lisp/wid-edit.el

   1 ;;; wid-edit.el --- Functions for creating and using widgets -*-byte-compile-dynamic: t; lexical-binding:t -*-
   2 ;;
   3 ;; Copyright (C) 1996-1997, 1999-2013 Free Software Foundation, Inc.
   4 ;;
   5 ;; Author: Per Abrahamsen <abraham@dina.kvl.dk>
   6 ;; Maintainer: FSF
   7 ;; Keywords: extensions
   8 ;; Package: emacs
   9
  10 ;; This file is part of GNU Emacs.
  11
  12 ;; GNU Emacs is free software: you can redistribute it and/or modify
  13 ;; it under the terms of the GNU General Public License as published by
  14 ;; the Free Software Foundation, either version 3 of the License, or
  15 ;; (at your option) any later version.
  16
  17 ;; GNU Emacs is distributed in the hope that it will be useful,
  18 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  19 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  20 ;; GNU General Public License for more details.
  21
  22 ;; You should have received a copy of the GNU General Public License
  23 ;; along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.
  24
  25 ;;; Wishlist items (from widget.texi):
  26
  27 ;; * The `menu-choice' tag should be prettier, something like the
  28 ;;   abbreviated menus in Open Look.
  29
  30 ;; * Finish `:tab-order'.
  31
  32 ;; * Make indentation work with glyphs and proportional fonts.
  33
  34 ;; * Add commands to show overview of object and class hierarchies to
  35 ;;   the browser.
  36
  37 ;; * Find a way to disable mouse highlight for inactive widgets.
  38
  39 ;; * Find a way to make glyphs look inactive.
  40
  41 ;; * Add `key-binding' widget.
  42
  43 ;; * Add `widget' widget for editing widget specifications.
  44
  45 ;; * Find clean way to implement variable length list.  See
  46 ;;   `TeX-printer-list' for an explanation.
  47
  48 ;; * `C-h' in `widget-prompt-value' should give type specific help.
  49
  50 ;; * A mailto widget. [This should work OK as a url-link if with
  51 ;;   browse-url-browser-function' set up appropriately.]
  52
  53 ;;; Commentary:
  54 ;;
  55 ;; See `widget.el'.
  56
  57 ;;; Code:
  58
  59 ;;; Compatibility.
  60
  61 (defun widget-event-point (event)
  62   "Character position of the end of event if that exists, or nil."
  63   (posn-point (event-end event)))
  64
  65 (defun widget-button-release-event-p (event)
  66   "Non-nil if EVENT is a mouse-button-release event object."
  67   (and (eventp event)
  68        (memq (event-basic-type event) '(mouse-1 mouse-2 mouse-3))
  69        (or (memq 'click (event-modifiers event))
  70            (memq  'drag (event-modifiers event)))))
  71
  72 ;;; Customization.
  73
  74 (defgroup widgets nil
  75   "Customization support for the Widget Library."
  76   :link '(custom-manual "(widget)Top")
  77   :link '(emacs-library-link :tag "Lisp File" "widget.el")
  78   :prefix "widget-"
  79   :group 'extensions)
  80
  81 (defgroup widget-documentation nil
  82   "Options controlling the display of documentation strings."
  83   :group 'widgets)
  84
  85 (defgroup widget-faces nil
  86   "Faces used by the widget library."
  87   :group 'widgets
  88   :group 'faces)
  89
  90 (defvar widget-documentation-face 'widget-documentation
  91   "Face used for documentation strings in widgets.
  92 This exists as a variable so it can be set locally in certain buffers.")
  93
  94 (defface widget-documentation '((((class color)
  95                                   (background dark))
  96                                  (:foreground "lime green"))
  97                                 (((class color)
  98                                   (background light))
  99                                  (:foreground "dark green"))
 100                                 (t nil))
 101   "Face used for documentation text."
 102   :group 'widget-documentation
 103   :group 'widget-faces)
 104 (define-obsolete-face-alias 'widget-documentation-face
 105   'widget-documentation "22.1")
 106
 107 (defvar widget-button-face 'widget-button
 108   "Face used for buttons in widgets.
 109 This exists as a variable so it can be set locally in certain buffers.")
 110
 111 (defface widget-button '((t (:weight bold)))
 112   "Face used for widget buttons."
 113   :group 'widget-faces)
 114 (define-obsolete-face-alias 'widget-button-face 'widget-button "22.1")
 115
 116 (defcustom widget-mouse-face 'highlight
 117   "Face used for widget buttons when the mouse is above them."
 118   :type 'face
 119   :group 'widget-faces)
 120
 121 ;; TTY gets special definitions here and in the next defface, because
 122 ;; the gray colors defined for other displays cause black text on a black
 123 ;; background, at least on light-background TTYs.
 124 (defface widget-field '((((type tty))
 125                          :background "yellow3"
 126                          :foreground "black")
 127                         (((class grayscale color)
 128                           (background light))
 129                          :background "gray85")
 130                         (((class grayscale color)
 131                           (background dark))
 132                          :background "dim gray")
 133                         (t
 134                          :slant italic))
 135   "Face used for editable fields."
 136   :group 'widget-faces)
 137 (define-obsolete-face-alias 'widget-field-face 'widget-field "22.1")
 138
 139 (defface widget-single-line-field '((((type tty))
 140                                      :background "green3"
 141                                      :foreground "black")
 142                                     (((class grayscale color)
 143                                       (background light))
 144                                      :background "gray85")
 145                                     (((class grayscale color)
 146                                       (background dark))
 147                                      :background "dim gray")
 148                                     (t
 149                                      :slant italic))
 150   "Face used for editable fields spanning only a single line."
 151   :group 'widget-faces)
 152 (define-obsolete-face-alias 'widget-single-line-field-face
 153   'widget-single-line-field "22.1")
 154
 155 ;;; This causes display-table to be loaded, and not usefully.
 156 ;;;(defvar widget-single-line-display-table
 157 ;;;  (let ((table (make-display-table)))
 158 ;;;    (aset table 9  "^I")
 159 ;;;    (aset table 10 "^J")
 160 ;;;    table)
 161 ;;;  "Display table used for single-line editable fields.")
 162
 163 ;;;(when (fboundp 'set-face-display-table)
 164 ;;;  (set-face-display-table 'widget-single-line-field-face
 165 ;;;                       widget-single-line-display-table))
 166
 167 ;;; Utility functions.
 168 ;;
 169 ;; These are not really widget specific.
 170
 171 (defun widget-princ-to-string (object)
 172   "Return string representation of OBJECT, any Lisp object.
 173 No quoting characters are used; no delimiters are printed around
 174 the contents of strings."
 175   (with-output-to-string
 176       (princ object)))
 177
 178 (defun widget-clear-undo ()
 179   "Clear all undo information."
 180   (buffer-disable-undo (current-buffer))
 181   (buffer-enable-undo))
 182
 183 (defcustom widget-menu-max-size 40
 184   "Largest number of items allowed in a popup-menu.
 185 Larger menus are read through the minibuffer."
 186   :group 'widgets
 187   :type 'integer)
 188
 189 (defcustom widget-menu-max-shortcuts 40
 190   "Largest number of items for which it works to choose one with a character.
 191 For a larger number of items, the minibuffer is used."
 192   :group 'widgets
 193   :type 'integer)
 194
 195 (defcustom widget-menu-minibuffer-flag nil
 196   "Control how to ask for a choice from the keyboard.
 197 Non-nil means use the minibuffer;
 198 nil means read a single character."
 199   :group 'widgets
 200   :type 'boolean)
 201
 202 (defun widget-choose (title items &optional event)
 203   "Choose an item from a list.
 204
 205 First argument TITLE is the name of the list.
 206 Second argument ITEMS is a list whose members are either
 207  (NAME . VALUE), to indicate selectable items, or just strings to
 208  indicate unselectable items.
 209 Optional third argument EVENT is an input event.
 210
 211 The user is asked to choose between each NAME from the items alist,
 212 and the VALUE of the chosen element will be returned.  If EVENT is a
 213 mouse event, and the number of elements in items is less than
 214 `widget-menu-max-size', a popup menu will be used, otherwise the
 215 minibuffer."
 216   (cond ((and (< (length items) widget-menu-max-size)
 217               event (display-popup-menus-p))
 218          ;; Mouse click.
 219          (x-popup-menu event
 220                        (list title (cons "" items))))
 221         ((or widget-menu-minibuffer-flag
 222              (> (length items) widget-menu-max-shortcuts))
 223          ;; Read the choice of name from the minibuffer.
 224          (setq items (widget-remove-if 'stringp items))
 225          (let ((val (completing-read (concat title ": ") items nil t)))
 226            (if (stringp val)
 227                (let ((try (try-completion val items)))
 228                  (when (stringp try)
 229                    (setq val try))
 230                  (cdr (assoc val items))))))
 231         (t
 232          ;; Construct a menu of the choices
 233          ;; and then use it for prompting for a single character.
 234          (let* ((overriding-terminal-local-map (make-sparse-keymap))
 235                 (next-digit ?0)
 236                 map choice some-choice-enabled value)
 237            ;; Define SPC as a prefix char to get to this menu.
 238            (define-key overriding-terminal-local-map " "
 239              (setq map (make-sparse-keymap title)))
 240            (with-current-buffer (get-buffer-create " widget-choose")
 241              (erase-buffer)
 242              (insert "Available choices:\n\n")
 243              (while items
 244                (setq choice (car items) items (cdr items))
 245                (if (consp choice)
 246                    (let* ((name (car choice))
 247                          (function (cdr choice)))
 248                      (insert (format "%c = %s\n" next-digit name))
 249                      (define-key map (vector next-digit) function)
 250                      (setq some-choice-enabled t)))
 251                ;; Allocate digits to disabled alternatives
 252                ;; so that the digit of a given alternative never varies.
 253                (setq next-digit (1+ next-digit)))
 254              (insert "\nC-g = Quit")
 255              (goto-char (point-min))
 256              (forward-line))
 257            (or some-choice-enabled
 258                (error "None of the choices is currently meaningful"))
 259            (define-key map [?\C-g] 'keyboard-quit)
 260            (define-key map [t] 'keyboard-quit)
 261            (define-key map [?\M-\C-v] 'scroll-other-window)
 262            (define-key map [?\M--] 'negative-argument)
 263            (setcdr map (nreverse (cdr map)))
 264            ;; Read a char with the menu, and return the result
 265            ;; that corresponds to it.
 266            (save-window-excursion
 267              (let ((buf (get-buffer " widget-choose")))
 268                (fit-window-to-buffer (display-buffer buf))
 269                (let ((cursor-in-echo-area t)
 270                      keys
 271                      (char 0)
 272                      (arg 1))
 273                  (while (not (or (and (integerp char)
 274                                       (>= char ?0) (< char next-digit))
 275                                  (eq value 'keyboard-quit)))
 276                    ;; Unread a SPC to lead to our new menu.
 277                    (setq unread-command-events (cons ?\s unread-command-events))
 278                    (setq keys (read-key-sequence title))
 279                    (setq value
 280                          (lookup-key overriding-terminal-local-map keys t)
 281                          char (aref keys 1))
 282                    (cond ((eq value 'scroll-other-window)
 283                           (let ((minibuffer-scroll-window
 284                                  (get-buffer-window buf)))
 285                             (if (> 0 arg)
 286                                 (scroll-other-window-down
 287                                  (window-height minibuffer-scroll-window))
 288                               (scroll-other-window))
 289                             (setq arg 1)))
 290                          ((eq value 'negative-argument)
 291                           (setq arg -1))
 292                          (t
 293                           (setq arg 1)))))))
 294            (when (eq value 'keyboard-quit)
 295              (error "Canceled"))
 296            value))))
 297
 298 (defun widget-remove-if (predicate list)
 299   (let (result (tail list))
 300     (while tail
 301       (or (funcall predicate (car tail))
 302           (setq result (cons (car tail) result)))
 303       (setq tail (cdr tail)))
 304     (nreverse result)))
 305
 306 ;;; Widget text specifications.
 307 ;;
 308 ;; These functions are for specifying text properties.
 309
 310 ;; We can set it to nil now that get_local_map uses get_pos_property.
 311 (defconst widget-field-add-space nil
 312   "Non-nil means add extra space at the end of editable text fields.
 313 If you don't add the space, it will become impossible to edit a zero
 314 size field.")
 315
 316 (defvar widget-field-use-before-change t
 317   "Non-nil means use `before-change-functions' to track editable fields.
 318 This enables the use of undo.  Using before hooks also means that
 319 the :notify function can't know the new value.")
 320
 321 (defun widget-specify-field (widget from to)
 322   "Specify editable button for WIDGET between FROM and TO."
 323   ;; Terminating space is not part of the field, but necessary in
 324   ;; order for local-map to work.  Remove next sexp if local-map works
 325   ;; at the end of the overlay.
 326   (save-excursion
 327     (goto-char to)
 328     (cond ((null (widget-get widget :size))
 329            (forward-char 1))
 330           (widget-field-add-space
 331            (insert-and-inherit " ")))
 332     (setq to (point)))
 333   (let ((keymap (widget-get widget :keymap))
 334         (face (or (widget-get widget :value-face) 'widget-field))
 335         (help-echo (widget-get widget :help-echo))
 336         (follow-link (widget-get widget :follow-link))
 337         (rear-sticky
 338          (or (not widget-field-add-space) (widget-get widget :size))))
 339     (if (functionp help-echo)
 340       (setq help-echo 'widget-mouse-help))
 341     (when (= (char-before to) ?\n)
 342       ;; When the last character in the field is a newline, we want to
 343       ;; give it a `field' char-property of `boundary', which helps the
 344       ;; C-n/C-p act more naturally when entering/leaving the field.  We
 345      ;; do this by making a small secondary overlay to contain just that
 346       ;; one character.
 347       (let ((overlay (make-overlay (1- to) to nil t nil)))
 348         (overlay-put overlay 'field 'boundary)
 349         ;; We need the real field for tabbing.
 350         (overlay-put overlay 'real-field widget)
 351         ;; Use `local-map' here, not `keymap', so that normal editing
 352         ;; works in the field when, say, Custom uses `suppress-keymap'.
 353         (overlay-put overlay 'local-map keymap)
 354         (overlay-put overlay 'face face)
 355         (overlay-put overlay 'follow-link follow-link)
 356         (overlay-put overlay 'help-echo help-echo))
 357       (setq to (1- to))
 358       (setq rear-sticky t))
 359     (let ((overlay (make-overlay from to nil nil rear-sticky)))
 360       (widget-put widget :field-overlay overlay)
 361       ;;(overlay-put overlay 'detachable nil)
 362       (overlay-put overlay 'field widget)
 363       (overlay-put overlay 'local-map keymap)
 364       (overlay-put overlay 'face face)
 365       (overlay-put overlay 'follow-link follow-link)
 366       (overlay-put overlay 'help-echo help-echo)))
 367   (widget-specify-secret widget))
 368
 369 (defun widget-specify-secret (field)
 370   "Replace text in FIELD with value of `:secret', if non-nil."
 371   (let ((secret (widget-get field :secret))
 372         (size (widget-get field :size)))
 373     (when secret
 374       (let ((begin (widget-field-start field))
 375             (end (widget-field-end field)))
 376         (when size
 377           (while (and (> end begin)
 378                       (eq (char-after (1- end)) ?\s))
 379             (setq end (1- end))))
 380         (while (< begin end)
 381           (let ((old (char-after begin)))
 382             (unless (eq old secret)
 383               (subst-char-in-region begin (1+ begin) old secret)
 384               (put-text-property begin (1+ begin) 'secret old))
 385             (setq begin (1+ begin))))))))
 386
 387 (defun widget-specify-button (widget from to)
 388   "Specify button for WIDGET between FROM and TO."
 389   (let ((overlay (make-overlay from to nil t nil))
 390         (follow-link (widget-get widget :follow-link))
 391         (help-echo (widget-get widget :help-echo)))
 392     (widget-put widget :button-overlay overlay)
 393     (if (functionp help-echo)
 394       (setq help-echo 'widget-mouse-help))
 395     (overlay-put overlay 'button widget)
 396     (overlay-put overlay 'keymap (widget-get widget :keymap))
 397     (overlay-put overlay 'evaporate t)
 398     ;; We want to avoid the face with image buttons.
 399     (unless (widget-get widget :suppress-face)
 400       (overlay-put overlay 'face (widget-apply widget :button-face-get))
 401       (overlay-put overlay 'mouse-face
 402                    ;; Make new list structure for the mouse-face value
 403                    ;; so that different widgets will have
 404                    ;; different `mouse-face' property values
 405                    ;; and will highlight separately.
 406                    (let ((mouse-face-value
 407                           (widget-apply widget :mouse-face-get)))
 408                      ;; If it's a list, copy it.
 409                      (if (listp mouse-face-value)
 410                          (copy-sequence mouse-face-value)
 411                        ;; If it's a symbol, put it in a list.
 412                        (list mouse-face-value)))))
 413     (overlay-put overlay 'pointer 'hand)
 414     (overlay-put overlay 'follow-link follow-link)
 415     (overlay-put overlay 'help-echo help-echo)))
 416
 417 (defun widget-mouse-help (_window overlay _point)
 418   "Help-echo callback for widgets whose :help-echo is a function."
 419   (with-current-buffer (overlay-buffer overlay)
 420     (let* ((widget (widget-at (overlay-start overlay)))
 421            (help-echo (if widget (widget-get widget :help-echo))))
 422       (if (functionp help-echo)
 423           (funcall help-echo widget)
 424         help-echo))))
 425
 426 (defun widget-specify-sample (widget from to)
 427   "Specify sample for WIDGET between FROM and TO."
