
 812         (to (copy-marker to)))
 813     (set-marker-insertion-type from t)
 814     (set-marker-insertion-type to nil)
 815     (widget-put widget :from from)
 816     (widget-put widget :to to)
 817     (when button-from
 818       (widget-specify-button widget button-from button-to))
 819     widget))
 820
 821 (defun widget-convert-button (type from to &rest args)
 822   "Return a widget of type TYPE with endpoint FROM TO.
 823 Optional ARGS are extra keyword arguments for TYPE.
 824 No text will be inserted to the buffer, instead the text between FROM
 825 and TO will be used as the widgets end points, as well as the widgets
 826 button end points."
 827   (apply 'widget-convert-text type from to from to args))
 828
 829 (defun widget-leave-text (widget)
 830   "Remove markers and overlays from WIDGET and its children."
 831   (let ((button (widget-get widget :button-overlay))
 832         (sample (widget-get widget :sample-overlay))
 833         (doc (widget-get widget :doc-overlay))
 834         (field (widget-get widget :field-overlay)))
 835     (set-marker (widget-get widget :from) nil)
 836     (set-marker (widget-get widget :to) nil)
 837     (when button
 838       (delete-overlay button))
 839     (when sample
 840       (delete-overlay sample))
 841     (when doc
 842       (delete-overlay doc))
 843     (when field
 844       (delete-overlay field))
 845     (mapc 'widget-leave-text (widget-get widget :children))))
 846
 847 ;;; Keymap and Commands.
 848
 849 ;;;###autoload
 850 (defvar widget-keymap
 851   (let ((map (make-sparse-keymap)))
 852     (define-key map "\t" 'widget-forward)
 853     (define-key map [(shift tab)] 'widget-backward)
 854     (define-key map [backtab] 'widget-backward)
 855     (define-key map [down-mouse-2] 'widget-button-click)
 856     (define-key map "\C-m" 'widget-button-press)
 857     map)
 858   "Keymap containing useful binding for buffers containing widgets.
 859 Recommended as a parent keymap for modes using widgets.")
 860
 861 (defvar widget-global-map global-map
 862   "Keymap used for events a widget does not handle itself.")
 863 (make-variable-buffer-local 'widget-global-map)
 864
 865 (defvar widget-field-keymap
 866   (let ((map (copy-keymap widget-keymap)))
 867     (define-key map "\C-k" 'widget-kill-line)
 868     (define-key map "\M-\t" 'widget-complete)
 869     (define-key map "\C-m" 'widget-field-activate)
 870     ;; Since the widget code uses a `field' property to identify fields,
 871     ;; ordinary beginning-of-line does the right thing.
 872     ;;  (define-key map "\C-a" 'widget-beginning-of-line)
 873     (define-key map "\C-e" 'widget-end-of-line)
 874     map)
 875   "Keymap used inside an editable field.")
 876
 877 (defvar widget-text-keymap
 878   (let ((map (copy-keymap widget-keymap)))
 879     ;; Since the widget code uses a `field' property to identify fields,
 880     ;; ordinary beginning-of-line does the right thing.
 881     ;;  (define-key map "\C-a" 'widget-beginning-of-line)
 882     (define-key map "\C-e" 'widget-end-of-line)
 883     map)
 884   "Keymap used inside a text field.")
 885
 886 (defun widget-field-activate (pos &optional event)
 887   "Invoke the editable field at point."
 888   (interactive "@d")
 889   (let ((field (widget-field-at pos)))
 890     (if field
 891         (widget-apply-action field event)
 892       (call-interactively
 893        (lookup-key widget-global-map (this-command-keys))))))
 894
 895 (defface widget-button-pressed
 896   '((((min-colors 88) (class color))
 897      (:foreground "red1"))
 898     (((class color))
 899      (:foreground "red"))
 900     (t
 901      (:weight bold :underline t)))
 902   "Face used for pressed buttons."
 903   :group 'widget-faces)
 904 ;; backward-compatibility alias
 905 (put 'widget-button-pressed-face 'face-alias 'widget-button-pressed)
 906
 907 (defun widget-button-click (event)
 908   "Invoke the button that the mouse is pointing at."
 909   (interactive "e")
 910   (if (widget-event-point event)
 911       (let* ((pos (widget-event-point event))
 912              (start (event-start event))
 913              (button (get-char-property
 914                       pos 'button (and (windowp (posn-window start))
 915                                        (window-buffer (posn-window start))))))
 916         (if button
 917             ;; Mouse click on a widget button.  Do the following
 918             ;; in a save-excursion so that the click on the button
 919             ;; doesn't change point.
 920             (save-selected-window
 921               (select-window (posn-window (event-start event)))
 922               (save-excursion
 923                 (goto-char (posn-point (event-start event)))
 924                 (let* ((overlay (widget-get button :button-overlay))
 925                        (face (overlay-get overlay 'face))
 926                        (mouse-face (overlay-get overlay 'mouse-face)))
 927                   (unwind-protect
 928                       ;; Read events, including mouse-movement events
 929                       ;; until we receive a release event.  Highlight/
 930                       ;; unhighlight the button the mouse was initially
 931                       ;; on when we move over it.
 932                       (save-excursion
 933                         (when face      ; avoid changing around image
 934                           (overlay-put overlay
 935                                        'face widget-button-pressed-face)
 936                           (overlay-put overlay
 937                                        'mouse-face widget-button-pressed-face))
 938                         (unless (widget-apply button :mouse-down-action event)
 939                           (let ((track-mouse t))
 940                             (while (not (widget-button-release-event-p event))
 941                               (setq event (read-event)
 942                                     pos (widget-event-point event))
 943                               (if (and pos
 944                                        (eq (get-char-property pos 'button)
 945                                            button))
 946                                   (when face
 947                                     (overlay-put overlay
 948                                                  'face
 949                                                  widget-button-pressed-face)
 950                                     (overlay-put overlay
 951                                                  'mouse-face
 952                                                  widget-button-pressed-face))
 953                                 (overlay-put overlay 'face face)
 954                                 (overlay-put overlay 'mouse-face mouse-face)))))
 955
 956                         ;; When mouse is released over the button, run
 957                         ;; its action function.
 958                         (when (and pos
 959                                    (eq (get-char-property pos 'button) button))
 960                           (widget-apply-action button event)))
 961                     (overlay-put overlay 'face face)
 962                     (overlay-put overlay 'mouse-face mouse-face))))
 963
 964               (unless (pos-visible-in-window-p (widget-event-point event))
 965                 (mouse-set-point event)
 966                 (beginning-of-line)
 967                 (recenter))
 968               )
 969
 970             (let ((up t) command)
 971               ;; Mouse click not on a widget button.  Find the global
 972               ;; command to run, and check whether it is bound to an
 973               ;; up event.
 974               (mouse-set-point event)
 975               (if (memq (event-basic-type event) '(mouse-1 down-mouse-1))
 976                   (cond ((setq command  ;down event
 977                                (lookup-key widget-global-map [down-mouse-1]))
 978                          (setq up nil))
 979                         ((setq command  ;up event
 980                                (lookup-key widget-global-map [mouse-1]))))
 981                 (cond ((setq command    ;down event
 982                              (lookup-key widget-global-map [down-mouse-2]))
 983                        (setq up nil))
 984                       ((setq command    ;up event
 985                              (lookup-key widget-global-map [mouse-2])))))
 986               (when up
 987                 ;; Don't execute up events twice.
 988                 (while (not (widget-button-release-event-p event))
 989                   (setq event (read-event))))
 990               (when command
 991                 (call-interactively command)))))
 992     (message "You clicked somewhere weird.")))
 993
 994 (defun widget-button-press (pos &optional event)
 995   "Invoke button at POS."
 996   (interactive "@d")
 997   (let ((button (get-char-property pos 'button)))
 998     (if button
 999         (widget-apply-action button event)
1000       (let ((command (lookup-key widget-global-map (this-command-keys))))
1001         (when (commandp command)
1002           (call-interactively command))))))
1003
1004 (defun widget-tabable-at (&optional pos)
1005   "Return the tabable widget at POS, or nil.
1006 POS defaults to the value of (point)."
1007   (let ((widget (widget-at pos)))
1008     (if widget
1009         (let ((order (widget-get widget :tab-order)))
1010           (if order
1011               (if (>= order 0)
1012                   widget)
1013             widget)))))
1014
1015 (defvar widget-use-overlay-change t
1016   "If non-nil, use overlay change functions to tab around in the buffer.
1017 This is much faster, but doesn't work reliably on Emacs 19.34.")
1018
1019 (defun widget-move (arg)
1020   "Move point to the ARG next field or button.
1021 ARG may be negative to move backward."
1022   (or (bobp) (> arg 0) (backward-char))
1023   (let ((wrapped 0)
1024         (number arg)
1025         (old (widget-tabable-at)))
1026     ;; Forward.
1027     (while (> arg 0)
1028       (cond ((eobp)
1029              (goto-char (point-min))
1030              (setq wrapped (1+ wrapped)))
1031             (widget-use-overlay-change
1032              (goto-char (next-overlay-change (point))))
1033             (t
1034              (forward-char 1)))
1035       (and (= wrapped 2)
1036            (eq arg number)
1037            (error "No buttons or fields found"))
1038       (let ((new (widget-tabable-at)))
1039         (when new
1040           (unless (eq new old)
1041             (setq arg (1- arg))
1042             (setq old new)))))
1043     ;; Backward.
1044     (while (< arg 0)
1045       (cond ((bobp)
1046              (goto-char (point-max))
1047              (setq wrapped (1+ wrapped)))
1048             (widget-use-overlay-change
1049              (goto-char (previous-overlay-change (point))))
1050             (t
1051              (backward-char 1)))
1052       (and (= wrapped 2)
1053            (eq arg number)
1054            (error "No buttons or fields found"))
1055       (let ((new (widget-tabable-at)))
1056         (when new
1057           (unless (eq new old)
1058             (setq arg (1+ arg))))))
1059     (let ((new (widget-tabable-at)))
1060       (while (eq (widget-tabable-at) new)
1061         (backward-char)))
1062     (forward-char))
1063   (widget-echo-help (point))
1064   (run-hooks 'widget-move-hook))
1065
1066 (defun widget-forward (arg)
1067   "Move point to the next field or button.
1068 With optional ARG, move across that many fields."
1069   (interactive "p")
1070   (run-hooks 'widget-forward-hook)
1071   (widget-move arg))
1072
1073 (defun widget-backward (arg)
1074   "Move point to the previous field or button.
1075 With optional ARG, move across that many fields."
1076   (interactive "p")
1077   (run-hooks 'widget-backward-hook)
1078   (widget-move (- arg)))
1079
1080 ;; Since the widget code uses a `field' property to identify fields,
1081 ;; ordinary beginning-of-line does the right thing.
1082 (defalias 'widget-beginning-of-line 'beginning-of-line)
1083
1084 (defun widget-end-of-line ()
1085   "Go to end of field or end of line, whichever is first.
1086 Trailing spaces at the end of padded fields are not considered part of
1087 the field."
1088   (interactive)
1089   ;; Ordinary end-of-line does the right thing, because we're inside
1090   ;; text with a `field' property.
1091   (end-of-line)
1092   (unless (eolp)
1093     ;; ... except that we want to ignore trailing spaces in fields that
1094     ;; aren't terminated by a newline, because they are used as padding,
1095     ;; and ignored when extracting the entered value of the field.
1096     (skip-chars-backward " " (field-beginning (1- (point))))))
1097
1098 (defun widget-kill-line ()
1099   "Kill to end of field or end of line, whichever is first."
1100   (interactive)
1101   (let* ((field (widget-field-find (point)))
1102          (end (and field (widget-field-end field))))
1103     (if (and field (> (line-beginning-position 2) end))
1104         (kill-region (point) end)
1105       (call-interactively 'kill-line))))
1106
1107 (defcustom widget-complete-field (lookup-key global-map "\M-\t")
1108   "Default function to call for completion inside fields."
1109   :options '(ispell-complete-word complete-tag lisp-complete-symbol)
1110   :type 'function
1111   :group 'widgets)
1112
1113 (defun widget-narrow-to-field ()
1114   "Narrow to field"
1115   (interactive)
1116   (let ((field (widget-field-find (point))))
1117     (if field
1118         (narrow-to-region (line-beginning-position) (line-end-position)))))
1119
1120 (defun widget-complete ()
1121   "Complete content of editable field from point.
1122 When not inside a field, move to the previous button or field."
1123   (interactive)
1124   (let ((field (widget-field-find (point))))
1125     (if field
1126         (save-restriction
1127           (widget-narrow-to-field)
1128           (widget-apply field :complete))
1129           (error "Not in an editable field"))))
1130
1131 ;;; Setting up the buffer.
1132
1133 (defvar widget-field-new nil
1134   "List of all newly created editable fields in the buffer.")
1135 (make-variable-buffer-local 'widget-field-new)
1136
1137 (defvar widget-field-list nil
1138   "List of all editable fields in the buffer.")
1139 (make-variable-buffer-local 'widget-field-list)
1140
1141 (defun widget-at (&optional pos)
1142   "The button or field at POS (default, point)."
1143   (or (get-char-property (or pos (point)) 'button)
1144       (widget-field-at pos)))
1145
1146 ;;;###autoload
1147 (defun widget-setup ()
1148   "Setup current buffer so editing string widgets works."
