--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/lisp/custom/widget-edit.el	Mon Aug 13 08:49:43 2007 +0200
@@ -0,0 +1,2202 @@
+;;; widget-edit.el --- Functions for creating and using widgets.
+;;
+;; Copyright (C) 1996 Free Software Foundation, Inc.
+;;
+;; Author: Per Abrahamsen <abraham@dina.kvl.dk>
+;; Keywords: extensions
+;; Version: 1.24
+;; X-URL: http://www.dina.kvl.dk/~abraham/custom/
+
+;;; Commentary:
+;;
+;; See `widget.el'.
+
+;;; Code:
+
+(require 'widget)
+(require 'cl)
+(autoload 'pp-to-string "pp")
+(autoload 'Info-goto-node "info")
+
+(if (string-match "XEmacs" emacs-version)
+    ;; XEmacs spell `intangible' as `atomic'.
+    (defun widget-make-intangible (from to side)
+      "Make text between FROM and TO atomic with regard to movement.
+Third argument should be `start-open' if it should be sticky to the rear,
+and `end-open' if it should sticky to the front."
+      (require 'atomic-extents)
+      (let ((ext (make-extent from to)))
+	 ;; XEmacs doesn't understant different kinds of read-only, so
+	 ;; we have to use extents instead.  
+	(put-text-property from to 'read-only nil)
+	(set-extent-property ext 'read-only t)
+	(set-extent-property ext 'start-open nil)
+	(set-extent-property ext 'end-open nil)
+	(set-extent-property ext side t)
+	(set-extent-property ext 'atomic t)))
+  (defun widget-make-intangible (from to size)
+    "Make text between FROM and TO intangible."
+    (put-text-property from to 'intangible 'front)))
+	  
+;; The following should go away when bundled with Emacs.
+(eval-and-compile
+  (condition-case ()
+      (require 'custom)
+    (error nil))
+
+  (unless (and (featurep 'custom) (fboundp 'custom-declare-variable))
+    ;; We have the old custom-library, hack around it!
+    (defmacro defgroup (&rest args) nil)
+    (defmacro defcustom (&rest args) nil)
+    (defmacro defface (&rest args) nil)
+    (when (fboundp 'copy-face)
+      (copy-face 'default 'widget-documentation-face)
+      (copy-face 'bold 'widget-button-face)
+      (copy-face 'italic 'widget-field-face))
+    (defvar widget-mouse-face 'highlight)
+    (defvar widget-menu-max-size 40)))
+
+;;; Compatibility.
+
+(unless (fboundp 'event-point)
+  ;; XEmacs function missing in Emacs.
+  (defun event-point (event)
+    "Return the character position of the given mouse-motion, button-press,
+or button-release event.  If the event did not occur over a window, or did
+not occur over text, then this returns nil.  Otherwise, it returns an index
+into the buffer visible in the event's window."
+    (posn-point (event-start event))))
+
+(unless (fboundp 'error-message-string)
+  ;; Emacs function missing in XEmacs.
+  (defun error-message-string (obj)
+    "Convert an error value to an error message."
+    (let ((buf (get-buffer-create " *error-message*")))
+      (erase-buffer buf)
+      (display-error obj buf)
+      (buffer-string buf))))
+
+;;; Customization.
+
+(defgroup widgets nil
+  "Customization support for the Widget Library."
+  :link '(custom-manual "(widget)Top")
+  :link '(url-link :tag "Development Page" 
+		   "http://www.dina.kvl.dk/~abraham/custom/")
+  :prefix "widget-"
+  :group 'emacs)
+
+(defface widget-documentation-face '((((class color)
+				       (background dark))
+				      (:foreground "lime green"))
+				     (((class color)
+				       (background light))
+				      (:foreground "dark green"))
+				     (t nil))
+  "Face used for documentation text."
+  :group 'widgets)
+
+(defface widget-button-face '((t (:bold t)))
+  "Face used for widget buttons."
+  :group 'widgets)
+
+(defcustom widget-mouse-face 'highlight
+  "Face used for widget buttons when the mouse is above them."
+  :type 'face
+  :group 'widgets)
+
+(defface widget-field-face '((((class grayscale color)
+			       (background light))
+			      (:background "light gray"))
+			     (((class grayscale color)
+			       (background dark))
+			      (:background "dark gray"))
+			     (t 
+			      (:italic t)))
+  "Face used for editable fields."
+  :group 'widgets)
+
+(defcustom widget-menu-max-size 40
+  "Largest number of items allowed in a popup-menu.
+Larger menus are read through the minibuffer."
+  :group 'widgets
+  :type 'integer)
+
+;;; Utility functions.
+;;
+;; These are not really widget specific.
+
+(defun widget-plist-member (plist prop)
+  ;; Return non-nil if PLIST has the property PROP.
+  ;; PLIST is a property list, which is a list of the form
+  ;; (PROP1 VALUE1 PROP2 VALUE2 ...).  PROP is a symbol.
+  ;; Unlike `plist-get', this allows you to distinguish between a missing
+  ;; property and a property with the value nil.
+  ;; The value is actually the tail of PLIST whose car is PROP.
+  (while (and plist (not (eq (car plist) prop)))
+    (setq plist (cdr (cdr plist))))
+  plist)
+
+(defun widget-princ-to-string (object)
+  ;; Return string representation of OBJECT, any Lisp object.
+  ;; No quoting characters are used; no delimiters are printed around
+  ;; the contents of strings.
+  (save-excursion
+    (set-buffer (get-buffer-create " *widget-tmp*"))
+    (erase-buffer)
+    (let ((standard-output (current-buffer)))
+      (princ object))
+    (buffer-string)))
+
+(defun widget-clear-undo ()
+  "Clear all undo information."
+  (buffer-disable-undo (current-buffer))
+  (buffer-enable-undo))
+
+(defun widget-choose (title items &optional event)
+  "Choose an item from a list.
+
+First argument TITLE is the name of the list.
+Second argument ITEMS is an alist (NAME . VALUE).
+Optional third argument EVENT is an input event.
+
+The user is asked to choose between each NAME from the items alist,
+and the VALUE of the chosen element will be returned.  If EVENT is a
+mouse event, and the number of elements in items is less than
+`widget-menu-max-size', a popup menu will be used, otherwise the
+minibuffer."
+  (cond ((and (< (length items) widget-menu-max-size)
+	      event (fboundp 'x-popup-menu) window-system)
+	 ;; We are in Emacs-19, pressed by the mouse
+	 (x-popup-menu event
+		       (list title (cons "" items))))
+	((and (< (length items) widget-menu-max-size)
+	      event (fboundp 'popup-menu) window-system)
+	 ;; We are in XEmacs, pressed by the mouse
+	 (let ((val (get-popup-menu-response
+		     (cons ""
+			   (mapcar
+			    (function
+			     (lambda (x)
+			       (vector (car x) (list (car x)) t)))
+			    items)))))
+	   (setq val (and val
+			  (listp (event-object val))
+			  (stringp (car-safe (event-object val)))
+			  (car (event-object val))))
+	   (cdr (assoc val items))))
+	(t
+	 (cdr (assoc (completing-read (concat title ": ")
+				      items nil t)
+		     items)))))
+
+;;; Widget text specifications.
+;; 
+;; These functions are for specifying text properties. 
+
+(defun widget-specify-none (from to)
+  ;; Clear all text properties between FROM and TO.
+  (set-text-properties from to nil))
+
+(defun widget-specify-text (from to)
+  ;; Default properties.
+  (add-text-properties from to (list 'read-only t
+				     'front-sticky t
+				     'start-open t
+				     'end-open t
+				     'rear-nonsticky nil)))
+
+(defun widget-specify-field (widget from to)
+  ;; Specify editable button for WIDGET between FROM and TO.
+  (widget-specify-field-update widget from to)
+
+  ;; Make it possible to edit the front end of the field.
+  (add-text-properties (1- from) from (list 'rear-nonsticky t
+					    'end-open t
+					    'invisible t))
+  (when (or (string-match "\\(.\\|\n\\)%v" (widget-get widget :format))
+	    (widget-get widget :hide-front-space))
+    ;; WARNING: This is going to lose horrible if the character just
+    ;; before the field can be modified (e.g. if it belongs to a
+    ;; choice widget).  We try to compensate by checking the format
+    ;; string, and hope the user hasn't changed the :create method.
+    (widget-make-intangible (- from 2) from 'end-open))
+  
+  ;; Make it possible to edit back end of the field.
+  (add-text-properties to (1+ to) (list 'front-sticky nil
+					'read-only t
+					'start-open t))
+
+  (cond ((widget-get widget :size)
+	 (put-text-property to (1+ to) 'invisible t)
+	 (when (or (string-match "%v\\(.\\|\n\\)" (widget-get widget :format))
+		   (widget-get widget :hide-rear-space))
+	   ;; WARNING: This is going to lose horrible if the character just
+	   ;; after the field can be modified (e.g. if it belongs to a
+	   ;; choice widget).  We try to compensate by checking the format
+	   ;; string, and hope the user hasn't changed the :create method.
+	   (widget-make-intangible to (+ to 2) 'start-open)))
+	((string-match "XEmacs" emacs-version)
+	 ;; XEmacs does not allow you to insert before a read-only
+	 ;; character, even if it is start.open.
+	 ;; XEmacs does allow you to delete an read-only extent, so
+	 ;; making the terminating newline read only doesn't help.
+	 ;; I tried putting an invisible intangible read-only space
+	 ;; before the newline, which gave really weird effects.
+	 ;; So for now, we just have trust the user not to delete the
+	 ;; newline.  
+	 (put-text-property to (1+ to) 'read-only nil))))
+
+(defun widget-specify-field-update (widget from to)
+  ;; Specify editable button for WIDGET between FROM and TO.
