From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.io!.POSTED.blaine.gmane.org!not-for-mail From: Yuan Fu Newsgroups: gmane.emacs.devel Subject: Re: [External] : Editions to the Widget Manual Date: Sun, 20 Aug 2023 16:56:20 -0700 Message-ID: <10646331-8D57-4760-B940-171EF043657A@gmail.com> References: <4776bb96-16d4-6d77-d7a8-4fc949070bf5@gmail.com> Mime-Version: 1.0 (Mac OS X Mail 16.0 \(3731.600.7\)) Content-Type: multipart/mixed; boundary="Apple-Mail=_10F3A5D0-319C-48D1-A362-8270E462F228" Injection-Info: ciao.gmane.io; posting-host="blaine.gmane.org:116.202.254.214"; logging-data="18727"; mail-complaints-to="usenet@ciao.gmane.io" Cc: Mauro Aranda , emacs-devel , Bryce Carson To: Drew Adams Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane-mx.org@gnu.org Mon Aug 21 01:57:40 2023 Return-path: Envelope-to: ged-emacs-devel@m.gmane-mx.org Original-Received: from lists.gnu.org ([209.51.188.17]) by ciao.gmane.io with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1qXsId-0004og-Em for ged-emacs-devel@m.gmane-mx.org; Mon, 21 Aug 2023 01:57:40 +0200 Original-Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1qXsHq-00064n-Vm; Sun, 20 Aug 2023 19:56:51 -0400 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1qXsHo-000626-9u for emacs-devel@gnu.org; Sun, 20 Aug 2023 19:56:48 -0400 Original-Received: from mail-pf1-x430.google.com ([2607:f8b0:4864:20::430]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1qXsHc-0002P1-O8 for emacs-devel@gnu.org; Sun, 20 Aug 2023 19:56:48 -0400 Original-Received: by mail-pf1-x430.google.com with SMTP id d2e1a72fcca58-68a41035828so311586b3a.1 for ; Sun, 20 Aug 2023 16:56:36 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20221208; t=1692575795; x=1693180595; h=references:to:cc:in-reply-to:date:subject:mime-version:message-id :from:from:to:cc:subject:date:message-id:reply-to; bh=VBcIzpgkJz1FrRzCx+Fpi++IH4cmwyEjK46xMHg40D0=; b=NUIXVf6eJKFsmc+rIIqmx2loZumnv4Giu79Rv7pj9NOItDMhiutNW5n++hFJCzZZ4k 9qx+MxtKXq1tifnhVdxQIW8YQyQTuVKGTWjOadrrRUi30mE47W/TtzRDQ/u7GrG3eC4w hBve98Guu4ODj2G1715b/14NjPRtqrWe3+JlrRqMio+DHnC58D8Jnvsrlu8UbxemDSWx 7kQrSvyZIN4qYWHsLsxvWkLcO/cWupeBFeCM4RAdfJRNO4CnYGAqw4JSU/8T2Z+YHRT6 W8IrLisXsMaBP59FcYzBQhjvG8D4IfwZgi9xAwYCp7+68ozZ39srhv1FNk7q3HsIKpmT kFNw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1692575795; x=1693180595; h=references:to:cc:in-reply-to:date:subject:mime-version:message-id :from:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=VBcIzpgkJz1FrRzCx+Fpi++IH4cmwyEjK46xMHg40D0=; b=XTlZ7G/u++GskjmaMn86FB4Zc34UwTpVo0TGJGin0pYcJ/xNsqLl6owWOK9IYr5keE aI9mf2HKOInq+kBbrmeVVPy4P9M4qMtqRRZXJMGd0KCZ9L0FR/+pXZGMDoDjRcbZ3xPw mb9wSgG1ab93p/3w77IaGkd3qHBDaGuuoTAwKuwQ5sEa5c1UOSCAhVsb1vFYYpCh2/Mm rSqnuVf0YhtmhXZ4K4XQBoUhCblTdavN/KCLBorGvtGNr3NTKemuLaS0IE+MZs28QkDD V9escm98eIlQ2Sh7me0A5ZYzYk5cFMVKeCJaDCqL3Vw3RVFU6T37PICr+q/t/Qjcp8qL Rtvg== X-Gm-Message-State: AOJu0YzI5G0kjxU7/kfInL/0S9DwB9vRpLYnUR1DCNiJAIxYP5csHnNr Q3Lrtj5teyDS1fHQN7X1d4w= X-Google-Smtp-Source: AGHT+IG+dw3CWWGQ9Mxt6jTLB1qeJf5LvAo/4lkGIJ2uo33GWllnGroEDSeObkWzYI3ghs7SEL5Wmw== X-Received: by 2002:a05:6a00:1884:b0:68a:3c7a:12a7 with SMTP id x4-20020a056a00188400b0068a3c7a12a7mr1985913pfh.5.1692575794562; Sun, 20 Aug 2023 16:56:34 -0700 (PDT) Original-Received: from smtpclient.apple (cpe-172-117-161-177.socal.res.rr.com. [172.117.161.177]) by smtp.gmail.com with ESMTPSA id ca20-20020a056a02069400b00563bee47a79sm4685619pgb.80.2023.08.20.16.56.32 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Sun, 20 Aug 2023 16:56:33 -0700 (PDT) In-Reply-To: X-Mailer: Apple Mail (2.3731.600.7) Received-SPF: pass client-ip=2607:f8b0:4864:20::430; envelope-from=casouri@gmail.com; helo=mail-pf1-x430.google.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, FREEMAIL_FROM=0.001, HTML_MESSAGE=0.001, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_HTML_ATTACH=0.01 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: emacs-devel@gnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: "Emacs development discussions." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: emacs-devel-bounces+ged-emacs-devel=m.gmane-mx.org@gnu.org Original-Sender: emacs-devel-bounces+ged-emacs-devel=m.gmane-mx.org@gnu.org Xref: news.gmane.io gmane.emacs.devel:309005 Archived-At: --Apple-Mail=_10F3A5D0-319C-48D1-A362-8270E462F228 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=utf-8 Thanks for working on this Mauro! The overall structure is clearer, and = the additional information is most welcome. I personally think it might = be better to move the default widget to under section 8.1 Basic types, = in its own subsection, so that it=E2=80=99s easier to look for. In the = same vein, adding some cindexes could further help users to find the = information they are looking for, when using the manual as a reference. > On Aug 20, 2023, at 2:59 PM, Drew Adams wrote: >=20 > Thanks for working on this, Mauro! >=20 > I don't work with texi (the original texi text > or patches or patched), but if you can point to > a non-texi version of the patched text (e.g. > plain-text or other) then if/when I get some > time I'll take a look. >=20 > Whether that happens or not, thanks again for > doing this. It will really help, I'm sure. Here=E2=80=99s the old and new version in HTML format. Yuan --Apple-Mail=_10F3A5D0-319C-48D1-A362-8270E462F228 Content-Disposition: attachment; filename=widget.old.html Content-Type: text/html; x-unix-mode=0644; name="widget.old.html" Content-Transfer-Encoding: quoted-printable The Emacs Widget Library

Next: Introduction   [Contents][Index]

The Emacs Widget = Library

Copyright © 2000–2023 Free Software Foundation, Inc.

Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.3 or any later version published by the Free Software Foundation; with no Invariant Sections, with the Front-Cover Texts being “A GNU = Manual”, and with the Back-Cover Texts as in (a) below. A copy of the license is included in the section entitled “GNU Free Documentation = License”.

(a) The FSF’s Back-Cover Text is: “You have the freedom = to copy and modify this GNU manual.”

Next: User = Interface, Previous: The= Emacs Widget Library, Up: The Emacs Widget Library   [Contents][Index]

1 Introduction

Most graphical user interface toolkits provide a number of standard user interface controls (sometimes known as “widgets” or = “gadgets”). Emacs doesn’t really support anything like this, except for an incredibly powerful text “widget.” On the other hand, Emacs = does provide the necessary primitives to implement many other widgets within a text buffer. The widget package = simplifies this task.

The basic widgets are:

link

Areas of text with an associated action. Intended for hypertext = links embedded in text.

push-button

Like link, but intended for stand-alone buttons.

editable-field

An editable text field. It can be either variable or fixed = length.

menu-choice

Allows the user to choose one of multiple options from a menu, = each option is itself a widget. Only the selected option will be visible in the buffer.

radio-button-choice

Allows the user to choose one of multiple options by activating = radio buttons. The options are implemented as widgets. All options will be visible in the buffer.

item

A simple constant widget intended to be used in the menu-choice and radio-button-choice widgets.

choice-item

A button item only intended for use in choices. When invoked, = the user will be asked to select another option from the choice widget.

toggle

A simple ‘on’/‘off’ switch.

checkbox

A checkbox (‘[ = ]’/‘[X]’).

editable-list

Create an editable list. The user can insert or delete items in = the list. Each list item is itself a widget.

Now, of what possible use can support for widgets be in a text = editor? I’m glad you asked. The answer is that widgets are useful for implementing forms. A form in Emacs is a buffer = where the user is supposed to fill out a number of fields, each of which has a specific meaning. The user is not supposed to change or delete any of the text between the fields. Examples of forms in Emacs are the forms package (of course), the customize buffers, the mail and news compose modes, and the HTML form support in the = w3 browser.

The advantages for a programmer of using the widget package to implement forms are:

  1. More complex fields than just editable text are supported.
  2. You can give the users immediate feedback if they enter = invalid data in a text field, and sometimes prevent entering invalid data.
  3. You can have fixed sized fields, thus allowing multiple fields = to be lined up in columns.
  4. It is simple to query or set the value of a field.
  5. Editing happens in the buffer, not in the mini-buffer.
  6. Packages using the library get a uniform look, making them = easier for the user to learn.
  7. As support for embedded graphics improve, the widget library = will be extended to use the GUI features. This means that your code using the widget library will also use the new graphic features automatically.

Next: Programming Example, Previous: Introduction, Up: The Emacs Widget Library   [Contents][Index]

2 User Interface

A form consists of read only text for documentation and some fields, where each field contains two parts, a tag and a value. The tags are used to identify the fields, so the documentation can refer to the ‘foo field’, meaning the field = tagged with ‘Foo’. Here is an example form: 

Here is some documentation.

Name: My Name     Choose: This option
Address:  Some Place
In some City
Some country.

See also _other work_ for more information.

Numbers: count to three below
[INS] [DEL] One
[INS] [DEL] Eh, =
two?
[INS] [DEL] Five!=

[INS]

Select multiple:

[X] This
[ ] That
[X] Thus

Select one:

(*) One
( ) Another One.
( ) A Final One.

[Apply Form] [Reset Form]

The top level widgets in this example are tagged ‘Name’, ‘Choose’, ‘Address’, ‘_other = work_’, ‘Numbers’, ‘Select multiple’, ‘Select one’, ‘[Apply Form]’, and ‘[Reset Form]’. There are = basically two things the user can do within a form, namely editing the editable text fields and activating the buttons.

2.1 Editable Text Fields

In the example, the value for the ‘Name’ is most likely displayed in an editable text field, and so are values for each of the members of the ‘Numbers’ list. All the = normal Emacs editing operations are available for editing these fields. The only restriction is that each change you make must be contained within a single editable text field. For example, capitalizing all text from the middle of one field to the middle of another field is prohibited.

Editable text fields are created by the editable-field widget.

Warning: In an editable-field widget, the editable field must not be adjacent to another widget—that won’t = work. You must put some text in between. Either make this text part of the editable-field widget itself, or insert = it with widget-insert.

The :format keyword is useful for = generating the necessary text; for instance, if you give it a value of "Name: %v ", the ‘Name: ’ part will provide = the necessary separating text before the field and the trailing space will provide the separating text after the field. If you don’t include the :size keyword, the field will extend to the = end of the line, and the terminating newline will provide separation after.

Warning: In an editable-field widget, the ‘%v’ escape must be preceded by some other text in the :format string (if specified).

The editing text fields are highlighted with the widget-field-face face, making them easy to = find.

Face: widget-field-face

Face used for other editing fields.

2.2 Buttons

Some portions of the buffer have an associated action, which can be invoked by a standard key or mouse command. = These portions are called buttons. The default commands for = activating a button are:

RET
Command: widget-button-press pos &optional = event

Invoke the button at pos, defaulting to = point. If point is not located on a button, invoke the binding in widget-global-map (by default the global = map).

mouse-2
Command: widget-button-click event = ¶

Invoke the button at the location of the mouse pointer. If the = mouse pointer is located in an editable text field, invoke the binding in widget-global-map (by default the global = map).

There are several different kind of buttons, all of which are present = in the example:

The Option Field Tags

When you invoke one of these buttons, you will be asked to choose between a number of different options. This is how you edit an option field. Option fields are created by the menu-choice widget. In the example, ‘Choose’ is an option field tag.

The ‘[INS]’ and ‘[DEL]’ buttons

Activating these will insert or delete elements from an editable = list. The list is created by the editable-list = widget.

Embedded Buttons

The ‘_other = work_’ is an example of an embedded button. Embedded buttons are not associated with any fields, but can = serve any purpose, such as implementing hypertext references. They are usually created by the link widget.

The ‘[ = ]’ and ‘[X]’ buttons

Activating one of these will convert it to the other. This is = useful for implementing multiple-choice fields. You can create them with the checkbox widget.

The ‘( = )’ and ‘(*)’ buttons

Only one radio button in a radio-button-choice widget can be selected at any time. When you invoke one of the unselected radio buttons, it will be selected and the previous selected radio button will become unselected.

The ‘[Apply Form]’ and ‘[Reset Form]’ = buttons

These are explicit buttons made with the push-button widget. The main difference from the link widget is that = the buttons will be displayed as GUI buttons when possible.

To make them easier to locate, buttons are emphasized in the buffer.

Face: widget-button-face

Face used for buttons.

User = Option: widget-mouse-face

Face used for highlighting a button when the mouse pointer moves = across it.

2.3 Navigation

You can use all the normal Emacs commands to move around in a form buffer, plus you will have these additional commands:

TAB
Command: widget-forward &optional count = ¶

Move point count buttons or editing = fields forward.

M-TAB
S-TAB
Command: widget-backward &optional count = ¶

Move point count buttons or editing = fields backward.

Next: Setting Up the Buffer, Previous: User = Interface, Up: The Emacs = Widget Library   [Contents][Index]

3 Programming = Example

Here is the code to implement the user interface example (see User Interface). 

(require 'widget)

(eval-when-compile
  (require 'wid-edit))

(defvar widget-example-repeat)

(defun widget-example ()
  "Create the widgets from the Widget manual."
  (interactive)
  (switch-to-buffer "*Widget Example*")
  (kill-all-local-variables)
  (make-local-variable 'widget-example-repeat)
  (let ((inhibit-read-only t))
    (erase-buffer))
  (remove-overlays)
  (widget-insert "Here is some documentation.\n\n")
  (widget-create 'editable-field
                 :size 13
                 :format "Name: %v " ; Text after the field!
                 "My Name")
  (widget-create 'menu-choice
                 :tag "Choose"
                 :value "This"
                 :help-echo "Choose me, please!"
                 :notify (lambda (widget &rest ignore)
                           (message "%s is a good choice!"
                                    (widget-value widget)))
                 '(item :tag "This option" :value =
"This")
                 '(choice-item "That option")
                 '(editable-field :menu-tag "No option" =
"Thus option"))
  (widget-create 'editable-field
                 :format "Address: %v"
                 "Some Place\nIn some City\nSome country.")
  (widget-insert "\nSee also ")
  (widget-create 'link
                 :notify (lambda (&rest ignore)
                           (widget-value-set widget-example-repeat
                                             '("En" =
"To" "Tre"))
                           (widget-setup))
                 "other work")
  (widget-insert
    " for more information.\n\nNumbers: count to three =
below\n")
  (setq widget-example-repeat
        (widget-create 'editable-list
                       :entry-format "%i %d %v"
                       :notify
                       (lambda (widget &rest ignore)
                         (let ((old (widget-get widget
                                                ':example-length))
                               (new (length (widget-value widget))))
                           (unless (eq old new)
                             (widget-put widget ':example-length new)
                             (message "You can count to %d." =
new))))
                       :value '("One" "Eh, two?" =
"Five!")
                       '(editable-field :value "three")))
  (widget-insert "\n\nSelect multiple:\n\n")
  (widget-create 'checkbox t)
  (widget-insert " This\n")
  (widget-create 'checkbox nil)
  (widget-insert " That\n")
  (widget-create 'checkbox
                 :notify (lambda (&rest ignore) (message =
"Tickle"))
                 t)
  (widget-insert " Thus\n\nSelect one:\n\n")
  (widget-create 'radio-button-choice
                 :value "One"
                 :notify (lambda (widget &rest ignore)
                           (message "You selected %s"
                                    (widget-value widget)))
                 '(item "One") '(item "Another =
One.")
                 '(item "A Final One."))
  (widget-insert "\n")
  (widget-create 'push-button
                 :notify (lambda (&rest ignore)
                           (if (=3D (length
                                   (widget-value widget-example-repeat))
                                  3)
                               (message "Congratulation!")
                             (error "Three was the count!")))
                 "Apply Form")
  (widget-insert " ")
  (widget-create 'push-button
                 :notify (lambda (&rest ignore)
                           (widget-example))
                 "Reset Form")
  (widget-insert "\n")
  (use-local-map widget-keymap)
  (widget-setup))

Next: Basic = Types, Previous: Programming Example, Up: The Emacs Widget Library   [Contents][Index]

4 Setting Up the = Buffer

Widgets are created with widget-create, = which returns a widget object. This object can be queried and = manipulated by other widget functions, until it is deleted with widget-delete. After the widgets have been created, widget-setup must be called to enable them.