1149   (let ((inhibit-read-only t)
1150         (inhibit-modification-hooks t)
1151         field)
1152     (while widget-field-new
1153       (setq field (car widget-field-new)
1154             widget-field-new (cdr widget-field-new)
1155             widget-field-list (cons field widget-field-list))
1156       (let ((from (car (widget-get field :field-overlay)))
1157             (to (cdr (widget-get field :field-overlay))))
1158         (widget-specify-field field
1159                               (marker-position from) (marker-position to))
1160         (set-marker from nil)
1161         (set-marker to nil))))
1162   (widget-clear-undo)
1163   (widget-add-change))
1164
1165 (defvar widget-field-last nil)
1166 ;; Last field containing point.
1167 (make-variable-buffer-local 'widget-field-last)
1168
1169 (defvar widget-field-was nil)
1170 ;; The widget data before the change.
1171 (make-variable-buffer-local 'widget-field-was)
1172
1173 (defun widget-field-at (pos)
1174   "Return the widget field at POS, or nil if none."
1175   (let ((field (get-char-property (or pos (point)) 'field)))
1176     (if (eq field 'boundary)
1177         (get-char-property (or pos (point)) 'real-field)
1178       field)))
1179
1180 (defun widget-field-buffer (widget)
1181   "Return the buffer of WIDGET's editing field."
1182   (let ((overlay (widget-get widget :field-overlay)))
1183     (cond ((overlayp overlay)
1184            (overlay-buffer overlay))
1185           ((consp overlay)
1186            (marker-buffer (car overlay))))))
1187
1188 (defun widget-field-start (widget)
1189   "Return the start of WIDGET's editing field."
1190   (let ((overlay (widget-get widget :field-overlay)))
1191     (if (overlayp overlay)
1192         (overlay-start overlay)
1193       (car overlay))))
1194
1195 (defun widget-field-end (widget)
1196   "Return the end of WIDGET's editing field."
1197   (let ((overlay (widget-get widget :field-overlay)))
1198     ;; Don't subtract one if local-map works at the end of the overlay,
1199     ;; or if a special `boundary' field has been added after the widget
1200     ;; field.
1201     (if (overlayp overlay)
1202         (if (and (not (eq (with-current-buffer
1203                               (widget-field-buffer widget)
1204                             (save-restriction
1205                               ;; `widget-narrow-to-field' can be
1206                               ;; active when this function is called
1207                               ;; from an change-functions hook. So
1208                               ;; temporarily remove field narrowing
1209                               ;; before to call `get-char-property'.
1210                               (widen)
1211                               (get-char-property (overlay-end overlay)
1212                                                  'field)))
1213                           'boundary))
1214                  (or widget-field-add-space
1215                      (null (widget-get widget :size))))
1216             (1- (overlay-end overlay))
1217           (overlay-end overlay))
1218       (cdr overlay))))
1219
1220 (defun widget-field-find (pos)
1221   "Return the field at POS.
1222 Unlike (get-char-property POS 'field) this, works with empty fields too."
1223   (let ((fields widget-field-list)
1224         field found)
1225     (while fields
1226       (setq field (car fields)
1227             fields (cdr fields))
1228       (when (and (<= (widget-field-start field) pos)
1229                  (<= pos (widget-field-end field)))
1230         (when found
1231           (error "Overlapping fields"))
1232         (setq found field)))
1233     found))
1234
1235 (defun widget-before-change (from to)
1236   ;; This is how, for example, a variable changes its state to `modified'.
1237   ;; when it is being edited.
1238   (unless inhibit-read-only
1239     (let ((from-field (widget-field-find from))
1240           (to-field (widget-field-find to)))
1241       (cond ((not (eq from-field to-field))
1242              (add-hook 'post-command-hook 'widget-add-change nil t)
1243              (signal 'text-read-only
1244                      '("Change should be restricted to a single field")))
1245             ((null from-field)
1246              (add-hook 'post-command-hook 'widget-add-change nil t)
1247              (signal 'text-read-only
1248                      '("Attempt to change text outside editable field")))
1249             (widget-field-use-before-change
1250              (widget-apply from-field :notify from-field))))))
1251
1252 (defun widget-add-change ()
1253   (remove-hook 'post-command-hook 'widget-add-change t)
1254   (add-hook 'before-change-functions 'widget-before-change nil t)
1255   (add-hook 'after-change-functions 'widget-after-change nil t))
1256
1257 (defun widget-after-change (from to old)
1258   "Adjust field size and text properties."
1259   (let ((field (widget-field-find from))
1260         (other (widget-field-find to)))
1261     (when field
1262       (unless (eq field other)
1263         (error "Change in different fields"))
1264       (let ((size (widget-get field :size)))
1265         (when size
1266           (let ((begin (widget-field-start field))
1267                 (end (widget-field-end field)))
1268             (cond ((< (- end begin) size)
1269                    ;; Field too small.
1270                    (save-excursion
1271                      (goto-char end)
1272                      (insert-char ?\  (- (+ begin size) end))))
1273                   ((> (- end begin) size)
1274                    ;; Field too large and
1275                    (if (or (< (point) (+ begin size))
1276                            (> (point) end))
1277                        ;; Point is outside extra space.
1278                        (setq begin (+ begin size))
1279                      ;; Point is within the extra space.
1280                      (setq begin (point)))
1281                    (save-excursion
1282                      (goto-char end)
1283                      (while (and (eq (preceding-char) ?\ )
1284                                  (> (point) begin))
1285                        (delete-backward-char 1)))))))
1286         (widget-specify-secret field))
1287       (widget-apply field :notify field))))
1288
1289 ;;; Widget Functions
1290 ;;
1291 ;; These functions are used in the definition of multiple widgets.
1292
1293 (defun widget-parent-action (widget &optional event)
1294   "Tell :parent of WIDGET to handle the :action.
1295 Optional EVENT is the event that triggered the action."
1296   (widget-apply (widget-get widget :parent) :action event))
1297
1298 (defun widget-children-value-delete (widget)
1299   "Delete all :children and :buttons in WIDGET."
1300   (mapc 'widget-delete (widget-get widget :children))
1301   (widget-put widget :children nil)
1302   (mapc 'widget-delete (widget-get widget :buttons))
1303   (widget-put widget :buttons nil))
1304
1305 (defun widget-children-validate (widget)
1306   "All the :children must be valid."
1307   (let ((children (widget-get widget :children))
1308         child found)
1309     (while (and children (not found))
1310       (setq child (car children)
1311             children (cdr children)
1312             found (widget-apply child :validate)))
1313     found))
1314
1315 (defun widget-child-value-get (widget)
1316   "Get the value of the first member of :children in WIDGET."
1317   (widget-value (car (widget-get widget :children))))
1318
1319 (defun widget-child-value-inline (widget)
1320   "Get the inline value of the first member of :children in WIDGET."
1321   (widget-apply (car (widget-get widget :children)) :value-inline))
1322
1323 (defun widget-child-validate (widget)
1324   "The result of validating the first member of :children in WIDGET."
1325   (widget-apply (car (widget-get widget :children)) :validate))
1326
1327 (defun widget-type-value-create (widget)
1328   "Convert and instantiate the value of the :type attribute of WIDGET.
1329 Store the newly created widget in the :children attribute.
1330
1331 The value of the :type attribute should be an unconverted widget type."
1332   (let ((value (widget-get widget :value))
1333         (type (widget-get widget :type)))
1334     (widget-put widget :children
1335                 (list (widget-create-child-value widget
1336                                                  (widget-convert type)
1337                                                  value)))))
1338
1339 (defun widget-type-default-get (widget)
1340   "Get default value from the :type attribute of WIDGET.
1341
1342 The value of the :type attribute should be an unconverted widget type."
1343   (widget-default-get (widget-convert (widget-get widget :type))))
1344
1345 (defun widget-type-match (widget value)
1346   "Non-nil if the :type value of WIDGET matches VALUE.
1347
1348 The value of the :type attribute should be an unconverted widget type."
1349   (widget-apply (widget-convert (widget-get widget :type)) :match value))
1350
1351 (defun widget-types-copy (widget)
1352   "Copy :args as widget types in WIDGET."
1353   (widget-put widget :args (mapcar 'widget-copy (widget-get widget :args)))
1354   widget)
1355
1356 ;; Made defsubst to speed up face editor creation.
1357 (defsubst widget-types-convert-widget (widget)
1358   "Convert :args as widget types in WIDGET."
1359   (widget-put widget :args (mapcar 'widget-convert (widget-get widget :args)))
1360   widget)
1361
1362 (defun widget-value-convert-widget (widget)
1363   "Initialize :value from :args in WIDGET."
1364   (let ((args (widget-get widget :args)))
1365     (when args
1366       (widget-put widget :value (car args))
1367       ;; Don't convert :value here, as this is done in `widget-convert'.
1368       ;; (widget-put widget :value (widget-apply widget
1369       ;;                                      :value-to-internal (car args)))
1370       (widget-put widget :args nil)))
1371   widget)
1372
1373 (defun widget-value-value-get (widget)
1374   "Return the :value property of WIDGET."
1375   (widget-get widget :value))
1376
1377 ;;; The `default' Widget.
1378
1379 (define-widget 'default nil
1380   "Basic widget other widgets are derived from."
1381   :value-to-internal (lambda (widget value) value)
1382   :value-to-external (lambda (widget value) value)
1383   :button-prefix 'widget-button-prefix
1384   :button-suffix 'widget-button-suffix
1385   :complete 'widget-default-complete
1386   :create 'widget-default-create
1387   :indent nil
1388   :offset 0
1389   :format-handler 'widget-default-format-handler
1390   :button-face-get 'widget-default-button-face-get
1391   :sample-face-get 'widget-default-sample-face-get
1392   :delete 'widget-default-delete
1393   :copy 'identity
1394   :value-set 'widget-default-value-set
1395   :value-inline 'widget-default-value-inline
1396   :value-delete 'ignore
1397   :default-get 'widget-default-default-get
1398   :menu-tag-get 'widget-default-menu-tag-get
1399   :validate #'ignore
1400   :active 'widget-default-active
1401   :activate 'widget-specify-active
1402   :deactivate 'widget-default-deactivate
1403   :mouse-down-action #'ignore
1404   :action 'widget-default-action
1405   :notify 'widget-default-notify
1406   :prompt-value 'widget-default-prompt-value)
1407
1408 (defun widget-default-complete (widget)
1409   "Call the value of the :complete-function property of WIDGET.
1410 If that does not exists, call the value of `widget-complete-field'."
1411   (call-interactively (or (widget-get widget :complete-function)
1412                           widget-complete-field)))
1413
1414 (defun widget-default-create (widget)
1415   "Create WIDGET at point in the current buffer."
1416   (widget-specify-insert
1417    (let ((from (point))
1418          button-begin button-end
1419          sample-begin sample-end
1420          doc-begin doc-end
1421          value-pos)
1422      (insert (widget-get widget :format))
1423      (goto-char from)
1424      ;; Parse escapes in format.
1425      (while (re-search-forward "%\\(.\\)" nil t)
1426        (let ((escape (char-after (match-beginning 1))))
1427          (delete-backward-char 2)
1428          (cond ((eq escape ?%)
1429                 (insert ?%))
1430                ((eq escape ?\[)
1431                 (setq button-begin (point))
1432                 (insert (widget-get-indirect widget :button-prefix)))
1433                ((eq escape ?\])
1434                 (insert (widget-get-indirect widget :button-suffix))
1435                 (setq button-end (point)))
1436                ((eq escape ?\{)
1437                 (setq sample-begin (point)))
1438                ((eq escape ?\})
1439                 (setq sample-end (point)))
1440                ((eq escape ?n)
1441                 (when (widget-get widget :indent)
1442                   (insert ?\n)
1443                   (insert-char ?  (widget-get widget :indent))))
1444                ((eq escape ?t)
1445                 (let ((image (widget-get widget :tag-glyph))
1446                       (tag (widget-get widget :tag)))
1447                   (cond (image
1448                          (widget-image-insert widget (or tag "image") image))
1449                         (tag
1450                          (insert tag))
1451                         (t
1452                          (princ (widget-get widget :value)
1453                                 (current-buffer))))))
1454                ((eq escape ?d)
1455                 (let ((doc (widget-get widget :doc)))
1456                   (when doc
1457                     (setq doc-begin (point))
1458                     (insert doc)
1459                     (while (eq (preceding-char) ?\n)
1460                       (delete-backward-char 1))
1461                     (insert ?\n)
1462                     (setq doc-end (point)))))
1463                ((eq escape ?v)
1464                 (if (and button-begin (not button-end))
1465                     (widget-apply widget :value-create)
1466                   (setq value-pos (point))))
1467                (t
1468                 (widget-apply widget :format-handler escape)))))
1469      ;; Specify button, sample, and doc, and insert value.
1470      (and button-begin button-end
1471           (widget-specify-button widget button-begin button-end))
1472      (and sample-begin sample-end
1473           (widget-specify-sample widget sample-begin sample-end))
1474      (and doc-begin doc-end
1475           (widget-specify-doc widget doc-begin doc-end))
1476      (when value-pos
1477        (goto-char value-pos)
1478        (widget-apply widget :value-create)))
1479    (let ((from (point-min-marker))
1480          (to (point-max-marker)))
1481      (set-marker-insertion-type from t)
1482      (set-marker-insertion-type to nil)
1483      (widget-put widget :from from)
1484      (widget-put widget :to to)))
1485   (widget-clear-undo))
1486
1487 (defun widget-default-format-handler (widget escape)
1488   ;; We recognize the %h escape by default.