+  (let ((map (widget-get widget :keymap))
+	(secret (widget-get widget :secret))
+	(secret-to to)
+	(size (widget-get widget :size))
+	(face (or (widget-get widget :value-face)
+		  'widget-field-face)))
+
+    (when secret 
+      (while (and size
+		  (not (zerop size))
+		  (> secret-to from)
+		  (eq (char-after (1- secret-to)) ?\ ))
+	(setq secret-to (1- secret-to)))
+
+      (save-excursion
+	(goto-char from)
+	(while (< (point) secret-to)
+	  (let ((old (get-text-property (point) 'secret)))
+	    (when old
+	      (subst-char-in-region (point) (1+ (point)) secret old)))
+	  (forward-char))))
+
+    (set-text-properties from to (list 'field widget
+				       'read-only nil
+				       'keymap map
+				       'local-map map
+				       'face face))
+
+    (when secret 
+      (save-excursion
+	(goto-char from)
+	(while (< (point) secret-to)
+	  (let ((old (following-char)))
+	    (subst-char-in-region (point) (1+ (point)) old secret)
+	    (put-text-property (point) (1+ (point)) 'secret old))
+	  (forward-char))))
+
+    (unless (widget-get widget :size)
+      (add-text-properties to (1+ to) (list 'field widget
+					    'face face
+					    'local-map map
+					    'keymap map)))))
+
+(defun widget-specify-button (widget from to)
+  ;; Specify button for WIDGET between FROM and TO.
+  (let ((face (widget-apply widget :button-face-get)))
+    (add-text-properties from to (list 'button widget
+				       'mouse-face widget-mouse-face
+				       'start-open t
+				       'end-open t
+				       'face face))))
+
+(defun widget-specify-sample (widget from to)
+  ;; Specify sample for WIDGET between FROM and TO.
+  (let ((face (widget-apply widget :sample-face-get)))
+    (when face
+      (add-text-properties from to (list 'start-open t
+					 'end-open t
+					 'face face)))))
+
+(defun widget-specify-doc (widget from to)
+  ;; Specify documentation for WIDGET between FROM and TO.
+  (add-text-properties from to (list 'widget-doc widget
+				     'face 'widget-documentation-face)))
+
+(defmacro widget-specify-insert (&rest form)
+  ;; Execute FORM without inheriting any text properties.
+  `(save-restriction
+     (let ((inhibit-read-only t)
+	   result
+	   after-change-functions)
+       (insert "<>")
+       (narrow-to-region (- (point) 2) (point))
+       (widget-specify-none (point-min) (point-max))
+       (goto-char (1+ (point-min)))
+       (setq result (progn ,@form))
+       (delete-region (point-min) (1+ (point-min)))
+       (delete-region (1- (point-max)) (point-max))
+       (goto-char (point-max))
+       result)))
+
+;;; Widget Properties.
+
+(defun widget-put (widget property value)
+  "In WIDGET set PROPERTY to VALUE.
+The value can later be retrived with `widget-get'."
+  (setcdr widget (plist-put (cdr widget) property value)))
+
+(defun widget-get (widget property)
+  "In WIDGET, get the value of PROPERTY.
+The value could either be specified when the widget was created, or
+later with `widget-put'."
+  (cond ((widget-plist-member (cdr widget) property)
+	 (plist-get (cdr widget) property))
+	((car widget)
+	 (widget-get (get (car widget) 'widget-type) property))
+	(t nil)))
+
+(defun widget-member (widget property)
+  "Non-nil iff there is a definition in WIDGET for PROPERTY."
+  (cond ((widget-plist-member (cdr widget) property)
+	 t)
+	((car widget)
+	 (widget-member (get (car widget) 'widget-type) property))
+	(t nil)))
+
+(defun widget-apply (widget property &rest args)
+  "Apply the value of WIDGET's PROPERTY to the widget itself.
+ARGS are passed as extra argments to the function."
+  (apply (widget-get widget property) widget args))
+
+(defun widget-value (widget)
+  "Extract the current value of WIDGET."
+  (widget-apply widget
+		:value-to-external (widget-apply widget :value-get)))
+
+(defun widget-value-set (widget value)
+  "Set the current value of WIDGET to VALUE."
+  (widget-apply widget
+		:value-set (widget-apply widget
+					 :value-to-internal value)))
+
+(defun widget-match-inline (widget vals)
+  ;; In WIDGET, match the start of VALS.
+  (cond ((widget-get widget :inline)
+	 (widget-apply widget :match-inline vals))
+	((and vals
+	      (widget-apply widget :match (car vals)))
+	 (cons (list (car vals)) (cdr vals)))
+	(t nil)))
+
+;;; Creating Widgets.
+
+;;;###autoload
+(defun widget-create (type &rest args)
+  "Create widget of TYPE.  
+The optional ARGS are additional keyword arguments."
+  (let ((widget (apply 'widget-convert type args)))
+    (widget-apply widget :create)
+    widget))
+
+(defun widget-create-child-and-convert (parent type &rest args)
+  "As part of the widget PARENT, create a child widget TYPE.
+The child is converted, using the keyword arguments ARGS."
+  (let ((widget (apply 'widget-convert type args)))
+    (widget-put widget :parent parent)
+    (unless (widget-get widget :indent)
+      (widget-put widget :indent (+ (or (widget-get parent :indent) 0)
+				    (or (widget-get widget :extra-offset) 0)
+				    (widget-get parent :offset))))
+    (widget-apply widget :create)
+    widget))
+
+(defun widget-create-child (parent type)
+  "Create widget of TYPE."
+  (let ((widget (copy-list type)))
+    (widget-put widget :parent parent)
+    (unless (widget-get widget :indent)
+      (widget-put widget :indent (+ (or (widget-get parent :indent) 0)
+				    (or (widget-get widget :extra-offset) 0)
+				    (widget-get parent :offset))))
+    (widget-apply widget :create)
+    widget))
+
+(defun widget-create-child-value (parent type value)
+  "Create widget of TYPE with value VALUE."
+  (let ((widget (copy-list type)))
+    (widget-put widget :value (widget-apply widget :value-to-internal value))
+    (widget-put widget :parent parent)
+    (unless (widget-get widget :indent)
+      (widget-put widget :indent (+ (or (widget-get parent :indent) 0)
+				    (or (widget-get widget :extra-offset) 0)
+				    (widget-get parent :offset))))
+    (widget-apply widget :create)
+    widget))
+
+;;;###autoload
+(defun widget-delete (widget)
+  "Delete WIDGET."
+  (widget-apply widget :delete))
+
+(defun widget-convert (type &rest args)
+  "Convert TYPE to a widget without inserting it in the buffer. 
+The optional ARGS are additional keyword arguments."
+  ;; Don't touch the type.
+  (let* ((widget (if (symbolp type) 
+		     (list type)
+		   (copy-list type)))
+	 (current widget)
+	 (keys args))
+    ;; First set the :args keyword.
+    (while (cdr current)		;Look in the type.
+      (let ((next (car (cdr current))))
+	(if (and (symbolp next) (eq (aref (symbol-name next) 0) ?:))
+	    (setq current (cdr (cdr current)))
+	  (setcdr current (list :args (cdr current)))
+	  (setq current nil))))
+    (while args				;Look in the args.
+      (let ((next (nth 0 args)))
+	(if (and (symbolp next) (eq (aref (symbol-name next) 0) ?:))
+	    (setq args (nthcdr 2 args))
+	  (widget-put widget :args args)
+	  (setq args nil))))
+    ;; Then Convert the widget.
+    (setq type widget)
+    (while type
+      (let ((convert-widget (plist-get (cdr type) :convert-widget)))
+	(if convert-widget
+	    (setq widget (funcall convert-widget widget))))
+      (setq type (get (car type) 'widget-type)))
+    ;; Finally set the keyword args.
+    (while keys 
+      (let ((next (nth 0 keys)))
+	(if (and (symbolp next) (eq (aref (symbol-name next) 0) ?:))
+	    (progn 
+	      (widget-put widget next (nth 1 keys))
+	      (setq keys (nthcdr 2 keys)))
+	  (setq keys nil))))
+    ;; Convert the :value to internal format.
+    (if (widget-member widget :value)
+	(let ((value (widget-get widget :value)))
+	  (widget-put widget
+		      :value (widget-apply widget :value-to-internal value))))
+    ;; Return the newly create widget.
+    widget))
+
+(defun widget-insert (&rest args)
+  "Call `insert' with ARGS and make the text read only."
+  (let ((inhibit-read-only t)
+	after-change-functions
+	(from (point)))
+    (apply 'insert args)
+    (widget-specify-text from (point))))
+
+;;; Keymap and Comands.
+
+(defvar widget-keymap nil
+  "Keymap containing useful binding for buffers containing widgets.
+Recommended as a parent keymap for modes using widgets.")
+
+(unless widget-keymap 
+  (setq widget-keymap (make-sparse-keymap))
+  (define-key widget-keymap "\t" 'widget-forward)
+  (define-key widget-keymap "\M-\t" 'widget-backward)
+  (define-key widget-keymap [(shift tab)] 'widget-backward)
+  (define-key widget-keymap [(shift tab)] 'widget-backward)
+  (define-key widget-keymap [backtab] 'widget-backward)
+  (if (string-match "XEmacs" (emacs-version))
+      (define-key widget-keymap [button2] 'widget-button-click)
+    (define-key widget-keymap [menu-bar] 'nil)
+    (define-key widget-keymap [mouse-2] 'widget-button-click))
+  (define-key widget-keymap "\C-m" 'widget-button-press))
+
+(defvar widget-global-map global-map
+  "Keymap used for events the widget does not handle themselves.")
+(make-variable-buffer-local 'widget-global-map)
+
+(defvar widget-field-keymap nil
+  "Keymap used inside an editable field.")