Function: widget-create type [ keyword argument ]… = ¶

Create and return a widget of type type. The syntax for the type argument is described = in Basic Types.

The keyword arguments can be used to overwrite the keyword arguments that are part of type.

Function: widget-delete widget

Delete widget and remove it from the = buffer.

Function: widget-setup

Set up a buffer to support widgets.

This should be called after creating all the widgets and before = allowing the user to edit them.

If you want to insert text outside the widgets in the form, the recommended way to do that is with widget-insert.

Function: widget-insert

Insert the arguments, either strings or characters, at point. The inserted text will be read-only.

There is a standard widget keymap which you might find useful.

Const: widget-keymap

TAB and C-TAB are bound to widget-forward and widget-backward, respectively. RET and mouse-2 are bound to widget-button-press and widget-button-click.

Variable: widget-global-map

Keymap used by widget-button-press = and widget-button-click when not on a button. By default this is global-map.

Next: Sexp = Types, Previous: Setting Up the Buffer, Up: The Emacs Widget Library   [Contents][Index]

5 Basic Types

This is the general syntax of a type specification: 

name ::=3D =
(name [keyword argument]... args)
     |   name

Where, name is a widget name, keyword is the name of a property, argument is the value of the = property, and args are interpreted in a widget specific way.

The following keyword arguments apply to all widgets:

:value

The initial value for widgets of this type. Typically, a widget represents its value in two formats: external and internal. The external format is the value as the rest of Emacs sees it, and the internal format is a representation that the widget defines and uses in a widget specific way.

Both formats might be the same for certain widgets and might differ for others, and there is no guarantee about which format the value stored in the :value property has. However, = when creating a widget or defining a new one (see Defining New Widgets), the :value should be in the external format.

:format

This string will be inserted in the buffer when you create a = widget. The following ‘%’ escapes are = available:

‘%[’
‘%]’

The text inside will be marked as a button.

By default, the text will be shown in widget-button-face, and surrounded by brackets.

User Option: widget-button-prefix

String to prefix buttons.

User Option: widget-button-suffix

String to suffix buttons.

‘%{’
‘%}’

The text inside will be displayed with the face specified by :sample-face.

‘%v’

This will be replaced with the buffer representation of the = widget’s value. What this is depends on the widget type.

Warning: In an editable-field widget, the ‘%v’ escape must be preceded by some other text in the format string (if specified).

‘%d’

Insert the string specified by :doc = here.

‘%h’

Like ‘%d’, with the = following modifications: If the documentation string is more than one line, it will add a button which will toggle between showing only the first line, and showing the full text. Furthermore, if there is no :doc property in = the widget, it will instead examine the :documentation-property = property. If it is a lambda expression, it will be called with the widget’s value as an argument, and the result will be used as the documentation text.

‘%t’

Insert the string specified by :tag = here, or the princ representation of the value if there is no tag.

‘%%’

Insert a literal ‘%’.

:button-face

Face used to highlight text inside %[ %] in the format.

:button-prefix
:button-suffix

Text around %[ %] in the format.

These can be

nil

No text is inserted.

a string

The string is inserted literally.

a symbol

The value of the symbol is expanded according to this table.

:doc

The string inserted by the ‘%d’ escape in the format string.

:tag

The string inserted by the ‘%t’ escape in the format string.

:tag-glyph

Name of image to use instead of the string specified by :tag on Emacsen that supports it.

:help-echo

Specifies how to display a message whenever you move to the = widget with either widget-forward or widget-backward or move the mouse over it (using the standard help-echo = mechanism). The argument is either a string to display, a function of one argument, the widget, which should return a string to display, or a form that evaluates to such a string.

:follow-link

Specifies how to interpret a mouse-1 = click on the widget. See Defining Clickable Text in the = Emacs Lisp Reference Manual.

:indent

An integer indicating the absolute number of spaces to indent = children of this widget.

:offset

An integer indicating how many extra spaces to add to the = widget’s grandchildren compared to this widget.

:extra-offset

An integer indicating how many extra spaces to add to the = widget’s children compared to this widget.

:notify

A function called each time the widget or a nested widget is = changed. The function is called with two or three arguments. The first argument is the widget itself, the second argument is the widget that was changed, and the third argument is the event leading to the change, if any.

:menu-tag

Tag used in the menu when the widget is used as an option in a menu-choice widget.

=
:menu-tag-get

Function used for finding the tag when the widget is used as an = option in a menu-choice widget. By default, the = tag used will be either the :menu-tag or :tag = property if present, or the princ representation of the :value property if = not.

:match

Should be a function called with two arguments, the widget and an external value, and should return non-nil if = the widget can represent the specified value.

:validate

A function which takes a widget as an argument, and returns nil if the widget’s current value is valid for the widget. Otherwise = it should return the widget containing the invalid data, and set that widget’s :error property to a string = explaining the error.

The following predefined function can be used:

Function: widget-children-validate widget

All the :children of widget must be valid.

:tab-order

Specify the order in which widgets are traversed with widget-forward or widget-backward. This is only partially implemented.

  1. Widgets with tabbing order -1 are = ignored.
  2. (Unimplemented) When on a widget with tabbing order n, go to the next widget in the buffer with tabbing order n+1 = or nil, whichever comes first.
  3. When on a widget with no tabbing order specified, go to the = next widget in the buffer with a positive tabbing order, or nil
:parent

The parent of a nested widget (e.g., a menu-choice item or an element of a editable-list widget).

:sibling-args

This keyword is only used for members of a radio-button-choice or checklist. The value should be a list of = extra keyword arguments, which will be used when creating the radio-button or checkbox associated with this item.

User Option: widget-image-directory = ¶

Directory where Widget should look for images. Widget will look here for a file with the same name as specified for the image, with either a .xpm (if supported) or = .xbm extension.

User Option: widget-image-enable

If non-nil, allow images to appear on = displays where they are supported.

Next: The url-link Widget, Up: Basic Types   [Contents][Index]

Syntax: 

type ::=3D =
(link [keyword argument]...  [ value ])

The value, if present, is used to initialize = the :value property. The value should be a string, which will be inserted in the buffer.

By default the link will be shown in brackets.

User = Option: widget-link-prefix

String to prefix links.

User = Option: widget-link-suffix

String to suffix links.

Next: The info-link Widget, Previous: The link = Widget, Up: Basic = Types   [Contents][Index]

Syntax: 

type ::=3D =
(url-link [keyword argument]...  url)

When this link is invoked, the WWW = browser specified by browse-url-browser-function will be called = with url.

Next: The = push-button Widget, Previous: The url-link Widget, Up: Basic Types   [Contents][Index]

Syntax: 

type ::=3D =
(info-link [keyword argument]...  address)

When this link is invoked, the built-in Info reader is started on address.

Next: The = editable-field Widget, Previous: The info-link Widget, Up: Basic Types   [Contents][Index]

5.4 The push-button Widget

Syntax: 

type ::=3D =
(push-button [keyword argument]...  [ value ])

The value, if present, is used to initialize = the :value property. The value should be a string, which will be inserted in the buffer.

By default the tag will be shown in brackets.

User Option: widget-push-button-prefix = ¶

String to prefix push buttons.

User Option: widget-push-button-suffix = ¶

String to suffix push buttons.

Next: The text Widget, Previous: The push-button Widget, Up: Basic Types   [Contents][Index]

5.5 The editable-field Widget

Syntax: 

type ::=3D =
(editable-field [keyword argument]... [ value ])

The value, if present, is used to initialize = the :value property. The value should be a string, which will be inserted in the field. This widget will match all string values.

The following extra properties are recognized:

:size

The width of the editable field.
By default the field will reach to the end of the line.

:value-face

Face used for highlighting the editable field. Default is widget-field-face, see User Interface.

:secret

Character used to display the value. You can set this to, e.g., = ?* if the field contains a password or other secret information. By default, this is nil, and the value is not = secret.

:valid-regexp

By default the :validate function = will match the content of the field with the value of this attribute. The default value is "" which matches everything.

:keymap

Keymap used in the editable field. The default value is widget-field-keymap, which allows you to use = all the normal editing commands, even if the buffer’s major mode suppresses some = of them. Pressing RET invokes the function = specified by :action.

Next: The = menu-choice Widget, Previous: The editable-field Widget, Up: Basic Types   = [Contents][Index]

5.6 The text Widget

This is just like editable-field, but = intended for multiline text fields. The default :keymap is widget-text-keymap, which does not rebind the RET key.

Next: The radio-button-choice = Widget, Previous: The = text Widget, Up: Basic Types   [Contents][Index]

5.7 The menu-choice Widget

Syntax: 

type ::=3D =
(menu-choice [keyword argument]... type ... )

The type argument represents each possible = choice. The widget’s value will be that of the chosen type argument. = This widget will match any value matching at least one of the specified type arguments.

:void

Widget type used as a fallback when the value does not match any = of the specified type arguments.

:case-fold

Set this to nil if you don’t = want to ignore case when prompting for a choice through the minibuffer.

:children

A list whose CAR is the widget = representing the currently chosen type in the buffer.

:choice

The current chosen type.

:args

The list of types.

Next: The item Widget, Previous: The menu-choice Widget, Up: Basic Types   [Contents][Index]

5.8 = The radio-button-choice Widget

Syntax: 

type ::=3D =
(radio-button-choice [keyword argument]...  type ... )

The component types specify the choices, with one radio button for each. The widget’s value will be that of the chosen type argument. This widget matches any value that matches at least one of the specified type arguments.

The following extra properties are recognized.

=
:entry-format

This string will be inserted for each entry in the list. The following ‘%’ escapes are = available:

‘%v’

Replace with the buffer representation of the type widget.

‘%b’

Replace with the radio button.

‘%%’

Insert a literal ‘%’.

:button-args

A list of keywords to pass to the radio buttons. Useful for = setting, e.g., the ‘:help-echo’ for each = button.

:buttons

The widgets representing the radio buttons.

:children

The widgets representing each type.

:choice

The current chosen type

:args

The list of types.

You can add extra radio button items to a radio-button-choice widget after it has been created with the function widget-radio-add-item.

Function: widget-radio-add-item widget type = ¶

Add to radio-button-choice widget = widget a new radio button item of type type.

Please note that such items added after the radio-button-choice widget has been created will not be = properly destructed when you call widget-delete.

Next: The = choice-item Widget, Previous: The = radio-button-choice Widget, Up: Basic Types   = [Contents][Index]

5.9 The item Widget

Syntax: 

item ::=3D =
(item [keyword argument]... value)

The value, if present, is used to initialize = the :value property. The value should be a string, which will be inserted in the buffer. This widget will only match the specified value.

Next: The toggle Widget, Previous: The item = Widget, Up: Basic = Types   [Contents][Index]

5.10 The choice-item Widget

Syntax: 

item ::=3D =
(choice-item [keyword argument]... value)

The value, if present, is used to initialize = the :value property. The value should be a string, which will be inserted in the buffer as a button. Activating the button of a choice-item is equivalent to activating the parent widget. This widget will only match the specified value.

Next: The checkbox Widget, Previous: The choice-item Widget, Up: Basic Types   [Contents][Index]

5.11 The toggle Widget

Syntax: 

type ::=3D =
(toggle [keyword argument]...)

The widget has two possible states, ‘on’ and ‘off’, which correspond to a t or nil value, respectively.

The following extra properties are recognized:

:on

A string representing the ‘on’ state. By default the string ‘on’.

:off

A string representing the ‘off’ state. By default the string ‘off’.

:on-glyph

Name of a glyph to be used instead of the ‘:on’ text string, on emacsen that supports this.

:off-glyph

Name of a glyph to be used instead of the ‘:off’ text string, on emacsen that supports this.

Next: The checklist Widget, Previous: The toggle = Widget, Up: Basic = Types   [Contents][Index]

5.12 The checkbox Widget

This widget has two possible states, ‘selected’ and ‘unselected’, which corresponds = to a t or nil = value.

Syntax: 

type ::=3D =
(checkbox [keyword argument]...)

Next: The = editable-list Widget, Previous: The checkbox Widget, Up: Basic Types   [Contents][Index]

5.13 The checklist Widget

Syntax: 

type ::=3D =
(checklist [keyword argument]...  type ... )

The type arguments represent each checklist = item. The widget’s value will be a list containing the values of all checked type arguments. The checklist widget will match a list whose elements all match at least one of the specified type = arguments.

The following extra properties are recognized:

:entry-format

This string will be inserted for each entry in the list. The following ‘%’ escapes are = available:

‘%v’

Replaced with the buffer representation of the type widget.

‘%b’

Replace with the checkbox.

‘%%’

Insert a literal ‘%’.

:greedy

Usually a checklist will only match if the items are in the exact sequence given in the specification. By setting :greedy to non-nil, it will allow the items to come in = any sequence. However, if you extract the value they will be in the sequence given in the checklist, i.e., the original sequence is forgotten.

:button-args

A list of keywords to pass to the checkboxes. Useful for = setting, e.g., the ‘:help-echo’ for each = checkbox.

:buttons

The widgets representing the checkboxes.

:children

The widgets representing each type.

:args

The list of types.

Next: The group Widget, Previous: The checklist = Widget, Up: Basic = Types   [Contents][Index]

5.14 The editable-list Widget

Syntax: 

type ::=3D =
(editable-list [keyword argument]... type)

The value is a list, where each member represents one widget of type type.

The following extra properties are recognized:

:entry-format

This string will be inserted for each entry in the list. The following ‘%’ escapes are = available:

‘%v’

This will be replaced with the buffer representation of the type widget.

‘%i’

Insert the [INS] button.

‘%d’

Insert the [DEL] button.

‘%%’

Insert a literal ‘%’.

:insert-button-args

A list of keyword arguments to pass to the insert buttons.

:delete-button-args

A list of keyword arguments to pass to the delete buttons.

:append-button-args

A list of keyword arguments to pass to the trailing insert = button.

:buttons

The widgets representing the insert and delete buttons.

:children

The widgets representing the elements of the list.

:args

List whose CAR is the type of the = list elements.

Previous: The = editable-list Widget, Up: Basic Types   = [Contents][Index]

5.15 The group Widget

This widget simply group other widgets together.

Syntax: 

type ::=3D =
(group [keyword argument]... type...)

The value is a list, with one member for each type.

Next: Properties, Previous: Basic Types, Up: The Emacs Widget Library   [Contents][Index]

6 Sexp Types

A number of widgets for editing s-expressions = (Lisp types), sexp for short, are also available. These basically fall in several categories described in this section.

Next: Generic Sexp = Widget, Up: Sexp = Types   [Contents][Index]

6.1 The Constant = Widgets

The const widget can contain any Lisp = expression, but the user is prohibited from editing it, which is mainly useful as a component of one of the composite widgets.

The syntax for the const widget is: 

type ::=3D =
(const [keyword argument]...  [ value ])

The value, if present, is used to initialize = the :value property and can be any s-expression.

Widget: const

This will display any valid s-expression in an immutable part of = the buffer.

There are two variations of the const = widget, namely variable-item and function-item. These should contain a symbol with a variable or function binding. The major difference from the const widget is that they will allow the = user to see the variable or function documentation for the symbol.

Widget: variable-item

An immutable symbol that is bound as a variable.

Widget: function-item

An immutable symbol that is bound as a function.

Next: Atomic Sexp = Widgets, Previous: The Constant Widgets, Up: Sexp Types   [Contents][Index]

6.2 Generic Sexp = Widget

The sexp widget can contain any Lisp = expression, and allows the user to edit it inline in the buffer.

The syntax for the sexp widget is: 

type ::=3D =
(sexp [keyword argument]...  [ value ])
Widget:= sexp

This will allow you to edit any valid s-expression in an editable = buffer field.

The sexp widget takes the same keyword = arguments as the editable-field widget. See The editable-field Widget.

Next: Composite Sexp = Widgets, Previous: Generic Sexp Widget, Up: Sexp Types   [Contents][Index]

6.3 Atomic Sexp = Widgets

The atoms are s-expressions that do not consist of other = s-expressions. For example, a string, a file name, or a symbol are atoms, while a list is a composite type. You can edit the value of an atom with the following widgets.

The syntax for all the atoms are: 

type ::=3D =
(construct [keyword =
argument]...  [ value =
])

The value, if present, is used to initialize = the :value property and must be an expression of the same type as the widget. That is, the string widget can only be initialized with a string.

All the atom widgets take the same keyword arguments as the editable-field widget. See The editable-field Widget.

Widget: string

Allows you to edit a string in an editable field.

Widget: regexp

Allows you to edit a regular expression in an editable field.

Widget: character

Allows you to enter a character in an editable field.

Widget:= file

Allows you to edit a file name in an editable field.

Keywords:

:must-match

If this is set to non-nil, only = existing file names will be allowed in the minibuffer.

Widget: directory

Allows you to edit a directory name in an editable field. Similar to the file widget.