 428   (let ((overlay (make-overlay from to nil t nil)))
 429     (overlay-put overlay 'face (widget-apply widget :sample-face-get))
 430     (overlay-put overlay 'evaporate t)
 431     (widget-put widget :sample-overlay overlay)))
 432
 433 (defun widget-specify-doc (widget from to)
 434   "Specify documentation for WIDGET between FROM and TO."
 435   (let ((overlay (make-overlay from to nil t nil)))
 436     (overlay-put overlay 'widget-doc widget)
 437     (overlay-put overlay 'face widget-documentation-face)
 438     (overlay-put overlay 'evaporate t)
 439     (widget-put widget :doc-overlay overlay)))
 440
 441 (defmacro widget-specify-insert (&rest form)
 442   "Execute FORM without inheriting any text properties."
 443   `(save-restriction
 444     (let ((inhibit-read-only t)
 445           (inhibit-modification-hooks t))
 446       (narrow-to-region (point) (point))
 447       (prog1 (progn ,@form)
 448         (goto-char (point-max))))))
 449
 450 (defface widget-inactive
 451   '((t :inherit shadow))
 452   "Face used for inactive widgets."
 453   :group 'widget-faces)
 454 (define-obsolete-face-alias 'widget-inactive-face
 455   'widget-inactive "22.1")
 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.  The type is a symbol."
 486   (car widget))
 487
 488 ;;;###autoload
 489 (defun widgetp (widget)
 490   "Return non-nil if 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 if 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 canceled.
 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 "images/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))
 640                      specs)))
 641            (find-image (nreverse 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 (featurep 'image)
 659            (setq image (widget-image-find image)))
 660       (progn (widget-put widget :suppress-face t)
 661              (insert-image image tag))
 662     (insert tag)))
 663
 664 (defun widget-move-and-invoke (event)
 665   "Move to where you click, and if it is an active field, invoke it."
 666   (interactive "e")
 667   (mouse-set-point event)
 668   (let ((pos (widget-event-point event)))
 669     (if (and pos (get-char-property pos 'button))
 670         (widget-button-click event))))
 671
 672 ;;; Buttons.
 673
 674 (defgroup widget-button nil
 675   "The look of various kinds of buttons."
 676   :group 'widgets)
 677
 678 (defcustom widget-button-prefix ""
 679   "String used as prefix for buttons."
 680   :type 'string
 681   :group 'widget-button)
 682
 683 (defcustom widget-button-suffix ""
 684   "String used as suffix for buttons."
 685   :type 'string
 686   :group 'widget-button)
 687
 688 ;;; Creating Widgets.
 689
 690 ;;;###autoload
 691 (defun widget-create (type &rest args)
 692   "Create widget of TYPE.
 693 The optional ARGS are additional keyword arguments."
 694   (let ((widget (apply 'widget-convert type args)))
 695     (widget-apply widget :create)
 696     widget))
 697
 698 (defun widget-create-child-and-convert (parent type &rest args)
 699   "As part of the widget PARENT, create a child widget TYPE.
 700 The child is converted, using the keyword arguments ARGS."
 701   (let ((widget (apply 'widget-convert type args)))
 702     (widget-put widget :parent parent)
 703     (unless (widget-get widget :indent)
 704       (widget-put widget :indent (+ (or (widget-get parent :indent) 0)
 705                                     (or (widget-get widget :extra-offset) 0)
 706                                     (widget-get parent :offset))))
 707     (widget-apply widget :create)
 708     widget))
 709
 710 (defun widget-create-child (parent type)
 711   "Create widget of TYPE."
 712   (let ((widget (widget-copy type)))
 713     (widget-put widget :parent parent)
 714     (unless (widget-get widget :indent)
 715       (widget-put widget :indent (+ (or (widget-get parent :indent) 0)
 716                                     (or (widget-get widget :extra-offset) 0)
 717                                     (widget-get parent :offset))))
 718     (widget-apply widget :create)
 719     widget))
 720
 721 (defun widget-create-child-value (parent type value)
 722   "Create widget of TYPE with value VALUE."
 723   (let ((widget (widget-copy type)))
 724     (widget-put widget :value (widget-apply widget :value-to-internal value))
 725     (widget-put widget :parent parent)
 726     (unless (widget-get widget :indent)
 727       (widget-put widget :indent (+ (or (widget-get parent :indent) 0)
 728                                     (or (widget-get widget :extra-offset) 0)
 729                                     (widget-get parent :offset))))
 730     (widget-apply widget :create)
 731     widget))
 732
 733 ;;;###autoload
 734 (defun widget-delete (widget)
 735   "Delete WIDGET."
 736   (widget-apply widget :delete))
 737
 738 (defun widget-copy (widget)
 739   "Make a deep copy of WIDGET."
 740   (widget-apply (copy-sequence widget) :copy))
 741
 742 (defun widget-convert (type &rest args)
 743   "Convert TYPE to a widget without inserting it in the buffer.
 744 The optional ARGS are additional keyword arguments."
 745   ;; Don't touch the type.
 746   (let* ((widget (if (symbolp type)
 747                      (list type)
 748                    (copy-sequence type)))
 749          (current widget)
 750          done
 751          (keys args))
 752     ;; First set the :args keyword.
 753     (while (cdr current)                ;Look in the type.
 754       (if (and (keywordp (cadr current))
 755                ;; If the last element is a keyword,
 756                ;; it is still the :args element,
 757                ;; even though it is a keyword.
 758                (cddr current))
 759           (if (eq (cadr current) :args)
 760               ;; If :args is explicitly specified, obey it.
 761               (setq current nil)
 762             ;; Some other irrelevant keyword.
 763             (setq current (cdr (cdr current))))
 764         (setcdr current (list :args (cdr current)))
 765         (setq current nil)))
 766     (while (and args (not done))        ;Look in ARGS.
 767       (cond ((eq (car args) :args)
 768              ;; Handle explicit specification of :args.
 769              (setq args (cadr args)
 770                    done t))
 771             ((keywordp (car args))
 772              (setq args (cddr args)))
 773             (t (setq done t))))
 774     (when done
 775       (widget-put widget :args args))
 776     ;; Then Convert the widget.
 777     (setq type widget)
 778     (while type
 779       (let ((convert-widget (plist-get (cdr type) :convert-widget)))
 780         (if convert-widget
 781             (setq widget (funcall convert-widget widget))))
 782       (setq type (get (car type) 'widget-type)))
 783     ;; Finally set the keyword args.
 784     (while keys
 785       (let ((next (nth 0 keys)))
 786         (if (keywordp next)
 787             (progn
 788               (widget-put widget next (nth 1 keys))
 789               (setq keys (nthcdr 2 keys)))
 790           (setq keys nil))))
 791     ;; Convert the :value to internal format.
 792     (if (widget-member widget :value)
 793         (widget-put widget
 794                     :value (widget-apply widget
 795                                          :value-to-internal
 796                                          (widget-get widget :value))))
 797     ;; Return the newly create widget.
 798     widget))
 799
 800 ;;;###autoload
 801 (defun widget-insert (&rest args)
 802   "Call `insert' with ARGS even if surrounding text is read only."
 803   (let ((inhibit-read-only t)
 804         (inhibit-modification-hooks t))
 805     (apply 'insert args)))
 806
 807 (defun widget-convert-text (type from to
 808                                  &optional button-from button-to
 809                                  &rest args)
 810   "Return a widget of type TYPE with endpoint FROM TO.
 811 No text will be inserted to the buffer, instead the text between FROM
 812 and TO will be used as the widgets end points.  If optional arguments
 813 BUTTON-FROM and BUTTON-TO are given, these will be used as the widgets
 814 button end points.
 815 Optional ARGS are extra keyword arguments for TYPE."
 816   (let ((widget (apply 'widget-convert type :delete 'widget-leave-text args))
 817         (from (copy-marker from))
 818         (to (copy-marker to)))
 819     (set-marker-insertion-type from t)
 820     (set-marker-insertion-type to nil)
 821     (widget-put widget :from from)
 822     (widget-put widget :to to)
 823     (when button-from
 824       (widget-specify-button widget button-from button-to))
 825     widget))
 826
 827 (defun widget-convert-button (type from to &rest args)
 828   "Return a widget of type TYPE with endpoint FROM TO.
 829 Optional ARGS are extra keyword arguments for TYPE.
 830 No text will be inserted to the buffer, instead the text between FROM
 831 and TO will be used as the widgets end points, as well as the widgets
 832 button end points."
 833   (apply 'widget-convert-text type from to from to args))
 834
 835 (defun widget-leave-text (widget)
 836   "Remove markers and overlays from WIDGET and its children."
 837   (let ((button (widget-get widget :button-overlay))
 838         (sample (widget-get widget :sample-overlay))
 839         (doc (widget-get widget :doc-overlay))
 840         (field (widget-get widget :field-overlay)))
 841     (set-marker (widget-get widget :from) nil)
 842     (set-marker (widget-get widget :to) nil)
 843     (when button
 844       (delete-overlay button))
 845     (when sample
 846       (delete-overlay sample))
 847     (when doc
 848       (delete-overlay doc))
 849     (when field
 850       (delete-overlay field))
 851     (mapc 'widget-leave-text (widget-get widget :children))))
 852
 853 ;;; Keymap and Commands.
 854
 855 ;; This alias exists only so that one can choose in doc-strings (e.g.
 856 ;; Custom-mode) which key-binding of widget-keymap one wants to refer to.
 857 ;; http://lists.gnu.org/archive/html/emacs-devel/2008-11/msg00480.html
 858 (define-obsolete-function-alias 'advertised-widget-backward
 859   'widget-backward "23.2")
 860
 861 ;;;###autoload
 862 (defvar widget-keymap
 863   (let ((map (make-sparse-keymap)))
 864     (define-key map "\t" 'widget-forward)
 865     (define-key map "\e\t" 'widget-backward)
 866     (define-key map [(shift tab)] 'widget-backward)
 867     (put 'widget-backward :advertised-binding [(shift tab)])
 868     (define-key map [backtab] 'widget-backward)
 869     (define-key map [down-mouse-2] 'widget-button-click)
 870     (define-key map [down-mouse-1] 'widget-button-click)
 871     ;; The following definition needs to avoid using escape sequences that
 872     ;; might get converted to ^M when building loaddefs.el
 873     (define-key map [(control ?m)] 'widget-button-press)
 874     map)
 875   "Keymap containing useful binding for buffers containing widgets.
 876 Recommended as a parent keymap for modes using widgets.
 877 Note that such modes will need to require wid-edit.")
 878
 879 (defvar widget-global-map global-map
 880   "Keymap used for events a widget does not handle itself.")
 881 (make-variable-buffer-local 'widget-global-map)
 882
 883 (defvar widget-field-keymap
 884   (let ((map (copy-keymap widget-keymap)))
 885     (define-key map "\C-k" 'widget-kill-line)
 886     (define-key map "\M-\t" 'widget-complete)
 887     (define-key map "\C-m" 'widget-field-activate)
 888     ;; Since the widget code uses a `field' property to identify fields,
 889     ;; ordinary beginning-of-line does the right thing.
 890     ;;  (define-key map "\C-a" 'widget-beginning-of-line)
 891     (define-key map "\C-e" 'widget-end-of-line)
 892     map)
 893   "Keymap used inside an editable field.")
 894
 895 (defvar widget-text-keymap
 896   (let ((map (copy-keymap widget-keymap)))
 897     ;; Since the widget code uses a `field' property to identify fields,
 898     ;; ordinary beginning-of-line does the right thing.
 899     ;;  (define-key map "\C-a" 'widget-beginning-of-line)
 900     (define-key map "\C-e" 'widget-end-of-line)
 901     map)
 902   "Keymap used inside a text field.")
 903
 904 (defun widget-field-activate (pos &optional event)
 905   "Invoke the editable field at point."
 906   (interactive "@d")
 907   (let ((field (widget-field-at pos)))
 908     (if field
 909         (widget-apply-action field event)
 910       (call-interactively
 911        (lookup-key widget-global-map (this-command-keys))))))
 912
 913 (defface widget-button-pressed
 914   '((((min-colors 88) (class color))
 915      (:foreground "red1"))
 916     (((class color))
 917      (:foreground "red"))
 918     (t
 919      (:weight bold :underline t)))
 920   "Face used for pressed buttons."
 921   :group 'widget-faces)
 922 (define-obsolete-face-alias 'widget-button-pressed-face
 923   'widget-button-pressed "22.1")
 924
 925 (defvar widget-button-click-moves-point nil
 926   "If non-nil, `widget-button-click' moves point to a button after invoking it.
 927 If nil, point returns to its original position after invoking a button.")
 928
 929 (defun widget-button-click (event)
 930   "Invoke the button that the mouse is pointing at."
 931   (interactive "e")
 932   (if (widget-event-point event)
 933       (let* ((oevent event)
 934              (mouse-1 (memq (event-basic-type event) '(mouse-1 down-mouse-1)))
 935              (pos (widget-event-point event))
 936              (start (event-start event))
 937              (button (get-char-property
 938                       pos 'button (and (windowp (posn-window start))
 939                                        (window-buffer (posn-window start)))))
 940              newpoint)
 941         (when (or (null button)
 942                   (catch 'button-press-cancelled
 943               ;; Mouse click on a widget button.  Do the following
 944               ;; in a save-excursion so that the click on the button
 945               ;; doesn't change point.
 946               (save-selected-window
 947                 (select-window (posn-window (event-start event)))
 948                 (save-excursion
 949                   (goto-char (posn-point (event-start event)))
 950                   (let* ((overlay (widget-get button :button-overlay))
 951                          (pressed-face (or (widget-get button :pressed-face)
 952                                            widget-button-pressed-face))
 953                          (face (overlay-get overlay 'face))
 954                          (mouse-face (overlay-get overlay 'mouse-face)))
 955                     (unwind-protect
 956                         ;; Read events, including mouse-movement
 957                         ;; events, waiting for a release event.  If we
 958                         ;; began with a mouse-1 event and receive a
 959                         ;; movement event, that means the user wants
 960                         ;; to perform drag-selection, so cancel the
 961                         ;; button press and do the default mouse-1
 962                         ;; action.  For mouse-2, just highlight/
 963                         ;; unhighlight the button the mouse was
 964                         ;; initially on when we move over it.
 965                         (save-excursion
 966                           (when face    ; avoid changing around image
 967                             (overlay-put overlay 'face pressed-face)
 968                             (overlay-put overlay 'mouse-face pressed-face))
 969                           (unless (widget-apply button :mouse-down-action event)
 970                             (let ((track-mouse t))
 971                               (while (not (widget-button-release-event-p event))
 972                                 (setq event (read-event))
 973                                 (when (and mouse-1 (mouse-movement-p event))
 974                                   (push event unread-command-events)
 975                                   (setq event oevent)
 976                                   (throw 'button-press-cancelled t))
 977                                 (unless (or (integerp event)
 978                                             (memq (car event) '(switch-frame select-window))
 979                                             (eq (car event) 'scroll-bar-movement))
 980                                   (setq pos (widget-event-point event))
 981                                   (if (and pos
 982                                            (eq (get-char-property pos 'button)
 983                                                button))
 984                                       (when face
 985                                         (overlay-put overlay 'face pressed-face)
 986                                         (overlay-put overlay 'mouse-face pressed-face))
 987                                     (overlay-put overlay 'face face)
 988                                     (overlay-put overlay 'mouse-face mouse-face))))))
 989
 990                           ;; When mouse is released over the button, run
 991                           ;; its action function.
 992                           (when (and pos (eq (get-char-property pos 'button) button))
 993                             (goto-char pos)
 994                             (widget-apply-action button event)
 995                             (if widget-button-click-moves-point
 996                                 (setq newpoint (point)))))
 997                       (overlay-put overlay 'face face)
 998                       (overlay-put overlay 'mouse-face mouse-face))))
 999
1000                 (if newpoint (goto-char newpoint))
1001                 ;; This loses if the widget action switches windows. -- cyd
1002                 ;; (unless (pos-visible-in-window-p (widget-event-point event))
1003                 ;;   (mouse-set-point event)
1004                 ;;   (beginning-of-line)
1005                 ;;   (recenter))
1006                 )
1007               nil))
1008           (let ((up t) command)
1009             ;; Mouse click not on a widget button.  Find the global
1010             ;; command to run, and check whether it is bound to an
1011             ;; up event.
1012             (if mouse-1
1013                 (cond ((setq command    ;down event
1014                              (lookup-key widget-global-map [down-mouse-1]))
1015                        (setq up nil))
1016                       ((setq command    ;up event
1017                              (lookup-key widget-global-map [mouse-1]))))
1018               (cond ((setq command      ;down event
1019                            (lookup-key widget-global-map [down-mouse-2]))
1020                      (setq up nil))
1021                     ((setq command      ;up event
1022                            (lookup-key widget-global-map [mouse-2])))))
1023             (when up
1024               ;; Don't execute up events twice.
1025               (while (not (widget-button-release-event-p event))
1026                 (setq event (read-event))))
1027             (when command
1028               (call-interactively command)))))
1029     (message "You clicked somewhere weird.")))
1030
1031 (defun widget-button-press (pos &optional event)
1032   "Invoke button at POS."