+
+(unless widget-field-keymap 
+  (setq widget-field-keymap (copy-keymap widget-keymap))
+  (define-key widget-field-keymap "\C-m" 'widget-field-activate)
+  (set-keymap-parent widget-field-keymap global-map))
+
+(defvar widget-text-keymap nil
+  "Keymap used inside a text field.")
+
+(unless widget-text-keymap 
+  (setq widget-text-keymap (copy-keymap widget-keymap))
+  (set-keymap-parent widget-text-keymap global-map))
+
+(defun widget-field-activate (pos &optional event)
+  "Activate the ediable field at point."
+  (interactive "@d")
+  (let* ((field (get-text-property pos 'field)))
+    (if field
+	(widget-apply field :action event)
+      (call-interactively
+       (lookup-key widget-global-map (this-command-keys))))))
+
+(defun widget-button-click (event)
+  "Activate button below mouse pointer."
+  (interactive "@e")
+  (widget-button-press (event-point event) event))
+
+(defun widget-button-press (pos &optional event)
+  "Activate button at POS."
+  (interactive "@d")
+  (let* ((button (get-text-property pos 'button)))
+    (if button
+	(widget-apply button :action event)
+      (call-interactively
+       (lookup-key widget-global-map (this-command-keys))))))
+
+(defun widget-move (arg)
+  "Move point to the ARG next field or button.
+ARG may be negative to move backward."
+  (while (> arg 0)
+    (setq arg (1- arg))
+    (let ((next (cond ((get-text-property (point) 'button)
+		       (next-single-property-change (point) 'button))
+		      ((get-text-property (point) 'field)
+		       (next-single-property-change (point) 'field))
+		      (t
+		       (point)))))
+      (if (null next)			; Widget extends to end. of buffer
+	  (setq next (point-min)))
+      (let ((button (next-single-property-change next 'button))
+	    (field (next-single-property-change next 'field)))
+	(cond ((or (get-text-property next 'button)
+		   (get-text-property next 'field))
+	       (goto-char next))
+	      ((and button field)
+	       (goto-char (min button field)))
+	      (button (goto-char button))
+	      (field (goto-char field))
+	      (t
+	       (let ((button (next-single-property-change (point-min) 'button))
+		     (field (next-single-property-change (point-min) 'field)))
+		 (cond ((and button field) (goto-char (min button field)))
+		       (button (goto-char button))
+		       (field (goto-char field))
+		       (t
+			(error "No buttons or fields found")))))))))
+  (while (< arg 0)
+    (if (= (point-min) (point))
+	(forward-char 1))
+    (setq arg (1+ arg))
+    (let ((previous (cond ((get-text-property (1- (point)) 'button)
+			   (previous-single-property-change (point) 'button))
+			  ((get-text-property (1- (point)) 'field)
+			   (previous-single-property-change (point) 'field))
+			  (t
+			   (point)))))
+      (if (null previous)		; Widget extends to beg. of buffer
+	  (setq previous (point-max)))
+      (let ((button (previous-single-property-change previous 'button))
+	    (field (previous-single-property-change previous 'field)))
+	(cond ((and button field)
+	       (goto-char (max button field)))
+	      (button (goto-char button))
+	      (field (goto-char field))
+	      (t
+	       (let ((button (previous-single-property-change
+			      (point-max) 'button))
+		     (field (previous-single-property-change
+			     (point-max) 'field)))
+		 (cond ((and button field) (goto-char (max button field)))
+		       (button (goto-char button))
+		       (field (goto-char field))
+		       (t
+			(error "No buttons or fields found"))))))))
+    (let ((button (previous-single-property-change (point) 'button))
+	  (field (previous-single-property-change (point) 'field)))
+      (cond ((and button field)
+	     (goto-char (max button field)))
+	    (button (goto-char button))
+	    (field (goto-char field)))))
+  (widget-echo-help (point))
+  (run-hooks 'widget-move-hook))
+
+(defun widget-forward (arg)
+  "Move point to the next field or button.
+With optional ARG, move across that many fields."
+  (interactive "p")
+  (run-hooks 'widget-forward-hook)
+  (widget-move arg))
+
+(defun widget-backward (arg)
+  "Move point to the previous field or button.
+With optional ARG, move across that many fields."
+  (interactive "p")
+  (run-hooks 'widget-backward-hook)
+  (widget-move (- arg)))
+
+;;; Setting up the buffer.
+
+(defvar widget-field-new nil)
+;; List of all newly created editable fields in the buffer.
+(make-variable-buffer-local 'widget-field-new)
+
+(defvar widget-field-list nil)
+;; List of all editable fields in the buffer.
+(make-variable-buffer-local 'widget-field-list)
+
+(defun widget-setup ()
+  "Setup current buffer so editing string widgets works."
+  (let ((inhibit-read-only t)
+	(after-change-functions nil)
+	field)
+    (while widget-field-new
+      (setq field (car widget-field-new)
+	    widget-field-new (cdr widget-field-new)
+	    widget-field-list (cons field widget-field-list))
+      (let ((from (widget-get field :value-from))
+	    (to (widget-get field :value-to)))
+	(widget-specify-field field from to)
+	(move-marker from (1- from))
+	(move-marker to (1+ to)))))
+  (widget-clear-undo)
+  ;; We need to maintain text properties and size of the editing fields.
+  (make-local-variable 'after-change-functions)
+  (if widget-field-list
+      (setq after-change-functions '(widget-after-change))
+    (setq after-change-functions nil)))
+
+(defvar widget-field-last nil)
+;; Last field containing point.
+(make-variable-buffer-local 'widget-field-last)
+
+(defvar widget-field-was nil)
+;; The widget data before the change.
+(make-variable-buffer-local 'widget-field-was)
+
+(defun widget-field-find (pos)
+  ;; Find widget whose editing field is located at POS.
+  ;; Return nil if POS is not inside and editing field.
+  ;; 
+  ;; This is only used in `widget-field-modified', since ordinarily
+  ;; you would just test the field property.
+  (let ((fields widget-field-list)
+	field found)
+    (while fields
+      (setq field (car fields)
+	    fields (cdr fields))
+      (let ((from (widget-get field :value-from))
+	    (to (widget-get field :value-to)))
+	(if (and from to (< from pos) (> to  pos))
+	    (setq fields nil
+		  found field))))
+    found))
+
+(defun widget-after-change (from to old)
+  ;; Adjust field size and text properties.
+  (condition-case nil
+      (let ((field (widget-field-find from))
+	    (inhibit-read-only t))
+	(cond ((null field))
+	      ((not (eq field (widget-field-find to)))
+	       (debug)
+	       (message "Error: `widget-after-change' called on two fields"))
+	      (t
+	       (let ((size (widget-get field :size)))
+		 (if size 
+		     (let ((begin (1+ (widget-get field :value-from)))
+			   (end (1- (widget-get field :value-to))))
+		       (widget-specify-field-update field begin end)
+		       (cond ((< (- end begin) size)
+			      ;; Field too small.
+			      (save-excursion
+				(goto-char end)
+				(insert-char ?\  (- (+ begin size) end))
+				(widget-specify-field-update field 
+							     begin
+							     (+ begin size))))
+			     ((> (- end begin) size)
+			      ;; Field too large and
+			      (if (or (< (point) (+ begin size))
+				      (> (point) end))
+				  ;; Point is outside extra space.
+				  (setq begin (+ begin size))
+				;; Point is within the extra space.
+				(setq begin (point)))
+			      (save-excursion
+				(goto-char end)
+				(while (and (eq (preceding-char) ?\ )
+					    (> (point) begin))
+				  (delete-backward-char 1))))))
+		   (widget-specify-field-update field from to)))
+	       (widget-apply field :notify field))))
+    (error (debug))))
+
+;;; Widget Functions
+;;
+;; These functions are used in the definition of multiple widgets. 
+
+(defun widget-children-value-delete (widget)
+  "Delete all :children and :buttons in WIDGET."
+  (mapcar 'widget-delete (widget-get widget :children))
+  (widget-put widget :children nil)
+  (mapcar 'widget-delete (widget-get widget :buttons))
+  (widget-put widget :buttons nil))
+
+(defun widget-types-convert-widget (widget)
+  "Convert :args as widget types in WIDGET."
+  (widget-put widget :args (mapcar 'widget-convert (widget-get widget :args)))
+  widget)
+
+;;; The `default' Widget.
+
+(define-widget 'default nil
+  "Basic widget other widgets are derived from."
+  :value-to-internal (lambda (widget value) value)
+  :value-to-external (lambda (widget value) value)
+  :create 'widget-default-create
+  :indent nil
+  :offset 0
+  :format-handler 'widget-default-format-handler
+  :button-face-get 'widget-default-button-face-get 
+  :sample-face-get 'widget-default-sample-face-get 
+  :delete 'widget-default-delete
+  :value-set 'widget-default-value-set
+  :value-inline 'widget-default-value-inline
+  :menu-tag-get 'widget-default-menu-tag-get
+  :validate (lambda (widget) nil)
+  :action 'widget-default-action
+  :notify 'widget-default-notify)
+
+(defun widget-default-create (widget)
+  "Create WIDGET at point in the current buffer."
+  (widget-specify-insert
+   (let ((from (point))
+	 (tag (widget-get widget :tag))
+	 (doc (widget-get widget :doc))
+	 button-begin button-end
+	 sample-begin sample-end
+	 doc-begin doc-end
+	 value-pos)
+     (insert (widget-get widget :format))
+     (goto-char from)
+     ;; Parse % escapes in format.