Widget: symbol

Allows you to edit a Lisp symbol in an editable field.

Widget: function

Allows you to edit a lambda expression, or a function name with = completion.

Widget: variable

Allows you to edit a variable name, with completion.

Widget: integer

Allows you to edit an integer in an editable field.

Widget: number

Allows you to edit a number in an editable field.

Widget: boolean

Allows you to edit a boolean. In Lisp this means a variable = which is either nil meaning false, or non-nil meaning true.

Previous: Atomic Sexp = Widgets, Up: Sexp = Types   [Contents][Index]

6.4 Composite Sexp = Widgets

The syntax for the composite widget construct is: 

type ::=3D =
(construct [keyword =
argument]...  component...)

where each component must be a widget type. = Each component widget will be displayed in the buffer, and will be editable by the user.

Widget:= cons

The value of a cons widget must be a = cons-cell whose CAR and CDR have two specified types. It uses = this syntax: 

type ::=3D =
(cons [keyword argument]...  car-type cdr-type)
Widget: choice

The value matched by a choice widget = must have one of a fixed set of types. The widget’s syntax is as follows: 

type ::=3D =
(choice [keyword argument]...  type ... )

The value of a choice widget can be = anything that matches any of the types.

Widget:= list

The value of a list widget must be a = list whose element types match the specified component types: 

type ::=3D =
(list [keyword argument]...  component-type...)

Thus, (list string number) matches lists = of two elements, the first being a string and the second being a number.

Widget: vector

The vector widget is like the list widget but matches vectors instead of lists. Thus, (vector string = number) matches vectors of two elements, the first being a string and the second being a number.

The above suffice for specifying fixed size lists and vectors. To = get variable length lists and vectors, you can use a choice, set, or repeat = widget together with the :inline keyword. If any component of a composite widget has the :inline keyword set, its value must be a = list which will then be spliced into the composite. For example, to specify a list whose first element must be a file name, and whose remaining elements should either be the symbol t or two strings (file = names), you can use the following widget specification: 

(list file
      (choice (const t)
              (list :inline t
                    :value ("foo" "bar")
                    string string)))

The value of a widget of this type will either have the form (file t) or (file string string).

This concept of :inline may be hard to = understand. It was certainly hard to implement, so instead of confusing you more by trying to explain it here, I’ll just suggest you meditate over it = for a while.

Widget: = set

Specifies a type whose values are the lists whose elements all = belong to a given set. The order of elements of the list is not significant. Here’s the syntax: 

type ::=3D =
(set [keyword argument]...  permitted-element ... )

Use const to specify each permitted = element, like this: (set (const a) (const b)).

Widget: repeat

Specifies a list of any number of elements that fit a certain = type. 

type ::=3D =
(repeat [keyword argument]...  type)

Next: Defining New Widgets, Previous: Sexp Types, Up: The Emacs Widget Library   [Contents][Index]

7 Properties

You can examine or set the value of a widget by using the widget = object that was returned by widget-create.

Function: widget-value widget

Return the current value contained in widget. It is an error to call this function on an uninitialized widget.

Function: widget-value-set widget value

Set the value contained in widget to = value. It is an error to call this function with an invalid value.

Important: You must call widget-setup = after modifying the value of a widget before the user is allowed to edit the widget again. It is enough to call widget-setup once if you modify multiple widgets. This is currently only necessary if the widget contains an editing field, but may be necessary for other widgets in the future.

If your application needs to associate some information with the = widget objects, for example a reference to the item being edited, it can be done with widget-put and widget-get. The property names must begin with a ‘:’.

Function: widget-put widget property value = ¶

In widget set property to value. property should be a symbol, while value can be anything.

Function: widget-get widget property = ¶

In widget return the value for property. property should be a symbol, the value is what = was last set by widget-put for property.

Function: widget-member widget property = ¶

Non-nil if widget has a value (even nil) for property property.

Function: widget-apply widget property &rest args = ¶

Apply the value of property to widget, passing args as additional arguments to the function. Return the result of that function call.

Occasionally it can be useful to know which kind of widget you have, i.e., the name of the widget type you gave when the widget was created.

Function: widget-type widget

Return the name of widget, a symbol.

Widgets can be in two states: active, which means they are modifiable = by the user, or inactive, which means they cannot be modified by the user. You can query or set the state with the following code: 

;; Examine if widget is active or not.
(if (widget-apply widget :active)
    (message "Widget is active.")
  (message "Widget is inactive.")

;; Make widget inactive.
(widget-apply widget :deactivate)

;; Make widget active.
(widget-apply widget :activate)

A widget is inactive if it, or any of its ancestors (found by following the :parent link), have been = deactivated. To make sure a widget is really active, you must therefore activate both it and all its ancestors. 

(while widget
  (widget-apply widget :activate)
  (setq widget (widget-get widget :parent)))

You can check if a widget has been made inactive by examining the = value of the :inactive keyword. If this is = non-nil, the widget itself has been deactivated. This is different from using the :active keyword, in that the latter tells you if the widget or any of its ancestors have been deactivated. Do not attempt to set the :inactive keyword directly. Use the :activate :deactivate keywords instead.

Next: Widget = Browser, Previous: Properties, Up: The Emacs Widget Library   [Contents][Index]

8 Defining New = Widgets

You can define specialized widgets with define-widget. It allows you to create a shorthand for more complex widgets, including specifying component widgets and new default values for the keyword arguments.

Function: define-widget name class doc &rest args = ¶

Define a new widget type named name from = class.

name and class should both be symbols, class should be one of the existing widget types.

The third argument doc is a documentation = string for the widget.

After the new widget has been defined, the following two calls will create identical widgets: 

  • (widget-create name)

  • (apply widget-create class args)

Using define-widget just stores the = definition of the widget type in the widget-type property of name, which is what widget-create uses.

If you only want to specify defaults for keywords with no complex conversions, you can use identity as your = conversion function.

The following additional keyword arguments are useful when defining = new widgets:

:convert-widget

Function to convert a widget type before creating a widget of = that type. It takes a widget type as an argument, and returns the converted widget type. When a widget is created, this function is called for the widget type and all the widget’s parent types, most derived first.

The following predefined functions can be used here:

Function: widget-types-convert-widget widget = ¶

Convert :args as widget types in widget.

Function: widget-value-convert-widget widget = ¶

Initialize :value from :args in widget.

:copy

Function to deep copy a widget type. It takes a shallow copy of = the widget type as an argument (made by copy-sequence), and returns a deep copy. The purpose of this is to avoid having different instances of combined widgets share nested attributes.

The following predefined functions can be used here:

Function: widget-types-copy widget

Copy :args as widget types in widget.

:value-to-internal

Function to convert the value to the internal format. The = function takes two arguments, a widget and an external value, and returns the internal value. The function is called on the present :value when the widget is created, and on any value set later with widget-value-set.

:value-to-external

Function to convert the value to the external format. The = function takes two arguments, a widget and an internal value, and returns the external value.

:create

Function to create a widget from scratch. The function takes one argument, a widget type, and creates a widget of that type, inserts it in the buffer, and returns a widget object.

:delete

Function to delete a widget. The function takes one argument, a = widget, and should remove all traces of the widget from the buffer.

The default value is:

Function: widget-default-delete widget

Remove widget from the buffer. Delete all :children and :buttons in widget.

In most cases you should not change this value, but instead use :value-delete to make any additional = cleanup.

:value-create

Function to expand the ‘%v’= escape in the format string. It will be called with the widget as its argument and should insert a representation of the widget’s value in the buffer.

Nested widgets should be listed in :children or :buttons to make sure they are automatically deleted.

:value-delete

Should remove the representation of the widget’s value from = the buffer. It will be called with the widget as its argument. It doesn’t = have to remove the text, but it should release markers and delete nested widgets if these are not listed in :children or = :buttons.

:value-get

Function to extract the value of a widget, as it is displayed in = the buffer.

The following predefined function can be used here:

Function: widget-value-value-get widget = ¶

Return the :value property of widget.

:format-handler

Function to handle unknown ‘%’ escapes in the format string. It will be called with the widget and the character that follows the ‘%’ as arguments. You can set = this to allow your widget to handle non-standard escapes.

You should end up calling widget-default-format-handler to handle unknown escape sequences, which will handle the ‘%h’ and any future escape sequences, as well as give an error for unknown escapes.

:action

Function to handle user initiated events. By default, :notify the parent.

The following predefined function can be used here:

Function: widget-parent-action widget &optional event = ¶

Tell :parent of widget to handle the :action. Optional event is the event that triggered the = action.

:prompt-value

Function to prompt for a value in the minibuffer. The function = should take four arguments, widget, prompt, value, and unbound and should return a value for widget = entered by the user. prompt is the prompt to use. value is the default value to use, unless unbound is non-nil, in which case there is no default value. The function should read the value using the method most natural for this widget, and does not have to check that it matches.

If you want to define a new widget from scratch, use the default widget as its base.

Widget: default

Widget used as a base for other widgets.

It provides most of the functionality that is referred to as = “by default” in this text.

Next: Widget = Minor Mode, Previous: Defining New Widgets, Up: The Emacs Widget Library =   [Contents][Index]

9 Widget Browser

There is a separate package to browse widgets. This is intended to = help programmers who want to examine the content of a widget. The browser shows the value of each keyword, but uses links for certain keywords such as ‘:parent’, which avoids = printing cyclic structures.

Command: widget-browse widget = ¶

Create a widget browser for widget. When called interactively, prompt for widget.

Command: widget-browse-other-window widget = ¶

Create a widget browser for widget and = show it in another window. When called interactively, prompt for widget.

Command: widget-browse-at pos = ¶

Create a widget browser for the widget at pos. When called interactively, use the position of point.

Next: Utilities, = Previous: Widget = Browser, Up: The Emacs = Widget Library   [Contents][Index]

10 Widget Minor = Mode

There is a minor mode for manipulating widgets in major modes that don’t provide any support for widgets themselves. This is mostly intended to be useful for programmers doing experiments.

Command: widget-minor-mode

Toggle minor mode for traversing widgets. With arg, turn widget mode on if and only if arg is positive.

Variable: widget-minor-mode-keymap = ¶

Keymap used in widget-minor-mode.

Next: Wishlist, Previous: Widget Minor Mode, Up: The Emacs Widget Library   [Contents][Index]

11 Utilities

Function: widget-prompt-value widget prompt [ value unbound ] = ¶

Prompt for a value matching widget, = using prompt. The current value is assumed to be value, = unless unbound is non-nil.

Function: widget-get-sibling widget

Get the item which widget is assumed to = toggle. This is only meaningful for radio buttons or checkboxes in a list.

Function: widget-choose title items &optional event = ¶

Prompt the user to choose an item from a list of options.

title is the name of the list of options. = items should be a menu, with its items in the simple format or in the extended format. See Defining Menus in the Emacs Lisp = Reference Manual. Independently of the format, you don’t have to = provide a title for the menu, just pass the desired title in title. The optional event is an input event. If event is a mouse event and the number of elements in items is = less than the user option widget-menu-max-size, then widget-choose uses a popup menu to prompt the user. Otherwise, widget-choose uses the minibuffer.

When items is a keymap menu, the returned = value is the symbol in the key vector, as in the argument of define-key (see Changing Key Bindings in the = Emacs Lisp Reference Manual). When items is a list whose = selectable items are of the form (name . value) = (i.e., the simplified format), then the return value is the value of the = chosen element.

Next: GNU Free Documentation License, Previous: Utilities, Up: The Emacs Widget Library =   [Contents][Index]

12 Wishlist

  • It should be possible to add or remove items from a list with C-k and C-o (suggested by RMS).
  • The ‘[INS]’ and = ‘[DEL]’ buttons should be = replaced by a single dash (‘-’). The dash should be = a button that, when invoked, asks whether you want to add or delete an item (RMS= wanted to git rid of the ugly buttons, the dash is my idea).
  • The menu-choice tag should be = prettier, something like the abbreviated menus in Open Look.
  • Finish :tab-order.
  • Make indentation work with glyphs and proportional fonts.
  • Add commands to show overview of object and class hierarchies = to the browser.
  • Find a way to disable mouse highlight for inactive widgets.
  • Find a way to make glyphs look inactive.
  • Add property-list widget.
  • Add association-list widget.
  • Add key-binding widget.
  • Add widget widget for editing = widget specifications.
  • Find clean way to implement variable length list. See TeX-printer-list for an explanation.
  • C-h in widget-prompt-value should give type specific = help.
  • Add a mailto widget.

Next: Index, = Previous: Wishlist, Up: The Emacs Widget Library   [Contents][Index]

Appendix = A GNU Free Documentation License

Version 1.3, 3 November 2008 
Copyright © 2000, 2001, 2002, =
2007, 2008 Free Software Foundation, Inc.
https://fsf.org/

Everyone is permitted to copy and distribute verbatim copies
of this license document, but changing it is not allowed.
  1. PREAMBLE

    The purpose of this License is to make a manual, textbook, or other functional and useful document free in the sense = of freedom: to assure everyone the effective freedom to copy and redistribute it, with or without modifying it, either commercially or noncommercially. Secondarily, this License preserves for the author and publisher a way to get credit for their work, while not being considered responsible for modifications made by others.

    This License is a kind of “copyleft”, which means that = derivative works of the document must themselves be free in the same sense. It complements the GNU General Public License, which is a copyleft license designed for free software.

    We have designed this License in order to use it for manuals for free software, because free software needs free documentation: a free program should come with manuals providing the same freedoms that the software does. But this License is not limited to software manuals; it can be used for any textual work, regardless of subject matter or whether it is published as a printed book. We recommend this License principally for works whose purpose is instruction or reference.

  2. APPLICABILITY AND DEFINITIONS

    This License applies to any manual or other work, in any medium, that contains a notice placed by the copyright holder saying it can be distributed under the terms of this License. Such a notice grants a world-wide, royalty-free license, unlimited in duration, to use that work under the conditions stated herein. The “Document”, = below, refers to any such manual or work. Any member of the public is a licensee, and is addressed as “you”. You accept the license = if you copy, modify or distribute the work in a way requiring permission under copyright law.

    A “Modified Version” of the Document means any work = containing the Document or a portion of it, either copied verbatim, or with modifications and/or translated into another language.

    A “Secondary Section” is a named appendix or a = front-matter section of the Document that deals exclusively with the relationship of the publishers or authors of the Document to the Document’s overall subject (or to related matters) and contains nothing that could fall directly within that overall subject. (Thus, if the Document is in part a textbook of mathematics, a Secondary Section may not explain any mathematics.) The relationship could be a matter of historical connection with the subject or with related matters, or of legal, commercial, philosophical, ethical or political position regarding them.

    The “Invariant Sections” are certain Secondary Sections = whose titles are designated, as being those of Invariant Sections, in the notice that says that the Document is released under this License. If a section does not fit the above definition of Secondary then it is not allowed to be designated as Invariant. The Document may contain zero Invariant Sections. If the Document does not identify any Invariant Sections then there are none.

    The “Cover Texts” are certain short passages of text that = are listed, as Front-Cover Texts or Back-Cover Texts, in the notice that says that the Document is released under this License. A Front-Cover Text may be at most 5 words, and a Back-Cover Text may be at most 25 words.

    A “Transparent” copy of the Document means a = machine-readable copy, represented in a format whose specification is available to the general public, that is suitable for revising the document straightforwardly with generic text editors or (for images composed of pixels) generic paint programs or (for drawings) some widely available drawing editor, and that is suitable for input to text formatters or for automatic translation to a variety of formats suitable for input to text formatters. A copy made in an otherwise Transparent file format whose markup, or absence of markup, has been arranged to thwart or discourage subsequent modification by readers is not Transparent. An image format is not Transparent if used for any substantial amount of text. A copy that is not “Transparent” is called = “Opaque”.

    Examples of suitable formats for Transparent copies include plain ASCII without markup, Texinfo input format, LaTeX input format, SGML or XML using a publicly available DTD, and standard-conforming simple HTML, PostScript or PDF designed for human modification. Examples of transparent image formats include PNG, XCF and JPG. Opaque formats include proprietary formats that can be read and edited only by proprietary word processors, SGML or XML for which the DTD and/or processing tools are not generally available, and the machine-generated HTML, PostScript or PDF produced by some word processors for output purposes only.

    The “Title Page” means, for a printed book, the title = page itself, plus such following pages as are needed to hold, legibly, the material this License requires to appear in the title page. For works in formats which do not have any title page as such, “Title = Page” means the text near the most prominent appearance of the work’s title, preceding the beginning of the body of the text.

    The “publisher” means any person or entity that = distributes copies of the Document to the public.

    A section “Entitled XYZ” means a named subunit of the = Document whose title either is precisely XYZ or contains XYZ in parentheses following text that translates XYZ in another language. (Here XYZ stands for a specific section name mentioned below, such as = “Acknowledgements”, “Dedications”, “Endorsements”, or = “History”.) To “Preserve the Title” of such a section when you modify the Document means that it remains a section “Entitled XYZ” according to this definition.

    The Document may include Warranty Disclaimers next to the notice = which states that this License applies to the Document. These Warranty Disclaimers are considered to be included by reference in this License, but only as regards disclaiming warranties: any other implication that these Warranty Disclaimers may have is void and has no effect on the meaning of this License.