1489   (let* ((buttons (widget-get widget :buttons)))
1490     (cond ((eq escape ?h)
1491            (let* ((doc-property (widget-get widget :documentation-property))
1492                   (doc-try (cond ((widget-get widget :doc))
1493                                  ((functionp doc-property)
1494                                   (funcall doc-property
1495                                            (widget-get widget :value)))
1496                                  ((symbolp doc-property)
1497                                   (documentation-property
1498                                    (widget-get widget :value)
1499                                    doc-property))))
1500                   (doc-text (and (stringp doc-try)
1501                                  (> (length doc-try) 1)
1502                                  doc-try))
1503                   (doc-indent (widget-get widget :documentation-indent)))
1504              (when doc-text
1505                (and (eq (preceding-char) ?\n)
1506                     (widget-get widget :indent)
1507                     (insert-char ?  (widget-get widget :indent)))
1508                ;; The `*' in the beginning is redundant.
1509                (when (eq (aref doc-text  0) ?*)
1510                  (setq doc-text (substring doc-text 1)))
1511                ;; Get rid of trailing newlines.
1512                (when (string-match "\n+\\'" doc-text)
1513                  (setq doc-text (substring doc-text 0 (match-beginning 0))))
1514                (push (widget-create-child-and-convert
1515                       widget 'documentation-string
1516                       :indent (cond ((numberp doc-indent )
1517                                      doc-indent)
1518                                     ((null doc-indent)
1519                                      nil)
1520                                     (t 0))
1521                       doc-text)
1522                      buttons))))
1523           (t
1524            (error "Unknown escape `%c'" escape)))
1525     (widget-put widget :buttons buttons)))
1526
1527 (defun widget-default-button-face-get (widget)
1528   ;; Use :button-face or widget-button-face
1529   (or (widget-get widget :button-face)
1530       (let ((parent (widget-get widget :parent)))
1531         (if parent
1532             (widget-apply parent :button-face-get)
1533           widget-button-face))))
1534
1535 (defun widget-default-sample-face-get (widget)
1536   ;; Use :sample-face.
1537   (widget-get widget :sample-face))
1538
1539 (defun widget-default-delete (widget)
1540   "Remove widget from the buffer."
1541   (let ((from (widget-get widget :from))
1542         (to (widget-get widget :to))
1543         (inactive-overlay (widget-get widget :inactive))
1544         (button-overlay (widget-get widget :button-overlay))
1545         (sample-overlay (widget-get widget :sample-overlay))
1546         (doc-overlay (widget-get widget :doc-overlay))
1547         (inhibit-modification-hooks t)
1548         (inhibit-read-only t))
1549     (widget-apply widget :value-delete)
1550     (widget-children-value-delete widget)
1551     (when inactive-overlay
1552       (delete-overlay inactive-overlay))
1553     (when button-overlay
1554       (delete-overlay button-overlay))
1555     (when sample-overlay
1556       (delete-overlay sample-overlay))
1557     (when doc-overlay
1558       (delete-overlay doc-overlay))
1559     (when (< from to)
1560       ;; Kludge: this doesn't need to be true for empty formats.
1561       (delete-region from to))
1562     (set-marker from nil)
1563     (set-marker to nil))
1564   (widget-clear-undo))
1565
1566 (defun widget-default-value-set (widget value)
1567   "Recreate widget with new value."
1568   (let* ((old-pos (point))
1569          (from (copy-marker (widget-get widget :from)))
1570          (to (copy-marker (widget-get widget :to)))
1571          (offset (if (and (<= from old-pos) (<= old-pos to))
1572                      (if (>= old-pos (1- to))
1573                          (- old-pos to 1)
1574                        (- old-pos from)))))
1575     ;;??? Bug: this ought to insert the new value before deleting the old one,
1576     ;; so that markers on either side of the value automatically
1577     ;; stay on the same side.  -- rms.
1578     (save-excursion
1579       (goto-char (widget-get widget :from))
1580       (widget-apply widget :delete)
1581       (widget-put widget :value value)
1582       (widget-apply widget :create))
1583     (if offset
1584         (if (< offset 0)
1585             (goto-char (+ (widget-get widget :to) offset 1))
1586           (goto-char (min (+ from offset) (1- (widget-get widget :to))))))))
1587
1588 (defun widget-default-value-inline (widget)
1589   "Wrap value in a list unless it is inline."
1590   (if (widget-get widget :inline)
1591       (widget-value widget)
1592     (list (widget-value widget))))
1593
1594 (defun widget-default-default-get (widget)
1595   "Get `:value'."
1596   (widget-get widget :value))
1597
1598 (defun widget-default-menu-tag-get (widget)
1599   "Use tag or value for menus."
1600   (or (widget-get widget :menu-tag)
1601       (widget-get widget :tag)
1602       (widget-princ-to-string (widget-get widget :value))))
1603
1604 (defun widget-default-active (widget)
1605   "Return t iff this widget active (user modifiable)."
1606   (or (widget-get widget :always-active)
1607       (and (not (widget-get widget :inactive))
1608            (let ((parent (widget-get widget :parent)))
1609              (or (null parent)
1610                  (widget-apply parent :active))))))
1611
1612 (defun widget-default-deactivate (widget)
1613   "Make WIDGET inactive for user modifications."
1614   (widget-specify-inactive widget
1615                            (widget-get widget :from)
1616                            (widget-get widget :to)))
1617
1618 (defun widget-default-action (widget &optional event)
1619   "Notify the parent when a widget changes."
1620   (let ((parent (widget-get widget :parent)))
1621     (when parent
1622       (widget-apply parent :notify widget event))))
1623
1624 (defun widget-default-notify (widget child &optional event)
1625   "Pass notification to parent."
1626   (widget-default-action widget event))
1627
1628 (defun widget-default-prompt-value (widget prompt value unbound)
1629   "Read an arbitrary value.  Stolen from `set-variable'."
1630 ;; (let ((initial (if unbound
1631 ;; nil
1632 ;; It would be nice if we could do a `(cons val 1)' here.
1633 ;; (prin1-to-string (custom-quote value))))))
1634   (eval-minibuffer prompt))
1635
1636 ;;; The `item' Widget.
1637
1638 (define-widget 'item 'default
1639   "Constant items for inclusion in other widgets."
1640   :convert-widget 'widget-value-convert-widget
1641   :value-create 'widget-item-value-create
1642   :value-delete 'ignore
1643   :value-get 'widget-value-value-get
1644   :match 'widget-item-match
1645   :match-inline 'widget-item-match-inline
1646   :action 'widget-item-action
1647   :format "%t\n")
1648
1649 (defun widget-item-value-create (widget)
1650   "Insert the printed representation of the value."
1651   (princ (widget-get widget :value) (current-buffer)))
1652
1653 (defun widget-item-match (widget value)
1654   ;; Match if the value is the same.
1655   (equal (widget-get widget :value) value))
1656
1657 (defun widget-item-match-inline (widget values)
1658   ;; Match if the value is the same.
1659   (let ((value (widget-get widget :value)))
1660     (and (listp value)
1661          (<= (length value) (length values))
1662          (let ((head (widget-sublist values 0 (length value))))
1663            (and (equal head value)
1664                 (cons head (widget-sublist values (length value))))))))
1665
1666 (defun widget-sublist (list start &optional end)
1667   "Return the sublist of LIST from START to END.
1668 If END is omitted, it defaults to the length of LIST."
1669   (if (> start 0) (setq list (nthcdr start list)))
1670   (if end
1671       (unless (<= end start)
1672         (setq list (copy-sequence list))
1673         (setcdr (nthcdr (- end start 1) list) nil)
1674         list)
1675     (copy-sequence list)))
1676
1677 (defun widget-item-action (widget &optional event)
1678   ;; Just notify itself.
1679   (widget-apply widget :notify widget event))
1680
1681 ;;; The `push-button' Widget.
1682
1683 ;; (defcustom widget-push-button-gui t
1684 ;;   "If non nil, use GUI push buttons when available."
1685 ;;   :group 'widgets
1686 ;;   :type 'boolean)
1687
1688 ;; Cache already created GUI objects.
1689 ;; (defvar widget-push-button-cache nil)
1690
1691 (defcustom widget-push-button-prefix "["
1692   "String used as prefix for buttons."
1693   :type 'string
1694   :group 'widget-button)
1695
1696 (defcustom widget-push-button-suffix "]"
1697   "String used as suffix for buttons."
1698   :type 'string
1699   :group 'widget-button)
1700
1701 (define-widget 'push-button 'item
1702   "A pushable button."
1703   :button-prefix ""
1704   :button-suffix ""
1705   :value-create 'widget-push-button-value-create
1706   :format "%[%v%]")
1707
1708 (defun widget-push-button-value-create (widget)
1709   "Insert text representing the `on' and `off' states."
1710   (let* ((tag (or (widget-get widget :tag)
1711                   (widget-get widget :value)))
1712          (tag-glyph (widget-get widget :tag-glyph))
1713          (text (concat widget-push-button-prefix
1714                        tag widget-push-button-suffix)))
1715     (if tag-glyph
1716         (widget-image-insert widget text tag-glyph)
1717       (insert text))))
1718
1719 ;; (defun widget-gui-action (widget)
1720 ;;   "Apply :action for WIDGET."
1721 ;;   (widget-apply-action widget (this-command-keys)))
1722
1723 ;;; The `link' Widget.
1724
1725 (defcustom widget-link-prefix "["
1726   "String used as prefix for links."
1727   :type 'string
1728   :group 'widget-button)
1729
1730 (defcustom widget-link-suffix "]"
1731   "String used as suffix for links."
1732   :type 'string
1733   :group 'widget-button)
1734
1735 (define-widget 'link 'item
1736   "An embedded link."
1737   :button-prefix 'widget-link-prefix
1738   :button-suffix 'widget-link-suffix
1739   :follow-link "\C-m"
1740   :help-echo "Follow the link."
1741   :format "%[%t%]")
1742
1743 ;;; The `info-link' Widget.
1744
1745 (define-widget 'info-link 'link
1746   "A link to an info file."
1747   :action 'widget-info-link-action)
1748
1749 (defun widget-info-link-action (widget &optional event)
1750   "Open the info node specified by WIDGET."
1751   (info (widget-value widget)))
1752
1753 ;;; The `url-link' Widget.
1754
1755 (define-widget 'url-link 'link
1756   "A link to an www page."
1757   :action 'widget-url-link-action)
1758
1759 (defun widget-url-link-action (widget &optional event)
1760   "Open the url specified by WIDGET."
1761   (browse-url (widget-value widget)))
1762
1763 ;;; The `function-link' Widget.
1764
1765 (define-widget 'function-link 'link
1766   "A link to an Emacs function."
1767   :action 'widget-function-link-action)
1768
1769 (defun widget-function-link-action (widget &optional event)
1770   "Show the function specified by WIDGET."
1771   (describe-function (widget-value widget)))
1772
1773 ;;; The `variable-link' Widget.
1774
1775 (define-widget 'variable-link 'link
1776   "A link to an Emacs variable."
1777   :action 'widget-variable-link-action)
1778
1779 (defun widget-variable-link-action (widget &optional event)
1780   "Show the variable specified by WIDGET."
1781   (describe-variable (widget-value widget)))
1782
1783 ;;; The `file-link' Widget.
1784
1785 (define-widget 'file-link 'link
1786   "A link to a file."
1787   :action 'widget-file-link-action)
1788
1789 (defun widget-file-link-action (widget &optional event)
1790   "Find the file specified by WIDGET."
1791   (find-file (widget-value widget)))
1792
1793 ;;; The `emacs-library-link' Widget.
1794
1795 (define-widget 'emacs-library-link 'link
1796   "A link to an Emacs Lisp library file."
1797   :action 'widget-emacs-library-link-action)
1798
1799 (defun widget-emacs-library-link-action (widget &optional event)
1800   "Find the Emacs Library file specified by WIDGET."
1801   (find-file (locate-library (widget-value widget))))
1802
1803 ;;; The `emacs-commentary-link' Widget.
1804
1805 (define-widget 'emacs-commentary-link 'link
1806   "A link to Commentary in an Emacs Lisp library file."
1807   :action 'widget-emacs-commentary-link-action)
1808
1809 (defun widget-emacs-commentary-link-action (widget &optional event)
1810   "Find the Commentary section of the Emacs file specified by WIDGET."
1811   (finder-commentary (widget-value widget)))
1812
1813 ;;; The `editable-field' Widget.
1814
1815 (define-widget 'editable-field 'default
1816   "An editable text field."
1817   :convert-widget 'widget-value-convert-widget
1818   :keymap widget-field-keymap
1819   :format "%v"
1820   :help-echo "M-TAB: complete field; RET: enter value"
1821   :value ""
1822   :prompt-internal 'widget-field-prompt-internal
1823   :prompt-history 'widget-field-history
1824   :prompt-value 'widget-field-prompt-value
1825   :action 'widget-field-action
1826   :validate 'widget-field-validate
1827   :valid-regexp ""
1828   :error "Field's value doesn't match allowed forms"
1829   :value-create 'widget-field-value-create
1830   :value-delete 'widget-field-value-delete
1831   :value-get 'widget-field-value-get
1832   :match 'widget-field-match)
1833
1834 (defvar widget-field-history nil
1835   "History of field minibuffer edits.")
1836
1837 (defun widget-field-prompt-internal (widget prompt initial history)
1838   "Read string for WIDGET promptinhg with PROMPT.
1839 INITIAL is the initial input and HISTORY is a symbol containing
1840 the earlier input."
1841   (read-string prompt initial history))
1842
1843 (defun widget-field-prompt-value (widget prompt value unbound)
1844   "Prompt for a string."