+     (while (re-search-forward "%\\(.\\)" nil t)
+       (let ((escape (aref (match-string 1) 0)))
+	 (replace-match "" t t)
+	 (cond ((eq escape ?%)
+		(insert "%"))
+	       ((eq escape ?\[)
+		(setq button-begin (point)))
+	       ((eq escape ?\])
+		(setq button-end (point)))
+	       ((eq escape ?\{)
+		(setq sample-begin (point)))
+	       ((eq escape ?\})
+		(setq sample-end (point)))
+	       ((eq escape ?n)
+		(when (widget-get widget :indent)
+		  (insert "\n")
+		  (insert-char ?  (widget-get widget :indent))))
+	       ((eq escape ?t)
+		(if tag
+		    (insert tag)
+		  (let ((standard-output (current-buffer)))
+		    (princ (widget-get widget :value)))))
+	       ((eq escape ?d)
+		(when doc
+		  (setq doc-begin (point))
+		  (insert doc)
+		  (while (eq (preceding-char) ?\n)
+		    (delete-backward-char 1))
+		  (insert "\n")
+		  (setq doc-end (point))))
+	       ((eq escape ?v)
+		(if (and button-begin (not button-end))
+		    (widget-apply widget :value-create)
+		  (setq value-pos (point))))
+	       (t 
+		(widget-apply widget :format-handler escape)))))
+     ;; Specify button, sample, and doc, and insert value.
+     (and button-begin button-end
+	  (widget-specify-button widget button-begin button-end))
+     (and sample-begin sample-end
+	  (widget-specify-sample widget sample-begin sample-end))
+     (and doc-begin doc-end
+	  (widget-specify-doc widget doc-begin doc-end))
+     (when value-pos
+       (goto-char value-pos)
+       (widget-apply widget :value-create)))
+   (let ((from (copy-marker (point-min)))
+	 (to (copy-marker (point-max))))
+     (widget-specify-text from to)
+     (set-marker-insertion-type from t)
+     (set-marker-insertion-type to nil)
+     (widget-put widget :from from)
+     (widget-put widget :to to))))
+
+(defun widget-default-format-handler (widget escape)
+  ;; We recognize the %h escape by default.
+  (let* ((buttons (widget-get widget :buttons))
+	 (doc-property (widget-get widget :documentation-property))
+	 (doc-try (cond ((widget-get widget :doc))
+			((symbolp doc-property)
+			 (documentation-property (widget-get widget :value)
+						 doc-property))
+			(t
+			 (funcall doc-property (widget-get widget :value)))))
+	 (doc-text (and (stringp doc-try)
+			(> (length doc-try) 1)
+			doc-try)))
+    (cond ((eq escape ?h)
+	   (when doc-text
+	     (and (eq (preceding-char) ?\n)
+		  (widget-get widget :indent)
+		  (insert-char ?  (widget-get widget :indent)))
+	     ;; The `*' in the beginning is redundant.
+	     (when (eq (aref doc-text  0) ?*)
+	       (setq doc-text (substring doc-text 1)))
+	     ;; Get rid of trailing newlines.
+	     (when (string-match "\n+\\'" doc-text)
+	       (setq doc-text (substring doc-text 0 (match-beginning 0))))
+	     (push (if (string-match "\n." doc-text)
+		       ;; Allow multiline doc to be hiden.
+		       (widget-create-child-and-convert
+			widget 'widget-help 
+			:doc (progn
+			       (string-match "\\`.*" doc-text)
+			       (match-string 0 doc-text))
+			:widget-doc doc-text
+			"?")
+		     ;; A single line is just inserted.
+		     (widget-create-child-and-convert
+		      widget 'item :format "%d" :doc doc-text nil))
+		   buttons)))
+	  (t 
+	   (error "Unknown escape `%c'" escape)))
+    (widget-put widget :buttons buttons)))
+
+(defun widget-default-button-face-get (widget)
+  ;; Use :button-face or widget-button-face
+  (or (widget-get widget :button-face) 'widget-button-face))
+
+(defun widget-default-sample-face-get (widget)
+  ;; Use :sample-face.
+  (widget-get widget :sample-face))
+
+(defun widget-default-delete (widget)
+  ;; Remove widget from the buffer.
+  (let ((from (widget-get widget :from))
+	(to (widget-get widget :to))
+	(inhibit-read-only t)
+	after-change-functions)
+    (widget-apply widget :value-delete)
+    (delete-region from to)
+    (set-marker from nil)
+    (set-marker to nil)))
+
+(defun widget-default-value-set (widget value)
+  ;; Recreate widget with new value.
+  (save-excursion
+    (goto-char (widget-get widget :from))
+    (widget-apply widget :delete)
+    (widget-put widget :value value)
+    (widget-apply widget :create)))
+
+(defun widget-default-value-inline (widget)
+  ;; Wrap value in a list unless it is inline.
+  (if (widget-get widget :inline)
+      (widget-value widget)
+    (list (widget-value widget))))
+
+(defun widget-default-menu-tag-get (widget)
+  ;; Use tag or value for menus.
+  (or (widget-get widget :menu-tag)
+      (widget-get widget :tag)
+      (widget-princ-to-string (widget-get widget :value))))
+
+(defun widget-default-action (widget &optional event)
+  ;; Notify the parent when a widget change
+  (let ((parent (widget-get widget :parent)))
+    (when parent
+      (widget-apply parent :notify widget event))))
+
+(defun widget-default-notify (widget child &optional event)
+  ;; Pass notification to parent.
+  (widget-default-action widget event))
+
+;;; The `item' Widget.
+
+(define-widget 'item 'default
+  "Constant items for inclusion in other widgets."
+  :convert-widget 'widget-item-convert-widget
+  :value-create 'widget-item-value-create
+  :value-delete 'ignore
+  :value-get 'widget-item-value-get
+  :match 'widget-item-match
+  :match-inline 'widget-item-match-inline
+  :action 'widget-item-action
+  :format "%t\n")
+
+(defun widget-item-convert-widget (widget)
+  ;; Initialize :value from :args in WIDGET.
+  (let ((args (widget-get widget :args)))
+    (when args 
+      (widget-put widget :value (widget-apply widget
+					      :value-to-internal (car args)))
+      (widget-put widget :args nil)))
+  widget)
+
+(defun widget-item-value-create (widget)
+  ;; Insert the printed representation of the value.
+  (let ((standard-output (current-buffer)))
+    (princ (widget-get widget :value))))
+
+(defun widget-item-match (widget value)
+  ;; Match if the value is the same.
+  (equal (widget-get widget :value) value))
+
+(defun widget-item-match-inline (widget values)
+  ;; Match if the value is the same.
+  (let ((value (widget-get widget :value)))
+    (and (listp value)
+	 (<= (length value) (length values))
+	 (let ((head (subseq values 0 (length value))))
+	   (and (equal head value)
+		(cons head (subseq values (length value))))))))
+
+(defun widget-item-action (widget &optional event)
+  ;; Just notify itself.
+  (widget-apply widget :notify widget event))
+
+(defun widget-item-value-get (widget)
+  ;; Items are simple.
+  (widget-get widget :value))
+
+;;; The `push-button' Widget.
+
+(define-widget 'push-button 'item
+  "A pushable button."
+  :format "%[[%t]%]")
+
+;;; The `link' Widget.
+
+(define-widget 'link 'item
+  "An embedded link."
+  :help-echo "Push me to follow the link."
+  :format "%[_%t_%]")
+
+;;; The `info-link' Widget.
+
+(define-widget 'info-link 'link
+  "A link to an info file."
+  :action 'widget-info-link-action)
+
+(defun widget-info-link-action (widget &optional event)
+  "Open the info node specified by WIDGET."
+  (Info-goto-node (widget-value widget)))
+
+;;; The `url-link' Widget.
+
+(define-widget 'url-link 'link
+  "A link to an www page."
+  :action 'widget-url-link-action)
+
+(defun widget-url-link-action (widget &optional event)
+  "Open the url specified by WIDGET."
+  (require 'browse-url)
+  (funcall browse-url-browser-function (widget-value widget)))
+
+;;; The `editable-field' Widget.
+
+(define-widget 'editable-field 'default
+  "An editable text field."
+  :convert-widget 'widget-item-convert-widget
+  :keymap widget-field-keymap
+  :format "%v"
+  :value ""
+  :action 'widget-field-action
+  :validate 'widget-field-validate
+  :valid-regexp ""
+  :error "No match"
+  :value-create 'widget-field-value-create
+  :value-delete 'widget-field-value-delete
+  :value-get 'widget-field-value-get
+  :match 'widget-field-match)
+
+;; History of field minibuffer edits.
+(defvar widget-field-history nil)
+
+(defun widget-field-action (widget &optional event)
+  ;; Edit the value in the minibuffer.
+  (let ((tag (widget-apply widget :menu-tag-get))
+	(invalid (widget-apply widget :validate)))
+    (when invalid
+      (error (widget-get invalid :error)))
+    (widget-value-set widget 
+		      (widget-apply widget 
+				    :value-to-external
+				    (read-string (concat tag ": ") 
+						 (widget-apply 
+						  widget
+						  :value-to-internal
+						  (widget-value widget))
+						 'widget-field-history)))
+    (widget-apply widget :notify widget event)
+    (widget-setup)))
+
+(defun widget-field-validate (widget)
+  ;; Valid if the content matches `:valid-regexp'.
+  (save-excursion
+    (let ((value (widget-apply widget :value-get))
+	  (regexp (widget-get widget :valid-regexp)))
+      (if (string-match regexp value)
+	  nil
+	widget))))
+
+(defun widget-field-value-create (widget)
+  ;; Create an editable text field.
+  (insert " ")
+  (let ((size (widget-get widget :size))
+	(value (widget-get widget :value))
+	(from (point)))
+    (insert value)
+    (and size
+	 (< (length value) size)
+	 (insert-char ?\  (- size (length value))))
+    (unless (memq widget widget-field-list)
+      (setq widget-field-new (cons widget widget-field-new)))
+    (widget-put widget :value-to (copy-marker (point)))
+    (set-marker-insertion-type (widget-get widget :value-to) nil)
+    (if (null size)
+	(insert ?\n)
+      (insert ?\ ))
+    (widget-put widget :value-from (copy-marker from))
+    (set-marker-insertion-type (widget-get widget :value-from) t)))
+
+(defun widget-field-value-delete (widget)
+  ;; Remove the widget from the list of active editing fields.