  3. VERBATIM COPYING

    You may copy and distribute the Document in any medium, either commercially or noncommercially, provided that this License, the copyright notices, and the license notice saying this License applies to the Document are reproduced in all copies, and that you add no other conditions whatsoever to those of this License. You may not use technical measures to obstruct or control the reading or further copying of the copies you make or distribute. However, you may accept compensation in exchange for copies. If you distribute a large enough number of copies you must also follow the conditions in section 3.

    You may also lend copies, under the same conditions stated above, and you may publicly display copies.

  4. COPYING IN QUANTITY

    If you publish printed copies (or copies in media that commonly have printed covers) of the Document, numbering more than 100, and the Document’s license notice requires Cover Texts, you must enclose = the copies in covers that carry, clearly and legibly, all these Cover Texts: Front-Cover Texts on the front cover, and Back-Cover Texts on the back cover. Both covers must also clearly and legibly identify you as the publisher of these copies. The front cover must present the full title with all words of the title equally prominent and visible. You may add other material on the covers in addition. Copying with changes limited to the covers, as long as they preserve the title of the Document and satisfy these conditions, can be treated as verbatim copying in other respects.

    If the required texts for either cover are too voluminous to fit legibly, you should put the first ones listed (as many as fit reasonably) on the actual cover, and continue the rest onto adjacent pages.

    If you publish or distribute Opaque copies of the Document numbering more than 100, you must either include a machine-readable Transparent copy along with each Opaque copy, or state in or with each Opaque copy a computer-network location from which the general network-using public has access to download using public-standard network protocols a complete Transparent copy of the Document, free of added material. If you use the latter option, you must take reasonably prudent steps, when you begin distribution of Opaque copies in quantity, to ensure that this Transparent copy will remain thus accessible at the stated location until at least one year after the last time you distribute an Opaque copy (directly or through your agents or retailers) of that edition to the public.

    It is requested, but not required, that you contact the authors of = the Document well before redistributing any large number of copies, to give them a chance to provide you with an updated version of the Document.

  5. MODIFICATIONS

    You may copy and distribute a Modified Version of the Document under the conditions of sections 2 and 3 above, provided that you release the Modified Version under precisely this License, with the Modified Version filling the role of the Document, thus licensing distribution and modification of the Modified Version to whoever possesses a copy of it. In addition, you must do these things in the Modified Version:

    1. Use in the Title Page (and on the covers, if any) a title distinct from that of the Document, and from those of previous versions (which should, if there were any, be listed in the History section of the Document). You may use the same title as a previous version if the original publisher of that version gives permission.
    2. List on the Title Page, as authors, one or more persons or = entities responsible for authorship of the modifications in the Modified Version, together with at least five of the principal authors of the Document (all of its principal authors, if it has fewer than five), unless they release you from this requirement.
    3. State on the Title page the name of the publisher of the Modified Version, as the publisher.
    4. Preserve all the copyright notices of the Document.
    5. Add an appropriate copyright notice for your modifications adjacent to the other copyright notices.
    6. Include, immediately after the copyright notices, a license = notice giving the public permission to use the Modified Version under the terms of this License, in the form shown in the Addendum below.
    7. Preserve in that license notice the full lists of Invariant = Sections and required Cover Texts given in the Document’s license notice.
    8. Include an unaltered copy of this License.
    9. Preserve the section Entitled “History”, Preserve = its Title, and add to it an item stating at least the title, year, new authors, and publisher of the Modified Version as given on the Title Page. If there is no section Entitled “History” in the Document, = create one stating the title, year, authors, and publisher of the Document as given on its Title Page, then add an item describing the Modified Version as stated in the previous sentence.
    10. Preserve the network location, if any, given in the Document = for public access to a Transparent copy of the Document, and likewise the network locations given in the Document for previous versions it was based on. These may be placed in the “History” = section. You may omit a network location for a work that was published at least four years before the Document itself, or if the original publisher of the version it refers to gives permission.
    11. For any section Entitled “Acknowledgements” or = “Dedications”, Preserve the Title of the section, and preserve in the section all the substance and tone of each of the contributor acknowledgements and/or dedications given therein.
    12. Preserve all the Invariant Sections of the Document, unaltered in their text and in their titles. Section numbers or the equivalent are not considered part of the section titles.
    13. Delete any section Entitled “Endorsements”. Such = a section may not be included in the Modified Version.
    14. Do not retitle any existing section to be Entitled = “Endorsements” or to conflict in title with any Invariant Section.
    15. Preserve any Warranty Disclaimers.

    If the Modified Version includes new front-matter sections or appendices that qualify as Secondary Sections and contain no material copied from the Document, you may at your option designate some or all of these sections as invariant. To do this, add their titles to the list of Invariant Sections in the Modified Version’s license = notice. These titles must be distinct from any other section titles.

    You may add a section Entitled “Endorsements”, provided = it contains nothing but endorsements of your Modified Version by various parties—for example, statements of peer review or that the text = has been approved by an organization as the authoritative definition of a standard.

    You may add a passage of up to five words as a Front-Cover Text, and = a passage of up to 25 words as a Back-Cover Text, to the end of the list of Cover Texts in the Modified Version. Only one passage of Front-Cover Text and one of Back-Cover Text may be added by (or through arrangements made by) any one entity. If the Document already includes a cover text for the same cover, previously added by you or by arrangement made by the same entity you are acting on behalf of, you may not add another; but you may replace the old one, on explicit permission from the previous publisher that added the old one.

    The author(s) and publisher(s) of the Document do not by this License give permission to use their names for publicity for or to assert or imply endorsement of any Modified Version.

  6. COMBINING DOCUMENTS

    You may combine the Document with other documents released under this License, under the terms defined in section 4 above for modified versions, provided that you include in the combination all of the Invariant Sections of all of the original documents, unmodified, and list them all as Invariant Sections of your combined work in its license notice, and that you preserve all their Warranty Disclaimers.

    The combined work need only contain one copy of this License, and multiple identical Invariant Sections may be replaced with a single copy. If there are multiple Invariant Sections with the same name but different contents, make the title of each such section unique by adding at the end of it, in parentheses, the name of the original author or publisher of that section if known, or else a unique number. Make the same adjustment to the section titles in the list of Invariant Sections in the license notice of the combined work.

    In the combination, you must combine any sections Entitled = “History” in the various original documents, forming one section Entitled “History”; likewise combine any sections Entitled = “Acknowledgements”, and any sections Entitled “Dedications”. You must delete = all sections Entitled “Endorsements.”

  7. COLLECTIONS OF DOCUMENTS

    You may make a collection consisting of the Document and other = documents released under this License, and replace the individual copies of this License in the various documents with a single copy that is included in the collection, provided that you follow the rules of this License for verbatim copying of each of the documents in all other respects.

    You may extract a single document from such a collection, and = distribute it individually under this License, provided you insert a copy of this License into the extracted document, and follow this License in all other respects regarding verbatim copying of that document.

  8. AGGREGATION WITH INDEPENDENT WORKS

    A compilation of the Document or its derivatives with other separate and independent documents or works, in or on a volume of a storage or distribution medium, is called an “aggregate” if the = copyright resulting from the compilation is not used to limit the legal rights of the compilation’s users beyond what the individual works = permit. When the Document is included in an aggregate, this License does not apply to the other works in the aggregate which are not themselves derivative works of the Document.

    If the Cover Text requirement of section 3 is applicable to these copies of the Document, then if the Document is less than one half of the entire aggregate, the Document’s Cover Texts may be placed on covers that bracket the Document within the aggregate, or the electronic equivalent of covers if the Document is in electronic form. Otherwise they must appear on printed covers that bracket the whole aggregate.

  9. TRANSLATION

    Translation is considered a kind of modification, so you may distribute translations of the Document under the terms of section 4. Replacing Invariant Sections with translations requires special permission from their copyright holders, but you may include translations of some or all Invariant Sections in addition to the original versions of these Invariant Sections. You may include a translation of this License, and all the license notices in the Document, and any Warranty Disclaimers, provided that you also include the original English version of this License and the original versions of those notices and disclaimers. In case of a disagreement between the translation and the original version of this License or a notice or disclaimer, the original version will prevail.

    If a section in the Document is Entitled = “Acknowledgements”, “Dedications”, or “History”, the requirement = (section 4) to Preserve its Title (section 1) will typically require changing the actual title.

  10. TERMINATION

    You may not copy, modify, sublicense, or distribute the Document except as expressly provided under this License. Any attempt otherwise to copy, modify, sublicense, or distribute it is void, and will automatically terminate your rights under this License.

    However, if you cease all violation of this License, then your = license from a particular copyright holder is reinstated (a) provisionally, unless and until the copyright holder explicitly and finally terminates your license, and (b) permanently, if the copyright holder fails to notify you of the violation by some reasonable means prior to 60 days after the cessation.

    Moreover, your license from a particular copyright holder is reinstated permanently if the copyright holder notifies you of the violation by some reasonable means, this is the first time you have received notice of violation of this License (for any work) from that copyright holder, and you cure the violation prior to 30 days after your receipt of the notice.

    Termination of your rights under this section does not terminate the licenses of parties who have received copies or rights from you under this License. If your rights have been terminated and not permanently reinstated, receipt of a copy of some or all of the same material does not give you any rights to use it.

  11. FUTURE REVISIONS OF THIS LICENSE

    The Free Software Foundation may publish new, revised versions of the GNU Free Documentation License from time to time. Such new versions will be similar in spirit to the present version, but may differ in detail to address new problems or concerns. See https://www.gnu.org/licenses/.

    Each version of the License is given a distinguishing version number. If the Document specifies that a particular numbered version of this License “or any later version” applies to it, you have the = option of following the terms and conditions either of that specified version or of any later version that has been published (not as a draft) by the Free Software Foundation. If the Document does not specify a version number of this License, you may choose any version ever published (not as a draft) by the Free Software Foundation. If the Document specifies that a proxy can decide which future versions of this License can be used, that proxy’s public statement of acceptance = of a version permanently authorizes you to choose that version for the Document.

  12. RELICENSING

    “Massive Multiauthor Collaboration Site” (or “MMC = Site”) means any World Wide Web server that publishes copyrightable works and also provides prominent facilities for anybody to edit those works. A public wiki that anybody can edit is an example of such a server. A “Massive Multiauthor Collaboration” (or “MMC”) = contained in the site means any set of copyrightable works thus published on the MMC site.

    “CC-BY-SA” means the Creative Commons Attribution-Share = Alike 3.0 license published by Creative Commons Corporation, a not-for-profit corporation with a principal place of business in San Francisco, California, as well as future copyleft versions of that license published by that same organization.

    “Incorporate” means to publish or republish a Document, = in whole or in part, as part of another Document.

    An MMC is “eligible for relicensing” if it is licensed = under this License, and if all works that were first published under this License somewhere other than this MMC, and subsequently incorporated in whole or in part into the MMC, (1) had no cover texts or invariant sections, and (2) were thus incorporated prior to November 1, 2008.

    The operator of an MMC Site may republish an MMC contained in the = site under CC-BY-SA on the same site at any time before August 1, 2009, provided the MMC is eligible for relicensing.

ADDENDUM: = How to use this License for your documents

To use this License in a document you have written, include a copy of the License in the document and put the following copyright and license notices just after the title page: 

  Copyright (C) =
 year  your name.
  Permission is granted to copy, distribute and/or modify this document
  under the terms of the GNU Free Documentation License, Version 1.3
  or any later version published by the Free Software Foundation;
  with no Invariant Sections, no Front-Cover Texts, and no Back-Cover
  Texts.  A copy of the license is included in the section entitled =
``GNU
  Free Documentation License''.

If you have Invariant Sections, Front-Cover Texts and Back-Cover = Texts, replace the “with…Texts.” line with this: 

    with the =
Invariant Sections being list their titles, =
with
    the Front-Cover Texts being list, and with =
the Back-Cover Texts
    being list.

If you have Invariant Sections without Cover Texts, or some other combination of the three, merge those two alternatives to suit the situation.

If your document contains nontrivial examples of program code, we recommend releasing these examples in parallel under your choice of free software license, such as the GNU General Public License, to permit their use in free software.

Previous: GNU Free Documentation License, Up: The Emacs Widget Library   [Contents][Index]

Index

This is an alphabetical listing of all concepts, functions, commands, variables, and widgets described in this manual.

Jump to:   = A  =20 B  =20 C  =20 D  =20 E  =20 F  =20 G  =20 H  =20 I  =20 K  =20 L  =20 M  =20 N  =20 O  =20 P  =20 R  =20 S  =20 T  =20 U  =20 V  =20 W  =20
<= td class=3D"printindex-index-section">atoms<= td class=3D"printindex-index-section">atomsatoms= atoms= =  
Index = Entry  = Section
A
action = keyword: Defining New Widgets
activate a = widget: Widget Properties
active widget: Widget = Properties
append-button-arg= s keyword: editable-list
args = keyword: menu-choice
args = keyword: radio-button-choice
args = keyword: checklist
args = keyword: editable-list
atomic sexp = widget: atoms
B
basic widgets: Introduction
boolean: atoms
browse-url-browser-function, and = url-link = widget: url-link
button = widgets: User Interface
button-args keyword: radio-button-choice
button-args keyword: checklist
button-face keyword: Basic = Types
button-prefix keyword: Basic = Types
button-suffix keyword: Basic = Types
buttons = keyword: radio-button-choice
buttons = keyword: checklist
buttons = keyword: editable-list
C
case-fold = keyword: menu-choice
character: 
checkbox = widget: checkbox
checklist = widget: checklist
children = keyword: menu-choice
children = keyword: radio-button-choice
children = keyword: checklist
children = keyword: editable-list
choice: composite
choice = keyword: menu-choice
choice = keyword: radio-button-choice
choice-item= widget: choice-item
composite sexp = widgets: composite
cons: composite
const: constants
constant = widgets: constants
convert-widget keyword: Defining New Widgets
copy = keyword: Defining New Widgets
create = keyword: Defining New Widgets
D
deactivate a = widget: Widget Properties
default: Defining New Widgets
define-widget:=  Defining New Widgets
defining new = widgets: Defining New Widgets
delete = keyword: Defining New Widgets
delete-button-arg= s keyword: editable-list
directory: 
doc = keyword: Basic = Types
E
editable-field widget: editable-field
editable-list widget: editable-list
embedded = buttons: User Interface
entry-format keyword: radio-button-choice
entry-format keyword: checklist
entry-format keyword: editable-list
example of using = widgets: Programming Example
external = format: Basic Types
extra-offset keyword: Basic = Types
F
file: atoms
follow-link keyword: Basic = Types
format = keyword: Basic = Types
format-handler keyword: Defining New Widgets
function: 
function-item:=  constants
G
generic sexp = widget: generic
greedy = keyword: checklist
group = widget: group
H
help-echo = keyword: Basic = Types
I
inactive = widget: Widget Properties
indent = keyword: Basic = Types
info-link = widget: info-link
insert-button-arg= s keyword: editable-list
integer: atoms
internal = format: Basic Types
item = widget: item
K
keymap = keyword: editable-field
keyword = arguments: Basic = Types
L
link = widget: link
list: composite
M
match = keyword: Basic = Types
menu-choice= widget: menu-choice
menu-tag = keyword: Basic = Types
menu-tag-get keyword: Basic = Types
mouse-2 = (on button = widgets): User = Interface
must-match = keyword: atoms
N
new widgets: Defining New Widgets
notify = keyword: Basic = Types
number: atoms
O
off-glyph = keyword: toggle
offset = keyword: Basic = Types
on-glyph = keyword: toggle
option field = tag: User Interface
P
parent = keyword: Basic = Types
prompt-value keyword: Defining New Widgets
properties of = widgets: Widget Properties
push-button= widget: push-button
R
radio-button-choi= ce widget: radio-button-choice
regexp: atoms
repeat: composite
S
secret = keyword: editable-field
set: composite
sexp: generic
sexp types: Sexp = Types
sibling-args keyword: Basic = Types
size = keyword: editable-field
string: atoms
symbol: atoms
T
tab-order = keyword: Basic = Types
tag = keyword: Basic = Types
tag-glyph = keyword: Basic = Types
text = widget: text
todo: Widget = Wishlist
toggle = widget: toggle
U
url-link = widget: url-link
utility functions for = widgets: Utilities
V
valid-regexp keyword: editable-field
validate = keyword: Basic = Types
value = keyword: Basic = Types
value-create keyword: Defining New Widgets
value-delete keyword: Defining New Widgets
value-face = keyword: editable-field
value-get = keyword: Defining New Widgets
value-to-external<= span class=3D"r"> keyword: Defining New Widgets
value-to-internal<= span class=3D"r"> keyword: Defining New Widgets
variable: 
variable-item:=  constants
vector: composite
void = keyword: menu-choice
W
widget = browser: Widget Browser
widget = buttons: User Interface
widget library, why use = it: Introduction
widget minor = mode: Widget Minor Mode
widget = properties: Widget = Properties
widget-apply:&n= bsp;Widget Properties
widget-backward: User Interface
widget-browse:=  Widget Browser
widget-browse-at= : Widget Browser
widget-browse= -other-window: Widget = Browser
widget-button-click: User Interface
widget-button-click: Setting Up the Buffer
widget-button-face= : User Interface
widget-button-prefix: Basic Types
widget-button-press: User Interface
widget-button-press: Setting Up the Buffer
widget-button-suffix: Basic Types
widget-children-val= idate: Basic = Types
widget-choose:=  Utilities
widget-create:=  Setting Up the Buffer
widget-default-delete<= /code>: Defining New Widgets
widget-def= ault-format-handler: Defining New Widgets
widget-delete:=  Setting Up the Buffer
widget-field-face: User Interface
widget-field-keymap: editable-field
widget-forward:User Interface
widget-get: = Widget Properties
widget-get-sibling= : Utilities
widget-global-map: Setting Up the Buffer
widget-image-director= y: Basic Types
widget-image-enable: Basic Types
widget-insert:=  Setting Up the Buffer
widget-keymap:=  Setting Up the Buffer
widget-link-prefix= : link
widget-link-suffix= : link
widget-member:=  Widget Properties
widget-minor-mode: Widget Minor Mode
widget-minor-mo= de-keymap: Widget = Minor Mode
widget-mouse-face: User Interface
widget-parent-action: Defining New Widgets
widget-prompt-value: Utilities
widget-push-bu= tton-prefix: push-button
widget-push-bu= tton-suffix: push-button
widget-put: = Widget Properties
widget-radio-add-i= tem: radio-button-choice
widget-setup:&n= bsp;Setting Up the Buffer
widget-text-keymap= : text
widget-type:&nbs= p;Widget Properties
widget-types= -convert-widget: Defining New Widgets
widget-types-copy: Defining New Widgets
widget-value:&n= bsp;Widget Properties
widget-value= -convert-widget: Defining New Widgets
widget-value-set= : Widget Properties
widget-value-valu= e-get: Defining New Widgets
widgets, basic = types: Introduction
widgets, programming = example: Programming Example
Jump to:   = A  =20 B  =20 C  =20 D  =20 E  =20 F  =20 G  =20 H  =20 I  =20 K  =20 L  =20 M  =20 N  =20 O  =20 P  =20 R  =20 S  =20 T  =20 U  =20 V  =20 W  =20
--Apple-Mail=_10F3A5D0-319C-48D1-A362-8270E462F228 Content-Disposition: attachment; filename=widget.new.html Content-Type: text/html; x-unix-mode=0644; name="widget.new.html" Content-Transfer-Encoding: quoted-printable The Emacs Widget Library

Next: Introduction   [Contents][Index]

The Emacs Widget = Library

Copyright © 2000–2023 Free Software Foundation, Inc.

Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.3 or any later version published by the Free Software Foundation; with no Invariant Sections, with the Front-Cover Texts being “A GNU = Manual”, and with the Back-Cover Texts as in (a) below. A copy of the license is included in the section entitled “GNU Free Documentation = License”.

(a) The FSF’s Back-Cover Text is: “You have the freedom = to copy and modify this GNU manual.”

Next: User = Interface, Previous: The= Emacs Widget Library, Up: The Emacs Widget Library   [Contents][Index]

1 Introduction

Most graphical user interface toolkits provide a number of standard user interface controls (sometimes known as “widgets” or = “gadgets”). Emacs doesn’t really support anything like this, except for an incredibly powerful text “widget”. On the other hand, Emacs = does provide the necessary primitives to implement many other widgets within a text buffer. The widget package = simplifies this task.

The basic widgets are:

link

Areas of text with an associated action. Intended for hypertext = links embedded in text.

push-button

Like link, but intended for stand-alone buttons.

editable-field

An editable text field. It can be either variable or fixed = length.

menu-choice

Allows the user to choose one of multiple options from a menu, = where each option is itself a widget. Only the selected option is visible in the buffer.

radio-button-choice

Allows the user to choose one of multiple options by activating = radio buttons. The options are implemented as widgets. All options are visible in the buffer, with the selected one marked as chosen.

item

A simple constant widget intended to be used in the menu-choice and radio-button-choice widgets.

choice-item

A button item only intended for use in choices. When invoked, = the user will be asked to select another option from the choice widget.

toggle

A simple ‘on’/‘off’ switch.

checkbox

A checkbox (‘[ = ]’/‘[X]’).

editable-list

Create an editable list. The user can insert or delete items in = the list. Each list item is itself a widget.

Now, of what possible use can support for widgets be in a text = editor? I’m glad you asked. The answer is that widgets are useful for implementing forms. A form in Emacs is a buffer = where the user is supposed to fill out a number of fields, each of which has a specific meaning. The user is not supposed to change or delete any of the text between the fields. Examples of forms in Emacs are the forms package (of course), the customize buffers, the mail and news compose modes, and the HTML form support in the = w3 browser.

The advantages for a programmer of using the widget package to implement forms are:

  1. More complex fields than just editable text are supported.
  2. You can give the users immediate feedback if they enter = invalid data in a text field, and sometimes prevent entering invalid data.
  3. You can have fixed sized fields, thus allowing multiple fields = to be lined up in columns.
  4. It is simple to query or set the value of a field.
  5. Editing happens in the buffer, not in the mini-buffer.
  6. Packages using the library get a uniform look, making them = easier for the user to learn.
  7. As support for embedded graphics improve, the widget library = will be extended to use the GUI features. This means that your code using the widget library will also use the new graphic features automatically.

Next: Programming Example, Previous: Introduction, Up: The Emacs Widget Library   [Contents][Index]

2 User Interface

A form consists of read only text for documentation and some fields, where each field contains two parts, a tag and a value. The tags are used to identify the fields, so the documentation can refer to the ‘foo field’, meaning the field = tagged with ‘Foo’. Here is an example form: 

Here is some documentation.

Name: My Name     Choose: This option
Address:  Some Place
In some City
Some country.

See also _other work_ for more information.

Numbers: count to three below
[INS] [DEL] One
[INS] [DEL] Eh, =
two?
[INS] [DEL] Five!=

[INS]

Select multiple:

[X] This
[ ] That
[X] Thus

Select one:

(*) One
( ) Another One.
( ) A Final One.

[Apply Form] [Reset Form]

The top level widgets in this example are tagged ‘Name’, ‘Choose’, ‘Address’, ‘_other = work_’, ‘Numbers’, ‘Select multiple’, ‘Select one’, ‘[Apply Form]’, and ‘[Reset Form]’. There are = basically two things the user can do within a form, namely editing the editable text fields and activating the buttons.

2.1 Editable Text Fields

In the example, the value for the ‘Name’ is most likely displayed in an editable text field, and so are values for each of the members of the ‘Numbers’ list. All the = normal Emacs editing operations are available for editing these fields. The only restriction is that each change you make must be contained within a single editable text field. For example, capitalizing all text from the middle of one field to the middle of another field is prohibited.

Editable text fields are created by the editable-field widget.

The :format keyword is useful for = generating the necessary text; for instance, if you give it a value of "Name: %v ", the ‘Name: ’ part will provide = the necessary separating text before the field and the trailing space will provide the separating text after the field. If you don’t include the :size keyword, the field will extend to the = end of the line, and the terminating newline will provide separation after.

The editing text fields are highlighted with the widget-field-face face, making them easy to = find.

2.2 Buttons

Some portions of the buffer have an associated action, which can be invoked by a standard key or mouse command. = These portions are called buttons. The default commands for = activating a button are widget-button-press and widget-button-click. The user typically interacts with the buttons with a key, like RET, or with the mouse buttons.

There are several different kind of buttons, all of which are present = in the example:

The Option Field Tags

When you invoke one of these buttons, you will be asked to choose between a number of different options. This is how you edit an option field. Option fields are created by the menu-choice widget. In the example, ‘Choose’ is an option field tag.

The ‘[INS]’ and ‘[DEL]’ buttons

Activating these will insert or delete elements from an editable = list. The list is created by the editable-list = widget.

Embedded Buttons

The ‘_other = work_’ is an example of an embedded button. Embedded buttons are not associated with any fields, but can = serve any purpose, such as implementing hypertext references. They are usually created by the link widget.

The ‘[ = ]’ and ‘[X]’ buttons

Activating one of these will convert it to the other. This is = useful for implementing multiple-choice fields. You can create them with the checkbox widget.

The ‘( = )’ and ‘(*)’ buttons

Only one radio button in a radio-button-choice widget can be selected at any time. When you invoke one of the unselected radio buttons, it will be selected and the previous selected radio button will become unselected.

The ‘[Apply Form]’ and ‘[Reset Form]’ = buttons

These are explicit buttons made with the push-button widget. The main difference from the link widget is that = the buttons will be displayed as GUI buttons when possible.

To make them easier to locate, buttons are emphasized in the buffer with a distinctive face, like widget-button-face or widget-mouse-face.

2.3 Navigation

You can use all the normal Emacs commands to move around in a form buffer, plus you will have these additional commands to navigate from widget to widget: widget-forward and widget-backward.

Next: Widgets = Basics, Previous: User Interface, Up: The Emacs Widget Library   [Contents][Index]

3 Programming = Example

Here is the code to implement the user interface example (see User Interface). 

(require 'widget)

(eval-when-compile
  (require 'wid-edit))

(defvar widget-example-repeat)

(defun widget-example ()
  "Create the widgets from the Widget manual."
  (interactive)
  (switch-to-buffer "*Widget Example*")
  (kill-all-local-variables)
  (make-local-variable 'widget-example-repeat)
  (let ((inhibit-read-only t))
    (erase-buffer))
  (remove-overlays)
  (widget-insert "Here is some documentation.\n\n")
  (widget-create 'editable-field
                 :size 13
                 :format "Name: %v " ; Text after the field!
                 "My Name")
  (widget-create 'menu-choice
                 :tag "Choose"
                 :value "This"
                 :help-echo "Choose me, please!"
                 :notify (lambda (widget &rest ignore)
                           (message "%s is a good choice!"
                                    (widget-value widget)))
                 '(item :tag "This option" :value =
"This")
                 '(choice-item "That option")
                 '(editable-field :menu-tag "No option" =
"Thus option"))
  (widget-create 'editable-field
                 :format "Address: %v"
                 "Some Place\nIn some City\nSome country.")
  (widget-insert "\nSee also ")
  (widget-create 'link
                 :notify (lambda (&rest ignore)
                           (widget-value-set widget-example-repeat
                                             '("En" =
"To" "Tre"))
                           (widget-setup))
                 "other work")
  (widget-insert
    " for more information.\n\nNumbers: count to three =
below\n")
  (setq widget-example-repeat
        (widget-create 'editable-list
                       :entry-format "%i %d %v"
                       :notify
                       (lambda (widget &rest ignore)
                         (let ((old (widget-get widget
                                                ':example-length))
                               (new (length (widget-value widget))))
                           (unless (eq old new)
                             (widget-put widget ':example-length new)
                             (message "You can count to %d." =
new))))
                       :value '("One" "Eh, two?" =
"Five!")
                       '(editable-field :value "three")))
  (widget-insert "\n\nSelect multiple:\n\n")
  (widget-create 'checkbox t)
  (widget-insert " This\n")
  (widget-create 'checkbox nil)
  (widget-insert " That\n")
  (widget-create 'checkbox
                 :notify (lambda (&rest ignore) (message =
"Tickle"))
                 t)
  (widget-insert " Thus\n\nSelect one:\n\n")
  (widget-create 'radio-button-choice
                 :value "One"
                 :notify (lambda (widget &rest ignore)
                           (message "You selected %s"
                                    (widget-value widget)))
                 '(item "One") '(item "Another =
One.")
                 '(item "A Final One."))
  (widget-insert "\n")
  (widget-create 'push-button
                 :notify (lambda (&rest ignore)
                           (if (=3D (length
                                   (widget-value widget-example-repeat))
                                  3)
                               (message "Congratulation!")
                             (error "Three was the count!")))
                 "Apply Form")
  (widget-insert " ")
  (widget-create 'push-button
                 :notify (lambda (&rest ignore)
                           (widget-example))
                 "Reset Form")
  (widget-insert "\n")
  (use-local-map widget-keymap)
  (widget-setup))

Next: Setting Up the Buffer, Previous: Programming = Example, Up: The Emacs = Widget Library   [Contents][Index]

4 Widgets Basics

The Widget Library deals with widgets objects. A widget object has properties whose value may be anything, be it numbers, strings, symbols, functions, etc. Those properties are referred to as keywords and are responsible for the way a widget is represented in a buffer, and control the way a user or a program can interact with it.

The library defines several widget types, and gives you a way to define new types as well. In addition, widgets can derive from other types, creating a sort of widget inheritance. In fact, all widgets defined in the Widget Library share a common parent, the default widget. In this manual, when we talk about a default behavior, we usually mean the behavior as defined by this default widget. See Widget Gallery, for a = description of each defined widget.

Defining a new type that derives from a previous one is not mandatory to create widgets that work very different from a specified type. When creating a widget, you can override any default property, including functions, that control the widget. That is, you can specialize a widget on creation, without having to define it as a new type of widget.

In addition to the function for defining a widget, this library provides functions to create widgets, query and change its properties, respond to user events and destroy them. The following sections describe them.

One important property of a widget is its value.= All widgets may have a value, which is stored in a so-called internal format. For the rest of Emacs, the widget presents its value in a so-called external format. Both formats can be equal or = different, and each widget is responsible for defining how the conversion between each format should happen.

The value property is an important property for almost all widgets, and perhaps more important for editable-field = widgets. This type of widgets allow the user to edit them via the usual editing commands in Emacs. They can also be edited programmatically. Important: You must call widget-setup = after modifying the value of a widget before the user is allowed to edit the widget again. It is enough to call widget-setup once if you modify multiple widgets. This is currently only necessary if the widget contains an editing field, but may be necessary for other widgets in the future.

If your application needs to associate some information with the = widget objects, for example a reference to the item being edited, it can be done with the widget-put and widget-get functions. The property names, as shown, are keywords, so they must begin with a ‘:’.

Next: Working with Widgets, Previous: Widgets = Basics, Up: The Emacs = Widget Library   [Contents][Index]

5 Setting Up the = Buffer

To show the widgets in a buffer, you have to create them. Widget creation is actually a two-step process: conversion and creation per se. With simple projects, usually the conversion step isn’t = really important, and you only care about widget creation, so feel free to skip the conversion description until you really need to know it.

Widget conversion is the process that involves taking a widget specification and transforming it into a widget = object, suitable to be created, queried and manipulated with other widget functions. Widget creation is the process that takes a widget object and actually inserts it in the buffer.

The simplest function to create a widget is widget-create, which gets a widget specification and returns a widget object.

Function: widget-create type [ keyword argument ]… = args = ¶

Create and return a widget of type type, = converting it.

type is a symbol that specifies a widget = type. keyword may be one of the properties supported by the widget type, and argument specify the value for that property. = These keyword arguments can be used to overwrite the keyword arguments that are part of type by default, as well as to provide other = properties not present in type by default. args holds additional information for the creation of type and each = widget type is responsible for handling that information in a specific way.

The syntax for the type argument is = described in Widget = Gallery, and in more detail in every widget where it’s = relevant.

There are other functions for creating widgets, useful when you work with composite widgets. That is, widgets that are part of other widgets.

Function: widget-create-child-and-convert parent type &rest args = ¶

Create a widget of type type as a child = of parent.

Before creating it, converts type using the = keyword arguments provided in args. Adds the :indent property, unless it is = already present, and sets it to the sum of the values of: :indent = and :offset from parent and :extra-offset from type.

Returns a widget object, with the property :parent set to PARENT.

Function: widget-create-child parent type

Create a widget of type type as a child = of parent.

This function is like widget-create-child-and-convert but it doesn’t convert type, so it expects an = already converted widget.

Function: widget-create-child-value parent type value = ¶

Create a widget of type type as a child = of parent with value value.

This function is like widget-create-child, = but it lets you specify a value for the widget.

Converts value to the internal format, as = specified by type, and stores it into the :value property of type. That means, value should be in the external = format, as specified by type.

All these creating functions described here use the function stored = in the :create property. So, to modify the = creation logic for a widget, you can provide a different :create = function.

When you’re done creating widgets and you’re ready for = the user to interact with the buffer, use the function widget-setup.

Function: widget-setup

Setup the current buffer, so that editable widgets can be edited.

This should be called after creating all the widgets and before = allowing the user to edit them.

As mentioned, all these functions return a widget object. That = widget object can be queried and manipulated with widget functions that take widgets as arguments, until deleting it with the widgets functions available to delete widgets. Even if you don’t save the returned widget object, you still can interact programmatically with the widget. See Working = with Widgets.

Function: widget-delete widget

Delete the widget widget and remove it = from the buffer.

Function: widget-children-value-delete widget = ¶

Delete all children and buttons in widget widget.

This function does not delete widget itself, = only the widgets stored in the :children and :buttons properties. It also sets those properties to nil.

As with the creation mechanism, the function stored in :delete controls the deletion mechanism for a widget.

Additionally, the library provides a way to make a copy of a widget.

Function: widget-copy widget

Makes a copy of widget widget and = returns it.

It uses the function stored in the :copy = property of widget and returns the widget that that function returns.

As discussed, there is a conversion step when creating a widget. To do the conversion without actually creating the widget, you can use the widget-convert function.

Function: = widget-convert type &rest args = ¶

Convert type to a widget object, using = keyword arguments args.