1845   (widget-apply widget
1846                 :value-to-external
1847                 (widget-apply widget
1848                               :prompt-internal prompt
1849                               (unless unbound
1850                                 (cons (widget-apply widget
1851                                                     :value-to-internal value)
1852                                       0))
1853                               (widget-get widget :prompt-history))))
1854
1855 (defvar widget-edit-functions nil)
1856
1857 (defun widget-field-action (widget &optional event)
1858   "Move to next field."
1859   (widget-forward 1)
1860   (run-hook-with-args 'widget-edit-functions widget))
1861
1862 (defun widget-field-validate (widget)
1863   "Valid if the content matches `:valid-regexp'."
1864   (unless (string-match (widget-get widget :valid-regexp)
1865                         (widget-apply widget :value-get))
1866     widget))
1867
1868 (defun widget-field-value-create (widget)
1869   "Create an editable text field."
1870   (let ((size (widget-get widget :size))
1871         (value (widget-get widget :value))
1872         (from (point))
1873         ;; This is changed to a real overlay in `widget-setup'.  We
1874         ;; need the end points to behave differently until
1875         ;; `widget-setup' is called.
1876         (overlay (cons (make-marker) (make-marker))))
1877     (widget-put widget :field-overlay overlay)
1878     (insert value)
1879     (and size
1880          (< (length value) size)
1881          (insert-char ?\  (- size (length value))))
1882     (unless (memq widget widget-field-list)
1883       (setq widget-field-new (cons widget widget-field-new)))
1884     (move-marker (cdr overlay) (point))
1885     (set-marker-insertion-type (cdr overlay) nil)
1886     (when (null size)
1887       (insert ?\n))
1888     (move-marker (car overlay) from)
1889     (set-marker-insertion-type (car overlay) t)))
1890
1891 (defun widget-field-value-delete (widget)
1892   "Remove the widget from the list of active editing fields."
1893   (setq widget-field-list (delq widget widget-field-list))
1894   (setq widget-field-new (delq widget widget-field-new))
1895   ;; These are nil if the :format string doesn't contain `%v'.
1896   (let ((overlay (widget-get widget :field-overlay)))
1897     (when (overlayp overlay)
1898       (delete-overlay overlay))))
1899
1900 (defun widget-field-value-get (widget)
1901   "Return current text in editing field."
1902   (let ((from (widget-field-start widget))
1903         (to (widget-field-end widget))
1904         (buffer (widget-field-buffer widget))
1905         (size (widget-get widget :size))
1906         (secret (widget-get widget :secret))
1907         (old (current-buffer)))
1908     (if (and from to)
1909         (progn
1910           (set-buffer buffer)
1911           (while (and size
1912                       (not (zerop size))
1913                       (> to from)
1914                       (eq (char-after (1- to)) ?\ ))
1915             (setq to (1- to)))
1916           (let ((result (buffer-substring-no-properties from to)))
1917             (when secret
1918               (let ((index 0))
1919                 (while (< (+ from index) to)
1920                   (aset result index
1921                         (get-char-property (+ from index) 'secret))
1922                   (setq index (1+ index)))))
1923             (set-buffer old)
1924             result))
1925       (widget-get widget :value))))
1926
1927 (defun widget-field-match (widget value)
1928   ;; Match any string.
1929   (stringp value))
1930
1931 ;;; The `text' Widget.
1932
1933 (define-widget 'text 'editable-field
1934   "A multiline text area."
1935   :keymap widget-text-keymap)
1936
1937 ;;; The `menu-choice' Widget.
1938
1939 (define-widget 'menu-choice 'default
1940   "A menu of options."
1941   :convert-widget  'widget-types-convert-widget
1942   :copy 'widget-types-copy
1943   :format "%[%t%]: %v"
1944   :case-fold t
1945   :tag "choice"
1946   :void '(item :format "invalid (%t)\n")
1947   :value-create 'widget-choice-value-create
1948   :value-get 'widget-child-value-get
1949   :value-inline 'widget-child-value-inline
1950   :default-get 'widget-choice-default-get
1951   :mouse-down-action 'widget-choice-mouse-down-action
1952   :action 'widget-choice-action
1953   :error "Make a choice"
1954   :validate 'widget-choice-validate
1955   :match 'widget-choice-match
1956   :match-inline 'widget-choice-match-inline)
1957
1958 (defun widget-choice-value-create (widget)
1959   "Insert the first choice that matches the value."
1960   (let ((value (widget-get widget :value))
1961         (args (widget-get widget :args))
1962         (explicit (widget-get widget :explicit-choice))
1963         current)
1964     (if (and explicit (equal value (widget-get widget :explicit-choice-value)))
1965         (progn
1966           ;; If the user specified the choice for this value,
1967           ;; respect that choice as long as the value is the same.
1968           (widget-put widget :children (list (widget-create-child-value
1969                                               widget explicit value)))
1970           (widget-put widget :choice explicit))
1971       (while args
1972         (setq current (car args)
1973               args (cdr args))
1974         (when (widget-apply current :match value)
1975           (widget-put widget :children (list (widget-create-child-value
1976                                               widget current value)))
1977           (widget-put widget :choice current)
1978           (setq args nil
1979                 current nil)))
1980       (when current
1981         (let ((void (widget-get widget :void)))
1982           (widget-put widget :children (list (widget-create-child-and-convert
1983                                               widget void :value value)))
1984           (widget-put widget :choice void))))))
1985
1986 (defun widget-choice-default-get (widget)
1987   ;; Get default for the first choice.
1988   (widget-default-get (car (widget-get widget :args))))
1989
1990 (defcustom widget-choice-toggle nil
1991   "If non-nil, a binary choice will just toggle between the values.
1992 Otherwise, the user will explicitly have to choose between the values
1993 when he invoked the menu."
1994   :type 'boolean
1995   :group 'widgets)
1996
1997 (defun widget-choice-mouse-down-action (widget &optional event)
1998   ;; Return non-nil if we need a menu.
1999   (let ((args (widget-get widget :args))
2000         (old (widget-get widget :choice)))
2001     (cond ((not (display-popup-menus-p))
2002            ;; No place to pop up a menu.
2003            nil)
2004           ((< (length args) 2)
2005            ;; Empty or singleton list, just return the value.
2006            nil)
2007           ((> (length args) widget-menu-max-size)
2008            ;; Too long, prompt.
2009            nil)
2010           ((> (length args) 2)
2011            ;; Reasonable sized list, use menu.
2012            t)
2013           ((and widget-choice-toggle (memq old args))
2014            ;; We toggle.
2015            nil)
2016           (t
2017            ;; Ask which of the two.
2018            t))))
2019
2020 (defun widget-choice-action (widget &optional event)
2021   ;; Make a choice.
2022   (let ((args (widget-get widget :args))
2023         (old (widget-get widget :choice))
2024         (tag (widget-apply widget :menu-tag-get))
2025         (completion-ignore-case (widget-get widget :case-fold))
2026         this-explicit
2027         current choices)
2028     ;; Remember old value.
2029     (if (and old (not (widget-apply widget :validate)))
2030         (let* ((external (widget-value widget))
2031                (internal (widget-apply old :value-to-internal external)))
2032           (widget-put old :value internal)))
2033     ;; Find new choice.
2034     (setq current
2035           (cond ((= (length args) 0)
2036                  nil)
2037                 ((= (length args) 1)
2038                  (nth 0 args))
2039                 ((and widget-choice-toggle
2040                       (= (length args) 2)
2041                       (memq old args))
2042                  (if (eq old (nth 0 args))
2043                      (nth 1 args)
2044                    (nth 0 args)))
2045                 (t
2046                  (while args
2047                    (setq current (car args)
2048                          args (cdr args))
2049                    (setq choices
2050                          (cons (cons (widget-apply current :menu-tag-get)
2051                                      current)
2052                                choices)))
2053                  (setq this-explicit t)
2054                  (widget-choose tag (reverse choices) event))))
2055     (when current
2056       ;; If this was an explicit user choice,
2057       ;; record the choice, and the record the value it was made for.
2058       ;; widget-choice-value-create will respect this choice,
2059       ;; as long as the value is the same.
2060       (when this-explicit
2061         (widget-put widget :explicit-choice current)
2062         (widget-put widget :explicit-choice-value (widget-get widget :value)))
2063       (widget-value-set widget (widget-default-get current))
2064       (widget-setup)
2065       (widget-apply widget :notify widget event)))
2066   (run-hook-with-args 'widget-edit-functions widget))
2067
2068 (defun widget-choice-validate (widget)
2069   ;; Valid if we have made a valid choice.
2070   (if (eq (widget-get widget :void) (widget-get widget :choice))
2071       widget
2072     (widget-apply (car (widget-get widget :children)) :validate)))
2073
2074 (defun widget-choice-match (widget value)
2075   ;; Matches if one of the choices matches.
2076   (let ((args (widget-get widget :args))
2077         current found)
2078     (while (and args (not found))
2079       (setq current (car args)
2080             args (cdr args)
2081             found (widget-apply current :match value)))
2082     found))
2083
2084 (defun widget-choice-match-inline (widget values)
2085   ;; Matches if one of the choices matches.
2086   (let ((args (widget-get widget :args))
2087         current found)
2088     (while (and args (null found))
2089       (setq current (car args)
2090             args (cdr args)
2091             found (widget-match-inline current values)))
2092     found))
2093
2094 ;;; The `toggle' Widget.
2095
2096 (define-widget 'toggle 'item
2097   "Toggle between two states."
2098   :format "%[%v%]\n"
2099   :value-create 'widget-toggle-value-create
2100   :action 'widget-toggle-action
2101   :match (lambda (widget value) t)
2102   :on "on"
2103   :off "off")
2104
2105 (defun widget-toggle-value-create (widget)
2106   "Insert text representing the `on' and `off' states."
2107   (if (widget-value widget)
2108       (let ((image (widget-get widget :on-glyph)))
2109         (and (display-graphic-p)
2110              (listp image)
2111              (not (eq (car image) 'image))
2112              (widget-put widget :on-glyph (setq image (eval image))))
2113         (widget-image-insert widget
2114                              (widget-get widget :on)
2115                              image))
2116     (let ((image (widget-get widget :off-glyph)))
2117       (and (display-graphic-p)
2118            (listp image)
2119            (not (eq (car image) 'image))
2120            (widget-put widget :off-glyph (setq image (eval image))))
2121       (widget-image-insert widget (widget-get widget :off) image))))
2122
2123 (defun widget-toggle-action (widget &optional event)
2124   ;; Toggle value.
2125   (widget-value-set widget (not (widget-value widget)))
2126   (widget-apply widget :notify widget event)
2127   (run-hook-with-args 'widget-edit-functions widget))
2128
2129 ;;; The `checkbox' Widget.
2130
2131 (define-widget 'checkbox 'toggle
2132   "A checkbox toggle."
2133   :button-suffix ""
2134   :button-prefix ""
2135   :format "%[%v%]"
2136   :on "[X]"
2137   ;; We could probably do the same job as the images using single
2138   ;; space characters in a boxed face with a stretch specification to
2139   ;; make them square.
2140   :on-glyph '(create-image "\300\300\141\143\067\076\034\030"
2141                            'xbm t :width 8 :height 8
2142                            :background "grey75" ; like default mode line
2143                            :foreground "black"
2144                            :relief -2
2145                            :ascent 'center)
2146   :off "[ ]"
2147   :off-glyph '(create-image (make-string 8 0)
2148                             'xbm t :width 8 :height 8
2149                             :background "grey75"
2150                             :foreground "black"
2151                             :relief -2
2152                             :ascent 'center)
2153   :help-echo "Toggle this item."
2154   :action 'widget-checkbox-action)
2155
2156 (defun widget-checkbox-action (widget &optional event)
2157   "Toggle checkbox, notify parent, and set active state of sibling."
2158   (widget-toggle-action widget event)
2159   (let ((sibling (widget-get-sibling widget)))
2160     (when sibling
2161       (if (widget-value widget)
2162           (widget-apply sibling :activate)
2163         (widget-apply sibling :deactivate)))))
2164
2165 ;;; The `checklist' Widget.
2166
2167 (define-widget 'checklist 'default
2168   "A multiple choice widget."
2169   :convert-widget 'widget-types-convert-widget
2170   :copy 'widget-types-copy
2171   :format "%v"
2172   :offset 4
2173   :entry-format "%b %v"
2174   :greedy nil
2175   :value-create 'widget-checklist-value-create
2176   :value-get 'widget-checklist-value-get
2177   :validate 'widget-checklist-validate
2178   :match 'widget-checklist-match
2179   :match-inline 'widget-checklist-match-inline)
2180
2181 (defun widget-checklist-value-create (widget)
2182   ;; Insert all values
2183   (let ((alist (widget-checklist-match-find widget (widget-get widget :value)))
2184         (args (widget-get widget :args)))
2185     (while args
2186       (widget-checklist-add-item widget (car args) (assq (car args) alist))
2187       (setq args (cdr args)))
2188     (widget-put widget :children (nreverse (widget-get widget :children)))))
2189
2190 (defun widget-checklist-add-item (widget type chosen)
2191   "Create checklist item in WIDGET of type TYPE.
2192 If the item is checked, CHOSEN is a cons whose cdr is the value."
2193   (and (eq (preceding-char) ?\n)
2194        (widget-get widget :indent)
2195        (insert-char ?  (widget-get widget :indent)))
2196   (widget-specify-insert
2197    (let* ((children (widget-get widget :children))
2198           (buttons (widget-get widget :buttons))
2199           (button-args (or (widget-get type :sibling-args)
2200                            (widget-get widget :button-args)))
2201           (from (point))
2202           child button)
2203      (insert (widget-get widget :entry-format))
2204      (goto-char from)
2205      ;; Parse % escapes in format.