1033   (interactive "@d")
1034   (let ((button (get-char-property pos 'button)))
1035     (if button
1036         (widget-apply-action button event)
1037       (let ((command (lookup-key widget-global-map (this-command-keys))))
1038         (when (commandp command)
1039           (call-interactively command))))))
1040
1041 (defun widget-tabable-at (&optional pos)
1042   "Return the tabable widget at POS, or nil.
1043 POS defaults to the value of (point)."
1044   (let ((widget (widget-at pos)))
1045     (if widget
1046         (let ((order (widget-get widget :tab-order)))
1047           (if order
1048               (if (>= order 0)
1049                   widget)
1050             widget)))))
1051
1052 (defvar widget-use-overlay-change t
1053   "If non-nil, use overlay change functions to tab around in the buffer.
1054 This is much faster.")
1055
1056 (defun widget-move (arg)
1057   "Move point to the ARG next field or button.
1058 ARG may be negative to move backward."
1059   (or (bobp) (> arg 0) (backward-char))
1060   (let ((wrapped 0)
1061         (number arg)
1062         (old (widget-tabable-at)))
1063     ;; Forward.
1064     (while (> arg 0)
1065       (cond ((eobp)
1066              (goto-char (point-min))
1067              (setq wrapped (1+ wrapped)))
1068             (widget-use-overlay-change
1069              (goto-char (next-overlay-change (point))))
1070             (t
1071              (forward-char 1)))
1072       (and (= wrapped 2)
1073            (eq arg number)
1074            (error "No buttons or fields found"))
1075       (let ((new (widget-tabable-at)))
1076         (when new
1077           (unless (eq new old)
1078             (setq arg (1- arg))
1079             (setq old new)))))
1080     ;; Backward.
1081     (while (< arg 0)
1082       (cond ((bobp)
1083              (goto-char (point-max))
1084              (setq wrapped (1+ wrapped)))
1085             (widget-use-overlay-change
1086              (goto-char (previous-overlay-change (point))))
1087             (t
1088              (backward-char 1)))
1089       (and (= wrapped 2)
1090            (eq arg number)
1091            (error "No buttons or fields found"))
1092       (let ((new (widget-tabable-at)))
1093         (when new
1094           (unless (eq new old)
1095             (setq arg (1+ arg))))))
1096     (let ((new (widget-tabable-at)))
1097       (while (eq (widget-tabable-at) new)
1098         (backward-char)))
1099     (forward-char))
1100   (widget-echo-help (point))
1101   (run-hooks 'widget-move-hook))
1102
1103 (defun widget-forward (arg)
1104   "Move point to the next field or button.
1105 With optional ARG, move across that many fields."
1106   (interactive "p")
1107   (run-hooks 'widget-forward-hook)
1108   (widget-move arg))
1109
1110 (defun widget-backward (arg)
1111   "Move point to the previous field or button.
1112 With optional ARG, move across that many fields."
1113   (interactive "p")
1114   (run-hooks 'widget-backward-hook)
1115   (widget-move (- arg)))
1116
1117 ;; Since the widget code uses a `field' property to identify fields,
1118 ;; ordinary beginning-of-line does the right thing.
1119 (defalias 'widget-beginning-of-line 'beginning-of-line)
1120
1121 (defun widget-end-of-line ()
1122   "Go to end of field or end of line, whichever is first.
1123 Trailing spaces at the end of padded fields are not considered part of
1124 the field."
1125   (interactive)
1126   ;; Ordinary end-of-line does the right thing, because we're inside
1127   ;; text with a `field' property.
1128   (end-of-line)
1129   (unless (eolp)
1130     ;; ... except that we want to ignore trailing spaces in fields that
1131     ;; aren't terminated by a newline, because they are used as padding,
1132     ;; and ignored when extracting the entered value of the field.
1133     (skip-chars-backward " " (field-beginning (1- (point))))))
1134
1135 (defun widget-kill-line ()
1136   "Kill to end of field or end of line, whichever is first."
1137   (interactive)
1138   (let* ((field (widget-field-find (point)))
1139          (end (and field (widget-field-end field))))
1140     (if (and field (> (line-beginning-position 2) end))
1141         (kill-region (point) end)
1142       (call-interactively 'kill-line))))
1143
1144 (defun widget-narrow-to-field ()
1145   "Narrow to field."
1146   (interactive)
1147   (let ((field (widget-field-find (point))))
1148     (if field
1149         (narrow-to-region (line-beginning-position) (line-end-position)))))
1150
1151 ;; This used to say:
1152 ;; "When not inside a field, move to the previous button or field."
1153 ;; but AFAICS, it has always just thrown an error.
1154 (defun widget-complete ()
1155   "Complete content of editable field from point.
1156 When not inside a field, signal an error."
1157   (interactive)
1158   (let ((data (widget-completions-at-point)))
1159     (cond
1160      ((functionp data) (funcall data))
1161      ((consp data)
1162       (let ((completion-extra-properties (nth 3 data)))
1163         (completion-in-region (nth 0 data) (nth 1 data) (nth 2 data)
1164                               (plist-get completion-extra-properties
1165                                          :predicate))))
1166      (t
1167       (error "Not in an editable field")))))
1168 ;; We may want to use widget completion in buffers where the major mode
1169 ;; hasn't added widget-completions-at-point to completion-at-point-functions,
1170 ;; so it's not really obsolete (yet).
1171 ;; (make-obsolete 'widget-complete 'completion-at-point "24.1")
1172
1173 (defun widget-completions-at-point ()
1174   (let ((field (widget-field-find (point))))
1175     (when field
1176       (widget-apply field :completions-function))))
1177
1178 ;;; Setting up the buffer.
1179
1180 (defvar widget-field-new nil
1181   "List of all newly created editable fields in the buffer.")
1182 (make-variable-buffer-local 'widget-field-new)
1183
1184 (defvar widget-field-list nil
1185   "List of all editable fields in the buffer.")
1186 (make-variable-buffer-local 'widget-field-list)
1187
1188 (defun widget-at (&optional pos)
1189   "The button or field at POS (default, point)."
1190   (or (get-char-property (or pos (point)) 'button)
1191       (widget-field-at pos)))
1192
1193 ;;;###autoload
1194 (defun widget-setup ()
1195   "Setup current buffer so editing string widgets works."
1196   (let ((inhibit-read-only t)
1197         (inhibit-modification-hooks t)
1198         field)
1199     (while widget-field-new
1200       (setq field (car widget-field-new)
1201             widget-field-new (cdr widget-field-new)
1202             widget-field-list (cons field widget-field-list))
1203       (let ((from (car (widget-get field :field-overlay)))
1204             (to (cdr (widget-get field :field-overlay))))
1205         (widget-specify-field field
1206                               (marker-position from) (marker-position to))
1207         (set-marker from nil)
1208         (set-marker to nil))))
1209   (widget-clear-undo)
1210   (widget-add-change))
1211
1212 (defvar widget-field-last nil)
1213 ;; Last field containing point.
1214 (make-variable-buffer-local 'widget-field-last)
1215
1216 (defvar widget-field-was nil)
1217 ;; The widget data before the change.
1218 (make-variable-buffer-local 'widget-field-was)
1219
1220 (defun widget-field-at (pos)
1221   "Return the widget field at POS, or nil if none."
1222   (let ((field (get-char-property (or pos (point)) 'field)))
1223     (if (eq field 'boundary)
1224         (get-char-property (or pos (point)) 'real-field)
1225       field)))
1226
1227 (defun widget-field-buffer (widget)
1228   "Return the buffer of WIDGET's editing field."
1229   (let ((overlay (widget-get widget :field-overlay)))
1230     (cond ((overlayp overlay)
1231            (overlay-buffer overlay))
1232           ((consp overlay)
1233            (marker-buffer (car overlay))))))
1234
1235 (defun widget-field-start (widget)
1236   "Return the start of WIDGET's editing field."
1237   (let ((overlay (widget-get widget :field-overlay)))
1238     (if (overlayp overlay)
1239         (overlay-start overlay)
1240       (car overlay))))
1241
1242 (defun widget-field-end (widget)
1243   "Return the end of WIDGET's editing field."
1244   (let ((overlay (widget-get widget :field-overlay)))
1245     ;; Don't subtract one if local-map works at the end of the overlay,
1246     ;; or if a special `boundary' field has been added after the widget
1247     ;; field.
1248     (if (overlayp overlay)
1249         ;; Don't proceed if overlay has been removed from buffer.
1250         (when (overlay-buffer overlay)
1251           (if (and (not (eq (with-current-buffer
1252                                 (widget-field-buffer widget)
1253                               (save-restriction
1254                                 ;; `widget-narrow-to-field' can be
1255                                 ;; active when this function is called
1256                                 ;; from an change-functions hook. So
1257                                 ;; temporarily remove field narrowing
1258                                 ;; before to call `get-char-property'.
1259                                 (widen)
1260                                 (get-char-property (overlay-end overlay)
1261                                                    'field)))
1262                             'boundary))
1263                    (or widget-field-add-space
1264                        (null (widget-get widget :size))))
1265               (1- (overlay-end overlay))
1266             (overlay-end overlay)))
1267       (cdr overlay))))
1268
1269 (defun widget-field-text-end (widget)
1270   (let ((to   (widget-field-end widget))
1271         (size (widget-get widget :size)))
1272     (if (or (null size) (zerop size))
1273         to
1274       (let ((from (widget-field-start widget)))
1275         (if (and from to)
1276             (with-current-buffer (widget-field-buffer widget)
1277               (while (and (> to from)
1278                           (eq (char-after (1- to)) ?\s))
1279                 (setq to (1- to)))
1280               to))))))
1281
1282 (defun widget-field-find (pos)
1283   "Return the field at POS.
1284 Unlike (get-char-property POS 'field), this works with empty fields too."
1285   (let ((fields widget-field-list)
1286         field found)
1287     (while fields
1288       (setq field (car fields)
1289             fields (cdr fields))
1290       (when (and (<= (widget-field-start field) pos)
1291                  (<= pos (widget-field-end field)))
1292         (when found
1293           (error "Overlapping fields"))
1294         (setq found field)))
1295     found))
1296
1297 (defun widget-before-change (from to)
1298   ;; This is how, for example, a variable changes its state to `modified'.
1299   ;; when it is being edited.
1300   (unless inhibit-read-only
1301     (let ((from-field (widget-field-find from))
1302           (to-field (widget-field-find to)))
1303       (cond ((not (eq from-field to-field))
1304              (add-hook 'post-command-hook 'widget-add-change nil t)
1305              (signal 'text-read-only
1306                      '("Change should be restricted to a single field")))
1307             ((null from-field)
1308              (add-hook 'post-command-hook 'widget-add-change nil t)
1309              (signal 'text-read-only
1310                      '("Attempt to change text outside editable field")))
1311             (widget-field-use-before-change
1312              (widget-apply from-field :notify from-field))))))
1313
1314 (defun widget-add-change ()
1315   (remove-hook 'post-command-hook 'widget-add-change t)
1316   (add-hook 'before-change-functions 'widget-before-change nil t)
1317   (add-hook 'after-change-functions 'widget-after-change nil t))
1318
1319 (defun widget-after-change (from to _old)
1320   "Adjust field size and text properties."
1321   (let ((field (widget-field-find from))
1322         (other (widget-field-find to)))
1323     (when field
1324       (unless (eq field other)
1325         (error "Change in different fields"))
1326       (let ((size (widget-get field :size)))
1327         (when size
1328           (let ((begin (widget-field-start field))
1329                 (end (widget-field-end field)))
1330             (cond ((< (- end begin) size)
1331                    ;; Field too small.
1332                    (save-excursion
1333                      (goto-char end)
1334                      (insert-char ?\s (- (+ begin size) end))))
1335                   ((> (- end begin) size)
1336                    ;; Field too large and
1337                    (if (or (< (point) (+ begin size))
1338                            (> (point) end))
1339                        ;; Point is outside extra space.
1340                        (setq begin (+ begin size))
1341                      ;; Point is within the extra space.
1342                      (setq begin (point)))
1343                    (save-excursion
1344                      (goto-char end)
1345                      (while (and (eq (preceding-char) ?\s)
1346                                  (> (point) begin))
1347                        (delete-char -1)))))))
1348         (widget-specify-secret field))
1349       (widget-apply field :notify field))))
1350
1351 ;;; Widget Functions
1352 ;;
1353 ;; These functions are used in the definition of multiple widgets.
1354
1355 (defun widget-parent-action (widget &optional event)
1356   "Tell :parent of WIDGET to handle the :action.
1357 Optional EVENT is the event that triggered the action."
1358   (widget-apply (widget-get widget :parent) :action event))
1359
1360 (defun widget-children-value-delete (widget)
1361   "Delete all :children and :buttons in WIDGET."
1362   (mapc 'widget-delete (widget-get widget :children))
1363   (widget-put widget :children nil)
1364   (mapc 'widget-delete (widget-get widget :buttons))
1365   (widget-put widget :buttons nil))
1366
1367 (defun widget-children-validate (widget)
1368   "All the :children must be valid."
1369   (let ((children (widget-get widget :children))
1370         child found)
1371     (while (and children (not found))
1372       (setq child (car children)
1373             children (cdr children)
1374             found (widget-apply child :validate)))
1375     found))
1376
1377 (defun widget-child-value-get (widget)
1378   "Get the value of the first member of :children in WIDGET."
1379   (widget-value (car (widget-get widget :children))))
1380
1381 (defun widget-child-value-inline (widget)
1382   "Get the inline value of the first member of :children in WIDGET."
1383   (widget-apply (car (widget-get widget :children)) :value-inline))
1384
1385 (defun widget-child-validate (widget)
1386   "The result of validating the first member of :children in WIDGET."
1387   (widget-apply (car (widget-get widget :children)) :validate))
1388
1389 (defun widget-type-value-create (widget)
1390   "Convert and instantiate the value of the :type attribute of WIDGET.
1391 Store the newly created widget in the :children attribute.
1392
1393 The value of the :type attribute should be an unconverted widget type."
1394   (let ((value (widget-get widget :value))
1395         (type (widget-get widget :type)))
1396     (widget-put widget :children
1397                 (list (widget-create-child-value widget
1398                                                  (widget-convert type)
1399                                                  value)))))
1400
1401 (defun widget-type-default-get (widget)
1402   "Get default value from the :type attribute of WIDGET.
1403
1404 The value of the :type attribute should be an unconverted widget type."
1405   (widget-default-get (widget-convert (widget-get widget :type))))
1406
1407 (defun widget-type-match (widget value)
1408   "Non-nil if the :type value of WIDGET matches VALUE.
1409
1410 The value of the :type attribute should be an unconverted widget type."
1411   (widget-apply (widget-convert (widget-get widget :type)) :match value))
1412
1413 (defun widget-types-copy (widget)
1414   "Copy :args as widget types in WIDGET."
1415   (widget-put widget :args (mapcar 'widget-copy (widget-get widget :args)))
1416   widget)
1417
1418 ;; Made defsubst to speed up face editor creation.
1419 (defsubst widget-types-convert-widget (widget)
1420   "Convert :args as widget types in WIDGET."
1421   (widget-put widget :args (mapcar 'widget-convert (widget-get widget :args)))
1422   widget)
1423
1424 (defun widget-value-convert-widget (widget)
1425   "Initialize :value from :args in WIDGET."
1426   (let ((args (widget-get widget :args)))
1427     (when args
1428       (widget-put widget :value (car args))
1429       ;; Don't convert :value here, as this is done in `widget-convert'.
1430       ;; (widget-put widget :value (widget-apply widget
1431       ;;                                      :value-to-internal (car args)))
1432       (widget-put widget :args nil)))
1433   widget)
1434
1435 (defun widget-value-value-get (widget)
1436   "Return the :value property of WIDGET."
1437   (widget-get widget :value))
1438
1439 ;;; The `default' Widget.
1440
1441 (define-widget 'default nil
1442   "Basic widget other widgets are derived from."
1443   :value-to-internal (lambda (_widget value) value)
1444   :value-to-external (lambda (_widget value) value)
1445   :button-prefix 'widget-button-prefix
1446   :button-suffix 'widget-button-suffix
1447   :completions-function #'widget-default-completions
1448   :create 'widget-default-create
1449   :indent nil
1450   :offset 0
1451   :format-handler 'widget-default-format-handler
1452   :button-face-get 'widget-default-button-face-get
1453   :mouse-face-get 'widget-default-mouse-face-get
1454   :sample-face-get 'widget-default-sample-face-get
1455   :delete 'widget-default-delete
1456   :copy 'identity
1457   :value-set 'widget-default-value-set
1458   :value-inline 'widget-default-value-inline
1459   :value-delete 'ignore
1460   :default-get 'widget-default-default-get
1461   :menu-tag-get 'widget-default-menu-tag-get
1462   :validate #'ignore
1463   :active 'widget-default-active
1464   :activate 'widget-specify-active
1465   :deactivate 'widget-default-deactivate
1466   :mouse-down-action #'ignore
1467   :action 'widget-default-action
1468   :notify 'widget-default-notify
1469   :prompt-value 'widget-default-prompt-value)
1470
1471 (defvar widget--completing-widget)
1472
1473 (defun widget-default-completions (widget)
1474   "Return completion data, like `completion-at-point-functions' would."
1475   (let ((completions (widget-get widget :completions)))
1476     (if completions
1477         (list (widget-field-start widget)
1478               (max (point) (widget-field-text-end widget))
1479               completions)
1480       (if (widget-get widget :complete)
1481           (lambda () (widget-apply widget :complete))
1482         (if (widget-get widget :complete-function)
1483             (lambda ()
1484               (let ((widget--completing-widget widget))
1485                 (call-interactively
1486                  (widget-get widget :complete-function)))))))))
1487
1488 (defun widget-default-create (widget)
1489   "Create WIDGET at point in the current buffer."