Returns a widget object, suitable for creation. It calls the = function stored in the :convert-widget property, = after putting into the :args property the arguments that the widget = in question needs. If type has a :value = property, either originally or after doing the conversion, this function converts the value stored in :value to the internal format, and stores it = into :value.

Apart from only creating widgets in the buffer, It’s useful to = have plain text. For inserting text, the recommended way is with the widget-insert function.

Function: widget-insert &rest args

Insert args, either strings or = characters, at point.

Uses insert to perform the insertion, = passing args as argument. See Insertion in the Emacs Lisp Reference = Manual, for more information about args.

The resulting text will be read-only.

Next: Widgets and the Buffer, Previous: Setting Up = the Buffer, Up: The = Emacs Widget Library   [Contents][Index]

6 Working with = Widgets

This section covers the more important functions needed to query and manipulate widgets in a generic way. Widgets may have additional functions for interacting with them, those are described in the description for each widget. See Widget Gallery.

Function: widgetp widget

Non-nil if widget is a widget.

Function: widget-type widget

Return the type of widget widget, a = symbol.

This function is useful to find out which kind of widget widget represents, i.e., the name of the widget type when the widget was created.

Function: widget-member widget property = ¶

Non-nil if widget widget has a value (even nil) for property property.

Function: widget-get widget property = ¶

For widget widget, return the value of = the property property.

property should be a keyword, and the value = is what was last set by widget-put for property.

Function: widget-put widget property value = ¶

For widget widget, set the property property to value. property should be a keyword, while value can be anything.

Function: widget-at &optional pos = ¶

Return the widget at position pos, or at = point if pos is nil.

Function: widget-field-at pos

Return the widget field at position POS, or nil if there is none.

Function: widget-apply widget property &rest args = ¶

Apply the function stored in property to = widget, passing args as additional arguments to the function.

Returns the result of that function call.

Function: widget-value widget

Return the current value contained in widget.

Note that the value returned by this function might differ from = what’s stored in the :value property of widget. This is because this function extracts the current value of widget from the buffer, taking editions into account.

The value returned is in the external format, after getting it with the :value-get function.

It is an error to call this function on an uninitialized widget.

Function: widget-value-set widget value

Set the value contained in widget to = value.

Converts value to the internal format, and = then sets it by applying the :value-set function.

It is an error to call this function with an invalid value, that is, a value that widget cannot represent.

Function: widget-default-get widget

Return the default external value of widget widget.

The default value is the one stored in :value or the result of applying the :default-get function to the = arguments of widget, as stored in :args. A value of nil = is ignored by default, so in order for a widget to respect nil as a value, it has to override the :default-get = function.

Function: widget-type-default-get widget = ¶

Convert the :type attribute in widget and return its default value.

Function: widget-child-value-get widget = ¶

Return the value of the first member of :children in widget.

Function: widget-child-value-inline widget = ¶

Return the inline value of the first member of :children in widget.

The inline value is whatever the function stored in :value-inline returns.

Function: widget-type-value-create widget = ¶

Create a child widget for widget, of = type stored in :type.

Creates the child widget taking the value from the :value property and stores the newly created widget in the :children property of widget.

The value stored in :type should be an = unconverted widget type.

Function: widget-value-convert-widget widget = ¶

Initializes the :value property of = widget from :args.

Sets :args to nil and returns the modified widget widget.

Function: widget-value-value-get widget = ¶

Return the value stored in :value for = widget widget.

This is different to getting the current value for widget with widget-value, since that function extracts = the value from the buffer.

Function: widget-apply-action widget &optional event = ¶

Apply the function stored in :action = to widget, in response to event.

It is an error to call this function with an inactive widget.

Function: widget-parent-action widget &optional event = ¶

Tell :parent of widget to handle event.

Optional event is the event that triggered = the action.

Function: widget-child-validate widget

Check that the first member of :children in widget is = valid.

To be valid means that the widget value passes the checks that the function stored in :validate makes.

Function: widget-children-validate widget

Check that all :children in widget are valid.

Returns nil on success, or the first = child that isn’t valid.

Function: widget-type-match widget value

Return non-nil if VALUE matches the value for the :type widget.

As with the other type functions, the widget stored in :type should be an unconverted widget.

Function: widget-types-copy widget

Copy the :args value in widget and store them in :args.

Makes the copies by calling widget-copy = on each element present in :args. Returns the modified widget widget.

Function: widget-types-convert-widget widget = ¶

Convert the :args value in widget and store them in args.

Returns the modified widget widget.

Next: Widget = Gallery, Previous: Working with Widgets, Up: The Emacs Widget Library   [Contents][Index]

7 Widgets and the = Buffer

This chapter describes commands that are specific to buffers that contain widgets.

Const: widget-keymap

Keymap containing useful bindings for buffers containing widgets.

Binds TAB and C-TAB to widget-forward and widget-backward, respectively. It also = binds RET to widget-button-press and down-mouse-1 and down-mouse-2 to widget-button-click.

There’s also a keymap for events that the widget library = doesn’t need to handle.

Variable: widget-global-map

Keymap used by widget-button-press = and widget-button-click when not on a button. By default this is global-map.

In addition to these two keymaps, each widget might define a keymap = of its own, active when events happen at that widget.

The following navigation commands are available:

TAB
Command: widget-forward &optional count = ¶

Move point count buttons or editing = fields forward.

M-TAB
S-TAB
Command: widget-backward &optional count = ¶

Move point count buttons or editing = fields backward.

When editing an editable-field widget, = the following commands are available:

C-e
Command: widget-end-of-line

Move point to the end of field or end of line, whichever is = first.

C-k
Command: widget-kill-line

Kill to end of field or end of line, whichever is first.

M-TAB
Command: widget-complete

Complete the content of the editable field at point.

C-m
Command: widget-field-activate = ¶

Invoke the editable field at point.

The following two are commands that can execute widget actions.

RET
Command: widget-button-press pos &optional = event

Invoke the button at pos, defaulting to = point.

Invocation means to run the function stored in the :action property.

If point is not located on a button, invoke the binding in widget-global-map (by default the global = map).

mouse-2
Command: widget-button-click event = ¶

Invoke the button at the location of the mouse pointer.

If the mouse pointer is located in an editable text field, invoke the binding in widget-global-map (by default the = global map).

In case the mouse-click is on a widget, calls the function stored in the :mouse-down-action property.

Next: Defining New Widgets, Previous: Widgets = and the Buffer, Up: The = Emacs Widget Library   [Contents][Index]

All widgets can be created from a type specification. The general syntax of a type specification is: 

name ::=3D =
(name [keyword argument]... args)
     |   name

Where name is a widget name, as defined with define-widget, keyword is the name of a property and argument is the value for that property, and = args are interpreted in a widget specific way. See Defining New Widgets.

The most basic widget in the Widget Library is the default widget. It provides the basic behavior for all other widgets, and all its properties are present by default in derived widgets. You’re seldom (if ever) going to effectively create a default widget, but here we describe its properties and behavior, so that we can describe other widgets only by mentioning the properties and behavior those other widgets specialize.

Widget: default

Widget used as a base for other widgets.

It provides most of the functionality that is referred to as = “by default” in this text. If you want to define a new widget from scratch, use the default widget as its base.

The following keyword arguments apply to all widgets:

:create

Function to create a widget from scratch.

The function takes one argument, a widget type, and creates a widget of that type, inserts it in the buffer, and returns a widget object.

By default, it inserts the widget at point, using the format provided in the :format property.

:delete

Function to delete a widget.

The function should take one argument, a widget, and should remove = all traces of the widget from the buffer.

The default value is:

Function: widget-default-delete widget

Remove widget from the buffer. Delete all :children and :buttons in widget.

In most cases you should not change this value, but instead use :value-delete to make any additional = cleanup.

:value

The initial value for widgets of this type.

Typically, a widget represents its value in two formats: external and internal. The external format is the value as the rest of Emacs sees it, and the internal format is a representation that the widget defines and uses in a widget specific way.

Both formats might be the same for certain widgets and might differ for others, and there is no guarantee about which format the value stored in the :value property has. However, = when creating a widget or defining a new one (see Defining New Widgets), the :value should be in the external format.

:value-to-internal

Function to convert the value to the internal format.

The function takes two arguments, a widget and an external value, and returns the internal value. The function is called on the present :value when the widget is created, and on = any value set later with widget-value-set.

:value-to-external

Function to convert the value to the external format.

The function takes two arguments, a widget and an internal value, and returns the value in the external format.

:value-create

Function to expand the ‘%v’= escape in the format string.

It will be called with the widget as its argument and should insert a representation of the widget’s value in the buffer.

:value-delete

A function that should remove the representation of the = widget’s value from the buffer.

It will be called with the widget as its argument. It doesn’t = have to remove the text, but it should release markers and delete nested widgets if these are not listed in :children or = :buttons.

By default, it’s a no-op.

:value-get

Function to extract the value of a widget, as it is displayed in = the buffer.

:value-set

Function that takes a widget and a value as arguments, and = recreates it.

The value must already be in the internal format for widget. By default, it deletes the widget with the :delete function and creates it again with the :create function.

:value-inline

Function that takes a widget and returns its value, inlined.

Inlined means that if the widget is not inline (i.e., its :inline property is nil), the return value is wrapped in a list.

:default-get

Function that takes a widget and returns its default value.

By default, it just returns the value stored in :value.

:format

This string will be inserted in the buffer when you create a = widget. The following ‘%’ escapes are = available:

‘%[’
‘%]’

The text inside will be marked as a button.

By default, the text will be shown in widget-button-face, and surrounded by brackets.

‘%{’
‘%}’

The text inside will be displayed with the face specified by :sample-face.

‘%v’

This will be replaced with the buffer representation of the = widget’s value. What this is depends on the widget type.

‘%d’

Insert the string specified by :doc = here.

‘%h’

Like ‘%d’, with the = following modifications: If the documentation string is more than one line, it will add a button which will toggle between showing only the first line, and showing the full text. Furthermore, if there is no :doc property in = the widget, it will instead examine the :documentation-property = property. If it is a lambda expression, it will be called with the widget’s value as an argument, and the result will be used as the documentation text.

‘%t’

Insert the string specified by :tag = here, or the princ representation of the value if there is no tag.

‘%%’

Insert a literal ‘%’.

:button-face

Face used to highlight text inside %[ %] in the format.

:button-prefix
:button-suffix

Strings used as prefix and suffix for widgets that are buttons.

By default, the values are widget-button-prefix and widget-button-suffix.

Text around %[ %] in the format.

These can be

nil

No text is inserted.

a string

The string is inserted literally.

a symbol

The value of the symbol is expanded according to this table.

:doc

The string inserted by the ‘%d’ escape in the format string.

:tag

The string inserted by the ‘%t’ escape in the format string.

:tag-glyph

Name of image to use instead of the string specified by :tag on Emacsen that supports it.

:help-echo

Specifies how to display a message whenever you move to the = widget with either widget-forward or widget-backward or move the mouse over it (using the standard help-echo = mechanism).

The value is either a string to display, or a function of one argument, the widget. If a function, it should return a string to display, or a form that evaluates to such a string.

:follow-link

Specifies how to interpret a mouse-1 = click on the widget. See Defining Clickable Text in the = Emacs Lisp Reference Manual.

:indent

An integer indicating the absolute number of spaces to indent = children of this widget. Its value might be nil too, = which corresponds to a value of 0.

The default :create functions and the = functions that create the value per se use this property as a rudimentary layout mechanism for the widgets.

:offset

An integer indicating how many extra spaces to add to the = widget’s grandchildren compared to this widget.

:extra-offset

An integer indicating how many extra spaces to add to the = widget’s children compared to this widget.

:menu-tag

Tag used in the menu when the widget is used as an option in a menu-choice widget.

=
:menu-tag-get

Function that takes a widget and returns the tag when the widget = is used as an option in a menu-choice widget.

By default, the tag used will be either the :menu-tag or :tag property if present, or the princ representation of the :value property if not.

:match

Should be a function called with two arguments, the widget and an external value, and should return non-nil if = the widget can represent the specified value.

:validate

A function which takes a widget as an argument, and returns nil if the widget’s current value is valid for the widget.

Otherwise, it should return the widget containing the invalid data, and set that widget’s :error property = to a string explaining the error.

By default, it always returns nil.

:tab-order

Specify the order in which widgets are traversed with widget-forward or widget-backward. This is only partially implemented.

  1. Widgets with tabbing order -1 are = ignored.
  2. (Unimplemented) When on a widget with tabbing order n, go to the next widget in the buffer with tabbing order n+1 = or nil, whichever comes first.
  3. When on a widget with no tabbing order specified, go to the = next widget in the buffer with a positive tabbing order, or nil
:parent

The parent of a nested widget (e.g., a menu-choice item or an element of a editable-list widget).

:sibling-args

This keyword is only used for members of a radio-button-choice or checklist. The value should be a list of = extra keyword arguments, which will be used when creating the radio-button or checkbox associated with this item.

:completions-function

Function that takes a widget and returns completion data for that widget, like completion-at-point-functions = would. See Completion in the Emacs Lisp Reference = Manual. It’s used by editable-field widgets to provide = completions.

By default, it looks into the property :completions, which should be a completion table. If :completions= is nil, then it calls the function stored either in the :complete or :complete-function property.

:format-handler

Function to handle unknown ‘%’ escapes in the format string.

It takes a widget and the character that follows the ‘%’ as arguments. You can set this to allow your widget to handle non-standard escapes in your own specialized widgets.

You should end up calling widget-default-format-handler to handle unknown escape sequences, which will handle the ‘%h’ and any future escape sequences, as well as give an error for unknown escapes.

:button-face-get

Function to return the face used to fontify a widget button.

Takes a widget and returns an appropriate face for the widget. By default, it either returns the face stored in the :button-face property, or calls the :button-face-get = function from the parent of the widget, if it has one.

:mouse-face-get

Function to return the face used to fontify a widget when the = mouse pointer hovers over it.

Takes a widget and returns an appropriate face. By default, it = either returns the face stored in the :mouse-face = property, or calls the :button-face-get function from the = parent of the widget, if it has one.

:copy

Function to deep copy a widget type.

It takes a shallow copy of the widget type as an argument (made by copy-sequence), and returns a deep copy. = The purpose of this is to avoid having different instances of combined widgets share nested attributes.

Its value by default is identity.

:active

Function that takes a widget and returns t if it is active.

A widget might be effectively always active, if its :always-active property is t.

Widgets can be in two states: active, which means they are modifiable = by the user, or inactive, which means they cannot be modified by the user. You can query or set the state with the following code: 

;; Examine if widget is active or not.
(if (widget-apply widget :active)
    (message "Widget is active.")
  (message "Widget is inactive.")

;; Make widget inactive.
(widget-apply widget :deactivate)

;; Make widget active.
(widget-apply widget :activate)

A widget is inactive if it, or any of its ancestors (found by following the :parent link), have been = deactivated. To make sure a widget is really active, you must therefore activate both it and all its ancestors. 

(while widget
  (widget-apply widget :activate)
  (setq widget (widget-get widget :parent)))

You can check if a widget has been made inactive by examining the = value of the :inactive keyword. If this is = non-nil, the widget itself has been deactivated. This is different from using the :active keyword, in that the latter tells you if the widget or any of its ancestors have been deactivated. Do not attempt to set the :inactive keyword directly. Use the :activate :deactivate functions instead.

:activate

Function that takes a widget and makes it active for user modifications.

:deactivate

Function that takes a widget and makes it inactive for user modifications.

:action

Function that takes a widget and optionally an event, and handles = a user initiated event.

By default, uses the :notify function to = notify the widget’s parent about the event.

:mouse-down-action

Function that takes a widget and optionally an event, and handles = a mouse click on the widget.

By default, it does nothing.

:notify

A function called each time the widget or a nested widget is = changed.

The function is called with two or three arguments. The first = argument is the widget itself, the second argument is the widget that was changed, and the third argument is the event leading to the change, if any.

By default, it passes the notification to the widget’s parent.

:prompt-value

Function to prompt for a value in the minibuffer.

The function should take four arguments, a widget, a prompt (a string), a value and a boolean, and should return a value for the widget, entered by the user.

The prompt is the prompt to use. The value is the default value to use, unless the fourtha argument is non-nil, = in which case there is no default value.

The function should read the value using the method most natural for this widget, and does not have to check that it matches.

Next: Sexp = Types, Up: Widget Gallery   [Contents][Index]

8.1 Basic Types

Next: The link Widget, Up: Basic Types   [Contents][Index]

8.1.1 The item Widget

Syntax: 

type ::=3D =
(item [keyword argument]... value)

A useful widget that holds a constant value, and can be included in other widgets. Its super is the default = widget.

As can be seen in the syntax, the item = widget is one of the widget that handles the args argument to widget-create in a specific way. If present, value is used to = initialize the :value property. When created, it inserts = the value as a string in the buffer.

By default, it has the following properties:

:convert-widget

The function that allows it to handle value.

:value-create

Prints the representation of :value = in the buffer.

:value-get

Returns the value stored in :value.

:match

A value matches the item widget if = it’s equal to its :value.

:match-inline

Inline values match the item widget = if :value is a sublist of values.

:action

The item widget notifies itself of an = event.

:format

By default, the item widget inserts = its tag in the buffer.