+  (setq widget-field-list (delq widget widget-field-list))
+  ;; These are nil if the :format string doesn't contain `%v'.
+  (when (widget-get widget :value-from)
+    (set-marker (widget-get widget :value-from) nil))
+  (when (widget-get widget :value-from)
+    (set-marker (widget-get widget :value-to) nil)))
+
+(defun widget-field-value-get (widget)
+  ;; Return current text in editing field.
+  (let ((from (widget-get widget :value-from))
+	(to (widget-get widget :value-to))
+	(size (widget-get widget :size))
+	(secret (widget-get widget :secret))
+	(old (current-buffer)))
+    (if (and from to)
+	(progn 
+	  (set-buffer (marker-buffer from))
+	  (setq from (1+ from)
+		to (1- to))
+	  (while (and size
+		      (not (zerop size))
+		      (> to from)
+		      (eq (char-after (1- to)) ?\ ))
+	    (setq to (1- to)))
+	  (let ((result (buffer-substring-no-properties from to)))
+	    (when secret
+	      (let ((index 0))
+		(while (< (+ from index) to)
+		  (aset result index
+			(get-text-property (+ from index) 'secret))
+		  (setq index (1+ index)))))
+	    (set-buffer old)
+	    result))
+      (widget-get widget :value))))
+
+(defun widget-field-match (widget value)
+  ;; Match any string.
+  (stringp value))
+
+;;; The `text' Widget.
+
+(define-widget 'text 'editable-field
+  :keymap widget-text-keymap
+  "A multiline text area.")
+
+;;; The `menu-choice' Widget.
+
+(define-widget 'menu-choice 'default
+  "A menu of options."
+  :convert-widget  'widget-types-convert-widget
+  :format "%[%t%]: %v"
+  :case-fold t
+  :tag "choice"
+  :void '(item :format "invalid (%t)\n")
+  :value-create 'widget-choice-value-create
+  :value-delete 'widget-children-value-delete
+  :value-get 'widget-choice-value-get
+  :value-inline 'widget-choice-value-inline
+  :action 'widget-choice-action
+  :error "Make a choice"
+  :validate 'widget-choice-validate
+  :match 'widget-choice-match
+  :match-inline 'widget-choice-match-inline)
+
+(defun widget-choice-value-create (widget)
+  ;; Insert the first choice that matches the value.
+  (let ((value (widget-get widget :value))
+	(args (widget-get widget :args))
+	current)
+    (while args
+      (setq current (car args)
+	    args (cdr args))
+      (when (widget-apply current :match value)
+	(widget-put widget :children (list (widget-create-child-value
+					    widget current value)))
+	(widget-put widget :choice current)
+	(setq args nil
+	      current nil)))
+    (when current
+      (let ((void (widget-get widget :void)))
+	(widget-put widget :children (list (widget-create-child-and-convert
+					    widget void :value value)))
+	(widget-put widget :choice void)))))
+
+(defun widget-choice-value-get (widget)
+  ;; Get value of the child widget.
+  (widget-value (car (widget-get widget :children))))
+
+(defun widget-choice-value-inline (widget)
+  ;; Get value of the child widget.
+  (widget-apply (car (widget-get widget :children)) :value-inline))
+
+(defun widget-choice-action (widget &optional event)
+  ;; Make a choice.
+  (let ((args (widget-get widget :args))
+	(old (widget-get widget :choice))
+	(tag (widget-apply widget :menu-tag-get))
+	(completion-ignore-case (widget-get widget :case-fold))
+	current choices)
+    ;; Remember old value.
+    (if (and old (not (widget-apply widget :validate)))
+	(let* ((external (widget-value widget))
+	       (internal (widget-apply old :value-to-internal external)))
+	  (widget-put old :value internal)))
+    ;; Find new choice.
+    (setq current
+	  (cond ((= (length args) 0)
+		 nil)
+		((= (length args) 1)
+		 (nth 0 args))
+		((and (= (length args) 2)
+		      (memq old args))
+		 (if (eq old (nth 0 args))
+		     (nth 1 args)
+		   (nth 0 args)))
+		(t
+		 (while args
+		   (setq current (car args)
+			 args (cdr args))
+		   (setq choices
+			 (cons (cons (widget-apply current :menu-tag-get)
+				     current)
+			       choices)))
+		 (widget-choose tag (reverse choices) event))))
+    (when current
+      (widget-value-set widget 
+			(widget-apply current :value-to-external
+				      (widget-get current :value)))
+    (widget-apply widget :notify widget event)
+    (widget-setup)))
+  ;; Notify parent.
+  (widget-apply widget :notify widget event)
+  (widget-clear-undo))
+
+(defun widget-choice-validate (widget)
+  ;; Valid if we have made a valid choice.
+  (let ((void (widget-get widget :void))
+	(choice (widget-get widget :choice))
+	(child (car (widget-get widget :children))))
+    (if (eq void choice)
+	widget
+      (widget-apply child :validate))))
+
+(defun widget-choice-match (widget value)
+  ;; Matches if one of the choices matches.
+  (let ((args (widget-get widget :args))
+	current found)
+    (while (and args (not found))
+      (setq current (car args)
+	    args (cdr args)
+	    found (widget-apply current :match value)))
+    found))
+
+(defun widget-choice-match-inline (widget values)
+  ;; Matches if one of the choices matches.
+  (let ((args (widget-get widget :args))
+	current found)
+    (while (and args (null found))
+      (setq current (car args)
+	    args (cdr args)
+	    found (widget-match-inline current values)))
+    found))
+
+;;; The `toggle' Widget.
+
+(define-widget 'toggle 'menu-choice
+  "Toggle between two states."
+  :convert-widget 'widget-toggle-convert-widget
+  :format "%v"
+  :on "on"
+  :off "off")
+
+(defun widget-toggle-convert-widget (widget)
+  ;; Create the types representing the `on' and `off' states.
+  (let ((on-type (widget-get widget :on-type))
+	(off-type (widget-get widget :off-type)))
+    (unless on-type
+      (setq on-type
+	    (list 'choice-item 
+		  :value t
+		  :match (lambda (widget value) value)
+		  :tag (widget-get widget :on))))
+    (unless off-type
+      (setq off-type
+	    (list 'choice-item :value nil :tag (widget-get widget :off))))
+    (widget-put widget :args (list on-type off-type)))
+  widget)
+
+;;; The `checkbox' Widget.
+
+(define-widget 'checkbox 'toggle
+  "A checkbox toggle."
+  :convert-widget 'widget-item-convert-widget
+  :on-type '(choice-item :format "%[[X]%]" t)
+  :off-type  '(choice-item :format "%[[ ]%]" nil))
+
+;;; The `checklist' Widget.
+
+(define-widget 'checklist 'default
+  "A multiple choice widget."
+  :convert-widget 'widget-types-convert-widget
+  :format "%v"
+  :offset 4
+  :entry-format "%b %v"
+  :menu-tag "checklist"
+  :greedy nil
+  :value-create 'widget-checklist-value-create
+  :value-delete 'widget-children-value-delete
+  :value-get 'widget-checklist-value-get
+  :validate 'widget-checklist-validate
+  :match 'widget-checklist-match
+  :match-inline 'widget-checklist-match-inline)
+
+(defun widget-checklist-value-create (widget)
+  ;; Insert all values
+  (let ((alist (widget-checklist-match-find widget (widget-get widget :value)))
+	(args (widget-get widget :args)))
+    (while args 
+      (widget-checklist-add-item widget (car args) (assq (car args) alist))
+      (setq args (cdr args)))
+    (widget-put widget :children (nreverse (widget-get widget :children)))))
+
+(defun widget-checklist-add-item (widget type chosen)
+  ;; Create checklist item in WIDGET of type TYPE.
+  ;; If the item is checked, CHOSEN is a cons whose cdr is the value.
+  (and (eq (preceding-char) ?\n)
+       (widget-get widget :indent)
+       (insert-char ?  (widget-get widget :indent)))
+  (widget-specify-insert 
+   (let* ((children (widget-get widget :children))
+	  (buttons (widget-get widget :buttons))
+	  (from (point))
+	  child button)
+     (insert (widget-get widget :entry-format))
+     (goto-char from)
+     ;; Parse % escapes in format.
+     (while (re-search-forward "%\\([bv%]\\)" nil t)
+       (let ((escape (aref (match-string 1) 0)))
+	 (replace-match "" t t)
+	 (cond ((eq escape ?%)
+		(insert "%"))
+	       ((eq escape ?b)
+		(setq button (widget-create-child-and-convert
+			      widget 'checkbox :value (not (null chosen)))))
+	       ((eq escape ?v)
+		(setq child
+		      (cond ((not chosen)
+			     (widget-create-child widget type))
+			    ((widget-get type :inline)
+			     (widget-create-child-value
+			      widget type (cdr chosen)))
+			    (t
+			     (widget-create-child-value
+			      widget type (car (cdr chosen)))))))
+	       (t 
+		(error "Unknown escape `%c'" escape)))))
+     ;; Update properties.
+     (and button child (widget-put child :button button))
+     (and button (widget-put widget :buttons (cons button buttons)))
+     (and child (widget-put widget :children (cons child children))))))
+
+(defun widget-checklist-match (widget values)
+  ;; All values must match a type in the checklist.
+  (and (listp values)
+       (null (cdr (widget-checklist-match-inline widget values)))))
+
+(defun widget-checklist-match-inline (widget values)
+  ;; Find the values which match a type in the checklist.