2206      (while (re-search-forward "%\\([bv%]\\)" nil t)
2207        (let ((escape (char-after (match-beginning 1))))
2208          (delete-backward-char 2)
2209          (cond ((eq escape ?%)
2210                 (insert ?%))
2211                ((eq escape ?b)
2212                 (setq button (apply 'widget-create-child-and-convert
2213                                     widget 'checkbox
2214                                     :value (not (null chosen))
2215                                     button-args)))
2216                ((eq escape ?v)
2217                 (setq child
2218                       (cond ((not chosen)
2219                              (let ((child (widget-create-child widget type)))
2220                                (widget-apply child :deactivate)
2221                                child))
2222                             ((widget-get type :inline)
2223                              (widget-create-child-value
2224                               widget type (cdr chosen)))
2225                             (t
2226                              (widget-create-child-value
2227                               widget type (car (cdr chosen)))))))
2228                (t
2229                 (error "Unknown escape `%c'" escape)))))
2230      ;; Update properties.
2231      (and button child (widget-put child :button button))
2232      (and button (widget-put widget :buttons (cons button buttons)))
2233      (and child (widget-put widget :children (cons child children))))))
2234
2235 (defun widget-checklist-match (widget values)
2236   ;; All values must match a type in the checklist.
2237   (and (listp values)
2238        (null (cdr (widget-checklist-match-inline widget values)))))
2239
2240 (defun widget-checklist-match-inline (widget values)
2241   ;; Find the values which match a type in the checklist.
2242   (let ((greedy (widget-get widget :greedy))
2243         (args (copy-sequence (widget-get widget :args)))
2244         found rest)
2245     (while values
2246       (let ((answer (widget-checklist-match-up args values)))
2247         (cond (answer
2248                (let ((vals (widget-match-inline answer values)))
2249                  (setq found (append found (car vals))
2250                        values (cdr vals)
2251                        args (delq answer args))))
2252               (greedy
2253                (setq rest (append rest (list (car values)))
2254                      values (cdr values)))
2255               (t
2256                (setq rest (append rest values)
2257                      values nil)))))
2258     (cons found rest)))
2259
2260 (defun widget-checklist-match-find (widget vals)
2261   "Find the vals which match a type in the checklist.
2262 Return an alist of (TYPE MATCH)."
2263   (let ((greedy (widget-get widget :greedy))
2264         (args (copy-sequence (widget-get widget :args)))
2265         found)
2266     (while vals
2267       (let ((answer (widget-checklist-match-up args vals)))
2268         (cond (answer
2269                (let ((match (widget-match-inline answer vals)))
2270                  (setq found (cons (cons answer (car match)) found)
2271                        vals (cdr match)
2272                        args (delq answer args))))
2273               (greedy
2274                (setq vals (cdr vals)))
2275               (t
2276                (setq vals nil)))))
2277     found))
2278
2279 (defun widget-checklist-match-up (args vals)
2280   "Return the first type from ARGS that matches VALS."
2281   (let (current found)
2282     (while (and args (null found))
2283       (setq current (car args)
2284             args (cdr args)
2285             found (widget-match-inline current vals)))
2286     (if found
2287         current)))
2288
2289 (defun widget-checklist-value-get (widget)
2290   ;; The values of all selected items.
2291   (let ((children (widget-get widget :children))
2292         child result)
2293     (while children
2294       (setq child (car children)
2295             children (cdr children))
2296       (if (widget-value (widget-get child :button))
2297           (setq result (append result (widget-apply child :value-inline)))))
2298     result))
2299
2300 (defun widget-checklist-validate (widget)
2301   ;; Ticked chilren must be valid.
2302   (let ((children (widget-get widget :children))
2303         child button found)
2304     (while (and children (not found))
2305       (setq child (car children)
2306             children (cdr children)
2307             button (widget-get child :button)
2308             found (and (widget-value button)
2309                        (widget-apply child :validate))))
2310     found))
2311
2312 ;;; The `option' Widget
2313
2314 (define-widget 'option 'checklist
2315   "An widget with an optional item."
2316   :inline t)
2317
2318 ;;; The `choice-item' Widget.
2319
2320 (define-widget 'choice-item 'item
2321   "Button items that delegate action events to their parents."
2322   :action 'widget-parent-action
2323   :format "%[%t%] \n")
2324
2325 ;;; The `radio-button' Widget.
2326
2327 (define-widget 'radio-button 'toggle
2328   "A radio button for use in the `radio' widget."
2329   :notify 'widget-radio-button-notify
2330   :format "%[%v%]"
2331   :button-suffix ""
2332   :button-prefix ""
2333   :on "(*)"
2334   :on-glyph "radio1"
2335   :off "( )"
2336   :off-glyph "radio0")
2337
2338 (defun widget-radio-button-notify (widget child &optional event)
2339   ;; Tell daddy.
2340   (widget-apply (widget-get widget :parent) :action widget event))
2341
2342 ;;; The `radio-button-choice' Widget.
2343
2344 (define-widget 'radio-button-choice 'default
2345   "Select one of multiple options."
2346   :convert-widget 'widget-types-convert-widget
2347   :copy 'widget-types-copy
2348   :offset 4
2349   :format "%v"
2350   :entry-format "%b %v"
2351   :value-create 'widget-radio-value-create
2352   :value-get 'widget-radio-value-get
2353   :value-inline 'widget-radio-value-inline
2354   :value-set 'widget-radio-value-set
2355   :error "You must push one of the buttons"
2356   :validate 'widget-radio-validate
2357   :match 'widget-choice-match
2358   :match-inline 'widget-choice-match-inline
2359   :action 'widget-radio-action)
2360
2361 (defun widget-radio-value-create (widget)
2362   ;; Insert all values
2363   (let ((args (widget-get widget :args))
2364         arg)
2365     (while args
2366       (setq arg (car args)
2367             args (cdr args))
2368       (widget-radio-add-item widget arg))))
2369
2370 (defun widget-radio-add-item (widget type)
2371   "Add to radio widget WIDGET a new radio button item of type TYPE."
2372   ;; (setq type (widget-convert type))
2373   (and (eq (preceding-char) ?\n)
2374        (widget-get widget :indent)
2375        (insert-char ?  (widget-get widget :indent)))
2376   (widget-specify-insert
2377    (let* ((value (widget-get widget :value))
2378           (children (widget-get widget :children))
2379           (buttons (widget-get widget :buttons))
2380           (button-args (or (widget-get type :sibling-args)
2381                            (widget-get widget :button-args)))
2382           (from (point))
2383           (chosen (and (null (widget-get widget :choice))
2384                        (widget-apply type :match value)))
2385           child button)
2386      (insert (widget-get widget :entry-format))
2387      (goto-char from)
2388      ;; Parse % escapes in format.
2389      (while (re-search-forward "%\\([bv%]\\)" nil t)
2390        (let ((escape (char-after (match-beginning 1))))
2391          (delete-backward-char 2)
2392          (cond ((eq escape ?%)
2393                 (insert ?%))
2394                ((eq escape ?b)
2395                 (setq button (apply 'widget-create-child-and-convert
2396                                     widget 'radio-button
2397                                     :value (not (null chosen))
2398                                     button-args)))
2399                ((eq escape ?v)
2400                 (setq child (if chosen
2401                                 (widget-create-child-value
2402                                  widget type value)
2403                               (widget-create-child widget type)))
2404                 (unless chosen
2405                   (widget-apply child :deactivate)))
2406                (t
2407                 (error "Unknown escape `%c'" escape)))))
2408      ;; Update properties.
2409      (when chosen
2410        (widget-put widget :choice type))
2411      (when button
2412        (widget-put child :button button)
2413        (widget-put widget :buttons (nconc buttons (list button))))
2414      (when child
2415        (widget-put widget :children (nconc children (list child))))
2416      child)))
2417
2418 (defun widget-radio-value-get (widget)
2419   ;; Get value of the child widget.
2420   (let ((chosen (widget-radio-chosen widget)))
2421     (and chosen (widget-value chosen))))
2422
2423 (defun widget-radio-chosen (widget)
2424   "Return the widget representing the chosen radio button."
2425   (let ((children (widget-get widget :children))
2426         current found)
2427     (while children
2428       (setq current (car children)
2429             children (cdr children))
2430       (when (widget-apply (widget-get current :button) :value-get)
2431         (setq found current
2432               children nil)))
2433     found))
2434
2435 (defun widget-radio-value-inline (widget)
2436   ;; Get value of the child widget.
2437   (let ((children (widget-get widget :children))
2438         current found)
2439     (while children
2440       (setq current (car children)
2441             children (cdr children))
2442       (when (widget-apply (widget-get current :button) :value-get)
2443         (setq found (widget-apply current :value-inline)
2444               children nil)))
2445     found))
2446
2447 (defun widget-radio-value-set (widget value)
2448   ;; We can't just delete and recreate a radio widget, since children
2449   ;; can be added after the original creation and won't be recreated
2450   ;; by `:create'.
2451   (let ((children (widget-get widget :children))
2452         current found)
2453     (while children
2454       (setq current (car children)
2455             children (cdr children))
2456       (let* ((button (widget-get current :button))
2457              (match (and (not found)
2458                          (widget-apply current :match value))))
2459         (widget-value-set button match)
2460         (if match
2461             (progn
2462               (widget-value-set current value)
2463               (widget-apply current :activate))
2464           (widget-apply current :deactivate))
2465         (setq found (or found match))))))
2466
2467 (defun widget-radio-validate (widget)
2468   ;; Valid if we have made a valid choice.
2469   (let ((children (widget-get widget :children))
2470         current found button)
2471     (while (and children (not found))
2472       (setq current (car children)
2473             children (cdr children)
2474             button (widget-get current :button)
2475             found (widget-apply button :value-get)))
2476     (if found
2477         (widget-apply current :validate)
2478       widget)))
2479
2480 (defun widget-radio-action (widget child event)
2481   ;; Check if a radio button was pressed.
2482   (let ((children (widget-get widget :children))
2483         (buttons (widget-get widget :buttons))
2484         current)
2485     (when (memq child buttons)
2486       (while children
2487         (setq current (car children)
2488               children (cdr children))
2489         (let* ((button (widget-get current :button)))
2490           (cond ((eq child button)
2491                  (widget-value-set button t)
2492                  (widget-apply current :activate))
2493                 ((widget-value button)
2494                  (widget-value-set button nil)
2495                  (widget-apply current :deactivate)))))))
2496   ;; Pass notification to parent.
2497   (widget-apply widget :notify child event))
2498
2499 ;;; The `insert-button' Widget.
2500
2501 (define-widget 'insert-button 'push-button
2502   "An insert button for the `editable-list' widget."
2503   :tag "INS"
2504   :help-echo "Insert a new item into the list at this position."
2505   :action 'widget-insert-button-action)
2506
2507 (defun widget-insert-button-action (widget &optional event)
2508   ;; Ask the parent to insert a new item.
2509   (widget-apply (widget-get widget :parent)
2510                 :insert-before (widget-get widget :widget)))
2511
2512 ;;; The `delete-button' Widget.
2513
2514 (define-widget 'delete-button 'push-button
2515   "A delete button for the `editable-list' widget."
2516   :tag "DEL"
2517   :help-echo "Delete this item from the list."
2518   :action 'widget-delete-button-action)
2519
2520 (defun widget-delete-button-action (widget &optional event)
2521   ;; Ask the parent to insert a new item.
2522   (widget-apply (widget-get widget :parent)
2523                 :delete-at (widget-get widget :widget)))
2524
2525 ;;; The `editable-list' Widget.
2526
2527 ;; (defcustom widget-editable-list-gui nil
2528 ;;   "If non nil, use GUI push-buttons in editable list when available."
2529 ;;   :type 'boolean
2530 ;;   :group 'widgets)
2531
2532 (define-widget 'editable-list 'default
2533   "A variable list of widgets of the same type."
2534   :convert-widget 'widget-types-convert-widget
2535   :copy 'widget-types-copy
2536   :offset 12
2537   :format "%v%i\n"
2538   :format-handler 'widget-editable-list-format-handler
2539   :entry-format "%i %d %v"
2540   :value-create 'widget-editable-list-value-create
2541   :value-get 'widget-editable-list-value-get
2542   :validate 'widget-children-validate
2543   :match 'widget-editable-list-match
2544   :match-inline 'widget-editable-list-match-inline
2545   :insert-before 'widget-editable-list-insert-before
2546   :delete-at 'widget-editable-list-delete-at)
2547
2548 (defun widget-editable-list-format-handler (widget escape)
2549   ;; We recognize the insert button.
2550     ;; (let ((widget-push-button-gui widget-editable-list-gui))
2551     (cond ((eq escape ?i)
2552            (and (widget-get widget :indent)
2553                 (insert-char ?\  (widget-get widget :indent)))
2554            (apply 'widget-create-child-and-convert
2555                   widget 'insert-button
2556                   (widget-get widget :append-button-args)))
2557           (t
2558            (widget-default-format-handler widget escape)))
2559     ;; )
2560   )
2561
2562 (defun widget-editable-list-value-create (widget)
2563   ;; Insert all values
2564   (let* ((value (widget-get widget :value))
2565          (type (nth 0 (widget-get widget :args)))
2566          children)
2567     (widget-put widget :value-pos (copy-marker (point)))
2568     (set-marker-insertion-type (widget-get widget :value-pos) t)
2569     (while value
2570       (let ((answer (widget-match-inline type value)))
2571         (if answer
2572             (setq children (cons (widget-editable-list-entry-create
2573                                   widget
2574                                   (if (widget-get type :inline)
2575                                       (car answer)
2576                                     (car (car answer)))
2577                                   t)
2578                                  children)
2579                   value (cdr answer))
2580           (setq value nil))))
2581     (widget-put widget :children (nreverse children))))
2582
2583 (defun widget-editable-list-value-get (widget)
2584   ;; Get value of the child widget.