Next: The url-link Widget, Previous: The item = Widget, Up: Basic = Types   [Contents][Index]

Syntax: 

type ::=3D =
(link [keyword argument]...  [ value ])

A widget to represent an embedded link. Its super is the item widget.

The value, if present, is used to initialize = the :value property. The value should be a string, which will be inserted in the buffer.

By default, it has the following properties:

:button-prefix

The value of widget-link-prefix.

:button-suffix

The value of widget-link-suffix.

:keymap

A custom keymap for the link widget, so that it can respond to = mouse clicks.

:follow-link

This property allows the link to respect the value of mouse-1-click-follows-link. See Clickable Text in the Emacs Lisp = Reference Manual.

:format

Buttonizes the link, to make it clickable.

If you override this property, you should make sure to provide the ‘%[’ and ‘%]’ escape sequences, so that the link is clickable.

By default the link will be shown in brackets.

Next: The info-link Widget, Previous: The link = Widget, Up: Basic = Types   [Contents][Index]

Syntax: 

type ::=3D =
(url-link [keyword argument]...  url)

A widget to represent a link to a web page. Its super is the link widget.

It overrides the :action property to open = up the url specified.

Next: The = function-link Widget, Previous: The url-link Widget, Up: Basic Types   [Contents][Index]

Syntax: 

type ::=3D =
(info-link [keyword argument]...  address)

A widget to represent a link to an info file. Its super is the link widget.

It overrides the :action property, to a = function to start the built-in Info reader on address, when invoked.

Next: The = variable-link Widget, Previous: The info-link Widget, Up: Basic Types   [Contents][Index]

Syntax: 

type ::=3D =
(function-link [keyword argument]...  function)

A widget to represent a link to an Emacs function. Its super is the link widget.

It overrides the :action property, to a = function to describe function.

Next: The face-link Widget, Previous: The function-link Widget, Up: Basic Types   = [Contents][Index]

Syntax: 

type ::=3D =
(variable-link [keyword argument]...  var)

A widget to represent a link to an Emacs variable. Its super is the link widget.

It overrides the :action property, to a = function to describe var.

Next: The file-link Widget, Previous: The variable-link Widget, Up: Basic Types   = [Contents][Index]

Syntax: 

type ::=3D =
(face-link [keyword argument]...  face)

A widget to represent a link to an Emacs face. Its super is the link widget.

It overrides the :action property, to a = function to describe face.

Next: The emacs-library-link = Widget, Previous: The face-link Widget, Up: = Basic Types =   [Contents][Index]

Syntax: 

type ::=3D =
(file-link [keyword argument]...  file)

A widget to represent a link to a file. Its super is the link widget.

It overrides the :action property, to a = function to find the file file.

Next: The emacs-commentary-link = Widget, Previous: The file-link Widget, Up: = Basic Types =   [Contents][Index]

Syntax: 

type ::=3D =
(emacs-library-link [keyword argument]...  file)

A widget to represent a link to an Emacs Lisp file. Its super is the link widget.

It overrides the :action property, to a = function to find the file file.

Next: The = push-button Widget, Previous: The = emacs-library-link Widget, Up: Basic Types   = [Contents][Index]

Syntax: 

type ::=3D =
(emacs-commentary-link [keyword argument]...  file)

A widget to represent a link to the Comment section of an Emacs Lisp file. Its super is the link widget.

It overrides the :action property, to a = function to find the file file and put point in the Comment section.

Next: The = editable-field Widget, Previous: The = emacs-commentary-link Widget, Up: Basic Types   = [Contents][Index]

8.1.11 The = push-button Widget

Syntax: 

type ::=3D =
(push-button [keyword argument]...  [ value ])

A widget that acts as a pushable button. Its super is the item widget.

The value, if present, is used to initialize = the :value property. The value should be a string, which will be inserted in the buffer.

By default, it has the following properties:

:button-prefix

The empty string.

:button-suffix

The empty string.

:value-create

Inserts a representation of the “on” and = “off” states for the push button.

The representation might be an image, stored in the :tag-glyph property, or text. If it is text, it might be the value of the :tag property, or the :value of the widget, surrounded with widget-push-button-prefix and widget-push-button-suffix. See Customization.

:format

Buttonizes the widget, to make it clickable.

Next: The text Widget, Previous: The push-button Widget, Up: Basic Types   [Contents][Index]

8.1.12 The = editable-field Widget

Syntax: 

type ::=3D =
(editable-field [keyword argument]... [ value ])

A widget that can be edited by the user. Its super is the default widget.

The value, if present, is used to initialize = the :value property. The value should be a string, which will be inserted in the field. If not present, :value is the empty = string.

Warning: In an editable-field widget, the editable field must not be adjacent to another widget—that won’t = work. You must put some text in between. Either make this text part of the editable-field widget itself, or insert = it with widget-insert.

This widget either overrides or adds the following properties:

:convert-widget

Just like the item widget, this = function allows it to initialize :value from value.

:keymap

Keymap used in the editable field.

The default value is widget-field-keymap, = which allows the user to use all the normal editing commands, even if the buffer’s major mode suppresses some of them. Pressing RET = invokes the function specified by :action.

:format

By default, it specifies to insert only the widget’s value.

Warning: In an editable-field widget, the ‘%v’ escape must be preceded by some other text in the :format string (if specified).

:size

The width of the editable field.

By default the field will reach to the end of the line.

:value-face

Face used for highlighting the editable field.

Default is widget-field-face, see User Interface.

:secret

Character used to display the value.

You can set this to, e.g., ?* if the = field contains a password or other secret information. By default, this is nil, and the value is not secret.

:valid-regexp

By default the :validate function = will match the content of the field with the value of this attribute.

The default value is "" which = matches everything.

:validate

Returns nil if the current value of = the widget matches the :valid-regexp value.

:prompt-internal

A function to read a value for widget, used by the :prompt-value function.

:prompt-history

A variable that holds the history of field minibuffer edits.

:prompt-value

A function that uses the :prompt-internal function and the :prompt-history value to prompt for a = string, and retun the user response in the external format.

:action

When invoked, moves point to the next field.

:value-create

Function that takes care of creating the widget, respecting its :size and :value.

:value-set

Function to use to modify programatically the current value of = the widget.

:value-delete

Function that removes the widget so it cannot be edited anymore.

:value-get

Function to return the current text in the widget.

It takes an optional argument, no-truncate. = If no-truncate is nil, truncates trailing spaces.

:match

Function that makes the widget match any string value.

Next: The = menu-choice Widget, Previous: The editable-field Widget, Up: Basic Types   = [Contents][Index]

8.1.13 The text Widget

Syntax: 

type ::=3D =
(text [keyword argument]... [ value ])

A widget just like the editable-field = widget, but intended for multiline text fields. Its super is the editable-field widget.

It overrides the following properties:

:format

By default, prints a tag and the value.

:keymap

The default is widget-text-keymap, = which does not rebind the RET key.

Next: The radio-button-choice = Widget, Previous: The = text Widget, Up: Basic Types   [Contents][Index]

8.1.14 The = menu-choice Widget

Syntax: 

type ::=3D =
(menu-choice [keyword argument]... type ... )

A widget to represent a menu of options. Its super is the default widget.

The type argument represents each possible = choice. The widget’s value will be that of the chosen type argument.

It either overrides or adds the following properties:

:convert-widget

A function that takes care of converting each possible choice.

:copy

A function to copy each possible choice.

:format

By default, buttonize the tag and show the value.

:void

Widget type used as a fallback when the value does not match any = of the specified type arguments.

By default this is an item widget.

:case-fold

If nil don’t ignore case when = prompting for a choice through the minibuffer.

By default, its value is t.

:children

A list whose CAR is the widget = representing the currently chosen type in the buffer.

:choice

The current chosen type.

:args

The list of types.

:value-create

The function that inserts the current value for the widget.

It inserts the first choice that matches, as with the :match function, the value of the widget.

:value-get

Returns the value of the first child for the widget (see the description for :children above).

:value-inline

Returns the inline value of the first child for the widget.

:default-get

The default value for this widget is the default value for the = first choice, in case :value is missing.

This means that if you want a specific default value for the menu-choice widget, you should either pass a = :value property when creating it, or arrange the choices so that the first one can hold your desired default value.

:mouse-down-action

A function that takes care of showing a menu, if possible and = desired.

:action

A function that takes care of getting a new choice for the = widget.

Depending on the number of choices available, it may show a menu or just toggle the choices, or even do nothing at all.

After getting the choice, it recreates the widget and notifies it.

:validate

Returns nil if the widget’s = value is a valid choice.

:match

This widget will match any value matching at least one of the specified type arguments.

:match-inline

A function that returns non-nil if = the values match the widget, taking into account the :inline property.

=

Next: The = choice-item Widget, Previous: The menu-choice Widget, Up: Basic Types   [Contents][Index]

8.1.15 The radio-button-choice Widget

Syntax: 

type ::=3D =
(radio-button-choice [keyword argument]...  type ... )

A widget to represent a choice from multiple options. Its super is the default widget.

The component types specify the choices, = with one radio button for each. The widget’s value will be that of the chosen type argument.

It overrides the following properties:

:convert-widget

As other composite widgets, a function that takes care of = converting each available choice.

:copy

A function to copy each available choice.

:action

A function that checks if any radio button was pressed and = activates the pressed one, possibly deactivating an old one. Then, it notifies itself.

:entry-format

This string will be inserted for each entry in the list. The following ‘%’ escapes are = available:

‘%v’

Replace with the buffer representation of the type widget.

‘%b’

Replace with the radio button.

‘%%’

Insert a literal ‘%’.

:format

By default, it inserts its value.

:button-args

A list of keywords to pass to the radio buttons. Useful for = setting, e.g., the ‘:help-echo’ for each = button.

:buttons

The widgets representing the radio buttons.

:children

The widgets representing each type.

:choice

The current chosen type.

:args

The list of types.

:value-create

A function to insert all available choices.

:value-get

Returns the value for the chosen widget.

:value-set

A function to set the value to one of its available options.

:value-inline

A function that returns the inline value of the child widget.

:offset

By default, this widget has an offset of 4.

:validate

The widget validates if the current value is valid for one of its children.

:match

This widget matches any value that matches at least one of the specified type arguments.

:match-inline

Like the :match function, but taking = into account inline values.

You can add extra radio button items to a radio-button-choice widget after it has been created with the function widget-radio-add-item.

Function: widget-radio-add-item widget type = ¶

Add to radio-button-choice widget = widget a new radio button item of type type.

Please note that such items added after the radio-button-choice widget has been created will not be = properly destructed when you call widget-delete.

Next: The toggle Widget, Previous: The = radio-button-choice Widget, Up: Basic Types   = [Contents][Index]

8.1.16 The = choice-item Widget

Syntax: 

item ::=3D =
(choice-item [keyword argument]... value)

A widget to represent a choice in a menu-choice widget. Its super is the item widget.

The value, if present, is used to initialize = the :value property.

It overrides the following properties:

:action

Activating the button of a choice-item = is equivalent to activating the parent widget.

:format

By default, it buttonizes the tag (i.e., its value) and adds a = newline character at the end of the widget.

Next: The radio-button-toggle = Widget, Previous: The choice-item Widget, Up: = Basic Types =   [Contents][Index]

8.1.17 The toggle Widget

Syntax: 

type ::=3D =
(toggle [keyword argument]...)

A widget that can toggle between two states. Its super is the item widget.

The widget has two possible states, ‘on’ and ‘off’, which correspond to a t or nil value, respectively.

It either overrides or adds the following properties:

:format

By default, it buttonizes the value and adds a newline at the end = of the widget.

:on

A string representing the ‘on’ state. By default the string ‘on’.

:off

A string representing the ‘off’ state. By default the string ‘off’.

:on-glyph

Name of a glyph to be used instead of the ‘:on’ text string, on emacsen that supports this.

:off-glyph

Name of a glyph to be used instead of the ‘:off’ text string, on emacsen that supports this.

:value-create

A function for creating the widget’s value, according to = its ‘:on’ or ‘:off’ state.

:action

Function to toggle the state of the widget. After toggling, it notifies itself.

:match

This widget matches anything.

=

Next: The checkbox Widget, Previous: The toggle = Widget, Up: Basic = Types   [Contents][Index]

8.1.18 The radio-button-toggle Widget

Syntax: 

type ::=3D =
(radio-button-toggle [keyword argument]...)

A toggle to use in the radio widget.

It overrides the following properties:

:button-prefix

The empty string.

:button-suffix

The empty string.

:on

The string “(*)”, to represent the ‘on’ state.

:off

The string “( )”, to represent the ‘off’ state.

:on-glyph

The name of an image to represent the ‘on’ state.

:off-glpyh

The name of an image to represent the ‘off’ state.

:format

By default, it buttonizes its value.

:notify

A function to notify its parent.

Next: The checklist Widget, Previous: The = radio-button-toggle Widget, Up: Basic Types   = [Contents][Index]

8.1.19 The checkbox Widget

Syntax: 

type ::=3D =
(checkbox [keyword argument]...)

A widget to represent a toggle widget, with a checkbox. Its super is the toggle widget.

This widget has two possible states, ‘selected’ and ‘unselected’, which corresponds = to a t or nil value, respectively.

It either overrides or adds the following properties:

:button-prefix

The empty string.

:button-suffix

The empty string.

:format

By default, buttonizes the value.

:on

By default, the string “[X]”.

:off

By default, the string “[ ]”.

:on-glyph

The name of the image to use when the state is ‘on’.

:off-glyph

The name of the image to use when the state is ‘off’.

:action

A function that toggles the checkbox, notifies the parents and in = the ‘on’ state, activates its = siblings.

Next: The = editable-list Widget, Previous: The checkbox Widget, Up: Basic Types   [Contents][Index]

8.1.20 The checklist Widget

Syntax: 

type ::=3D =
(checklist [keyword argument]...  type ... )

A widget to represent a multiplice choice. Its super is the default widget.

The type arguments represent each checklist = item. The widget’s value will be a list containing the values of all checked type arguments.

It either overrides or adds the following properties:

:convert-widget

As other composite widgets, a function that takes care of = converting each checklist item.

:copy

A function to copy each checklist item.

:format

By default, it inserts its value.

:entry-format

This string will be inserted for each entry in the list. The following ‘%’ escapes are = available:

‘%v’

Replaced with the buffer representation of the type widget.

‘%b’

Replace with the checkbox.

‘%%’

Insert a literal ‘%’.

:button-args

A list of keywords to pass to the checkboxes. Useful for = setting, e.g., the ‘:help-echo’ for each = checkbox.

:buttons

The widgets representing the checkboxes.

:children

The widgets representing each type.

:args

The list of types.

:value-create

The function that takes care of inserting all values.

:value-get

A function that returns all values of selected items.

:validate

A function that ensures all selected children are valid.

:match

The checklist widget will match a list whose elements all match at least one of the specified type = arguments.

:match-inline

Like the :match function, but taking = into account the :inline property.

:greedy

Usually a checklist will only match if the items are in the exact sequence given in the specification. By setting :greedy to non-nil, it will allow the items to come in = any sequence. However, if you extract the value they will be in the sequence given in the checklist, i.e., the original sequence is forgotten.

Next: The group Widget, Previous: The checklist = Widget, Up: Basic = Types   [Contents][Index]

8.1.21 The = editable-list Widget

Syntax: 

type ::=3D =
(editable-list [keyword argument]... type)

A widget that can hold a variable list of widgets of the same type, represented by type. Its super is the default widget.

It either overrides or adds the following properties:

:convert-widget

As other composite widgets, a function that takes care of = converting each type in type.

:copy

A function to copy the types given in type.

:entry-format

This string will be inserted for each entry in the list. The following ‘%’ escapes are = available:

‘%v’

This will be replaced with the buffer representation of the type widget.

‘%i’

Insert the [INS] button, a widget of type = insert-button.

‘%d’

Insert the [DEL] button, a widget of type = delete-button.

‘%%’

Insert a literal ‘%’.

:insert-button-args

A list of keyword arguments to pass to the insert buttons.

:delete-button-args

A list of keyword arguments to pass to the delete buttons.

:append-button-args

A list of keyword arguments to pass to the trailing insert = button.

:buttons

The widgets representing the insert and delete buttons.

:format

By default, insert its value and at the and adds an insert = button.

This is useful so that new elements can be added to the list upon = user request.

:format-handler

A function that recognize the escape for inserting an insert = button.

:offset

By default, this widget has an offset of 12.

:children

The widgets representing the elements of the list.

:args

List whose CAR is the type of the = list elements.

:insert-before

Function to insert a new widget as a child of the editable-list widget.

This function inserts a recently deleted child, if there is one. = That is useful, so that the user can move elements in a list easily. If there is not a recently deleted child, it inserts a child with its default value.

:delete-at

Function to delete a child from the widget, and store it into the :last-deleted list, so that it can be = reinserted when the :insert-before function executes.

:value-create

The function that takes care of inserting all values.

:value-get

Function that returns a list with the value of the child widgets.

:validate

This widget validates if all children validate.

:match

To match, the value must be a list and all the list members must = match the specified type.

:match-inline

Like the :match function, but taking = into account inline values and widgets.

Next: The documentation-string = Widget, Previous: The editable-list Widget, = Up: Basic Types =   [Contents][Index]

8.1.22 The group Widget

Syntax: 

type ::=3D =
(group [keyword argument]... type...)