+  (let ((greedy (widget-get widget :greedy))
+	(args (copy-list (widget-get widget :args)))
+	found rest)
+    (while values
+      (let ((answer (widget-checklist-match-up args values)))
+	(cond (answer 
+	       (let ((vals (widget-match-inline answer values)))
+		 (setq found (append found (car vals))
+		       values (cdr vals)
+		       args (delq answer args))))
+	      (greedy
+	       (setq rest (append rest (list (car values)))
+		     values (cdr values)))
+	      (t 
+	       (setq rest (append rest values)
+		     values nil)))))
+    (cons found rest)))
+
+(defun widget-checklist-match-find (widget vals)
+  ;; Find the vals which match a type in the checklist.
+  ;; Return an alist of (TYPE MATCH).
+  (let ((greedy (widget-get widget :greedy))
+	(args (copy-list (widget-get widget :args)))
+	found)
+    (while vals
+      (let ((answer (widget-checklist-match-up args vals)))
+	(cond (answer 
+	       (let ((match (widget-match-inline answer vals)))
+		 (setq found (cons (cons answer (car match)) found)
+		       vals (cdr match)
+		       args (delq answer args))))
+	      (greedy
+	       (setq vals (cdr vals)))
+	      (t 
+	       (setq vals nil)))))
+    found))
+
+(defun widget-checklist-match-up (args vals)
+  ;; Rerturn the first type from ARGS that matches VALS.
+  (let (current found)
+    (while (and args (null found))
+      (setq current (car args)
+	    args (cdr args)
+	    found (widget-match-inline current vals)))
+    (if found
+	current
+      nil)))
+
+(defun widget-checklist-value-get (widget)
+  ;; The values of all selected items.
+  (let ((children (widget-get widget :children))
+	child result)
+    (while children 
+      (setq child (car children)
+	    children (cdr children))
+      (if (widget-value (widget-get child :button))
+	  (setq result (append result (widget-apply child :value-inline)))))
+    result))
+
+(defun widget-checklist-validate (widget)
+  ;; Ticked chilren must be valid.
+  (let ((children (widget-get widget :children))
+	child button found)
+    (while (and children (not found))
+      (setq child (car children)
+	    children (cdr children)
+	    button (widget-get child :button)
+	    found (and (widget-value button)
+		       (widget-apply child :validate))))
+    found))
+
+;;; The `option' Widget
+
+(define-widget 'option 'checklist
+  "An widget with an optional item."
+  :inline t)
+
+;;; The `choice-item' Widget.
+
+(define-widget 'choice-item 'item
+  "Button items that delegate action events to their parents."
+  :action 'widget-choice-item-action
+  :format "%[%t%] \n")
+
+(defun widget-choice-item-action (widget &optional event)
+  ;; Tell parent what happened.
+  (widget-apply (widget-get widget :parent) :action event))
+
+;;; The `radio-button' Widget.
+
+(define-widget 'radio-button 'toggle
+  "A radio button for use in the `radio' widget."
+  :notify 'widget-radio-button-notify
+  :on-type '(choice-item :format "%[(*)%]" t)
+  :off-type '(choice-item :format "%[( )%]" nil))
+
+(defun widget-radio-button-notify (widget child &optional event)
+  ;; Notify the parent.
+  (widget-apply (widget-get widget :parent) :action widget event))
+
+;;; The `radio-button-choice' Widget.
+
+(define-widget 'radio-button-choice 'default
+  "Select one of multiple options."
+  :convert-widget 'widget-types-convert-widget
+  :offset 4
+  :format "%v"
+  :entry-format "%b %v"
+  :menu-tag "radio"
+  :value-create 'widget-radio-value-create
+  :value-delete 'widget-children-value-delete
+  :value-get 'widget-radio-value-get
+  :value-inline 'widget-radio-value-inline
+  :value-set 'widget-radio-value-set
+  :error "You must push one of the buttons"
+  :validate 'widget-radio-validate
+  :match 'widget-choice-match
+  :match-inline 'widget-choice-match-inline
+  :action 'widget-radio-action)
+
+(defun widget-radio-value-create (widget)
+  ;; Insert all values
+  (let ((args (widget-get widget :args))
+	arg)
+    (while args 
+      (setq arg (car args)
+	    args (cdr args))
+      (widget-radio-add-item widget arg))))
+
+(defun widget-radio-add-item (widget type)
+  "Add to radio widget WIDGET a new radio button item of type TYPE."
+  ;; (setq type (widget-convert type))
+  (and (eq (preceding-char) ?\n)
+       (widget-get widget :indent)
+       (insert-char ?  (widget-get widget :indent)))
+  (widget-specify-insert 
+   (let* ((value (widget-get widget :value))
+	  (children (widget-get widget :children))
+	  (buttons (widget-get widget :buttons))
+	  (from (point))
+	  (chosen (and (null (widget-get widget :choice))
+		       (widget-apply type :match value)))
+	  child button)
+     (insert (widget-get widget :entry-format))
+     (goto-char from)
+     ;; Parse % escapes in format.
+     (while (re-search-forward "%\\([bv%]\\)" nil t)
+       (let ((escape (aref (match-string 1) 0)))
+	 (replace-match "" t t)
+	 (cond ((eq escape ?%)
+		(insert "%"))
+	       ((eq escape ?b)
+		(setq button (widget-create-child-and-convert
+			      widget 'radio-button 
+			      :value (not (null chosen)))))
+	       ((eq escape ?v)
+		(setq child (if chosen
+				(widget-create-child-value
+				 widget type value)
+			      (widget-create-child widget type))))
+	       (t 
+		(error "Unknown escape `%c'" escape)))))
+     ;; Update properties.
+     (when chosen
+       (widget-put widget :choice type))
+     (when button 
+       (widget-put child :button button)
+       (widget-put widget :buttons (nconc buttons (list button))))
+     (when child
+       (widget-put widget :children (nconc children (list child))))
+     child)))
+
+(defun widget-radio-value-get (widget)
+  ;; Get value of the child widget.
+  (let ((chosen (widget-radio-chosen widget)))
+    (and chosen (widget-value chosen))))
+
+(defun widget-radio-chosen (widget)
+  "Return the widget representing the chosen radio button."
+  (let ((children (widget-get widget :children))
+	current found)
+    (while children
+      (setq current (car children)
+	    children (cdr children))
+      (let* ((button (widget-get current :button))
+	     (value (widget-apply button :value-get)))
+	(when value
+	  (setq found current
+		children nil))))
+    found))
+
+(defun widget-radio-value-inline (widget)
+  ;; Get value of the child widget.
+  (let ((children (widget-get widget :children))
+	current found)
+    (while children
+      (setq current (car children)
+	    children (cdr children))
+      (let* ((button (widget-get current :button))
+	     (value (widget-apply button :value-get)))
+	(when value
+	  (setq found (widget-apply current :value-inline)
+		children nil))))
+    found))
+
+(defun widget-radio-value-set (widget value)
+  ;; We can't just delete and recreate a radio widget, since children
+  ;; can be added after the original creation and won't be recreated
+  ;; by `:create'.
+  (let ((children (widget-get widget :children))
+	current found)
+    (while children
+      (setq current (car children)
+	    children (cdr children))
+      (let* ((button (widget-get current :button))
+	     (match (and (not found)
+			 (widget-apply current :match value))))
+	(widget-value-set button match)
+	(if match 
+	    (widget-value-set current value))
+	(setq found (or found match))))))
+
+(defun widget-radio-validate (widget)
+  ;; Valid if we have made a valid choice.
+  (let ((children (widget-get widget :children))
+	current found button)
+    (while (and children (not found))
+      (setq current (car children)
+	    children (cdr children)
+	    button (widget-get current :button)
+	    found (widget-apply button :value-get)))
+    (if found
+	(widget-apply current :validate)
+      widget)))
+
+(defun widget-radio-action (widget child event)
+  ;; Check if a radio button was pressed.
+  (let ((children (widget-get widget :children))
+	(buttons (widget-get widget :buttons))
+	current)
+    (when (memq child buttons)
+      (while children
+	(setq current (car children)
+	      children (cdr children))
+	(let* ((button (widget-get current :button)))
+	  (cond ((eq child button)
+		 (widget-value-set button t))
+		((widget-value button)
+		 (widget-value-set button nil)))))))
+  ;; Pass notification to parent.
+  (widget-apply widget :notify child event))
+
+;;; The `insert-button' Widget.
+
+(define-widget 'insert-button 'push-button
+  "An insert button for the `editable-list' widget."
+  :tag "INS"
+  :action 'widget-insert-button-action)
+
+(defun widget-insert-button-action (widget &optional event)
+  ;; Ask the parent to insert a new item.
+  (widget-apply (widget-get widget :parent) 
+		:insert-before (widget-get widget :widget)))
+
+;;; The `delete-button' Widget.
+
+(define-widget 'delete-button 'push-button
+  "A delete button for the `editable-list' widget."
+  :tag "DEL"
+  :action 'widget-delete-button-action)
+
+(defun widget-delete-button-action (widget &optional event)
+  ;; Ask the parent to insert a new item.
+  (widget-apply (widget-get widget :parent) 
+		:delete-at (widget-get widget :widget)))
+
+;;; The `editable-list' Widget.
+
+(define-widget 'editable-list 'default
+  "A variable list of widgets of the same type."
+  :convert-widget 'widget-types-convert-widget
+  :offset 12
+  :format "%v%i\n"
+  :format-handler 'widget-editable-list-format-handler
+  :entry-format "%i %d %v"
+  :menu-tag "editable-list"
+  :value-create 'widget-editable-list-value-create
+  :value-delete 'widget-children-value-delete
+  :value-get 'widget-editable-list-value-get
+  :validate 'widget-editable-list-validate
+  :match 'widget-editable-list-match
+  :match-inline 'widget-editable-list-match-inline
+  :insert-before 'widget-editable-list-insert-before
+  :delete-at 'widget-editable-list-delete-at)
+
+(defun widget-editable-list-format-handler (widget escape)
+  ;; We recognize the insert button.