2585   (apply 'append (mapcar (lambda (child) (widget-apply child :value-inline))
2586                          (widget-get widget :children))))
2587
2588 (defun widget-editable-list-match (widget value)
2589   ;; Value must be a list and all the members must match the type.
2590   (and (listp value)
2591        (null (cdr (widget-editable-list-match-inline widget value)))))
2592
2593 (defun widget-editable-list-match-inline (widget value)
2594   (let ((type (nth 0 (widget-get widget :args)))
2595         (ok t)
2596         found)
2597     (while (and value ok)
2598       (let ((answer (widget-match-inline type value)))
2599         (if answer
2600             (setq found (append found (car answer))
2601                   value (cdr answer))
2602           (setq ok nil))))
2603     (cons found value)))
2604
2605 (defun widget-editable-list-insert-before (widget before)
2606   ;; Insert a new child in the list of children.
2607   (save-excursion
2608     (let ((children (widget-get widget :children))
2609           (inhibit-read-only t)
2610           before-change-functions
2611           after-change-functions)
2612       (cond (before
2613              (goto-char (widget-get before :entry-from)))
2614             (t
2615              (goto-char (widget-get widget :value-pos))))
2616       (let ((child (widget-editable-list-entry-create
2617                     widget nil nil)))
2618         (when (< (widget-get child :entry-from) (widget-get widget :from))
2619           (set-marker (widget-get widget :from)
2620                       (widget-get child :entry-from)))
2621         (if (eq (car children) before)
2622             (widget-put widget :children (cons child children))
2623           (while (not (eq (car (cdr children)) before))
2624             (setq children (cdr children)))
2625           (setcdr children (cons child (cdr children)))))))
2626   (widget-setup)
2627   (widget-apply widget :notify widget))
2628
2629 (defun widget-editable-list-delete-at (widget child)
2630   ;; Delete child from list of children.
2631   (save-excursion
2632     (let ((buttons (copy-sequence (widget-get widget :buttons)))
2633           button
2634           (inhibit-read-only t)
2635           before-change-functions
2636           after-change-functions)
2637       (while buttons
2638         (setq button (car buttons)
2639               buttons (cdr buttons))
2640         (when (eq (widget-get button :widget) child)
2641           (widget-put widget
2642                       :buttons (delq button (widget-get widget :buttons)))
2643           (widget-delete button))))
2644     (let ((entry-from (widget-get child :entry-from))
2645           (entry-to (widget-get child :entry-to))
2646           (inhibit-read-only t)
2647           before-change-functions
2648           after-change-functions)
2649       (widget-delete child)
2650       (delete-region entry-from entry-to)
2651       (set-marker entry-from nil)
2652       (set-marker entry-to nil))
2653     (widget-put widget :children (delq child (widget-get widget :children))))
2654   (widget-setup)
2655   (widget-apply widget :notify widget))
2656
2657 (defun widget-editable-list-entry-create (widget value conv)
2658   ;; Create a new entry to the list.
2659   (let ((type (nth 0 (widget-get widget :args)))
2660         ;; (widget-push-button-gui widget-editable-list-gui)
2661         child delete insert)
2662     (widget-specify-insert
2663      (save-excursion
2664        (and (widget-get widget :indent)
2665             (insert-char ?\  (widget-get widget :indent)))
2666        (insert (widget-get widget :entry-format)))
2667      ;; Parse % escapes in format.
2668      (while (re-search-forward "%\\(.\\)" nil t)
2669        (let ((escape (char-after (match-beginning 1))))
2670          (delete-backward-char 2)
2671          (cond ((eq escape ?%)
2672                 (insert ?%))
2673                ((eq escape ?i)
2674                 (setq insert (apply 'widget-create-child-and-convert
2675                                     widget 'insert-button
2676                                     (widget-get widget :insert-button-args))))
2677                ((eq escape ?d)
2678                 (setq delete (apply 'widget-create-child-and-convert
2679                                     widget 'delete-button
2680                                     (widget-get widget :delete-button-args))))
2681                ((eq escape ?v)
2682                 (if conv
2683                     (setq child (widget-create-child-value
2684                                  widget type value))
2685                   (setq child (widget-create-child-value
2686                                widget type (widget-default-get type)))))
2687                (t
2688                 (error "Unknown escape `%c'" escape)))))
2689      (let ((buttons (widget-get widget :buttons)))
2690        (if insert (push insert buttons))
2691        (if delete (push delete buttons))
2692        (widget-put widget :buttons buttons))
2693      (let ((entry-from (point-min-marker))
2694            (entry-to (point-max-marker)))
2695        (set-marker-insertion-type entry-from t)
2696        (set-marker-insertion-type entry-to nil)
2697        (widget-put child :entry-from entry-from)
2698        (widget-put child :entry-to entry-to)))
2699     (if insert (widget-put insert :widget child))
2700     (if delete (widget-put delete :widget child))
2701     child))
2702
2703 ;;; The `group' Widget.
2704
2705 (define-widget 'group 'default
2706   "A widget which groups other widgets inside."
2707   :convert-widget 'widget-types-convert-widget
2708   :copy 'widget-types-copy
2709   :format "%v"
2710   :value-create 'widget-group-value-create
2711   :value-get 'widget-editable-list-value-get
2712   :default-get 'widget-group-default-get
2713   :validate 'widget-children-validate
2714   :match 'widget-group-match
2715   :match-inline 'widget-group-match-inline)
2716
2717 (defun widget-group-value-create (widget)
2718   ;; Create each component.
2719   (let ((args (widget-get widget :args))
2720         (value (widget-get widget :value))
2721         arg answer children)
2722     (while args
2723       (setq arg (car args)
2724             args (cdr args)
2725             answer (widget-match-inline arg value)
2726             value (cdr answer))
2727       (and (eq (preceding-char) ?\n)
2728            (widget-get widget :indent)
2729            (insert-char ?\  (widget-get widget :indent)))
2730       (push (cond ((null answer)
2731                    (widget-create-child widget arg))
2732                   ((widget-get arg :inline)
2733                    (widget-create-child-value widget arg (car answer)))
2734                   (t
2735                    (widget-create-child-value widget arg (car (car answer)))))
2736             children))
2737     (widget-put widget :children (nreverse children))))
2738
2739 (defun widget-group-default-get (widget)
2740   ;; Get the default of the components.
2741   (mapcar 'widget-default-get (widget-get widget :args)))
2742
2743 (defun widget-group-match (widget values)
2744   ;; Match if the components match.
2745   (and (listp values)
2746        (let ((match (widget-group-match-inline widget values)))
2747          (and match (null (cdr match))))))
2748
2749 (defun widget-group-match-inline (widget vals)
2750   ;; Match if the components match.
2751   (let ((args (widget-get widget :args))
2752         argument answer found)
2753     (while args
2754       (setq argument (car args)
2755             args (cdr args)
2756             answer (widget-match-inline argument vals))
2757       (if answer
2758           (setq vals (cdr answer)
2759                 found (append found (car answer)))
2760         (setq vals nil
2761               args nil)))
2762     (if answer
2763         (cons found vals))))
2764
2765 ;;; The `visibility' Widget.
2766
2767 (define-widget 'visibility 'item
2768   "An indicator and manipulator for hidden items."
2769   :format "%[%v%]"
2770   :button-prefix ""
2771   :button-suffix ""
2772   :on "Hide"
2773   :off "Show"
2774   :value-create 'widget-visibility-value-create
2775   :action 'widget-toggle-action
2776   :match (lambda (widget value) t))
2777
2778 (defun widget-visibility-value-create (widget)
2779   ;; Insert text representing the `on' and `off' states.
2780   (let ((on (widget-get widget :on))
2781         (off (widget-get widget :off)))
2782     (if on
2783         (setq on (concat widget-push-button-prefix
2784                          on
2785                          widget-push-button-suffix))
2786       (setq on ""))
2787     (if off
2788         (setq off (concat widget-push-button-prefix
2789                           off
2790                           widget-push-button-suffix))
2791       (setq off ""))
2792     (if (widget-value widget)
2793         (widget-image-insert widget on "down" "down-pushed")
2794       (widget-image-insert widget off "right" "right-pushed"))))
2795
2796 ;;; The `documentation-link' Widget.
2797 ;;
2798 ;; This is a helper widget for `documentation-string'.
2799
2800 (define-widget 'documentation-link 'link
2801   "Link type used in documentation strings."
2802   :tab-order -1
2803   :help-echo "Describe this symbol"
2804   :action 'widget-documentation-link-action)
2805
2806 (defun widget-documentation-link-action (widget &optional event)
2807   "Display documentation for WIDGET's value.  Ignore optional argument EVENT."
2808   (let* ((string (widget-get widget :value))
2809          (symbol (intern string)))
2810     (if (and (fboundp symbol) (boundp symbol))
2811         ;; If there are two doc strings, give the user a way to pick one.
2812         (apropos (concat "\\`" (regexp-quote string) "\\'"))
2813       (if (fboundp symbol)
2814           (describe-function symbol)
2815         (describe-variable symbol)))))
2816
2817 (defcustom widget-documentation-links t
2818   "Add hyperlinks to documentation strings when non-nil."
2819   :type 'boolean
2820   :group 'widget-documentation)
2821
2822 (defcustom widget-documentation-link-regexp "`\\([^\n`' ]+\\)'"
2823   "Regexp for matching potential links in documentation strings.
2824 The first group should be the link itself."
2825   :type 'regexp
2826   :group 'widget-documentation)
2827
2828 (defcustom widget-documentation-link-p 'intern-soft
2829   "Predicate used to test if a string is useful as a link.
2830 The value should be a function.  The function will be called one
2831 argument, a string, and should return non-nil if there should be a
2832 link for that string."
2833   :type 'function
2834   :options '(widget-documentation-link-p)
2835   :group 'widget-documentation)
2836
2837 (defcustom widget-documentation-link-type 'documentation-link
2838   "Widget type used for links in documentation strings."
2839   :type 'symbol
2840   :group 'widget-documentation)
2841
2842 (defun widget-documentation-link-add (widget from to)
2843   (widget-specify-doc widget from to)
2844   (when widget-documentation-links
2845     (let ((regexp widget-documentation-link-regexp)
2846           (buttons (widget-get widget :buttons))
2847           (widget-mouse-face (default-value 'widget-mouse-face))
2848           (widget-button-face widget-documentation-face)
2849           (widget-button-pressed-face widget-documentation-face))
2850       (save-excursion
2851         (goto-char from)
2852         (while (re-search-forward regexp to t)
2853           (let ((name (match-string 1))
2854                 (begin (match-beginning 1))
2855                 (end (match-end 1)))
2856             (when (funcall widget-documentation-link-p name)
2857               (push (widget-convert-button widget-documentation-link-type
2858                                            begin end :value name)
2859                     buttons)))))
2860       (widget-put widget :buttons buttons)))
2861   (let ((indent (widget-get widget :indent)))
2862     (when (and indent (not (zerop indent)))
2863       (save-excursion
2864         (save-restriction
2865           (narrow-to-region from to)
2866           (goto-char (point-min))
2867           (while (search-forward "\n" nil t)
2868             (insert-char ?\  indent)))))))
2869
2870 ;;; The `documentation-string' Widget.
2871
2872 (define-widget 'documentation-string 'item
2873   "A documentation string."
2874   :format "%v"
2875   :action 'widget-documentation-string-action
2876   :value-create 'widget-documentation-string-value-create)
2877
2878 (defun widget-documentation-string-value-create (widget)
2879   ;; Insert documentation string.
2880   (let ((doc (widget-value widget))
2881         (indent (widget-get widget :indent))
2882         (shown (widget-get (widget-get widget :parent) :documentation-shown))
2883         (start (point)))
2884     (if (string-match "\n" doc)
2885         (let ((before (substring doc 0 (match-beginning 0)))
2886               (after (substring doc (match-beginning 0)))
2887               button)
2888           (insert before ?\ )
2889           (widget-documentation-link-add widget start (point))
2890           (setq button
2891                 (widget-create-child-and-convert
2892                  widget 'visibility
2893                  :help-echo "Show or hide rest of the documentation."
2894                  :on "Hide Rest"
2895                  :off "More"
2896                  :always-active t
2897                  :action 'widget-parent-action
2898                  shown))
2899           (when shown
2900             (setq start (point))
2901             (when (and indent (not (zerop indent)))
2902               (insert-char ?\  indent))
2903             (insert after)
2904             (widget-documentation-link-add widget start (point)))
2905           (widget-put widget :buttons (list button)))
2906       (insert doc)
2907       (widget-documentation-link-add widget start (point))))
2908   (insert ?\n))
2909
2910 (defun widget-documentation-string-action (widget &rest ignore)
2911   ;; Toggle documentation.
2912   (let ((parent (widget-get widget :parent)))
2913     (widget-put parent :documentation-shown
2914                 (not (widget-get parent :documentation-shown))))
2915   ;; Redraw.
2916   (widget-value-set widget (widget-value widget)))
2917 \f
2918 ;;; The Sexp Widgets.