1490   (widget-specify-insert
1491    (let ((from (point))
1492          button-begin button-end
1493          sample-begin sample-end
1494          doc-begin doc-end
1495          value-pos)
1496      (insert (widget-get widget :format))
1497      (goto-char from)
1498      ;; Parse escapes in format.
1499      (while (re-search-forward "%\\(.\\)" nil t)
1500        (let ((escape (char-after (match-beginning 1))))
1501          (delete-char -2)
1502          (cond ((eq escape ?%)
1503                 (insert ?%))
1504                ((eq escape ?\[)
1505                 (setq button-begin (point))
1506                 (insert (widget-get-indirect widget :button-prefix)))
1507                ((eq escape ?\])
1508                 (insert (widget-get-indirect widget :button-suffix))
1509                 (setq button-end (point)))
1510                ((eq escape ?\{)
1511                 (setq sample-begin (point)))
1512                ((eq escape ?\})
1513                 (setq sample-end (point)))
1514                ((eq escape ?n)
1515                 (when (widget-get widget :indent)
1516                   (insert ?\n)
1517                   (insert-char ?\s (widget-get widget :indent))))
1518                ((eq escape ?t)
1519                 (let ((image (widget-get widget :tag-glyph))
1520                       (tag (widget-get widget :tag)))
1521                   (cond (image
1522                          (widget-image-insert widget (or tag "image") image))
1523                         (tag
1524                          (insert tag))
1525                         (t
1526                          (princ (widget-get widget :value)
1527                                 (current-buffer))))))
1528                ((eq escape ?d)
1529                 (let ((doc (widget-get widget :doc)))
1530                   (when doc
1531                     (setq doc-begin (point))
1532                     (insert doc)
1533                     (while (eq (preceding-char) ?\n)
1534                       (delete-char -1))
1535                     (insert ?\n)
1536                     (setq doc-end (point)))))
1537                ((eq escape ?h)
1538                 (widget-add-documentation-string-button widget))
1539                ((eq escape ?v)
1540                 (if (and button-begin (not button-end))
1541                     (widget-apply widget :value-create)
1542                   (setq value-pos (point))))
1543                (t
1544                 (widget-apply widget :format-handler escape)))))
1545      ;; Specify button, sample, and doc, and insert value.
1546      (and button-begin button-end
1547           (widget-specify-button widget button-begin button-end))
1548      (and sample-begin sample-end
1549           (widget-specify-sample widget sample-begin sample-end))
1550      (and doc-begin doc-end
1551           (widget-specify-doc widget doc-begin doc-end))
1552      (when value-pos
1553        (goto-char value-pos)
1554        (widget-apply widget :value-create)))
1555    (let ((from (point-min-marker))
1556          (to (point-max-marker)))
1557      (set-marker-insertion-type from t)
1558      (set-marker-insertion-type to nil)
1559      (widget-put widget :from from)
1560      (widget-put widget :to to)))
1561   (widget-clear-undo))
1562
1563 (defun widget-default-format-handler (_widget escape)
1564   (error "Unknown escape `%c'" escape))
1565
1566 (defun widget-default-button-face-get (widget)
1567   ;; Use :button-face or widget-button-face
1568   (or (widget-get widget :button-face)
1569       (let ((parent (widget-get widget :parent)))
1570         (if parent
1571             (widget-apply parent :button-face-get)
1572           widget-button-face))))
1573
1574 (defun widget-default-mouse-face-get (widget)
1575   ;; Use :mouse-face or widget-mouse-face
1576   (or (widget-get widget :mouse-face)
1577       (let ((parent (widget-get widget :parent)))
1578         (if parent
1579             (widget-apply parent :mouse-face-get)
1580           widget-mouse-face))))
1581
1582 (defun widget-default-sample-face-get (widget)
1583   ;; Use :sample-face.
1584   (widget-get widget :sample-face))
1585
1586 (defun widget-default-delete (widget)
1587   "Remove widget from the buffer."
1588   (let ((from (widget-get widget :from))
1589         (to (widget-get widget :to))
1590         (inactive-overlay (widget-get widget :inactive))
1591         (button-overlay (widget-get widget :button-overlay))
1592         (sample-overlay (widget-get widget :sample-overlay))
1593         (doc-overlay (widget-get widget :doc-overlay))
1594         (inhibit-modification-hooks t)
1595         (inhibit-read-only t))
1596     (widget-apply widget :value-delete)
1597     (widget-children-value-delete widget)
1598     (when inactive-overlay
1599       (delete-overlay inactive-overlay))
1600     (when button-overlay
1601       (delete-overlay button-overlay))
1602     (when sample-overlay
1603       (delete-overlay sample-overlay))
1604     (when doc-overlay
1605       (delete-overlay doc-overlay))
1606     (when (< from to)
1607       ;; Kludge: this doesn't need to be true for empty formats.
1608       (delete-region from to))
1609     (set-marker from nil)
1610     (set-marker to nil))
1611   (widget-clear-undo))
1612
1613 (defun widget-default-value-set (widget value)
1614   "Recreate widget with new value."
1615   (let* ((old-pos (point))
1616          (from (copy-marker (widget-get widget :from)))
1617          (to (copy-marker (widget-get widget :to)))
1618          (offset (if (and (<= from old-pos) (<= old-pos to))
1619                      (if (>= old-pos (1- to))
1620                          (- old-pos to 1)
1621                        (- old-pos from)))))
1622     ;;??? Bug: this ought to insert the new value before deleting the old one,
1623     ;; so that markers on either side of the value automatically
1624     ;; stay on the same side.  -- rms.
1625     (save-excursion
1626       (goto-char (widget-get widget :from))
1627       (widget-apply widget :delete)
1628       (widget-put widget :value value)
1629       (widget-apply widget :create))
1630     (if offset
1631         (if (< offset 0)
1632             (goto-char (+ (widget-get widget :to) offset 1))
1633           (goto-char (min (+ from offset) (1- (widget-get widget :to))))))))
1634
1635 (defun widget-default-value-inline (widget)
1636   "Wrap value in a list unless it is inline."
1637   (if (widget-get widget :inline)
1638       (widget-value widget)
1639     (list (widget-value widget))))
1640
1641 (defun widget-default-default-get (widget)
1642   "Get `:value'."
1643   (widget-get widget :value))
1644
1645 (defun widget-default-menu-tag-get (widget)
1646   "Use tag or value for menus."
1647   (or (widget-get widget :menu-tag)
1648       (widget-get widget :tag)
1649       (widget-princ-to-string (widget-get widget :value))))
1650
1651 (defun widget-default-active (widget)
1652   "Return t if this widget is active (user modifiable)."
1653   (or (widget-get widget :always-active)
1654       (and (not (widget-get widget :inactive))
1655            (let ((parent (widget-get widget :parent)))
1656              (or (null parent)
1657                  (widget-apply parent :active))))))
1658
1659 (defun widget-default-deactivate (widget)
1660   "Make WIDGET inactive for user modifications."
1661   (widget-specify-inactive widget
1662                            (widget-get widget :from)
1663                            (widget-get widget :to)))
1664
1665 (defun widget-default-action (widget &optional event)
1666   "Notify the parent when a widget changes."
1667   (let ((parent (widget-get widget :parent)))
1668     (when parent
1669       (widget-apply parent :notify widget event))))
1670
1671 (defun widget-default-notify (widget _child &optional event)
1672   "Pass notification to parent."
1673   (widget-default-action widget event))
1674
1675 (defun widget-default-prompt-value (_widget prompt _value _unbound)
1676   "Read an arbitrary value."
1677   (eval-minibuffer prompt))
1678
1679 (defun widget-docstring (widget)
1680   "Return the documentation string specified by WIDGET, or nil if none.
1681 If WIDGET has a `:doc' property, that specifies the documentation string.
1682 Otherwise, try the `:documentation-property' property.  If this
1683 is a function, call it with the widget's value as an argument; if
1684 it is a symbol, use this symbol together with the widget's value
1685 as the argument to `documentation-property'."
1686   (let ((doc (or (widget-get widget :doc)
1687                  (let ((doc-prop (widget-get widget :documentation-property))
1688                        (value (widget-get widget :value)))
1689                    (cond ((functionp doc-prop)
1690                           (funcall doc-prop value))
1691                          ((symbolp doc-prop)
1692                           (documentation-property value doc-prop)))))))
1693     (when (and (stringp doc) (> (length doc) 0))
1694       ;; Remove any redundant `*' in the beginning.
1695       (when (eq (aref doc 0) ?*)
1696         (setq doc (substring doc 1)))
1697       ;; Remove trailing newlines.
1698       (when (string-match "\n+\\'" doc)
1699         (setq doc (substring doc 0 (match-beginning 0))))
1700       doc)))
1701
1702 ;;; The `item' Widget.
1703
1704 (define-widget 'item 'default
1705   "Constant items for inclusion in other widgets."
1706   :convert-widget 'widget-value-convert-widget
1707   :value-create 'widget-item-value-create
1708   :value-delete 'ignore
1709   :value-get 'widget-value-value-get
1710   :match 'widget-item-match
1711   :match-inline 'widget-item-match-inline
1712   :action 'widget-item-action
1713   :format "%t\n")
1714
1715 (defun widget-item-value-create (widget)
1716   "Insert the printed representation of the value."
1717   (princ (widget-get widget :value) (current-buffer)))
1718
1719 (defun widget-item-match (widget value)
1720   ;; Match if the value is the same.
1721   (equal (widget-get widget :value) value))
1722
1723 (defun widget-item-match-inline (widget vals)
1724   ;; Match if the value is the same.
1725   (let ((value (widget-get widget :value)))
1726     (and (listp value)
1727          (<= (length value) (length vals))
1728          (let ((head (widget-sublist vals 0 (length value))))
1729            (and (equal head value)
1730                 (cons head (widget-sublist vals (length value))))))))
1731
1732 (defun widget-sublist (list start &optional end)
1733   "Return the sublist of LIST from START to END.
1734 If END is omitted, it defaults to the length of LIST."
1735   (if (> start 0) (setq list (nthcdr start list)))
1736   (if end
1737       (unless (<= end start)
1738         (setq list (copy-sequence list))
1739         (setcdr (nthcdr (- end start 1) list) nil)
1740         list)
1741     (copy-sequence list)))
1742
1743 (defun widget-item-action (widget &optional event)
1744   ;; Just notify itself.
1745   (widget-apply widget :notify widget event))
1746
1747 ;;; The `push-button' Widget.
1748
1749 ;; (defcustom widget-push-button-gui t
1750 ;;   "If non-nil, use GUI push buttons when available."
1751 ;;   :group 'widgets
1752 ;;   :type 'boolean)
1753
1754 ;; Cache already created GUI objects.
1755 ;; (defvar widget-push-button-cache nil)
1756
1757 (defcustom widget-push-button-prefix "["
1758   "String used as prefix for buttons."
1759   :type 'string
1760   :group 'widget-button)
1761
1762 (defcustom widget-push-button-suffix "]"
1763   "String used as suffix for buttons."
1764   :type 'string
1765   :group 'widget-button)
1766
1767 (define-widget 'push-button 'item
1768   "A pushable button."
1769   :button-prefix ""
1770   :button-suffix ""
1771   :value-create 'widget-push-button-value-create
1772   :format "%[%v%]")
1773
1774 (defun widget-push-button-value-create (widget)
1775   "Insert text representing the `on' and `off' states."
1776   (let* ((tag (or (widget-get widget :tag)
1777                   (widget-get widget :value)))
1778          (tag-glyph (widget-get widget :tag-glyph))
1779          (text (concat widget-push-button-prefix
1780                        tag widget-push-button-suffix)))
1781     (if tag-glyph
1782         (widget-image-insert widget text tag-glyph)
1783       (insert text))))
1784
1785 ;; (defun widget-gui-action (widget)
1786 ;;   "Apply :action for WIDGET."
1787 ;;   (widget-apply-action widget (this-command-keys)))
1788
1789 ;;; The `link' Widget.
1790
1791 (defcustom widget-link-prefix "["
1792   "String used as prefix for links."
1793   :type 'string
1794   :group 'widget-button)
1795
1796 (defcustom widget-link-suffix "]"
1797   "String used as suffix for links."
1798   :type 'string
1799   :group 'widget-button)
1800
1801 (define-widget 'link 'item
1802   "An embedded link."
1803   :button-prefix 'widget-link-prefix
1804   :button-suffix 'widget-link-suffix
1805   :follow-link 'mouse-face
1806   :help-echo "Follow the link."
1807   :format "%[%t%]")
1808
1809 ;;; The `info-link' Widget.
1810
1811 (define-widget 'info-link 'link
1812   "A link to an info file."
1813   :action 'widget-info-link-action)
1814
1815 (defun widget-info-link-action (widget &optional _event)
1816   "Open the info node specified by WIDGET."
1817   (info (widget-value widget)))
1818
1819 ;;; The `url-link' Widget.
1820
1821 (define-widget 'url-link 'link
1822   "A link to an www page."
1823   :action 'widget-url-link-action)
1824
1825 (defun widget-url-link-action (widget &optional _event)
1826   "Open the URL specified by WIDGET."
1827   (browse-url (widget-value widget)))
1828
1829 ;;; The `function-link' Widget.
1830
1831 (define-widget 'function-link 'link
1832   "A link to an Emacs function."
1833   :action 'widget-function-link-action)
1834
1835 (defun widget-function-link-action (widget &optional _event)
1836   "Show the function specified by WIDGET."
1837   (describe-function (widget-value widget)))
1838
1839 ;;; The `variable-link' Widget.
1840
1841 (define-widget 'variable-link 'link
1842   "A link to an Emacs variable."
1843   :action 'widget-variable-link-action)
1844
1845 (defun widget-variable-link-action (widget &optional _event)
1846   "Show the variable specified by WIDGET."
1847   (describe-variable (widget-value widget)))
1848
1849 ;;; The `file-link' Widget.
1850
1851 (define-widget 'file-link 'link
1852   "A link to a file."
1853   :action 'widget-file-link-action)
1854
1855 (defun widget-file-link-action (widget &optional _event)
1856   "Find the file specified by WIDGET."
1857   (find-file (widget-value widget)))
1858
1859 ;;; The `emacs-library-link' Widget.
1860
1861 (define-widget 'emacs-library-link 'link
1862   "A link to an Emacs Lisp library file."
1863   :action 'widget-emacs-library-link-action)
1864
1865 (defun widget-emacs-library-link-action (widget &optional _event)
1866   "Find the Emacs library file specified by WIDGET."
1867   (find-file (locate-library (widget-value widget))))
1868
1869 ;;; The `emacs-commentary-link' Widget.
1870
1871 (define-widget 'emacs-commentary-link 'link
1872   "A link to Commentary in an Emacs Lisp library file."
1873   :action 'widget-emacs-commentary-link-action)
1874
1875 (defun widget-emacs-commentary-link-action (widget &optional _event)
1876   "Find the Commentary section of the Emacs file specified by WIDGET."
1877   (finder-commentary (widget-value widget)))
1878
1879 ;;; The `editable-field' Widget.
1880
1881 (define-widget 'editable-field 'default
1882   "An editable text field.
1883 Note: In an `editable-field' widget, the `%v' escape must be preceded
1884 by some other text in the `:format' string (if specified)."
1885   :convert-widget 'widget-value-convert-widget
1886   :keymap widget-field-keymap
1887   :format "%v"
1888   :help-echo "M-TAB: complete field; RET: enter value"
1889   :value ""
1890   :prompt-internal 'widget-field-prompt-internal
1891   :prompt-history 'widget-field-history
1892   :prompt-value 'widget-field-prompt-value
1893   :action 'widget-field-action
1894   :validate 'widget-field-validate
1895   :valid-regexp ""
1896   :error "Field's value doesn't match allowed forms"
1897   :value-create 'widget-field-value-create
1898   :value-set 'widget-field-value-set
1899   :value-delete 'widget-field-value-delete
1900   :value-get 'widget-field-value-get
1901   :match 'widget-field-match)
1902
1903 (defvar widget-field-history nil
1904   "History of field minibuffer edits.")
1905
1906 (defun widget-field-prompt-internal (_widget prompt initial history)
1907   "Read string for WIDGET prompting with PROMPT.
1908 INITIAL is the initial input and HISTORY is a symbol containing
1909 the earlier input."
1910   (read-string prompt initial history))
1911
1912 (defun widget-field-prompt-value (widget prompt value unbound)
1913   "Prompt for a string."
1914   (widget-apply widget
1915                 :value-to-external
1916                 (widget-apply widget
1917                               :prompt-internal prompt
1918                               (unless unbound
1919                                 (cons (widget-apply widget
1920                                                     :value-to-internal value)
1921                                       0))
1922                               (widget-get widget :prompt-history))))
1923
1924 (defvar widget-edit-functions nil)
1925
1926 (defun widget-field-action (widget &optional _event)
1927   "Move to next field."
1928   (widget-forward 1)
1929   (run-hook-with-args 'widget-edit-functions widget))
1930
1931 (defun widget-field-validate (widget)
1932   "Valid if the content matches `:valid-regexp'."