+  (cond ((eq escape ?i)
+	 (and (widget-get widget :indent)
+	      (insert-char ?  (widget-get widget :indent)))
+	 (widget-create-child-and-convert widget 'insert-button))
+	(t 
+	 (widget-default-format-handler widget escape))))
+
+(defun widget-editable-list-value-create (widget)
+  ;; Insert all values
+  (let* ((value (widget-get widget :value))
+	 (type (nth 0 (widget-get widget :args)))
+	 (inlinep (widget-get type :inline))
+	 children)
+    (widget-put widget :value-pos (copy-marker (point)))
+    (set-marker-insertion-type (widget-get widget :value-pos) t)
+    (while value
+      (let ((answer (widget-match-inline type value)))
+	(if answer
+	    (setq children (cons (widget-editable-list-entry-create
+				  widget
+				  (if inlinep
+				      (car answer)
+				    (car (car answer)))
+				  t)
+				 children)
+		  value (cdr answer))
+	  (setq value nil))))
+    (widget-put widget :children (nreverse children))))
+
+(defun widget-editable-list-value-get (widget)
+  ;; Get value of the child widget.
+  (apply 'append (mapcar (lambda (child) (widget-apply child :value-inline))
+			 (widget-get widget :children))))
+
+(defun widget-editable-list-validate (widget)
+  ;; All the chilren must be valid.
+  (let ((children (widget-get widget :children))
+	child found)
+    (while (and children (not found))
+      (setq child (car children)
+	    children (cdr children)
+	    found (widget-apply child :validate)))
+    found))
+
+(defun widget-editable-list-match (widget value)
+  ;; Value must be a list and all the members must match the type.
+  (and (listp value)
+       (null (cdr (widget-editable-list-match-inline widget value)))))
+
+(defun widget-editable-list-match-inline (widget value)
+  (let ((type (nth 0 (widget-get widget :args)))
+	(ok t)
+	found)
+    (while (and value ok)
+      (let ((answer (widget-match-inline type value)))
+	(if answer 
+	    (setq found (append found (car answer))
+		  value (cdr answer))
+	  (setq ok nil))))
+    (cons found value)))
+
+(defun widget-editable-list-insert-before (widget before)
+  ;; Insert a new child in the list of children.
+  (save-excursion
+    (let ((children (widget-get widget :children))
+	  (inhibit-read-only t)
+	  after-change-functions)
+      (cond (before 
+	     (goto-char (widget-get before :entry-from)))
+	    (t
+	     (goto-char (widget-get widget :value-pos))))
+      (let ((child (widget-editable-list-entry-create 
+		    widget nil nil)))
+	(when (< (widget-get child :entry-from) (widget-get widget :from))
+	  (set-marker (widget-get widget :from)
+		      (widget-get child :entry-from)))
+	(widget-specify-text (widget-get child :entry-from)
+			     (widget-get child :entry-to))
+	(if (eq (car children) before)
+	    (widget-put widget :children (cons child children))
+	  (while (not (eq (car (cdr children)) before))
+	    (setq children (cdr children)))
+	  (setcdr children (cons child (cdr children)))))))
+  (widget-setup)
+  (widget-apply widget :notify widget))
+
+(defun widget-editable-list-delete-at (widget child)
+  ;; Delete child from list of children.
+  (save-excursion
+    (let ((buttons (copy-list (widget-get widget :buttons)))
+	  button
+	  (inhibit-read-only t)
+	  after-change-functions)
+      (while buttons
+	(setq button (car buttons)
+	      buttons (cdr buttons))
+	(when (eq (widget-get button :widget) child)
+	  (widget-put widget
+		      :buttons (delq button (widget-get widget :buttons)))
+	  (widget-delete button))))
+    (let ((entry-from (widget-get child :entry-from))
+	  (entry-to (widget-get child :entry-to))
+	  (inhibit-read-only t)
+	  after-change-functions)
+      (widget-delete child)
+      (delete-region entry-from entry-to)
+      (set-marker entry-from nil)
+      (set-marker entry-to nil))
+    (widget-put widget :children (delq child (widget-get widget :children))))
+  (widget-setup)
+  (widget-apply widget :notify widget))
+
+(defun widget-editable-list-entry-create (widget value conv)
+  ;; Create a new entry to the list.
+  (let ((type (nth 0 (widget-get widget :args)))
+	child delete insert)
+    (widget-specify-insert 
+     (save-excursion
+       (and (widget-get widget :indent)
+	    (insert-char ?  (widget-get widget :indent)))
+       (insert (widget-get widget :entry-format)))
+     ;; Parse % escapes in format.
+     (while (re-search-forward "%\\(.\\)" nil t)
+       (let ((escape (aref (match-string 1) 0)))
+	 (replace-match "" t t)
+	 (cond ((eq escape ?%)
+		(insert "%"))
+	       ((eq escape ?i)
+		(setq insert (widget-create-child-and-convert
+			      widget 'insert-button)))
+	       ((eq escape ?d)
+		(setq delete (widget-create-child-and-convert
+			      widget 'delete-button)))
+	       ((eq escape ?v)
+		(if conv
+		    (setq child (widget-create-child-value 
+				 widget type value))
+		  (setq child (widget-create-child widget type))))
+	       (t 
+		(error "Unknown escape `%c'" escape)))))
+     (widget-put widget 
+		 :buttons (cons delete 
+				(cons insert
+				      (widget-get widget :buttons))))
+     (let ((entry-from (copy-marker (point-min)))
+	   (entry-to (copy-marker (point-max))))
+       (widget-specify-text entry-from entry-to)
+       (set-marker-insertion-type entry-from t)
+       (set-marker-insertion-type entry-to nil)
+       (widget-put child :entry-from entry-from)
+       (widget-put child :entry-to entry-to)))
+    (widget-put insert :widget child)
+    (widget-put delete :widget child)
+    child))
+
+;;; The `group' Widget.
+
+(define-widget 'group 'default
+  "A widget which group other widgets inside."
+  :convert-widget 'widget-types-convert-widget
+  :format "%v"
+  :value-create 'widget-group-value-create
+  :value-delete 'widget-children-value-delete
+  :value-get 'widget-editable-list-value-get
+  :validate 'widget-editable-list-validate
+  :match 'widget-group-match
+  :match-inline 'widget-group-match-inline)
+
+(defun widget-group-value-create (widget)
+  ;; Create each component.
+  (let ((args (widget-get widget :args))
+	(value (widget-get widget :value))
+	arg answer children)
+    (while args
+      (setq arg (car args)
+	    args (cdr args)
+	    answer (widget-match-inline arg value)
+	    value (cdr answer))
+      (and (eq (preceding-char) ?\n)
+	   (widget-get widget :indent)
+	   (insert-char ?  (widget-get widget :indent)))
+      (push (cond ((null answer)
+		   (widget-create-child widget arg))
+		  ((widget-get arg :inline)
+		   (widget-create-child-value widget arg  (car answer)))
+		  (t
+		   (widget-create-child-value widget arg  (car (car answer)))))
+	    children))
+    (widget-put widget :children (nreverse children))))
+
+(defun widget-group-match (widget values)
+  ;; Match if the components match.
+  (and (listp values)
+       (let ((match (widget-group-match-inline widget values)))
+	 (and match (null (cdr match))))))
+
+(defun widget-group-match-inline (widget vals)
+  ;; Match if the components match.
+  (let ((args (widget-get widget :args))
+	argument answer found)
+    (while args
+      (setq argument (car args)
+	    args (cdr args)
+	    answer (widget-match-inline argument vals))
+      (if answer 
+	  (setq vals (cdr answer)
+		found (append found (car answer)))
+	(setq vals nil
+	      args nil)))
+    (if answer
+	(cons found vals)
+      nil)))
+
+;;; The `widget-help' Widget.
+
+(define-widget 'widget-help 'push-button
+  "The widget documentation button."
+  :format "%[[%t]%] %d"
+  :help-echo "Push me to toggle the documentation."
+  :action 'widget-help-action)
+
+(defun widget-help-action (widget &optional event)
+  "Toggle documentation for WIDGET."
+  (let ((old (widget-get widget :doc))
+	(new (widget-get widget :widget-doc)))
+    (widget-put widget :doc new)
+    (widget-put widget :widget-doc old))
+  (widget-value-set widget (widget-value widget)))
+
+;;; The Sexp Widgets.
+
+(define-widget 'const 'item
+  "An immutable sexp."
+  :format "%t\n%d")
+
+(define-widget 'function-item 'item
+  "An immutable function name."
+  :format "%v\n%h"
+  :documentation-property (lambda (symbol)
+			    (condition-case nil
+				(documentation symbol t)
+			      (error nil))))
+
+(define-widget 'variable-item 'item
+  "An immutable variable name."
+  :format "%v\n%h"
+  :documentation-property 'variable-documentation)
+
+(define-widget 'string 'editable-field
+  "A string"
+  :tag "String"
+  :format "%[%t%]: %v")
+
+(define-widget 'regexp 'string
+  "A regular expression."
+  ;; Should do validation.
+  :tag "Regexp")
+
+(define-widget 'file 'string
+  "A file widget.  
+It will read a file name from the minibuffer when activated."
+  :format "%[%t%]: %v"
+  :tag "File"
+  :action 'widget-file-action)
+
+(defun widget-file-action (widget &optional event)
+  ;; Read a file name from the minibuffer.
+  (let* ((value (widget-value widget))
+	 (dir (file-name-directory value))
+	 (file (file-name-nondirectory value))
+	 (menu-tag (widget-apply widget :menu-tag-get))
+	 (must-match (widget-get widget :must-match))
+	 (answer (read-file-name (concat menu-tag ": (defalt `" value "') ")
+				 dir nil must-match file)))
+    (widget-value-set widget (abbreviate-file-name answer))
+    (widget-apply widget :notify widget event)
+    (widget-setup)))
+
+(define-widget 'directory 'file
+  "A directory widget.  