2919
2920 (define-widget 'const 'item
2921   "An immutable sexp."
2922   :prompt-value 'widget-const-prompt-value
2923   :format "%t\n%d")
2924
2925 (defun widget-const-prompt-value (widget prompt value unbound)
2926   ;; Return the value of the const.
2927   (widget-value widget))
2928
2929 (define-widget 'function-item 'const
2930   "An immutable function name."
2931   :format "%v\n%h"
2932   :documentation-property (lambda (symbol)
2933                             (condition-case nil
2934                                 (documentation symbol t)
2935                               (error nil))))
2936
2937 (define-widget 'variable-item 'const
2938   "An immutable variable name."
2939   :format "%v\n%h"
2940   :documentation-property 'variable-documentation)
2941
2942 (define-widget 'other 'sexp
2943   "Matches any value, but doesn't let the user edit the value.
2944 This is useful as last item in a `choice' widget.
2945 You should use this widget type with a default value,
2946 as in (other DEFAULT) or (other :tag \"NAME\" DEFAULT).
2947 If the user selects this alternative, that specifies DEFAULT
2948 as the value."
2949   :tag "Other"
2950   :format "%t%n"
2951   :value 'other)
2952
2953 (defvar widget-string-prompt-value-history nil
2954   "History of input to `widget-string-prompt-value'.")
2955
2956 (define-widget 'string 'editable-field
2957   "A string"
2958   :tag "String"
2959   :format "%{%t%}: %v"
2960   :complete-function 'ispell-complete-word
2961   :prompt-history 'widget-string-prompt-value-history)
2962
2963 (define-widget 'regexp 'string
2964   "A regular expression."
2965   :match 'widget-regexp-match
2966   :validate 'widget-regexp-validate
2967   ;; Doesn't work well with terminating newline.
2968   ;; :value-face 'widget-single-line-field
2969   :tag "Regexp")
2970
2971 (defun widget-regexp-match (widget value)
2972   ;; Match valid regexps.
2973   (and (stringp value)
2974        (condition-case nil
2975            (prog1 t
2976              (string-match value ""))
2977          (error nil))))
2978
2979 (defun widget-regexp-validate (widget)
2980   "Check that the value of WIDGET is a valid regexp."
2981   (condition-case data
2982       (prog1 nil
2983         (string-match (widget-value widget) ""))
2984     (error (widget-put widget :error (error-message-string data))
2985            widget)))
2986
2987 (define-widget 'file 'string
2988   "A file widget.
2989 It will read a file name from the minibuffer when invoked."
2990   :complete-function 'widget-file-complete
2991   :prompt-value 'widget-file-prompt-value
2992   :format "%{%t%}: %v"
2993   ;; Doesn't work well with terminating newline.
2994   ;; :value-face 'widget-single-line-field
2995   :tag "File")
2996
2997 (defun widget-file-complete ()
2998   "Perform completion on file name preceding point."
2999   (interactive)
3000   (let* ((end (point))
3001          (beg (save-excursion
3002                 (skip-chars-backward "^ ")
3003                 (point)))
3004          (pattern (buffer-substring beg end))
3005          (name-part (file-name-nondirectory pattern))
3006          (directory (file-name-directory pattern))
3007          (completion (file-name-completion name-part directory)))
3008     (cond ((eq completion t))
3009           ((null completion)
3010            (message "Can't find completion for \"%s\"" pattern)
3011            (ding))
3012           ((not (string= name-part completion))
3013            (delete-region beg end)
3014            (insert (expand-file-name completion directory)))
3015           (t
3016            (message "Making completion list...")
3017            (with-output-to-temp-buffer "*Completions*"
3018              (display-completion-list
3019               (sort (file-name-all-completions name-part directory)
3020                     'string<)))
3021            (message "Making completion list...%s" "done")))))
3022
3023 (defun widget-file-prompt-value (widget prompt value unbound)
3024   ;; Read file from minibuffer.
3025   (abbreviate-file-name
3026    (if unbound
3027        (read-file-name prompt)
3028      (let ((prompt2 (format "%s (default %s) " prompt value))
3029            (dir (file-name-directory value))
3030            (file (file-name-nondirectory value))
3031            (must-match (widget-get widget :must-match)))
3032        (read-file-name prompt2 dir nil must-match file)))))
3033
3034 ;;;(defun widget-file-action (widget &optional event)
3035 ;;;  ;; Read a file name from the minibuffer.
3036 ;;;  (let* ((value (widget-value widget))
3037 ;;;      (dir (file-name-directory value))
3038 ;;;      (file (file-name-nondirectory value))
3039 ;;;      (menu-tag (widget-apply widget :menu-tag-get))
3040 ;;;      (must-match (widget-get widget :must-match))
3041 ;;;      (answer (read-file-name (concat menu-tag ": (default `" value "') ")
3042 ;;;                              dir nil must-match file)))
3043 ;;;    (widget-value-set widget (abbreviate-file-name answer))
3044 ;;;    (widget-setup)
3045 ;;;    (widget-apply widget :notify widget event)))
3046
3047 ;; Fixme: use file-name-as-directory.
3048 (define-widget 'directory 'file
3049   "A directory widget.
3050 It will read a directory name from the minibuffer when invoked."
3051   :tag "Directory")
3052
3053 (defvar widget-symbol-prompt-value-history nil
3054   "History of input to `widget-symbol-prompt-value'.")
3055
3056 (define-widget 'symbol 'editable-field
3057   "A Lisp symbol."
3058   :value nil
3059   :tag "Symbol"
3060   :format "%{%t%}: %v"
3061   :match (lambda (widget value) (symbolp value))
3062   :complete-function 'lisp-complete-symbol
3063   :prompt-internal 'widget-symbol-prompt-internal
3064   :prompt-match 'symbolp
3065   :prompt-history 'widget-symbol-prompt-value-history
3066   :value-to-internal (lambda (widget value)
3067                        (if (symbolp value)
3068                            (symbol-name value)
3069                          value))
3070   :value-to-external (lambda (widget value)
3071                        (if (stringp value)
3072                            (intern value)
3073                          value)))
3074
3075 (defun widget-symbol-prompt-internal (widget prompt initial history)
3076   ;; Read file from minibuffer.
3077   (let ((answer (completing-read prompt obarray
3078                                  (widget-get widget :prompt-match)
3079                                  nil initial history)))
3080     (if (and (stringp answer)
3081              (not (zerop (length answer))))
3082         answer
3083       (error "No value"))))
3084
3085 (defvar widget-function-prompt-value-history nil
3086   "History of input to `widget-function-prompt-value'.")
3087
3088 (define-widget 'function 'restricted-sexp
3089   "A Lisp function."
3090   :complete-function (lambda ()
3091                        (interactive)
3092                        (lisp-complete-symbol 'fboundp))
3093   :prompt-value 'widget-field-prompt-value
3094   :prompt-internal 'widget-symbol-prompt-internal
3095   :prompt-match 'fboundp
3096   :prompt-history 'widget-function-prompt-value-history
3097   :action 'widget-field-action
3098   :match-alternatives '(functionp)
3099   :validate (lambda (widget)
3100               (unless (functionp (widget-value widget))
3101                 (widget-put widget :error (format "Invalid function: %S"
3102                                                   (widget-value widget)))
3103                 widget))
3104   :value 'ignore
3105   :tag "Function")
3106
3107 (defvar widget-variable-prompt-value-history nil
3108   "History of input to `widget-variable-prompt-value'.")
3109
3110 (define-widget 'variable 'symbol
3111   "A Lisp variable."
3112   :prompt-match 'boundp
3113   :prompt-history 'widget-variable-prompt-value-history
3114   :complete-function (lambda ()
3115                        (interactive)
3116                        (lisp-complete-symbol 'boundp))
3117   :tag "Variable")
3118
3119 (defvar widget-coding-system-prompt-value-history nil
3120   "History of input to `widget-coding-system-prompt-value'.")
3121
3122 (define-widget 'coding-system 'symbol
3123   "A MULE coding-system."
3124   :format "%{%t%}: %v"
3125   :tag "Coding system"
3126   :base-only nil
3127   :prompt-history 'widget-coding-system-prompt-value-history
3128   :prompt-value 'widget-coding-system-prompt-value
3129   :action 'widget-coding-system-action
3130   :complete-function (lambda ()
3131                        (interactive)
3132                        (lisp-complete-symbol 'coding-system-p))
3133   :validate (lambda (widget)
3134               (unless (coding-system-p (widget-value widget))
3135                 (widget-put widget :error (format "Invalid coding system: %S"
3136                                                   (widget-value widget)))
3137                 widget))
3138   :value 'undecided
3139   :prompt-match 'coding-system-p)
3140
3141 (defun widget-coding-system-prompt-value (widget prompt value unbound)
3142   "Read coding-system from minibuffer."
3143   (if (widget-get widget :base-only)
3144       (intern
3145        (completing-read (format "%s (default %s) " prompt value)
3146                         (mapcar #'list (coding-system-list t)) nil nil nil
3147                         coding-system-history))
3148       (read-coding-system (format "%s (default %s) " prompt value) value)))
3149
3150 (defun widget-coding-system-action (widget &optional event)
3151   (let ((answer
3152          (widget-coding-system-prompt-value
3153           widget
3154           (widget-apply widget :menu-tag-get)
3155           (widget-value widget)
3156           t)))
3157     (widget-value-set widget answer)
3158     (widget-apply widget :notify widget event)
3159     (widget-setup)))
3160 \f
3161 (define-widget 'sexp 'editable-field
3162   "An arbitrary Lisp expression."
3163   :tag "Lisp expression"
3164   :format "%{%t%}: %v"
3165   :value nil
3166   :validate 'widget-sexp-validate
3167   :match (lambda (widget value) t)
3168   :value-to-internal 'widget-sexp-value-to-internal
3169   :value-to-external (lambda (widget value) (read value))
3170   :prompt-history 'widget-sexp-prompt-value-history
3171   :prompt-value 'widget-sexp-prompt-value)
3172
3173 (defun widget-sexp-value-to-internal (widget value)
3174   ;; Use pp for printer representation.
3175   (let ((pp (if (symbolp value)
3176                 (prin1-to-string value)
3177               (pp-to-string value))))
3178     (while (string-match "\n\\'" pp)
3179       (setq pp (substring pp 0 -1)))
3180     (if (or (string-match "\n\\'" pp)
3181             (> (length pp) 40))
3182         (concat "\n" pp)
3183       pp)))
3184
3185 (defun widget-sexp-validate (widget)
3186   ;; Valid if we can read the string and there is no junk left after it.
3187   (with-temp-buffer
3188     (insert (widget-apply widget :value-get))
3189     (goto-char (point-min))
3190     (let (err)
3191       (condition-case data
3192           (progn
3193             ;; Avoid a confusing end-of-file error.
3194             (skip-syntax-forward "\\s-")
3195             (if (eobp)
3196                 (setq err "Empty sexp -- use `nil'?")
3197               (unless (widget-apply widget :match (read (current-buffer)))
3198                 (setq err (widget-get widget :type-error))))
3199             ;; Allow whitespace after expression.
3200             (skip-syntax-forward "\\s-")
3201             (if (and (not (eobp))
3202                      (not err))
3203                 (setq err (format "Junk at end of expression: %s"
3204                                   (buffer-substring (point)
3205                                                     (point-max))))))
3206         (end-of-file                    ; Avoid confusing error message.
3207          (setq err "Unbalanced sexp"))
3208         (error (setq err (error-message-string data))))
3209       (if (not err)
3210           nil
3211         (widget-put widget :error err)
3212         widget))))
3213
3214 (defvar widget-sexp-prompt-value-history nil
3215   "History of input to `widget-sexp-prompt-value'.")
3216
3217 (defun widget-sexp-prompt-value (widget prompt value unbound)
3218   ;; Read an arbitrary sexp.
3219   (let ((found (read-string prompt
3220                             (if unbound nil (cons (prin1-to-string value) 0))
3221                             (widget-get widget :prompt-history))))
3222     (let ((answer (read-from-string found)))
3223       (unless (= (cdr answer) (length found))
3224         (error "Junk at end of expression: %s"
3225                (substring found (cdr answer))))
3226       (car answer))))
3227
3228 (define-widget 'restricted-sexp 'sexp
3229   "A Lisp expression restricted to values that match.
3230 To use this type, you must define :match or :match-alternatives."
3231   :type-error "The specified value is not valid"
3232   :match 'widget-restricted-sexp-match
3233   :value-to-internal (lambda (widget value)
3234                        (if (widget-apply widget :match value)
3235                            (prin1-to-string value)
3236                          value)))
3237
3238 (defun widget-restricted-sexp-match (widget value)
3239   (let ((alternatives (widget-get widget :match-alternatives))
3240         matched)
3241     (while (and alternatives (not matched))
3242       (if (cond ((functionp (car alternatives))
3243                  (funcall (car alternatives) value))
3244                 ((and (consp (car alternatives))
3245                       (eq (car (car alternatives)) 'quote))
3246                  (eq value (nth 1 (car alternatives)))))
3247           (setq matched t))
3248       (setq alternatives (cdr alternatives)))
3249     matched))
3250 \f
3251 (define-widget 'integer 'restricted-sexp
3252   "An integer."
3253   :tag "Integer"
3254   :value 0
3255   :type-error "This field should contain an integer"
3256   :match-alternatives '(integerp))
3257
3258 (define-widget 'number 'restricted-sexp
3259   "A number (floating point or integer)."