1933   (unless (string-match (widget-get widget :valid-regexp)
1934                         (widget-apply widget :value-get))
1935     widget))
1936
1937 (defun widget-field-value-set (widget value)
1938   "Set an editable text field WIDGET to VALUE"
1939   (let ((from (widget-field-start widget))
1940         (to (widget-field-text-end widget))
1941         (buffer (widget-field-buffer widget)))
1942     (when (and from to (buffer-live-p buffer))
1943       (with-current-buffer buffer
1944         (goto-char from)
1945         (delete-char (- to from))
1946         (insert value)))))
1947
1948 (defun widget-field-value-create (widget)
1949   "Create an editable text field."
1950   (let ((size (widget-get widget :size))
1951         (value (widget-get widget :value))
1952         (from (point))
1953         ;; This is changed to a real overlay in `widget-setup'.  We
1954         ;; need the end points to behave differently until
1955         ;; `widget-setup' is called.
1956         (overlay (cons (make-marker) (make-marker))))
1957     (widget-put widget :field-overlay overlay)
1958     (insert value)
1959     (and size
1960          (< (length value) size)
1961          (insert-char ?\s (- size (length value))))
1962     (unless (memq widget widget-field-list)
1963       (setq widget-field-new (cons widget widget-field-new)))
1964     (move-marker (cdr overlay) (point))
1965     (set-marker-insertion-type (cdr overlay) nil)
1966     (when (null size)
1967       (insert ?\n))
1968     (move-marker (car overlay) from)
1969     (set-marker-insertion-type (car overlay) t)))
1970
1971 (defun widget-field-value-delete (widget)
1972   "Remove the widget from the list of active editing fields."
1973   (setq widget-field-list (delq widget widget-field-list))
1974   (setq widget-field-new (delq widget widget-field-new))
1975   ;; These are nil if the :format string doesn't contain `%v'.
1976   (let ((overlay (widget-get widget :field-overlay)))
1977     (when (overlayp overlay)
1978       (delete-overlay overlay))))
1979
1980 (defun widget-field-value-get (widget &optional no-truncate)
1981   "Return current text in editing field.
1982 Normally, trailing spaces within the editing field are truncated.
1983 But if NO-TRUNCATE is non-nil, include them."
1984   (let ((from (widget-field-start widget))
1985         (to   (if no-truncate
1986                   (widget-field-end widget)
1987                 (widget-field-text-end widget)))
1988         (buffer (widget-field-buffer widget))
1989         (secret (widget-get widget :secret))
1990         (old (current-buffer)))
1991     (if (and from to)
1992         (progn
1993           (set-buffer buffer)
1994           (let ((result (buffer-substring-no-properties from to)))
1995             (when secret
1996               (let ((index 0))
1997                 (while (< (+ from index) to)
1998                   (aset result index
1999                         (get-char-property (+ from index) 'secret))
2000                   (setq index (1+ index)))))
2001             (set-buffer old)
2002             result))
2003       (widget-get widget :value))))
2004
2005 (defun widget-field-match (_widget value)
2006   ;; Match any string.
2007   (stringp value))
2008
2009 ;;; The `text' Widget.
2010
2011 (define-widget 'text 'editable-field
2012   "A multiline text area."
2013   :keymap widget-text-keymap)
2014
2015 ;;; The `menu-choice' Widget.
2016
2017 (define-widget 'menu-choice 'default
2018   "A menu of options."
2019   :convert-widget  'widget-types-convert-widget
2020   :copy 'widget-types-copy
2021   :format "%[%t%]: %v"
2022   :case-fold t
2023   :tag "choice"
2024   :void '(item :format "invalid (%t)\n")
2025   :value-create 'widget-choice-value-create
2026   :value-get 'widget-child-value-get
2027   :value-inline 'widget-child-value-inline
2028   :default-get 'widget-choice-default-get
2029   :mouse-down-action 'widget-choice-mouse-down-action
2030   :action 'widget-choice-action
2031   :error "Make a choice"
2032   :validate 'widget-choice-validate
2033   :match 'widget-choice-match
2034   :match-inline 'widget-choice-match-inline)
2035
2036 (defun widget-choice-value-create (widget)
2037   "Insert the first choice that matches the value."
2038   (let ((value (widget-get widget :value))
2039         (args (widget-get widget :args))
2040         (explicit (widget-get widget :explicit-choice))
2041         current)
2042     (if explicit
2043         (progn
2044           ;; If the user specified the choice for this value,
2045           ;; respect that choice.
2046           (widget-put widget :children (list (widget-create-child-value
2047                                               widget explicit value)))
2048           (widget-put widget :choice explicit)
2049           (widget-put widget :explicit-choice nil))
2050       (while args
2051         (setq current (car args)
2052               args (cdr args))
2053         (when (widget-apply current :match value)
2054           (widget-put widget :children (list (widget-create-child-value
2055                                               widget current value)))
2056           (widget-put widget :choice current)
2057           (setq args nil
2058                 current nil)))
2059       (when current
2060         (let ((void (widget-get widget :void)))
2061           (widget-put widget :children (list (widget-create-child-and-convert
2062                                               widget void :value value)))
2063           (widget-put widget :choice void))))))
2064
2065 (defun widget-choice-default-get (widget)
2066   ;; Get default for the first choice.
2067   (widget-default-get (car (widget-get widget :args))))
2068
2069 (defcustom widget-choice-toggle nil
2070   "If non-nil, a binary choice will just toggle between the values.
2071 Otherwise, the user will explicitly have to choose between the values
2072 when he invoked the menu."
2073   :type 'boolean
2074   :group 'widgets)
2075
2076 (defun widget-choice-mouse-down-action (widget &optional _event)
2077   ;; Return non-nil if we need a menu.
2078   (let ((args (widget-get widget :args))
2079         (old (widget-get widget :choice)))
2080     (cond ((not (display-popup-menus-p))
2081            ;; No place to pop up a menu.
2082            nil)
2083           ((< (length args) 2)
2084            ;; Empty or singleton list, just return the value.
2085            nil)
2086           ((> (length args) widget-menu-max-size)
2087            ;; Too long, prompt.
2088            nil)
2089           ((> (length args) 2)
2090            ;; Reasonable sized list, use menu.
2091            t)
2092           ((and widget-choice-toggle (memq old args))
2093            ;; We toggle.
2094            nil)
2095           (t
2096            ;; Ask which of the two.
2097            t))))
2098
2099 (defun widget-choice-action (widget &optional event)
2100   ;; Make a choice.
2101   (let ((args (widget-get widget :args))
2102         (old (widget-get widget :choice))
2103         (tag (widget-apply widget :menu-tag-get))
2104         (completion-ignore-case (widget-get widget :case-fold))
2105         this-explicit
2106         current choices)
2107     ;; Remember old value.
2108     (if (and old (not (widget-apply widget :validate)))
2109         (let* ((external (widget-value widget))
2110                (internal (widget-apply old :value-to-internal external)))
2111           (widget-put old :value internal)))
2112     ;; Find new choice.
2113     (setq current
2114           (cond ((= (length args) 0)
2115                  nil)
2116                 ((= (length args) 1)
2117                  (nth 0 args))
2118                 ((and widget-choice-toggle
2119                       (= (length args) 2)
2120                       (memq old args))
2121                  (if (eq old (nth 0 args))
2122                      (nth 1 args)
2123                    (nth 0 args)))
2124                 (t
2125                  (while args
2126                    (setq current (car args)
2127                          args (cdr args))
2128                    (setq choices
2129                          (cons (cons (widget-apply current :menu-tag-get)
2130                                      current)
2131                                choices)))
2132                  (setq this-explicit t)
2133                  (widget-choose tag (reverse choices) event))))
2134     (when current
2135       ;; If this was an explicit user choice, record the choice,
2136       ;; so that widget-choice-value-create will respect it.
2137       (when this-explicit
2138         (widget-put widget :explicit-choice current))
2139       (widget-value-set widget (widget-default-get current))
2140       (widget-setup)
2141       (widget-apply widget :notify widget event)))
2142   (run-hook-with-args 'widget-edit-functions widget))
2143
2144 (defun widget-choice-validate (widget)
2145   ;; Valid if we have made a valid choice.
2146   (if (eq (widget-get widget :void) (widget-get widget :choice))
2147       widget
2148     (widget-apply (car (widget-get widget :children)) :validate)))
2149
2150 (defun widget-choice-match (widget value)
2151   ;; Matches if one of the choices matches.
2152   (let ((args (widget-get widget :args))
2153         current found)
2154     (while (and args (not found))
2155       (setq current (car args)
2156             args (cdr args)
2157             found (widget-apply current :match value)))
2158     found))
2159
2160 (defun widget-choice-match-inline (widget vals)
2161   ;; Matches if one of the choices matches.
2162   (let ((args (widget-get widget :args))
2163         current found)
2164     (while (and args (null found))
2165       (setq current (car args)
2166             args (cdr args)
2167             found (widget-match-inline current vals)))
2168     found))
2169
2170 ;;; The `toggle' Widget.
2171
2172 (define-widget 'toggle 'item
2173   "Toggle between two states."
2174   :format "%[%v%]\n"
2175   :value-create 'widget-toggle-value-create
2176   :action 'widget-toggle-action
2177   :match (lambda (_widget _value) t)
2178   :on "on"
2179   :off "off")
2180
2181 (defun widget-toggle-value-create (widget)
2182   "Insert text representing the `on' and `off' states."
2183   (let* ((val (widget-value widget))
2184          (text (widget-get widget (if val :on :off)))
2185          (img (widget-image-find
2186                (widget-get widget (if val :on-glyph :off-glyph)))))
2187     (widget-image-insert widget (or text "")
2188                          (if img
2189                              (append img '(:ascent center))))))
2190
2191 (defun widget-toggle-action (widget &optional event)
2192   ;; Toggle value.
2193   (widget-value-set widget (not (widget-value widget)))
2194   (widget-apply widget :notify widget event)
2195   (run-hook-with-args 'widget-edit-functions widget))
2196
2197 ;;; The `checkbox' Widget.
2198
2199 (define-widget 'checkbox 'toggle
2200   "A checkbox toggle."
2201   :button-suffix ""
2202   :button-prefix ""
2203   :format "%[%v%]"
2204   :on "[X]"
2205   ;; We could probably do the same job as the images using single
2206   ;; space characters in a boxed face with a stretch specification to
2207   ;; make them square.
2208   :on-glyph "checked"
2209   :off "[ ]"
2210   :off-glyph "unchecked"
2211   :help-echo "Toggle this item."
2212   :action 'widget-checkbox-action)
2213
2214 (defun widget-checkbox-action (widget &optional event)
2215   "Toggle checkbox, notify parent, and set active state of sibling."
2216   (widget-toggle-action widget event)
2217   (let ((sibling (widget-get-sibling widget)))
2218     (when sibling
2219       (if (widget-value widget)
2220           (widget-apply sibling :activate)
2221         (widget-apply sibling :deactivate))
2222       (widget-clear-undo))))
2223
2224 ;;; The `checklist' Widget.
2225
2226 (define-widget 'checklist 'default
2227   "A multiple choice widget."
2228   :convert-widget 'widget-types-convert-widget
2229   :copy 'widget-types-copy
2230   :format "%v"
2231   :offset 4
2232   :entry-format "%b %v"
2233   :greedy nil
2234   :value-create 'widget-checklist-value-create
2235   :value-get 'widget-checklist-value-get
2236   :validate 'widget-checklist-validate
2237   :match 'widget-checklist-match
2238   :match-inline 'widget-checklist-match-inline)
2239
2240 (defun widget-checklist-value-create (widget)
2241   ;; Insert all values
2242   (let ((alist (widget-checklist-match-find widget))
2243         (args  (widget-get widget :args)))
2244     (dolist (item args)
2245       (widget-checklist-add-item widget item (assq item alist)))
2246     (widget-put widget :children (nreverse (widget-get widget :children)))))
2247
2248 (defun widget-checklist-add-item (widget type chosen)
2249   "Create checklist item in WIDGET of type TYPE.
2250 If the item is checked, CHOSEN is a cons whose cdr is the value."
2251   (and (eq (preceding-char) ?\n)
2252        (widget-get widget :indent)
2253        (insert-char ?\s (widget-get widget :indent)))
2254   (widget-specify-insert
2255    (let* ((children (widget-get widget :children))
2256           (buttons (widget-get widget :buttons))
2257           (button-args (or (widget-get type :sibling-args)
2258                            (widget-get widget :button-args)))
2259           (from (point))
2260           child button)
2261      (insert (widget-get widget :entry-format))
2262      (goto-char from)
2263      ;; Parse % escapes in format.
2264      (while (re-search-forward "%\\([bv%]\\)" nil t)
2265        (let ((escape (char-after (match-beginning 1))))
2266          (delete-char -2)
2267          (cond ((eq escape ?%)
2268                 (insert ?%))
2269                ((eq escape ?b)
2270                 (setq button (apply 'widget-create-child-and-convert
2271                                     widget 'checkbox
2272                                     :value (not (null chosen))
2273                                     button-args)))
2274                ((eq escape ?v)
2275                 (setq child
2276                       (cond ((not chosen)
2277                              (let ((child (widget-create-child widget type)))
2278                                (widget-apply child :deactivate)
2279                                child))
2280                             ((widget-get type :inline)
2281                              (widget-create-child-value
2282                               widget type (cdr chosen)))
2283                             (t
2284                              (widget-create-child-value
2285                               widget type (car (cdr chosen)))))))
2286                (t
2287                 (error "Unknown escape `%c'" escape)))))
2288      ;; Update properties.
2289      (and button child (widget-put child :button button))
2290      (and button (widget-put widget :buttons (cons button buttons)))
2291      (and child (widget-put widget :children (cons child children))))))
2292
2293 (defun widget-checklist-match (widget vals)
2294   ;; All values must match a type in the checklist.
2295   (and (listp vals)
2296        (null (cdr (widget-checklist-match-inline widget vals)))))
2297
2298 (defun widget-checklist-match-inline (widget vals)
2299   ;; Find the values which match a type in the checklist.
2300   (let ((greedy (widget-get widget :greedy))
2301         (args (copy-sequence (widget-get widget :args)))
2302         found rest)
2303     (while vals
2304       (let ((answer (widget-checklist-match-up args vals)))
2305         (cond (answer
2306                (let ((vals2 (widget-match-inline answer vals)))
2307                  (setq found (append found (car vals2))
2308                        vals (cdr vals2)
2309                        args (delq answer args))))
2310               (greedy
2311                (setq rest (append rest (list (car vals)))
2312                      vals (cdr vals)))
2313               (t
2314                (setq rest (append rest vals)
2315                      vals nil)))))
2316     (cons found rest)))
2317
2318 (defun widget-checklist-match-find (widget &optional vals)
2319   "Find the vals which match a type in the checklist.
2320 Return an alist of (TYPE MATCH)."
2321   (or vals (setq vals (widget-get widget :value)))
2322   (let ((greedy (widget-get widget :greedy))
2323         (args (copy-sequence (widget-get widget :args)))
2324         found)
2325     (while vals
2326       (let ((answer (widget-checklist-match-up args vals)))
2327         (cond (answer
2328                (let ((match (widget-match-inline answer vals)))
2329                  (setq found (cons (cons answer (car match)) found)
2330                        vals (cdr match)
2331                        args (delq answer args))))
2332               (greedy
2333                (setq vals (cdr vals)))
2334               (t
2335                (setq vals nil)))))
2336     found))
2337
2338 (defun widget-checklist-match-up (args vals)
2339   "Return the first type from ARGS that matches VALS."
2340   (let (current found)
2341     (while (and args (null found))
2342       (setq current (car args)
2343             args (cdr args)
2344             found (widget-match-inline current vals)))
2345     (if found
2346         current)))
2347
2348 (defun widget-checklist-value-get (widget)
2349   ;; The values of all selected items.
2350   (let ((children (widget-get widget :children))
2351         child result)
2352     (while children
2353       (setq child (car children)
2354             children (cdr children))
2355       (if (widget-value (widget-get child :button))
2356           (setq result (append result (widget-apply child :value-inline)))))
2357     result))
2358
2359 (defun widget-checklist-validate (widget)
2360   ;; Ticked children must be valid.
2361   (let ((children (widget-get widget :children))
2362         child button found)
2363     (while (and children (not found))
2364       (setq child (car children)
2365             children (cdr children)
2366             button (widget-get child :button)
2367             found (and (widget-value button)
2368                        (widget-apply child :validate))))
2369     found))
2370
2371 ;;; The `option' Widget
2372
2373 (define-widget 'option 'checklist
2374   "An widget with an optional item."
2375   :inline t)
2376
2377 ;;; The `choice-item' Widget.
2378
2379 (define-widget 'choice-item 'item
2380   "Button items that delegate action events to their parents."
2381   :action 'widget-parent-action
2382   :format "%[%t%] \n")
2383
2384 ;;; The `radio-button' Widget.
2385
2386 (define-widget 'radio-button 'toggle
2387   "A radio button for use in the `radio' widget."
2388   :notify 'widget-radio-button-notify
2389   :format "%[%v%]"
2390   :button-suffix ""
2391   :button-prefix ""
2392   :on "(*)"
2393   :on-glyph "radio1"
2394   :off "( )"
2395   :off-glyph "radio0")
2396
2397 (defun widget-radio-button-notify (widget _child &optional event)
2398   ;; Tell daddy.
2399   (widget-apply (widget-get widget :parent) :action widget event))
2400
2401 ;;; The `radio-button-choice' Widget.
2402
2403 (define-widget 'radio-button-choice 'default
2404   "Select one of multiple options."