+It will read a directory name from the minibuffer when activated."
+  :tag "Directory")
+
+(define-widget 'symbol 'string
+  "A lisp symbol."
+  :value nil
+  :tag "Symbol"
+  :match (lambda (widget value) (symbolp value))
+  :value-to-internal (lambda (widget value)
+		       (if (symbolp value)
+			   (symbol-name value)
+			 value))
+  :value-to-external (lambda (widget value)
+		       (if (stringp value)
+			   (intern value)
+			 value)))
+
+(define-widget 'function 'sexp
+  ;; Should complete on functions.
+  "A lisp function."
+  :tag "Function")
+
+(define-widget 'variable 'symbol
+  ;; Should complete on variables.
+  "A lisp variable."
+  :tag "Variable")
+
+(define-widget 'sexp 'string
+  "An arbitrary lisp expression."
+  :tag "Lisp expression"
+  :value nil
+  :validate 'widget-sexp-validate
+  :match (lambda (widget value) t)
+  :value-to-internal 'widget-sexp-value-to-internal
+  :value-to-external (lambda (widget value) (read value)))
+
+(defun widget-sexp-value-to-internal (widget value)
+  ;; Use pp for printer representation.
+  (let ((pp (pp-to-string value)))
+    (while (string-match "\n\\'" pp)
+      (setq pp (substring pp 0 -1)))
+    (if (or (string-match "\n\\'" pp)
+	    (> (length pp) 40))
+	(concat "\n" pp)
+      pp)))
+
+(defun widget-sexp-validate (widget)
+  ;; Valid if we can read the string and there is no junk left after it.
+  (save-excursion
+    (let ((buffer (set-buffer (get-buffer-create " *Widget Scratch*"))))
+      (erase-buffer)
+      (insert (widget-apply widget :value-get))
+      (goto-char (point-min))
+      (condition-case data
+	  (let ((value (read buffer)))
+	    (if (eobp)
+		(if (widget-apply widget :match value)
+		    nil
+		  (widget-put widget :error (widget-get widget :type-error))
+		  widget)
+	      (widget-put widget
+			  :error (format "Junk at end of expression: %s"
+					 (buffer-substring (point)
+							   (point-max))))
+	      widget))
+	(error (widget-put widget :error (error-message-string data))
+	       widget)))))
+
+(define-widget 'integer 'sexp
+  "An integer."
+  :tag "Integer"
+  :value 0
+  :type-error "This field should contain an integer"
+  :value-to-internal (lambda (widget value)
+		       (if (integerp value) 
+			   (prin1-to-string value)
+			 value))
+  :match (lambda (widget value) (integerp value)))
+
+(define-widget 'character 'string
+  "An character."
+  :tag "Character"
+  :value 0
+  :size 1 
+  :format "%{%t%}: %v\n"
+  :type-error "This field should contain a character"
+  :value-to-internal (lambda (widget value)
+		       (if (integerp value) 
+			   (char-to-string value)
+			 value))
+  :value-to-external (lambda (widget value)
+		       (if (stringp value)
+			   (aref value 0)
+			 value))
+  :match (lambda (widget value) (integerp value)))
+
+(define-widget 'number 'sexp
+  "A floating point number."
+  :tag "Number"
+  :value 0.0
+  :type-error "This field should contain a number"
+  :value-to-internal (lambda (widget value)
+		       (if (numberp value)
+			   (prin1-to-string value)
+			 value))
+  :match (lambda (widget value) (numberp value)))
+
+(define-widget 'list 'group
+  "A lisp list."
+  :tag "List"
+  :format "%{%t%}:\n%v")
+
+(define-widget 'vector 'group
+  "A lisp vector."
+  :tag "Vector"
+  :format "%{%t%}:\n%v"
+  :match 'widget-vector-match
+  :value-to-internal (lambda (widget value) (append value nil))
+  :value-to-external (lambda (widget value) (apply 'vector value)))
+
+(defun widget-vector-match (widget value) 
+  (and (vectorp value)
+       (widget-group-match widget
+			   (widget-apply :value-to-internal widget value))))
+
+(define-widget 'cons 'group
+  "A cons-cell."
+  :tag "Cons-cell"
+  :format "%{%t%}:\n%v"
+  :match 'widget-cons-match
+  :value-to-internal (lambda (widget value)
+		       (list (car value) (cdr value)))
+  :value-to-external (lambda (widget value)
+		       (cons (nth 0 value) (nth 1 value))))
+
+(defun widget-cons-match (widget value) 
+  (and (consp value)
+       (widget-group-match widget
+			   (widget-apply widget :value-to-internal value))))
+
+(define-widget 'choice 'menu-choice
+  "A union of several sexp types."
+  :tag "Choice"
+  :format "%[%t%]: %v")
+
+(define-widget 'radio 'radio-button-choice
+  "A union of several sexp types."
+  :tag "Choice"
+  :format "%{%t%}:\n%v")
+
+(define-widget 'repeat 'editable-list
+  "A variable length homogeneous list."
+  :tag "Repeat"
+  :format "%{%t%}:\n%v%i\n")
+
+(define-widget 'set 'checklist
+  "A list of members from a fixed set."
+  :tag "Set"
+  :format "%{%t%}:\n%v")
+
+(define-widget 'boolean 'toggle
+  "To be nil or non-nil, that is the question."
+  :tag "Boolean"
+  :format "%{%t%}: %v")
+
+;;; The `color' Widget.
+
+(define-widget 'color-item 'choice-item
+  "A color name (with sample)."
+  :format "%v (%[sample%])\n"
+  :button-face-get 'widget-color-item-button-face-get)
+
+(defun widget-color-item-button-face-get (widget)
+  ;; We create a face from the value.
+  (require 'facemenu)
+  (condition-case nil
+      (facemenu-get-face (intern (concat "fg:" (widget-value widget))))
+    (error 'default)))
+
+(define-widget 'color 'push-button
+  "Choose a color name (with sample)."
+  :format "%[%t%]: %v"
+  :tag "Color"
+  :value "default"
+  :value-create 'widget-color-value-create
+  :value-delete 'widget-children-value-delete
+  :value-get 'widget-color-value-get
+  :value-set 'widget-color-value-set
+  :action 'widget-color-action
+  :match 'widget-field-match
+  :tag "Color")
+
+(defvar widget-color-choice-list nil)
+;; Variable holding the possible colors.
+
+(defun widget-color-choice-list ()
+  (unless widget-color-choice-list
+    (setq widget-color-choice-list 
+	  (mapcar '(lambda (color) (list color))
+		  (x-defined-colors))))
+  widget-color-choice-list)
+
+(defun widget-color-value-create (widget)
+  (let ((child (widget-create-child-and-convert
+		widget 'color-item (widget-get widget :value))))
+    (widget-put widget :children (list child))))
+
+(defun widget-color-value-get (widget)
+  ;; Pass command to first child.
+  (widget-apply (car (widget-get widget :children)) :value-get))
+
+(defun widget-color-value-set (widget value)
+  ;; Pass command to first child.
+  (widget-apply (car (widget-get widget :children)) :value-set value))
+
+(defvar widget-color-history nil
+  "History of entered colors")
+
+(defun widget-color-action (widget &optional event)
+  ;; Prompt for a color.
+  (let* ((tag (widget-apply widget :menu-tag-get))
+	 (prompt (concat tag ": "))
+	 (answer (cond ((string-match "XEmacs" emacs-version)
+			(read-color prompt))
+		       ((fboundp 'x-defined-colors)
+			(completing-read (concat tag ": ")
+					 (widget-color-choice-list) 
+					 nil nil nil 'widget-color-history))
+		       (t
+			(read-string prompt (widget-value widget))))))
+    (unless (zerop (length answer))
+      (widget-value-set widget answer)
+      (widget-apply widget :notify widget event)
+      (widget-setup))))
+
+;;; The Help Echo
+
+(defun widget-echo-help-mouse ()
+  "Display the help message for the widget under the mouse.
+Enable with (run-with-idle-timer 1 t 'widget-echo-help-mouse)"
+  (let* ((pos (mouse-position))
+	 (frame (car pos))
+	 (x (car (cdr pos)))
+	 (y (cdr (cdr pos)))
+	 (win (window-at x y frame))
+	 (where (coordinates-in-window-p (cons x y) win)))
+    (when (consp where)
+      (save-window-excursion
+	(progn ; save-excursion
+	  (select-window win)
+	  (let* ((result (compute-motion (window-start win)
+					 '(0 . 0)
+					 (window-end win)
+					 where
+					 (window-width win)
+					 (cons (window-hscroll) 0)
+					 win)))
+	    (when (and (eq (nth 1 result) x)
+		       (eq (nth 2 result) y))
+	      (widget-echo-help (nth 0 result))))))))
+  (unless track-mouse
+    (setq track-mouse t)
+    (add-hook 'post-command-hook 'widget-stop-mouse-tracking)))
+
+(defun widget-stop-mouse-tracking (&rest args)
+  "Stop the mouse tracking done while idle."
+  (remove-hook 'post-command-hook 'widget-stop-mouse-tracking)
+  (setq track-mouse nil))
+
+(defun widget-at (pos)
+  "The button or field at POS."
+  (or (get-text-property pos 'button)
+      (get-text-property pos 'field)))
+
+(defun widget-echo-help (pos)
+  "Display the help echo for widget at POS."
+  (let* ((widget (widget-at pos))
+	 (help-echo (and widget (widget-get widget :help-echo))))
+    (cond ((stringp help-echo)
+	   (message "%s" help-echo))
+	  ((and (symbolp help-echo) (fboundp help-echo)
+		(stringp (setq help-echo (funcall help-echo widget))))
+	   (message "%s" help-echo)))))
+
+;;; The End:
+
+(provide 'widget-edit)
+
+;; widget-edit.el ends here