3260   :tag "Number"
3261   :value 0.0
3262   :type-error "This field should contain a number (floating point or integer)"
3263   :match-alternatives '(numberp))
3264
3265 (define-widget 'float 'restricted-sexp
3266   "A floating point number."
3267   :tag "Floating point number"
3268   :value 0.0
3269   :type-error "This field should contain a floating point number"
3270   :match-alternatives '(floatp))
3271
3272 (define-widget 'character 'editable-field
3273   "A character."
3274   :tag "Character"
3275   :value 0
3276   :size 1
3277   :format "%{%t%}: %v\n"
3278   :valid-regexp "\\`.\\'"
3279   :error "This field should contain a single character"
3280   :value-to-internal (lambda (widget value)
3281                        (if (stringp value)
3282                            value
3283                          (char-to-string value)))
3284   :value-to-external (lambda (widget value)
3285                        (if (stringp value)
3286                            (aref value 0)
3287                          value))
3288   :match (lambda (widget value)
3289            (char-valid-p value)))
3290
3291 (define-widget 'list 'group
3292   "A Lisp list."
3293   :tag "List"
3294   :format "%{%t%}:\n%v")
3295
3296 (define-widget 'vector 'group
3297   "A Lisp vector."
3298   :tag "Vector"
3299   :format "%{%t%}:\n%v"
3300   :match 'widget-vector-match
3301   :value-to-internal (lambda (widget value) (append value nil))
3302   :value-to-external (lambda (widget value) (apply 'vector value)))
3303
3304 (defun widget-vector-match (widget value)
3305   (and (vectorp value)
3306        (widget-group-match widget
3307                            (widget-apply widget :value-to-internal value))))
3308
3309 (define-widget 'cons 'group
3310   "A cons-cell."
3311   :tag "Cons-cell"
3312   :format "%{%t%}:\n%v"
3313   :match 'widget-cons-match
3314   :value-to-internal (lambda (widget value)
3315                        (list (car value) (cdr value)))
3316   :value-to-external (lambda (widget value)
3317                        (apply 'cons value)))
3318
3319 (defun widget-cons-match (widget value)
3320   (and (consp value)
3321        (widget-group-match widget
3322                            (widget-apply widget :value-to-internal value))))
3323 \f
3324 ;;; The `lazy' Widget.
3325 ;;
3326 ;; Recursive datatypes.
3327
3328 (define-widget 'lazy 'default
3329   "Base widget for recursive datastructures.
3330
3331 The `lazy' widget will, when instantiated, contain a single inferior
3332 widget, of the widget type specified by the :type parameter.  The
3333 value of the `lazy' widget is the same as the value of the inferior
3334 widget.  When deriving a new widget from the 'lazy' widget, the :type
3335 parameter is allowed to refer to the widget currently being defined,
3336 thus allowing recursive datastructures to be described.
3337
3338 The :type parameter takes the same arguments as the defcustom
3339 parameter with the same name.
3340
3341 Most composite widgets, i.e. widgets containing other widgets, does
3342 not allow recursion.  That is, when you define a new widget type, none
3343 of the inferior widgets may be of the same type you are currently
3344 defining.
3345
3346 In Lisp, however, it is custom to define datastructures in terms of
3347 themselves.  A list, for example, is defined as either nil, or a cons
3348 cell whose cdr itself is a list.  The obvious way to translate this
3349 into a widget type would be
3350
3351   (define-widget 'my-list 'choice
3352     \"A list of sexps.\"
3353     :tag \"Sexp list\"
3354     :args '((const nil) (cons :value (nil) sexp my-list)))
3355
3356 Here we attempt to define my-list as a choice of either the constant
3357 nil, or a cons-cell containing a sexp and my-lisp.  This will not work
3358 because the `choice' widget does not allow recursion.
3359
3360 Using the `lazy' widget you can overcome this problem, as in this
3361 example:
3362
3363   (define-widget 'sexp-list 'lazy
3364     \"A list of sexps.\"
3365     :tag \"Sexp list\"
3366     :type '(choice (const nil) (cons :value (nil) sexp sexp-list)))"
3367   :format "%{%t%}: %v"
3368   ;; We don't convert :type because we want to allow recursive
3369   ;; datastructures.  This is slow, so we should not create speed
3370   ;; critical widgets by deriving from this.
3371   :convert-widget 'widget-value-convert-widget
3372   :value-create 'widget-type-value-create
3373   :value-get 'widget-child-value-get
3374   :value-inline 'widget-child-value-inline
3375   :default-get 'widget-type-default-get
3376   :match 'widget-type-match
3377   :validate 'widget-child-validate)
3378
3379 \f
3380 ;;; The `plist' Widget.
3381 ;;
3382 ;; Property lists.
3383
3384 (define-widget 'plist 'list
3385   "A property list."
3386   :key-type '(symbol :tag "Key")
3387   :value-type '(sexp :tag "Value")
3388   :convert-widget 'widget-plist-convert-widget
3389   :tag "Plist")
3390
3391 (defvar widget-plist-value-type)        ;Dynamic variable
3392
3393 (defun widget-plist-convert-widget (widget)
3394   ;; Handle `:options'.
3395   (let* ((options (widget-get widget :options))
3396          (widget-plist-value-type (widget-get widget :value-type))
3397          (other `(editable-list :inline t
3398                                 (group :inline t
3399                                        ,(widget-get widget :key-type)
3400                                        ,widget-plist-value-type)))
3401          (args (if options
3402                    (list `(checklist :inline t
3403                                      :greedy t
3404                                      ,@(mapcar 'widget-plist-convert-option
3405                                                options))
3406                          other)
3407                  (list other))))
3408     (widget-put widget :args args)
3409     widget))
3410
3411 (defun widget-plist-convert-option (option)
3412   ;; Convert a single plist option.
3413   (let (key-type value-type)
3414     (if (listp option)
3415         (let ((key (nth 0 option)))
3416           (setq value-type (nth 1 option))
3417           (if (listp key)
3418               (setq key-type key)
3419             (setq key-type `(const ,key))))
3420       (setq key-type `(const ,option)
3421             value-type widget-plist-value-type))
3422     `(group :format "Key: %v" :inline t ,key-type ,value-type)))
3423
3424
3425 ;;; The `alist' Widget.
3426 ;;
3427 ;; Association lists.
3428
3429 (define-widget 'alist 'list
3430   "An association list."
3431   :key-type '(sexp :tag "Key")
3432   :value-type '(sexp :tag "Value")
3433   :convert-widget 'widget-alist-convert-widget
3434   :tag "Alist")
3435
3436 (defvar widget-alist-value-type)        ;Dynamic variable
3437
3438 (defun widget-alist-convert-widget (widget)
3439   ;; Handle `:options'.
3440   (let* ((options (widget-get widget :options))
3441          (widget-alist-value-type (widget-get widget :value-type))
3442          (other `(editable-list :inline t
3443                                 (cons :format "%v"
3444                                       ,(widget-get widget :key-type)
3445                                       ,widget-alist-value-type)))
3446          (args (if options
3447                    (list `(checklist :inline t
3448                                      :greedy t
3449                                      ,@(mapcar 'widget-alist-convert-option
3450                                                options))
3451                          other)
3452                  (list other))))
3453     (widget-put widget :args args)
3454     widget))
3455
3456 (defun widget-alist-convert-option (option)
3457   ;; Convert a single alist option.
3458   (let (key-type value-type)
3459     (if (listp option)
3460         (let ((key (nth 0 option)))
3461           (setq value-type (nth 1 option))
3462           (if (listp key)
3463               (setq key-type key)
3464             (setq key-type `(const ,key))))
3465       (setq key-type `(const ,option)
3466             value-type widget-alist-value-type))
3467     `(cons :format "Key: %v" ,key-type ,value-type)))
3468 \f
3469 (define-widget 'choice 'menu-choice
3470   "A union of several sexp types."
3471   :tag "Choice"
3472   :format "%{%t%}: %[Value Menu%] %v"
3473   :button-prefix 'widget-push-button-prefix
3474   :button-suffix 'widget-push-button-suffix
3475   :prompt-value 'widget-choice-prompt-value)
3476
3477 (defun widget-choice-prompt-value (widget prompt value unbound)
3478   "Make a choice."
3479   (let ((args (widget-get widget :args))
3480         (completion-ignore-case (widget-get widget :case-fold))
3481         current choices old)
3482     ;; Find the first arg that matches VALUE.
3483     (let ((look args))
3484       (while look
3485         (if (widget-apply (car look) :match value)
3486             (setq old (car look)
3487                   look nil)
3488           (setq look (cdr look)))))
3489     ;; Find new choice.
3490     (setq current
3491           (cond ((= (length args) 0)
3492                  nil)
3493                 ((= (length args) 1)
3494                  (nth 0 args))
3495                 ((and (= (length args) 2)
3496                       (memq old args))
3497                  (if (eq old (nth 0 args))
3498                      (nth 1 args)
3499                    (nth 0 args)))
3500                 (t
3501                  (while args
3502                    (setq current (car args)
3503                          args (cdr args))
3504                    (setq choices
3505                          (cons (cons (widget-apply current :menu-tag-get)
3506                                      current)
3507                                choices)))
3508                  (let ((val (completing-read prompt choices nil t)))
3509                    (if (stringp val)
3510                        (let ((try (try-completion val choices)))
3511                          (when (stringp try)
3512                            (setq val try))
3513                          (cdr (assoc val choices)))
3514                      nil)))))
3515     (if current
3516         (widget-prompt-value current prompt nil t)
3517       value)))
3518 \f
3519 (define-widget 'radio 'radio-button-choice
3520   "A union of several sexp types."
3521   :tag "Choice"
3522   :format "%{%t%}:\n%v"
3523   :prompt-value 'widget-choice-prompt-value)
3524
3525 (define-widget 'repeat 'editable-list
3526   "A variable length homogeneous list."
3527   :tag "Repeat"
3528   :format "%{%t%}:\n%v%i\n")
3529
3530 (define-widget 'set 'checklist
3531   "A list of members from a fixed set."
3532   :tag "Set"
3533   :format "%{%t%}:\n%v")
3534
3535 (define-widget 'boolean 'toggle
3536   "To be nil or non-nil, that is the question."
3537   :tag "Boolean"
3538   :prompt-value 'widget-boolean-prompt-value
3539   :button-prefix 'widget-push-button-prefix
3540   :button-suffix 'widget-push-button-suffix
3541   :format "%{%t%}: %[Toggle%]  %v\n"
3542   :on "on (non-nil)"
3543   :off "off (nil)")
3544
3545 (defun widget-boolean-prompt-value (widget prompt value unbound)
3546   ;; Toggle a boolean.
3547   (y-or-n-p prompt))
3548 \f
3549 ;;; The `color' Widget.
3550
3551 ;; Fixme: match
3552 (define-widget 'color 'editable-field
3553   "Choose a color name (with sample)."
3554   :format "%t: %v (%{sample%})\n"
3555   :size 10
3556   :tag "Color"
3557   :value "black"
3558   :complete 'widget-color-complete
3559   :sample-face-get 'widget-color-sample-face-get
3560   :notify 'widget-color-notify
3561   :action 'widget-color-action)
3562
3563 (defun widget-color-complete (widget)
3564   "Complete the color in WIDGET."
3565   (require 'facemenu)                   ; for facemenu-color-alist
3566   (let* ((prefix (buffer-substring-no-properties (widget-field-start widget)
3567                                                  (point)))
3568          (list (or facemenu-color-alist (defined-colors)))
3569          (completion (try-completion prefix list)))
3570     (cond ((eq completion t)
3571            (message "Exact match."))
3572           ((null completion)
3573            (error "Can't find completion for \"%s\"" prefix))
3574           ((not (string-equal prefix completion))
3575            (insert-and-inherit (substring completion (length prefix))))
3576           (t
3577            (message "Making completion list...")
3578            (with-output-to-temp-buffer "*Completions*"
3579              (display-completion-list (all-completions prefix list nil)))
3580            (message "Making completion list...done")))))
3581
3582 (defun widget-color-sample-face-get (widget)
3583   (let* ((value (condition-case nil
3584                     (widget-value widget)
3585                   (error (widget-get widget :value)))))
3586     (if (color-defined-p value)
3587         (list (cons 'foreground-color value))
3588       'default)))
3589
3590 (defun widget-color-action (widget &optional event)
3591   "Prompt for a color."
3592   (let* ((tag (widget-apply widget :menu-tag-get))
3593          (prompt (concat tag ": "))
3594          (value (widget-value widget))
3595          (start (widget-field-start widget))
3596          (answer (facemenu-read-color prompt)))
3597     (unless (zerop (length answer))
3598       (widget-value-set widget answer)
3599       (widget-setup)
3600       (widget-apply widget :notify widget event))))
3601
3602 (defun widget-color-notify (widget child &optional event)
3603   "Update the sample, and notofy the parent."
3604   (overlay-put (widget-get widget :sample-overlay)
3605                'face (widget-apply widget :sample-face-get))
3606   (widget-default-notify widget child event))
3607 \f
3608 ;;; The Help Echo
3609
3610 (defun widget-echo-help (pos)
3611   "Display help-echo text for widget at POS."
3612   (let* ((widget (widget-at pos))
3613          (help-echo (and widget (widget-get widget :help-echo))))
3614     (if (functionp help-echo)
3615         (setq help-echo (funcall help-echo widget)))
3616     (if help-echo (message "%s" (eval help-echo)))))
3617
3618 ;;; The End:
3619
3620 (provide 'wid-edit)
3621
3622 ;;; arch-tag: a076e75e-18a1-4b46-8be5-3f317bcbc707
3623 ;;; wid-edit.el ends here