2405   :convert-widget 'widget-types-convert-widget
2406   :copy 'widget-types-copy
2407   :offset 4
2408   :format "%v"
2409   :entry-format "%b %v"
2410   :value-create 'widget-radio-value-create
2411   :value-get 'widget-radio-value-get
2412   :value-inline 'widget-radio-value-inline
2413   :value-set 'widget-radio-value-set
2414   :error "You must push one of the buttons"
2415   :validate 'widget-radio-validate
2416   :match 'widget-choice-match
2417   :match-inline 'widget-choice-match-inline
2418   :action 'widget-radio-action)
2419
2420 (defun widget-radio-value-create (widget)
2421   ;; Insert all values
2422   (let ((args (widget-get widget :args))
2423         arg)
2424     (while args
2425       (setq arg (car args)
2426             args (cdr args))
2427       (widget-radio-add-item widget arg))))
2428
2429 (defun widget-radio-add-item (widget type)
2430   "Add to radio widget WIDGET a new radio button item of type TYPE."
2431   ;; (setq type (widget-convert type))
2432   (and (eq (preceding-char) ?\n)
2433        (widget-get widget :indent)
2434        (insert-char ?\s (widget-get widget :indent)))
2435   (widget-specify-insert
2436    (let* ((value (widget-get widget :value))
2437           (children (widget-get widget :children))
2438           (buttons (widget-get widget :buttons))
2439           (button-args (or (widget-get type :sibling-args)
2440                            (widget-get widget :button-args)))
2441           (from (point))
2442           (chosen (and (null (widget-get widget :choice))
2443                        (widget-apply type :match value)))
2444           child button)
2445      (insert (widget-get widget :entry-format))
2446      (goto-char from)
2447      ;; Parse % escapes in format.
2448      (while (re-search-forward "%\\([bv%]\\)" nil t)
2449        (let ((escape (char-after (match-beginning 1))))
2450          (delete-char -2)
2451          (cond ((eq escape ?%)
2452                 (insert ?%))
2453                ((eq escape ?b)
2454                 (setq button (apply 'widget-create-child-and-convert
2455                                     widget 'radio-button
2456                                     :value (not (null chosen))
2457                                     button-args)))
2458                ((eq escape ?v)
2459                 (setq child (if chosen
2460                                 (widget-create-child-value
2461                                  widget type value)
2462                               (widget-create-child widget type)))
2463                 (unless chosen
2464                   (widget-apply child :deactivate)))
2465                (t
2466                 (error "Unknown escape `%c'" escape)))))
2467      ;; Update properties.
2468      (when chosen
2469        (widget-put widget :choice type))
2470      (when button
2471        (widget-put child :button button)
2472        (widget-put widget :buttons (nconc buttons (list button))))
2473      (when child
2474        (widget-put widget :children (nconc children (list child))))
2475      child)))
2476
2477 (defun widget-radio-value-get (widget)
2478   ;; Get value of the child widget.
2479   (let ((chosen (widget-radio-chosen widget)))
2480     (and chosen (widget-value chosen))))
2481
2482 (defun widget-radio-chosen (widget)
2483   "Return the widget representing the chosen radio button."
2484   (let ((children (widget-get widget :children))
2485         current found)
2486     (while children
2487       (setq current (car children)
2488             children (cdr children))
2489       (when (widget-apply (widget-get current :button) :value-get)
2490         (setq found current
2491               children nil)))
2492     found))
2493
2494 (defun widget-radio-value-inline (widget)
2495   ;; Get value of the child widget.
2496   (let ((children (widget-get widget :children))
2497         current found)
2498     (while children
2499       (setq current (car children)
2500             children (cdr children))
2501       (when (widget-apply (widget-get current :button) :value-get)
2502         (setq found (widget-apply current :value-inline)
2503               children nil)))
2504     found))
2505
2506 (defun widget-radio-value-set (widget value)
2507   ;; We can't just delete and recreate a radio widget, since children
2508   ;; can be added after the original creation and won't be recreated
2509   ;; by `:create'.
2510   (let ((children (widget-get widget :children))
2511         current found)
2512     (while children
2513       (setq current (car children)
2514             children (cdr children))
2515       (let* ((button (widget-get current :button))
2516              (match (and (not found)
2517                          (widget-apply current :match value))))
2518         (widget-value-set button match)
2519         (if match
2520             (progn
2521               (widget-value-set current value)
2522               (widget-apply current :activate))
2523           (widget-apply current :deactivate))
2524         (setq found (or found match))))))
2525
2526 (defun widget-radio-validate (widget)
2527   ;; Valid if we have made a valid choice.
2528   (let ((children (widget-get widget :children))
2529         current found button)
2530     (while (and children (not found))
2531       (setq current (car children)
2532             children (cdr children)
2533             button (widget-get current :button)
2534             found (widget-apply button :value-get)))
2535     (if found
2536         (widget-apply current :validate)
2537       widget)))
2538
2539 (defun widget-radio-action (widget child event)
2540   ;; Check if a radio button was pressed.
2541   (let ((children (widget-get widget :children))
2542         (buttons (widget-get widget :buttons))
2543         current)
2544     (when (memq child buttons)
2545       (while children
2546         (setq current (car children)
2547               children (cdr children))
2548         (let* ((button (widget-get current :button)))
2549           (cond ((eq child button)
2550                  (widget-value-set button t)
2551                  (widget-apply current :activate))
2552                 ((widget-value button)
2553                  (widget-value-set button nil)
2554                  (widget-apply current :deactivate)))))))
2555   ;; Pass notification to parent.
2556   (widget-apply widget :notify child event))
2557
2558 ;;; The `insert-button' Widget.
2559
2560 (define-widget 'insert-button 'push-button
2561   "An insert button for the `editable-list' widget."
2562   :tag "INS"
2563   :help-echo "Insert a new item into the list at this position."
2564   :action 'widget-insert-button-action)
2565
2566 (defun widget-insert-button-action (widget &optional _event)
2567   ;; Ask the parent to insert a new item.
2568   (widget-apply (widget-get widget :parent)
2569                 :insert-before (widget-get widget :widget)))
2570
2571 ;;; The `delete-button' Widget.
2572
2573 (define-widget 'delete-button 'push-button
2574   "A delete button for the `editable-list' widget."
2575   :tag "DEL"
2576   :help-echo "Delete this item from the list."
2577   :action 'widget-delete-button-action)
2578
2579 (defun widget-delete-button-action (widget &optional _event)
2580   ;; Ask the parent to insert a new item.
2581   (widget-apply (widget-get widget :parent)
2582                 :delete-at (widget-get widget :widget)))
2583
2584 ;;; The `editable-list' Widget.
2585
2586 ;; (defcustom widget-editable-list-gui nil
2587 ;;   "If non-nil, use GUI push-buttons in editable list when available."
2588 ;;   :type 'boolean
2589 ;;   :group 'widgets)
2590
2591 (define-widget 'editable-list 'default
2592   "A variable list of widgets of the same type."
2593   :convert-widget 'widget-types-convert-widget
2594   :copy 'widget-types-copy
2595   :offset 12
2596   :format "%v%i\n"
2597   :format-handler 'widget-editable-list-format-handler
2598   :entry-format "%i %d %v"
2599   :value-create 'widget-editable-list-value-create
2600   :value-get 'widget-editable-list-value-get
2601   :validate 'widget-children-validate
2602   :match 'widget-editable-list-match
2603   :match-inline 'widget-editable-list-match-inline
2604   :insert-before 'widget-editable-list-insert-before
2605   :delete-at 'widget-editable-list-delete-at)
2606
2607 (defun widget-editable-list-format-handler (widget escape)
2608   ;; We recognize the insert button.
2609     ;; (let ((widget-push-button-gui widget-editable-list-gui))
2610     (cond ((eq escape ?i)
2611            (and (widget-get widget :indent)
2612                 (insert-char ?\s (widget-get widget :indent)))
2613            (apply 'widget-create-child-and-convert
2614                   widget 'insert-button
2615                   (widget-get widget :append-button-args)))
2616           (t
2617            (widget-default-format-handler widget escape)))
2618     ;; )
2619   )
2620
2621 (defun widget-editable-list-value-create (widget)
2622   ;; Insert all values
2623   (let* ((value (widget-get widget :value))
2624          (type (nth 0 (widget-get widget :args)))
2625          children)
2626     (widget-put widget :value-pos (copy-marker (point)))
2627     (set-marker-insertion-type (widget-get widget :value-pos) t)
2628     (while value
2629       (let ((answer (widget-match-inline type value)))
2630         (if answer
2631             (setq children (cons (widget-editable-list-entry-create
2632                                   widget
2633                                   (if (widget-get type :inline)
2634                                       (car answer)
2635                                     (car (car answer)))
2636                                   t)
2637                                  children)
2638                   value (cdr answer))
2639           (setq value nil))))
2640     (widget-put widget :children (nreverse children))))
2641
2642 (defun widget-editable-list-value-get (widget)
2643   ;; Get value of the child widget.
2644   (apply 'append (mapcar (lambda (child) (widget-apply child :value-inline))
2645                          (widget-get widget :children))))
2646
2647 (defun widget-editable-list-match (widget value)
2648   ;; Value must be a list and all the members must match the type.
2649   (and (listp value)
2650        (null (cdr (widget-editable-list-match-inline widget value)))))
2651
2652 (defun widget-editable-list-match-inline (widget value)
2653   (let ((type (nth 0 (widget-get widget :args)))
2654         (ok t)
2655         found)
2656     (while (and value ok)
2657       (let ((answer (widget-match-inline type value)))
2658         (if answer
2659             (setq found (append found (car answer))
2660                   value (cdr answer))
2661           (setq ok nil))))
2662     (cons found value)))
2663
2664 (defun widget-editable-list-insert-before (widget before)
2665   ;; Insert a new child in the list of children.
2666   (save-excursion
2667     (let ((children (widget-get widget :children))
2668           (inhibit-read-only t)
2669           before-change-functions
2670           after-change-functions)
2671       (cond (before
2672              (goto-char (widget-get before :entry-from)))
2673             (t
2674              (goto-char (widget-get widget :value-pos))))
2675       (let ((child (widget-editable-list-entry-create
2676                     widget nil nil)))
2677         (when (< (widget-get child :entry-from) (widget-get widget :from))
2678           (set-marker (widget-get widget :from)
2679                       (widget-get child :entry-from)))
2680         (if (eq (car children) before)
2681             (widget-put widget :children (cons child children))
2682           (while (not (eq (car (cdr children)) before))
2683             (setq children (cdr children)))
2684           (setcdr children (cons child (cdr children)))))))
2685   (widget-setup)
2686   (widget-apply widget :notify widget))
2687
2688 (defun widget-editable-list-delete-at (widget child)
2689   ;; Delete child from list of children.
2690   (save-excursion
2691     (let ((buttons (copy-sequence (widget-get widget :buttons)))
2692           button
2693           (inhibit-read-only t)
2694           before-change-functions
2695           after-change-functions)
2696       (while buttons
2697         (setq button (car buttons)
2698               buttons (cdr buttons))
2699         (when (eq (widget-get button :widget) child)
2700           (widget-put widget
2701                       :buttons (delq button (widget-get widget :buttons)))
2702           (widget-delete button))))
2703     (let ((entry-from (widget-get child :entry-from))
2704           (entry-to (widget-get child :entry-to))
2705           (inhibit-read-only t)
2706           before-change-functions
2707           after-change-functions)
2708       (widget-delete child)
2709       (delete-region entry-from entry-to)
2710       (set-marker entry-from nil)
2711       (set-marker entry-to nil))
2712     (widget-put widget :children (delq child (widget-get widget :children))))
2713   (widget-setup)
2714   (widget-apply widget :notify widget))
2715
2716 (defun widget-editable-list-entry-create (widget value conv)
2717   ;; Create a new entry to the list.
2718   (let ((type (nth 0 (widget-get widget :args)))
2719         ;; (widget-push-button-gui widget-editable-list-gui)
2720         child delete insert)
2721     (widget-specify-insert
2722      (save-excursion
2723        (and (widget-get widget :indent)
2724             (insert-char ?\s (widget-get widget :indent)))
2725        (insert (widget-get widget :entry-format)))
2726      ;; Parse % escapes in format.
2727      (while (re-search-forward "%\\(.\\)" nil t)
2728        (let ((escape (char-after (match-beginning 1))))
2729          (delete-char -2)
2730          (cond ((eq escape ?%)
2731                 (insert ?%))
2732                ((eq escape ?i)
2733                 (setq insert (apply 'widget-create-child-and-convert
2734                                     widget 'insert-button
2735                                     (widget-get widget :insert-button-args))))
2736                ((eq escape ?d)
2737                 (setq delete (apply 'widget-create-child-and-convert
2738                                     widget 'delete-button
2739                                     (widget-get widget :delete-button-args))))
2740                ((eq escape ?v)
2741                 (if conv
2742                     (setq child (widget-create-child-value
2743                                  widget type value))
2744                   (setq child (widget-create-child-value
2745                                widget type (widget-default-get type)))))
2746                (t
2747                 (error "Unknown escape `%c'" escape)))))
2748      (let ((buttons (widget-get widget :buttons)))
2749        (if insert (push insert buttons))
2750        (if delete (push delete buttons))
2751        (widget-put widget :buttons buttons))
2752      (let ((entry-from (point-min-marker))
2753            (entry-to (point-max-marker)))
2754        (set-marker-insertion-type entry-from t)
2755        (set-marker-insertion-type entry-to nil)
2756        (widget-put child :entry-from entry-from)
2757        (widget-put child :entry-to entry-to)))
2758     (if insert (widget-put insert :widget child))
2759     (if delete (widget-put delete :widget child))
2760     child))
2761
2762 ;;; The `group' Widget.
2763
2764 (define-widget 'group 'default
2765   "A widget which groups other widgets inside."
2766   :convert-widget 'widget-types-convert-widget
2767   :copy 'widget-types-copy
2768   :format "%v"
2769   :value-create 'widget-group-value-create
2770   :value-get 'widget-editable-list-value-get
2771   :default-get 'widget-group-default-get
2772   :validate 'widget-children-validate
2773   :match 'widget-group-match
2774   :match-inline 'widget-group-match-inline)
2775
2776 (defun widget-group-value-create (widget)
2777   ;; Create each component.
2778   (let ((args (widget-get widget :args))
2779         (value (widget-get widget :value))
2780         arg answer children)
2781     (while args
2782       (setq arg (car args)
2783             args (cdr args)
2784             answer (widget-match-inline arg value)
2785             value (cdr answer))
2786       (and (eq (preceding-char) ?\n)
2787            (widget-get widget :indent)
2788            (insert-char ?\s (widget-get widget :indent)))
2789       (push (cond ((null answer)
2790                    (widget-create-child widget arg))
2791                   ((widget-get arg :inline)
2792                    (widget-create-child-value widget arg (car answer)))
2793                   (t
2794                    (widget-create-child-value widget arg (car (car answer)))))
2795             children))
2796     (widget-put widget :children (nreverse children))))
2797
2798 (defun widget-group-default-get (widget)
2799   ;; Get the default of the components.
2800   (mapcar 'widget-default-get (widget-get widget :args)))
2801
2802 (defun widget-group-match (widget vals)
2803   ;; Match if the components match.
2804   (and (listp vals)
2805        (let ((match (widget-group-match-inline widget vals)))
2806          (and match (null (cdr match))))))
2807
2808 (defun widget-group-match-inline (widget vals)
2809   ;; Match if the components match.
2810   (let ((args (widget-get widget :args))
2811         argument answer found)
2812     (while args
2813       (setq argument (car args)
2814             args     (cdr args))
2815       (if (setq answer (widget-match-inline argument vals))
2816           (setq found (append found (car answer))
2817                 vals (cdr answer))
2818         (setq vals nil
2819               args nil)))
2820     (if answer
2821         (cons found vals))))
2822
2823 ;;; The `visibility' Widget.
2824
2825 (define-widget 'visibility 'item
2826   "An indicator and manipulator for hidden items.
2827
2828 The following properties have special meanings for this widget:
2829 :on-glyph  Image filename or spec to display when the item is visible.
2830 :on        Text shown if the \"on\" image is nil or cannot be displayed.
2831 :off-glyph Image filename or spec to display when the item is hidden.
2832 :off       Text shown if the \"off\" image is nil cannot be displayed."
2833   :format "%[%v%]"
2834   :button-prefix ""
2835   :button-suffix ""
2836   :on-glyph "down"
2837   :on "Hide"
2838   :off-glyph "right"
2839   :off "Show"
2840   :value-create 'widget-visibility-value-create
2841   :action 'widget-toggle-action
2842   :match (lambda (_widget _value) t))
2843
2844 (defalias 'widget-visibility-value-create 'widget-toggle-value-create)
2845
2846 ;;; The `documentation-link' Widget.
2847 ;;
2848 ;; This is a helper widget for `documentation-string'.
2849
2850 (define-widget 'documentation-link 'link
2851   "Link type used in documentation strings."
2852   :tab-order -1
2853   :help-echo "Describe this symbol"
2854   :action 'widget-documentation-link-action)
2855
2856 (defun widget-documentation-link-action (widget &optional _event)
2857   "Display documentation for WIDGET's value.  Ignore optional argument EVENT."
2858   (let* ((string (widget-get widget :value))
2859          (symbol (intern string)))
2860     (if (and (fboundp symbol) (boundp symbol))
2861         ;; If there are two doc strings, give the user a way to pick one.
2862         (apropos (concat "\\`" (regexp-quote string) "\\'"))
2863       (if (fboundp symbol)
2864           (describe-function symbol)
2865         (describe-variable symbol)))))
2866
2867 (defcustom widget-documentation-links t
2868   "Add hyperlinks to documentation strings when non-nil."
2869   :type 'boolean
2870   :group 'widget-documentation)
2871
2872 (defcustom widget-documentation-link-regexp "`\\([^\n`' ]+\\)'"
2873   "Regexp for matching potential links in documentation strings.
2874 The first group should be the link itself."
2875   :type 'regexp
2876   :group 'widget-documentation)
2877
2878 (defcustom widget-documentation-link-p 'intern-soft
2879   "Predicate used to test if a string is useful as a link.
2880 The value should be a function.  The function will be called with one
2881 argument, a string, and should return non-nil if there should be a
2882 link for that string."
2883   :type 'function
2884   :options '(widget-documentation-link-p)
2885   :group 'widget-documentation)
2886
2887 (defcustom widget-documentation-link-type 'documentation-link
2888   "Widget type used for links in documentation strings."
2889   :type 'symbol
2890   :group 'widget-documentation)
2891
2892 (defun widget-documentation-link-add (widget from to)
2893   (widget-specify-doc widget from to)
2894   (when widget-documentation-links
2895     (let ((regexp widget-documentation-link-regexp)
2896           (buttons (widget-get widget :buttons))
2897           (widget-mouse-face (default-value 'widget-mouse-face))
2898           (widget-button-face widget-documentation-face)
2899           (widget-button-pressed-face widget-documentation-face))
2900       (save-excursion
2901         (goto-char from)
2902         (while (re-search-forward regexp to t)
2903           (let ((name (match-string 1))
2904                 (begin (match-beginning 1))
2905                 (end (match-end 1)))
2906             (when (funcall widget-documentation-link-p name)
2907               (push (widget-convert-button widget-documentation-link-type
2908                                            begin end :value name)
2909                     buttons)))))
2910       (widget-put widget :buttons buttons))))
2911
2912 ;;; The `documentation-string' Widget.
2913
2914 (define-widget 'documentation-string 'item
2915   "A documentation string."
2916   :format "%v"
2917   :action 'widget-documentation-string-action
2918   :value-create 'widget-documentation-string-value-create
2919   :visibility-widget 'visibility)
2920
2921 (defun widget-documentation-string-value-create (widget)
2922   ;; Insert documentation string.
2923   (let ((doc (widget-value widget))
2924         (indent (widget-get widget :indent))
2925         (shown (widget-get (widget-get widget :parent) :documentation-shown))
2926         (start (point)))
2927     (if (string-match "\n" doc)
2928         (let ((before (substring doc 0 (match-beginning 0)))
2929               (after (substring doc (match-end 0)))
2930               button end)
2931           (widget-documentation-string-indent-to indent)
2932           (insert before ?\s)
2933           (widget-documentation-link-add widget start (point))
2934           (setq button
2935                 (widget-create-child-and-convert
2936                  widget (widget-get widget :visibility-widget)
2937                  :help-echo "Show or hide rest of the documentation."
2938                  :on "Hide"
2939                  :off "More"
2940                  :always-active t
2941                  :action 'widget-parent-action
2942                  shown))
2943           (when shown
2944             (insert ?\n)
2945             (setq start (point))
2946             (when (and indent (not (zerop indent)))
2947               (insert-char ?\s indent))
2948             (insert after)
2949             (setq end (point))
2950             (widget-documentation-link-add widget start end)
2951             ;; Indent the subsequent lines.
2952             (when (and indent (> indent 0))
2953               (save-excursion
2954                 (save-restriction
2955                   (narrow-to-region start end)
2956                   (goto-char (point-min))
2957                   (while (search-forward "\n" nil t)
2958                     (widget-documentation-string-indent-to indent))))))
2959           (widget-put widget :buttons (list button)))
2960       (widget-documentation-string-indent-to indent)
2961       (insert doc)
2962       (widget-documentation-link-add widget start (point))))
2963   (insert ?\n))
2964
2965 (defun widget-documentation-string-indent-to (col)
2966   (when (and (numberp col)
2967              (> col 0))
2968     (let ((opoint (point)))
2969       (indent-to col)
2970       (put-text-property opoint (point)
2971                          'display `(space :align-to ,col)))))
2972
2973 (defun widget-documentation-string-action (widget &rest _ignore)
2974   ;; Toggle documentation.
2975   (let ((parent (widget-get widget :parent)))
2976     (widget-put parent :documentation-shown
2977                 (not (widget-get parent :documentation-shown))))
2978   ;; Redraw.
2979   (widget-value-set widget (widget-value widget)))
2980
2981 (defun widget-add-documentation-string-button (widget &rest args)
2982   "Insert a new `documentation-string' widget based on WIDGET.
2983 The new widget becomes a child of WIDGET, and is also added to
2984 its `:buttons' list.  The documentation string is found from
2985 WIDGET using the function `widget-docstring'.
2986 Optional ARGS specifies additional keyword arguments for the
2987 `documentation-string' widget."
2988   (let ((doc (widget-docstring widget))
2989         (indent (widget-get widget :indent))
2990         (doc-indent (widget-get widget :documentation-indent)))
2991     (when doc
2992       (and (eq (preceding-char) ?\n)
2993            indent
2994            (insert-char ?\s indent))
2995       (unless (or (numberp doc-indent) (null doc-indent))
2996         (setq doc-indent 0))
2997       (widget-put widget :buttons
2998                   (cons (apply 'widget-create-child-and-convert
2999                                widget 'documentation-string
3000                                :indent doc-indent
3001                                (nconc args (list doc)))
3002                         (widget-get widget :buttons))))))
3003 \f
3004 ;;; The Sexp Widgets.
3005
3006 (define-widget 'const 'item
3007   "An immutable sexp."
3008   :prompt-value 'widget-const-prompt-value
3009   :format "%t\n%d")
3010
3011 (defun widget-const-prompt-value (widget _prompt _value _unbound)
3012   ;; Return the value of the const.
3013   (widget-value widget))
3014
3015 (define-widget 'function-item 'const
3016   "An immutable function name."
3017   :format "%v\n%h"
3018   :documentation-property (lambda (symbol)
3019                             (condition-case nil
3020                                 (documentation symbol t)
3021                               (error nil))))
3022
3023 (define-widget 'variable-item 'const
3024   "An immutable variable name."
3025   :format "%v\n%h"
3026   :documentation-property 'variable-documentation)
3027
3028 (define-widget 'other 'sexp
3029   "Matches any value, but doesn't let the user edit the value.
3030 This is useful as last item in a `choice' widget.
3031 You should use this widget type with a default value,
3032 as in (other DEFAULT) or (other :tag \"NAME\" DEFAULT).
3033 If the user selects this alternative, that specifies DEFAULT
3034 as the value."
3035   :tag "Other"
3036   :format "%t%n"
3037   :value 'other)
3038
3039 (defvar widget-string-prompt-value-history nil
3040   "History of input to `widget-string-prompt-value'.")
3041
3042 (define-widget 'string 'editable-field
3043   "A string"
3044   :tag "String"
3045   :format "%{%t%}: %v"
3046   :complete-function 'ispell-complete-word
3047   :prompt-history 'widget-string-prompt-value-history)
3048
3049 (define-widget 'regexp 'string
3050   "A regular expression."
3051   :match 'widget-regexp-match
3052   :validate 'widget-regexp-validate
3053   ;; Doesn't work well with terminating newline.
3054   ;; :value-face 'widget-single-line-field
3055   :tag "Regexp")
3056
3057 (defun widget-regexp-match (_widget value)
3058   ;; Match valid regexps.
3059   (and (stringp value)
3060        (condition-case nil
3061            (prog1 t
3062              (string-match value ""))
3063          (error nil))))
3064
3065 (defun widget-regexp-validate (widget)
3066   "Check that the value of WIDGET is a valid regexp."
3067   (condition-case data
3068       (prog1 nil
3069         (string-match (widget-value widget) ""))
3070     (error (widget-put widget :error (error-message-string data))
3071            widget)))
3072
3073 (define-widget 'file 'string
3074   "A file widget.
3075 It reads a file name from an editable text field."
3076   :completions #'completion-file-name-table
3077   :prompt-value 'widget-file-prompt-value
3078   :format "%{%t%}: %v"
3079   ;; Doesn't work well with terminating newline.
3080   ;; :value-face 'widget-single-line-field
3081   :tag "File")
3082
3083 (defun widget-file-prompt-value (widget prompt value unbound)
3084   ;; Read file from minibuffer.
3085   (abbreviate-file-name
3086    (if unbound
3087        (read-file-name prompt)
3088      (let ((prompt2 (format "%s (default %s): " prompt value))
3089            (dir (file-name-directory value))
3090            (file (file-name-nondirectory value))
3091            (must-match (widget-get widget :must-match)))
3092        (read-file-name prompt2 dir nil must-match file)))))
3093
3094 ;;;(defun widget-file-action (widget &optional event)
3095 ;;;  ;; Read a file name from the minibuffer.
3096 ;;;  (let* ((value (widget-value widget))
3097 ;;;      (dir (file-name-directory value))
3098 ;;;      (file (file-name-nondirectory value))
3099 ;;;      (menu-tag (widget-apply widget :menu-tag-get))
3100 ;;;      (must-match (widget-get widget :must-match))
3101 ;;;      (answer (read-file-name (concat menu-tag " (default " value "): ")
3102 ;;;                              dir nil must-match file)))
3103 ;;;    (widget-value-set widget (abbreviate-file-name answer))
3104 ;;;    (widget-setup)
3105 ;;;    (widget-apply widget :notify widget event)))
3106
3107 ;; Fixme: use file-name-as-directory.
3108 (define-widget 'directory 'file
3109   "A directory widget.
3110 It reads a directory name from an editable text field."
3111   :tag "Directory")
3112
3113 (defvar widget-symbol-prompt-value-history nil
3114   "History of input to `widget-symbol-prompt-value'.")
3115
3116 (define-widget 'symbol 'editable-field
3117   "A Lisp symbol."
3118   :value nil
3119   :tag "Symbol"
3120   :format "%{%t%}: %v"
3121   :match (lambda (_widget value) (symbolp value))
3122   :completions obarray
3123   :prompt-internal 'widget-symbol-prompt-internal
3124   :prompt-match 'symbolp
3125   :prompt-history 'widget-symbol-prompt-value-history
3126   :value-to-internal (lambda (_widget value)
3127                        (if (symbolp value)
3128                            (symbol-name value)
3129                          value))
3130   :value-to-external (lambda (_widget value)
3131                        (if (stringp value)
3132                            (intern value)
3133                          value)))
3134
3135 (defun widget-symbol-prompt-internal (widget prompt initial history)
3136   ;; Read file from minibuffer.
3137   (let ((answer (completing-read prompt obarray
3138                                  (widget-get widget :prompt-match)
3139                                  nil initial history)))
3140     (if (and (stringp answer)
3141              (not (zerop (length answer))))
3142         answer
3143       (error "No value"))))
3144
3145 (defvar widget-function-prompt-value-history nil
3146   "History of input to `widget-function-prompt-value'.")
3147
3148 (define-widget 'function 'restricted-sexp
3149   "A Lisp function."
3150   :completions (apply-partially #'completion-table-with-predicate
3151                                 obarray #'fboundp 'strict)
3152   :prompt-value 'widget-field-prompt-value
3153   :prompt-internal 'widget-symbol-prompt-internal
3154   :prompt-match 'fboundp
3155   :prompt-history 'widget-function-prompt-value-history
3156   :action 'widget-field-action
3157   :match-alternatives '(functionp)
3158   :validate (lambda (widget)
3159               (unless (functionp (widget-value widget))
3160                 (widget-put widget :error (format "Invalid function: %S"
3161                                                   (widget-value widget)))
3162                 widget))
3163   :value 'ignore
3164   :tag "Function")
3165
3166 (defvar widget-variable-prompt-value-history nil
3167   "History of input to `widget-variable-prompt-value'.")
3168
3169 (define-widget 'variable 'symbol
3170   "A Lisp variable."
3171   :prompt-match 'boundp
3172   :prompt-history 'widget-variable-prompt-value-history
3173   :completions (apply-partially #'completion-table-with-predicate
3174                                 obarray #'boundp 'strict)
3175   :tag "Variable")
3176
3177 (define-widget 'coding-system 'symbol
3178   "A MULE coding-system."
3179   :format "%{%t%}: %v"
3180   :tag "Coding system"
3181   :base-only nil
3182   :prompt-history 'coding-system-value-history
3183   :prompt-value 'widget-coding-system-prompt-value
3184   :action 'widget-coding-system-action
3185   :completions (apply-partially #'completion-table-with-predicate
3186                                 obarray #'coding-system-p 'strict)
3187   :validate (lambda (widget)
3188               (unless (coding-system-p (widget-value widget))
3189                 (widget-put widget :error (format "Invalid coding system: %S"
3190                                                   (widget-value widget)))
3191                 widget))
3192   :value 'undecided
3193   :prompt-match 'coding-system-p)
3194
3195 (defun widget-coding-system-prompt-value (widget prompt value _unbound)
3196   "Read coding-system from minibuffer."
3197   (if (widget-get widget :base-only)
3198       (intern
3199        (completing-read (format "%s (default %s): " prompt value)
3200                         (mapcar #'list (coding-system-list t)) nil nil nil
3201                         coding-system-history))
3202       (read-coding-system (format "%s (default %s): " prompt value) value)))
3203
3204 (defun widget-coding-system-action (widget &optional event)
3205   (let ((answer
3206          (widget-coding-system-prompt-value
3207           widget
3208           (widget-apply widget :menu-tag-get)
3209           (widget-value widget)
3210           t)))
3211     (widget-value-set widget answer)
3212     (widget-apply widget :notify widget event)
3213     (widget-setup)))
3214 \f
3215 ;;; I'm not sure about what this is good for?  KFS.
3216 (defvar widget-key-sequence-prompt-value-history nil
3217   "History of input to `widget-key-sequence-prompt-value'.")
3218
3219 (defvar widget-key-sequence-default-value [ignore]
3220   "Default value for an empty key sequence.")
3221
3222 (defvar widget-key-sequence-map
3223   (let ((map (make-sparse-keymap)))
3224     (set-keymap-parent map widget-field-keymap)
3225     (define-key map [(control ?q)] 'widget-key-sequence-read-event)
3226     map))
3227
3228 (define-widget 'key-sequence 'restricted-sexp
3229   "A key sequence."
3230   :prompt-value 'widget-field-prompt-value
3231   :prompt-internal 'widget-symbol-prompt-internal
3232 ; :prompt-match 'fboundp   ;; What was this good for?  KFS
3233   :prompt-history 'widget-key-sequence-prompt-value-history
3234   :action 'widget-field-action
3235   :match-alternatives '(stringp vectorp)
3236   :format "%{%t%}: %v"
3237   :validate 'widget-key-sequence-validate
3238   :value-to-internal 'widget-key-sequence-value-to-internal
3239   :value-to-external 'widget-key-sequence-value-to-external
3240   :value widget-key-sequence-default-value
3241   :keymap widget-key-sequence-map
3242   :help-echo "C-q: insert KEY, EVENT, or CODE; RET: enter value"
3243   :tag "Key sequence")
3244
3245 (defun widget-key-sequence-read-event (ev)
3246   (interactive (list
3247                 (let ((inhibit-quit t) quit-flag)
3248                   (read-event "Insert KEY, EVENT, or CODE: "))))
3249   (let ((ev2 (and (memq 'down (event-modifiers ev))
3250                   (read-event)))
3251         (tr (and (keymapp function-key-map)
3252                  (lookup-key function-key-map (vector ev)))))
3253     (when (and (integerp ev)
3254                (or (and (<= ?0 ev) (< ev (+ ?0 (min 10 read-quoted-char-radix))))
3255                    (and (<= ?a (downcase ev))
3256                         (< (downcase ev) (+ ?a -10 (min 36 read-quoted-char-radix))))))
3257       (setq unread-command-events (cons ev unread-command-events)
3258             ev (read-quoted-char (format "Enter code (radix %d)" read-quoted-char-radix))
3259             tr nil)
3260       (if (and (integerp ev) (not (characterp ev)))
3261           (insert (char-to-string ev))))  ;; throw invalid char error
3262     (setq ev (key-description (list ev)))
3263     (when (arrayp tr)
3264       (setq tr (key-description (list (aref tr 0))))
3265       (if (y-or-n-p (format "Key %s is translated to %s -- use %s? " ev tr tr))
3266           (setq ev tr ev2 nil)))
3267     (insert (if (= (char-before) ?\s)  "" " ") ev " ")
3268     (if ev2
3269         (insert (key-description (list ev2)) " "))))
3270
3271 (defun widget-key-sequence-validate (widget)
3272   (unless (or (stringp (widget-value widget))
3273               (vectorp (widget-value widget)))
3274     (widget-put widget :error (format "Invalid key sequence: %S"
3275                                       (widget-value widget)))
3276     widget))
3277
3278 (defun widget-key-sequence-value-to-internal (widget value)
3279   (if (widget-apply widget :match value)
3280       (if (equal value widget-key-sequence-default-value)
3281           ""
3282         (key-description value))
3283     value))
3284
3285 (defun widget-key-sequence-value-to-external (_widget value)
3286   (if (stringp value)
3287       (if (string-match "\\`[[:space:]]*\\'" value)
3288           widget-key-sequence-default-value
3289         (read-kbd-macro value))
3290     value))
3291
3292 \f
3293 (define-widget 'sexp 'editable-field
3294   "An arbitrary Lisp expression."
3295   :tag "Lisp expression"
3296   :format "%{%t%}: %v"
3297   :value nil
3298   :validate 'widget-sexp-validate
3299   :match (lambda (_widget _value) t)
3300   :value-to-internal 'widget-sexp-value-to-internal
3301   :value-to-external (lambda (_widget value) (read value))
3302   :prompt-history 'widget-sexp-prompt-value-history
3303   :prompt-value 'widget-sexp-prompt-value)
3304
3305 (defun widget-sexp-value-to-internal (_widget value)
3306   ;; Use pp for printer representation.
3307   (let ((pp (if (symbolp value)
3308                 (prin1-to-string value)
3309               (pp-to-string value))))
3310     (while (string-match "\n\\'" pp)
3311       (setq pp (substring pp 0 -1)))
3312     (if (or (string-match "\n\\'" pp)
3313             (> (length pp) 40))
3314         (concat "\n" pp)
3315       pp)))
3316
3317 (defun widget-sexp-validate (widget)
3318   ;; Valid if we can read the string and there is no junk left after it.
3319   (with-temp-buffer
3320     (insert (widget-apply widget :value-get))
3321     (goto-char (point-min))
3322     (let (err)
3323       (condition-case data ;Note: We get a spurious byte-compile warning here.
3324           (progn
3325             ;; Avoid a confusing end-of-file error.
3326             (skip-syntax-forward "\\s-")
3327             (if (eobp)
3328                 (setq err "Empty sexp -- use `nil'?")
3329               (unless (widget-apply widget :match (read (current-buffer)))
3330                 (setq err (widget-get widget :type-error))))
3331             ;; Allow whitespace after expression.
3332             (skip-syntax-forward "\\s-")
3333             (if (and (not (eobp))
3334                      (not err))
3335                 (setq err (format "Junk at end of expression: %s"
3336                                   (buffer-substring (point)
3337                                                     (point-max))))))
3338         (end-of-file                    ; Avoid confusing error message.
3339          (setq err "Unbalanced sexp"))
3340         (error (setq err (error-message-string data))))
3341       (if (not err)
3342           nil
3343         (widget-put widget :error err)
3344         widget))))
3345
3346 (defvar widget-sexp-prompt-value-history nil
3347   "History of input to `widget-sexp-prompt-value'.")
3348
3349 (defun widget-sexp-prompt-value (widget prompt value unbound)
3350   ;; Read an arbitrary sexp.
3351   (let ((found (read-string prompt
3352                             (if unbound nil (cons (prin1-to-string value) 0))
3353                             (widget-get widget :prompt-history))))
3354     (let ((answer (read-from-string found)))
3355       (unless (= (cdr answer) (length found))
3356         (error "Junk at end of expression: %s"
3357                (substring found (cdr answer))))
3358       (car answer))))
3359
3360 (define-widget 'restricted-sexp 'sexp
3361   "A Lisp expression restricted to values that match.
3362 To use this type, you must define :match or :match-alternatives."
3363   :type-error "The specified value is not valid"
3364   :match 'widget-restricted-sexp-match
3365   :value-to-internal (lambda (widget value)
3366                        (if (widget-apply widget :match value)
3367                            (prin1-to-string value)
3368                          value)))
3369
3370 (defun widget-restricted-sexp-match (widget value)
3371   (let ((alternatives (widget-get widget :match-alternatives))
3372         matched)
3373     (while (and alternatives (not matched))
3374       (if (cond ((functionp (car alternatives))
3375                  (funcall (car alternatives) value))
3376                 ((and (consp (car alternatives))
3377                       (eq (car (car alternatives)) 'quote))
3378                  (eq value (nth 1 (car alternatives)))))
3379           (setq matched t))
3380       (setq alternatives (cdr alternatives)))
3381     matched))
3382 \f
3383 (define-widget 'integer 'restricted-sexp
3384   "An integer."
3385   :tag "Integer"
3386   :value 0
3387   :type-error "This field should contain an integer"
3388   :match-alternatives '(integerp))
3389
3390 (define-widget 'number 'restricted-sexp
3391   "A number (floating point or integer)."
3392   :tag "Number"
3393   :value 0.0
3394   :type-error "This field should contain a number (floating point or integer)"
3395   :match-alternatives '(numberp))
3396
3397 (define-widget 'float 'restricted-sexp
3398   "A floating point number."
3399   :tag "Floating point number"
3400   :value 0.0
3401   :type-error "This field should contain a floating point number"
3402   :match-alternatives '(floatp))
3403
3404 (define-widget 'character 'editable-field
3405   "A character."
3406   :tag "Character"
3407   :value 0
3408   :size 1
3409   :format "%{%t%}: %v\n"
3410   :valid-regexp "\\`.\\'"
3411   :error "This field should contain a single character"
3412   :value-get (lambda (w) (widget-field-value-get w t))
3413   :value-to-internal (lambda (_widget value)
3414                        (if (stringp value)
3415                            value
3416                          (char-to-string value)))
3417   :value-to-external (lambda (_widget value)
3418                        (if (stringp value)
3419                            (aref value 0)
3420                          value))
3421   :match (lambda (_widget value)
3422            (characterp value)))
3423
3424 (define-widget 'list 'group
3425   "A Lisp list."
3426   :tag "List"
3427   :format "%{%t%}:\n%v")
3428
3429 (define-widget 'vector 'group
3430   "A Lisp vector."
3431   :tag "Vector"
3432   :format "%{%t%}:\n%v"
3433   :match 'widget-vector-match
3434   :value-to-internal (lambda (_widget value) (append value nil))
3435   :value-to-external (lambda (_widget value) (apply 'vector value)))
3436
3437 (defun widget-vector-match (widget value)
3438   (and (vectorp value)
3439        (widget-group-match widget
3440                            (widget-apply widget :value-to-internal value))))
3441
3442 (define-widget 'cons 'group
3443   "A cons-cell."
3444   :tag "Cons-cell"
3445   :format "%{%t%}:\n%v"
3446   :match 'widget-cons-match
3447   :value-to-internal (lambda (_widget value)
3448                        (list (car value) (cdr value)))
3449   :value-to-external (lambda (_widget value)
3450                        (apply 'cons value)))
3451
3452 (defun widget-cons-match (widget value)
3453   (and (consp value)
3454        (widget-group-match widget
3455                            (widget-apply widget :value-to-internal value))))
3456 \f
3457 ;;; The `lazy' Widget.
3458 ;;
3459 ;; Recursive datatypes.
3460
3461 (define-widget 'lazy 'default
3462   "Base widget for recursive datastructures.
3463
3464 The `lazy' widget will, when instantiated, contain a single inferior
3465 widget, of the widget type specified by the :type parameter.  The
3466 value of the `lazy' widget is the same as the value of the inferior
3467 widget.  When deriving a new widget from the 'lazy' widget, the :type
3468 parameter is allowed to refer to the widget currently being defined,
3469 thus allowing recursive datastructures to be described.
3470
3471 The :type parameter takes the same arguments as the defcustom
3472 parameter with the same name.
3473
3474 Most composite widgets, i.e. widgets containing other widgets, does
3475 not allow recursion.  That is, when you define a new widget type, none
3476 of the inferior widgets may be of the same type you are currently
3477 defining.
3478
3479 In Lisp, however, it is custom to define datastructures in terms of
3480 themselves.  A list, for example, is defined as either nil, or a cons
3481 cell whose cdr itself is a list.  The obvious way to translate this
3482 into a widget type would be
3483
3484   (define-widget 'my-list 'choice
3485     \"A list of sexps.\"
3486     :tag \"Sexp list\"
3487     :args '((const nil) (cons :value (nil) sexp my-list)))
3488
3489 Here we attempt to define my-list as a choice of either the constant
3490 nil, or a cons-cell containing a sexp and my-lisp.  This will not work
3491 because the `choice' widget does not allow recursion.
3492
3493 Using the `lazy' widget you can overcome this problem, as in this
3494 example:
3495
3496   (define-widget 'sexp-list 'lazy
3497     \"A list of sexps.\"
3498     :tag \"Sexp list\"
3499     :type '(choice (const nil) (cons :value (nil) sexp sexp-list)))"
3500   :format "%{%t%}: %v"
3501   ;; We don't convert :type because we want to allow recursive
3502   ;; datastructures.  This is slow, so we should not create speed
3503   ;; critical widgets by deriving from this.
3504   :convert-widget 'widget-value-convert-widget
3505   :value-create 'widget-type-value-create
3506   :value-get 'widget-child-value-get
3507   :value-inline 'widget-child-value-inline
3508   :default-get 'widget-type-default-get
3509   :match 'widget-type-match
3510   :validate 'widget-child-validate)
3511
3512 \f
3513 ;;; The `plist' Widget.
3514 ;;
3515 ;; Property lists.
3516
3517 (define-widget 'plist 'list
3518   "A property list."
3519   :key-type '(symbol :tag "Key")
3520   :value-type '(sexp :tag "Value")
3521   :convert-widget 'widget-plist-convert-widget
3522   :tag "Plist")
3523
3524 (defvar widget-plist-value-type)        ;Dynamic variable
3525
3526 (defun widget-plist-convert-widget (widget)
3527   ;; Handle `:options'.
3528   (let* ((options (widget-get widget :options))
3529          (widget-plist-value-type (widget-get widget :value-type))
3530          (other `(editable-list :inline t
3531                                 (group :inline t
3532                                        ,(widget-get widget :key-type)
3533                                        ,widget-plist-value-type)))
3534          (args (if options
3535                    (list `(checklist :inline t
3536                                      :greedy t
3537                                      ,@(mapcar 'widget-plist-convert-option
3538                                                options))
3539                          other)
3540                  (list other))))
3541     (widget-put widget :args args)
3542     widget))
3543
3544 (defun widget-plist-convert-option (option)
3545   ;; Convert a single plist option.
3546   (let (key-type value-type)
3547     (if (listp option)
3548         (let ((key (nth 0 option)))
3549           (setq value-type (nth 1 option))
3550           (if (listp key)
3551               (setq key-type key)
3552             (setq key-type `(const ,key))))
3553       (setq key-type `(const ,option)
3554             value-type widget-plist-value-type))
3555     `(group :format "Key: %v" :inline t ,key-type ,value-type)))
3556
3557
3558 ;;; The `alist' Widget.
3559 ;;
3560 ;; Association lists.
3561
3562 (define-widget 'alist 'list
3563   "An association list."
3564   :key-type '(sexp :tag "Key")
3565   :value-type '(sexp :tag "Value")
3566   :convert-widget 'widget-alist-convert-widget
3567   :tag "Alist")
3568
3569 (defvar widget-alist-value-type)        ;Dynamic variable
3570
3571 (defun widget-alist-convert-widget (widget)
3572   ;; Handle `:options'.
3573   (let* ((options (widget-get widget :options))
3574          (widget-alist-value-type (widget-get widget :value-type))
3575          (other `(editable-list :inline t
3576                                 (cons :format "%v"
3577                                       ,(widget-get widget :key-type)
3578                                       ,widget-alist-value-type)))
3579          (args (if options
3580                    (list `(checklist :inline t
3581                                      :greedy t
3582                                      ,@(mapcar 'widget-alist-convert-option
3583                                                options))
3584                          other)
3585                  (list other))))
3586     (widget-put widget :args args)
3587     widget))
3588
3589 (defun widget-alist-convert-option (option)
3590   ;; Convert a single alist option.
3591   (let (key-type value-type)
3592     (if (listp option)
3593         (let ((key (nth 0 option)))
3594           (setq value-type (nth 1 option))
3595           (if (listp key)
3596               (setq key-type key)
3597             (setq key-type `(const ,key))))
3598       (setq key-type `(const ,option)
3599             value-type widget-alist-value-type))
3600     `(cons :format "Key: %v" ,key-type ,value-type)))
3601 \f
3602 (define-widget 'choice 'menu-choice
3603   "A union of several sexp types."
3604   :tag "Choice"
3605   :format "%{%t%}: %[Value Menu%] %v"
3606   :button-prefix 'widget-push-button-prefix
3607   :button-suffix 'widget-push-button-suffix
3608   :prompt-value 'widget-choice-prompt-value)
3609
3610 (defun widget-choice-prompt-value (widget prompt value _unbound)
3611   "Make a choice."
3612   (let ((args (widget-get widget :args))
3613         (completion-ignore-case (widget-get widget :case-fold))
3614         current choices old)
3615     ;; Find the first arg that matches VALUE.
3616     (let ((look args))
3617       (while look
3618         (if (widget-apply (car look) :match value)
3619             (setq old (car look)
3620                   look nil)
3621           (setq look (cdr look)))))
3622     ;; Find new choice.
3623     (setq current
3624           (cond ((= (length args) 0)
3625                  nil)
3626                 ((= (length args) 1)
3627                  (nth 0 args))
3628                 ((and (= (length args) 2)
3629                       (memq old args))
3630                  (if (eq old (nth 0 args))
3631                      (nth 1 args)
3632                    (nth 0 args)))
3633                 (t
3634                  (while args
3635                    (setq current (car args)
3636                          args (cdr args))
3637                    (setq choices
3638                          (cons (cons (widget-apply current :menu-tag-get)
3639                                      current)
3640                                choices)))
3641                  (let ((val (completing-read prompt choices nil t)))
3642                    (if (stringp val)
3643                        (let ((try (try-completion val choices)))
3644                          (when (stringp try)
3645                            (setq val try))
3646                          (cdr (assoc val choices)))
3647                      nil)))))
3648     (if current
3649         (widget-prompt-value current prompt nil t)
3650       value)))
3651 \f
3652 (define-widget 'radio 'radio-button-choice
3653   "A union of several sexp types."
3654   :tag "Choice"
3655   :format "%{%t%}:\n%v"
3656   :prompt-value 'widget-choice-prompt-value)
3657
3658 (define-widget 'repeat 'editable-list
3659   "A variable length homogeneous list."
3660   :tag "Repeat"
3661   :format "%{%t%}:\n%v%i\n")
3662
3663 (define-widget 'set 'checklist
3664   "A list of members from a fixed set."
3665   :tag "Set"
3666   :format "%{%t%}:\n%v")
3667
3668 (define-widget 'boolean 'toggle
3669   "To be nil or non-nil, that is the question."
3670   :tag "Boolean"
3671   :prompt-value 'widget-boolean-prompt-value
3672   :button-prefix 'widget-push-button-prefix
3673   :button-suffix 'widget-push-button-suffix
3674   :format "%{%t%}: %[Toggle%]  %v\n"
3675   :on "on (non-nil)"
3676   :off "off (nil)")
3677
3678 (defun widget-boolean-prompt-value (_widget prompt _value _unbound)
3679   ;; Toggle a boolean.
3680   (y-or-n-p prompt))
3681 \f
3682 ;;; The `color' Widget.
3683
3684 ;; Fixme: match
3685 (define-widget 'color 'editable-field
3686   "Choose a color name (with sample)."
3687   :format "%{%t%}: %v (%{sample%})\n"
3688   :value-create 'widget-color-value-create
3689   :size 10
3690   :tag "Color"
3691   :value "black"
3692   :completions (or facemenu-color-alist (defined-colors))
3693   :sample-face-get 'widget-color-sample-face-get
3694   :notify 'widget-color-notify
3695   :action 'widget-color-action)
3696
3697 (defun widget-color-value-create (widget)
3698   (widget-field-value-create widget)
3699   (widget-insert " ")
3700   (widget-create-child-and-convert
3701    widget 'push-button
3702    :tag " Choose " :action 'widget-color--choose-action)
3703   (widget-insert " "))
3704
3705 (defun widget-color--choose-action (widget &optional _event)
3706   (list-colors-display
3707    nil nil
3708    `(lambda (color)
3709       (when (buffer-live-p ,(current-buffer))
3710         (widget-value-set ',(widget-get widget :parent) color)
3711         (let* ((buf (get-buffer "*Colors*"))
3712                (win (get-buffer-window buf 0)))
3713           (bury-buffer buf)
3714           (and win (> (length (window-list)) 1)
3715                (delete-window win)))
3716         (pop-to-buffer ,(current-buffer))))))
3717
3718 (defun widget-color-sample-face-get (widget)
3719   (let* ((value (condition-case nil
3720                     (widget-value widget)
3721                   (error (widget-get widget :value)))))
3722     (if (color-defined-p value)
3723         (list (cons 'foreground-color value))
3724       'default)))
3725
3726 (defun widget-color-action (widget &optional event)
3727   "Prompt for a color."
3728   (let* ((tag (widget-apply widget :menu-tag-get))
3729          (prompt (concat tag ": "))
3730          (answer (facemenu-read-color prompt)))
3731     (unless (zerop (length answer))
3732       (widget-value-set widget answer)
3733       (widget-setup)
3734       (widget-apply widget :notify widget event))))
3735
3736 (defun widget-color-notify (widget child &optional event)
3737   "Update the sample, and notify the parent."
3738   (overlay-put (widget-get widget :sample-overlay)
3739                'face (widget-apply widget :sample-face-get))
3740   (widget-default-notify widget child event))
3741 \f
3742 ;;; The Help Echo
3743
3744 (defun widget-echo-help (pos)
3745   "Display help-echo text for widget at POS."
3746   (let* ((widget (widget-at pos))
3747          (help-echo (and widget (widget-get widget :help-echo))))
3748     (if (functionp help-echo)
3749         (setq help-echo (funcall help-echo widget)))
3750     (if help-echo (message "%s" (eval help-echo)))))
3751
3752 ;;; The End:
3753
3754 (provide 'wid-edit)
3755
3756 ;;; wid-edit.el ends here