A widget to group other widgets. Its super is the default widget.

Its value is a list, with one member for each type.

It overrides the following properties:

:convert-widget

As other composite widgets, a function that takes care of = converting each widget in type.

:copy

A function to copy the types given in type.

:format

By default, displays a newline character and its value.

:value-create

A function to create each of its components.

:value-get

The same function used by the editable-list widget.

:default-get

A function that returns a list whose members are the default = values of each widget it groups.

:validate

This widget validates if all of its children validate.

:match

This widget matches a value that matches each of its components.

:match-inline

As :match, but taking into account = widgets and values that are inline.

Previous: The group Widget, Up: Basic Types   [Contents][Index]

8.1.23= The documentation-string Widget

Syntax: 

type ::=3D =
(documentation-string [keyword argument]... value)

A widget to represent a documentation string. Its super is the item widget.

It either overrides or adds the following properties:

:format

By default, insert its value.

:value-create

Function to insert a documentation string, possibly hiding part = of the documentation if its large.

To show or hide the rest of the documentation, uses a visibility widget.

:action

Function to toggle showing the documentation upon an event.

:visibility-widget

A symbol, the type of the widget to use for the visibility = widget.

This is, by default, the symbol visibility.=

Previous: Basic = Types, Up: Widget Gallery   [Contents][Index]

8.2 Sexp Types

A number of widgets for editing s-expressions = (Lisp types), sexp for short, are also available. These basically fall in several categories described in this section.

Next: Generic Sexp = Widget, Up: Sexp = Types   [Contents][Index]

8.2.1 The Constant = Widgets

The const widget can contain any Lisp = expression, but the user is prohibited from editing it, which is mainly useful as a component of one of the composite widgets.

The syntax for the const widget is: 

type ::=3D =
(const [keyword argument]...  [ value ])

Its super is the item widget. The value, if present, is used to initialize the :value property and = can be any s-expression.

Widget: const

This will display any valid s-expression in an immutable part of = the buffer.

It overrides the :prompt-value function, = to avoid prompting and just return the widget’s value.

There are two variations of the const = widget, namely variable-item and function-item. These should contain a symbol with a variable or function binding, respectively. The major difference from the const widget is that = they will allow the user to see the variable or function documentation for the symbol.

This is accomplished via using the ‘%h’ format escape, and adding an appropiate :documentation-property = function for each widget.

Widget: variable-item

An immutable symbol that is bound as a variable.

Widget: function-item

An immutable symbol that is bound as a function.

Next: Atomic Sexp = Widgets, Previous: The Constant Widgets, Up: Sexp Types   [Contents][Index]

8.2.2 Generic Sexp = Widget

The sexp widget can contain any Lisp = expression, and allows the user to edit it inline in the buffer.

The syntax for the sexp widget is: 

type ::=3D =
(sexp [keyword argument]...  [ value ])
Widget:= sexp

This widget represents an editable field that’s useful to = edit any valid s-expression.

The sexp widget takes the same keyword = arguments as the editable-field widget. See The editable-field Widget.

Its default value is nil.

Widget: restricted-sexp

A widget to edit Lisp expressions restricted to certain values or types. Its super is the sexp widget.

It works just like the sexp widget, but it overrides the :match function to match for certain values. To use this widget, either you must define a :match function or give a :match-alternatives property. The :match-alternatives property holds a list of predicate functions to call when checking if a given value matches the widget. Each predicate function will be called with one argument, the value to be matched, and should return non-nil on success.

As an example, the integer widget = overrides :match-alternatives to (integerp).

Next: Composite Sexp = Widgets, Previous: Generic Sexp Widget, Up: Sexp Types   [Contents][Index]

8.2.3 Atomic Sexp = Widgets

The atoms are s-expressions that do not consist of other = s-expressions. For example, a string, a file name, or a symbol are atoms, while a list is a composite type. You can edit the value of an atom with the widgets described in this section.

The syntax for all the atoms is: 

type ::=3D =
(construct [keyword =
argument]...  [ value =
])

The value, if present, is used to initialize = the :value property and must be an expression of the same type as the widget. That is, for example, the string widget can only be initialized with a string.

All the atom widgets take the same keyword arguments as the editable-field widget. See The editable-field Widget.

Widget: string

An editable field widget that can represent any Lisp string.

It offers completion via the ispell library and the :complete property.

Widget: regexp

An editable field widget that can represent a regular expression.

Overrides the :match and the :validate properties to check that the value is a valid regexp.

Widget: character

An editable field widget that can represent a character.

The character widget represents some characters (like the newline character) in a special manner, to make it easier for the user to see what’s the content of the character field.

Widget:= file

A widget for editing file names.

Keywords:

:completions

Offers file name completion to the user.

:prompt-value

A function to read a file name from the minibuffer.

:must-match

If this is set to non-nil, only = existing file names are allowed when prompting for a value in the minibuffer.

:match

The widget matches if the value is a string, and the file whose = name is that string is an existing file, or if :must-match is nil.

:validate

The widget is valid if its value matches.

Widget: directory

A widget for editing directory names.

Its super is the file widget, and it = overrides the :completions property, to offer completions = only for directories.

Widget: symbol

A widget for editing a Lisp symbol.

Its value by default is nil.

Widget: function

A widget for editing a lambda expression, or a function name, = offering completion. Its super is the restricted-sexp = widget.

Widget: variable

A widget for editing variable names, offering completion. Its = super is the symbol widget.

Widget: integer

A widget for editing integers in an editable field. Its super is = the restricted-sexp widget.

It has a default :value of 0.

Widget: natnum

A widget for editing non-negative integers. Its super is the restricted-sexp widget.

It has a default :value of 0.

Widget: float

A widget for editing a floating point number. Its super is the restricted-sexp widget.

It has a default :value of 0.0.

Widget: number

A widget for editing a number, either floating point or integer. = Its super is the restricted-sexp widget.

It has a default :value of 0.0.

Widget: boolean

A widget for editing a boolean value. Its super is the toggle widget.

Its value may be nil, meaning false, or = non-nil, meaning true.

Widget: color

A widget to edit a color name.

In addition, shows a sample that shows the selected color, if any.

Widget: other

A widget useful as the last item in a choice widget, since it matches any value.

Its super is the sexp widget, and its = :value is other, by default.

Widget: coding-system

A widget that can represent a coding system name, offering completions. See Coding Systems in the Emacs Lisp = Reference Manual. Its super is the symbol = widget.

It has a default value of undecided.

Widget: = key

A widget to represent a key sequence.

It uses a special keymap as the :keymap.

Previous: Atomic Sexp = Widgets, Up: Sexp = Types   [Contents][Index]

8.2.4 Composite = Sexp Widgets

The syntax for the composite widget construct is: 

type ::=3D =
(construct [keyword =
argument]...  component...)

where each component must be a widget type. = Each component widget will be displayed in the buffer, and will be editable by the user.

Widget:= cons

A widget to edit cons-cell values. Its super is the group widget.

The value of a cons widget must be a = cons-cell whose CAR and CDR have two specified types. It uses = this syntax: 

type ::=3D =
(cons [keyword argument]...  car-type cdr-type)
Widget: choice

A widget to hold a value of one of a fixed set of types. Its = super is the menu-choice widget.

The widget’s syntax is as follows: 

type ::=3D =
(choice [keyword argument]...  type ... )

The value of a choice widget can be = anything that matches any of the types.

This widget only displays the widget that corresponds to the current choice.

Widget: radio

A widget to hold a value of one of a fixed set of options. Its = super is the radio-button-choice widget.

Widget:= list

A widget to edit a list value. Its super is the group widget.

The value of a list widget must be a list = whose element types match the specified component types: 

type ::=3D =
(list [keyword argument]...  component-type...)

Thus, for example, (list string number) = matches lists of two elements, the first being a string and the second being a number.

Widget: vector

A widget to edit a vector value. Its super is the group widget.

The vector widget is like the list widget but matches vectors instead of lists. Thus, for example, (vector= string number) matches vectors of two elements, the first being a string = and the second being a number.

The above suffice for specifying fixed size lists and vectors. To = get variable length lists and vectors, you can use a choice, set, or repeat = widget together with the :inline keyword. If any component of a composite widget has the :inline keyword set, its value must be a = list which will then be spliced into the composite. For example, to specify a list whose first element must be a file name, and whose remaining elements should either be the symbol t or two strings (file = names), you can use the following widget specification: 

(list file
      (choice (const t)
              (list :inline t
                    :value ("foo" "bar")
                    string string)))

The value of a widget of this type will either have the form (file t) or (file string string).

This concept of :inline may be hard to = understand. It was certainly hard to implement, so instead of confusing you more by trying to explain it here, I’ll just suggest you meditate over it = for a while.

Widget: = set

A widget to hold a list of members from a fixed set. Its super = is the checklist widget.

Its value is a list where the elements all belong to a given set. = The order of elements of the list is not significant.

Here’s the syntax: 

type ::=3D =
(set [keyword argument]...  permitted-element ... )

Use const to specify each permitted = element, like this: (set (const a) (const b)).

Widget: repeat

Specifies a list of any number of elements that fit a certain = type. Its super is the editable-list widget. 

type ::=3D =
(repeat [keyword argument]...  type)
Widget: plist

A widget to edit property lists. Its super is the list widget.

It recognizes the following properties:

:options

A given set of recommended key-value values for the plist widget. Each option shows up as a checklist item.

:key-type

The widget type to use for the plist keys. By default, it uses = the symbol widget.

:value-type

The widget type to use for the plist values. By default, it uses = the sexp widget.

Widget: alist

A widget to edit association lists. Its super is the list widget.

It recognizes the same properties that the plist widget, with the difference that the :key-type uses by = default a sexp widget.

Most composite widgets do not allow for recursion. That is, none of the contained widgets may be of the same type that is currently being defined. To allow for this kind of widgets, there’s the lazy widget.

Widget:= lazy

A base widget for recursive data structures. Its super is the default widget.

When instantiated, it contains a single inferior widget of the widget type specified in the :type property. Its = value is the same as the value of this inferior widget.

Next: Inspecting Widgets, Previous: Widget Gallery, Up: The Emacs Widget Library   [Contents][Index]

9 Defining New = Widgets

You can define specialized widgets with define-widget. It allows you to create a shorthand for more complex widgets, including specifying component widgets and new default values for the keyword arguments.

Function: define-widget name class doc &rest args = ¶

Define a new widget type named name that = derives from class.

name and class = should both be symbols, and class should be one of the existing widget types.

The third argument doc is a documentation = string for the widget.

args should be key-value pairs, overriding = keyword values of class, or adding new recognized keywords for = name.

Usually, you’ll want to derive from an existing widget type, = like the editable-field widget, or the default widget, but it’s also possible to derive from nothing, by passing a value of nil as class. Note that if you do this, = you’re entirely responsible for defining a whole new default behavior for your widgets.

After using this function, the following two calls will create identical widgets: 

  • (widget-create name)

  • (apply widget-create class args)

Using define-widget just stores the = definition of the widget type in the widget-type property of name, which is what widget-create uses.

If you only want to specify defaults for keywords with no complex conversions, you can use identity as your = conversion function.

When defining new widgets, the :convert-widget property might be useful:

:convert-widget

Function to convert a widget type before creating a widget of = that type.

It takes a widget type as an argument, and returns the converted widget type. When a widget is created, this function is called for the widget type and all the widget’s parent types, most derived = first.

The predefined functions widget-types-convert-widget and widget-value-convert-widget can be used = here.

Next: Widget = Minor Mode, Previous: Defining New Widgets, Up: The Emacs Widget Library =   [Contents][Index]

10 Inspecting = Widgets

There is a separate package to browse widgets, in ‘wid-browse.el’. This is = intended to help programmers who want to examine the content of a widget. The browser shows the value of each keyword, but uses links for certain keywords such as ‘:parent’, which avoids printing = cyclic structures.

Command: widget-browse widget = ¶

Create a widget browser for widget.

When called interactively, prompt for widget.

Command: widget-browse-other-window widget = ¶

Create a widget browser for widget and = show it in another window.

When called interactively, prompt for widget.

Command: widget-browse-at pos = ¶

Create a widget browser for the widget at pos.

When called interactively, use the position of point.

In addition, there’s a function to describe the widget at = point.

Command: widget-describe &optional widget-or-pos = ¶

Describe the widget at point.

When called from Lisp, widget-or-pos might = be the widget to describe or a buffer position where a widget is present. If widget-or-pos is nil,= the widget to describe is the widget at point.

This command sets up a help buffer for providing information about = the widget, mainly its :action and :mouse-down-action functions, and provides links to describe it in more detail using the widget-browse commands described above.

Next: Utilities, = Previous: Inspecting Widgets, Up: The Emacs Widget Library   [Contents][Index]

11 Widget Minor = Mode

There is a minor mode for manipulating widgets in major modes that don’t provide any support for widgets themselves. This is mostly intended to be useful for programmers doing experiments.

Command: widget-minor-mode

Toggle minor mode for traversing widgets. With arg, turn widget mode on if and only if arg is positive.

Variable: widget-minor-mode-keymap = ¶

Keymap used in widget-minor-mode.

Next: Customization, Previous: Widget Minor Mode, Up: The Emacs Widget Library   [Contents][Index]

12 Utilities

Here we describe some utility functions that don’t really have = a place earlier in this manual.

Function: widget-prompt-value widget prompt [ value unbound ] = ¶

Prompt for a value matching widget, = using prompt. The current value is assumed to be value, = unless unbound is non-nil.

Converts widget before prompting, and for = prompting it uses the :prompt-value function. This function = returns the user “answer”, and it’s an error if that answer = doesn’t match the widget, as with the :match function.

If the answer matches the widget, returns the answer.

Function: widget-get-sibling widget

Get the item which widget should toggle. This is only meaningful for radio buttons or checkboxes in a list.

Function: widget-choose title items &optional event = ¶

Prompt the user to choose an item from a list of options.

title is the name of the list of options. = items should be a menu, with its items in the simple format or in the extended format. See Defining Menus in the Emacs Lisp = Reference Manual. Independently of the format, you don’t have to = provide a title for the menu, just pass the desired title in title. The optional event is an input event. If event is a mouse event and the number of elements in items is = less than the user option widget-menu-max-size, then widget-choose uses a popup menu to prompt the user. Otherwise, widget-choose uses the minibuffer.

When items is a keymap menu, the returned = value is the symbol in the key vector, as in the argument of define-key (see Changing Key Bindings in the = Emacs Lisp Reference Manual). When items is a list whose = selectable items are of the form (name . value) = (i.e., the simplified format), then the return value is the value of the = chosen element.

Function: widget-image-find image

Create a graphical button from image, an = image or a file name sans extension.

If image is a file name, the file should be = in widget-image-directory, or in a place where = find-image will find it.

Function: widget-image-insert widget tag image = ¶

As part of widget, insert the text tag or, if supported, the image image.

image should be as described in widget-image-find.

Function: widget-echo-help pos

Display help-echo text for the widget at pos.

Uses the value of :help-echo. If it is a = function, it calls it to get a string. Otherwise, it evals it.

Next: Wishlist, Previous: Utilities, Up: The Emacs Widget Library   [Contents][Index]

13 Customization

This chapter is about the customization options for the Widget library, for the end user.

Face: widget-field-face

Face used for other editing fields.

Face: widget-button-face

Face used for buttons.

User = Option: widget-mouse-face

Face used for highlighting a button when the mouse pointer moves across it.

The default value is highlight.

User Option: widget-image-directory = ¶

Directory where Widget should look for images.

Widget will look here for a file with the same name as specified for = the image, with either a .xpm (if supported) or = .xbm extension.

User= Option: widget-image-enable

If non-nil, allow images to appear on = displays where they are supported.

User Option: widget-image-conversion = ¶

An alist to convert symbols from image formats to file name = suffixes.

Each element is a cons cell (format . suffix), where format is a symbol that represents an image = format and suffix is its correspondent suffix.

User Option: widget-button-prefix

String to prefix buttons.

User Option: widget-button-suffix

String to suffix buttons.

User Option: widget-push-button-prefix = ¶

String to prefix push buttons.

User Option: widget-push-button-suffix = ¶

String to suffix push buttons.

User = Option: widget-link-prefix

String to prefix links.

User = Option: widget-link-suffix

String to suffix links.

User Option: widget-choice-toggle

If non-nil, toggle when there are = just two options.

By default, its value is nil.

User Option: widget-documentation-links = ¶

If non-nil, add hyperlinks to = documentation strings.

User Option: widget-documentation-link-regexp = ¶

A regexp that matches potential links in documentation strings. = The link itself should match to the first group.

User Option: widget-documentation-link-p = ¶

A predicate function to test if a string is useful as a link. = The function is called with one argument, a string, and should return non-nil if there should be a link for that = string.

By default, the value is intern-soft.

User Option: widget-documentation-link-type = ¶

A symbol that represents a widget type to use for links in documentation strings.

By default, the value is documentation-link.

User Option: widget-menu-max-size = ¶

Maximum size for a popup menu. By default, its value is 40.

If a function ask you to choose from a menu that is larger than this value, it will use the minibuffer.

User Option: widget-menu-max-shortcuts = ¶

Largest number of items for which it works to choose one with a character.

For a larger number, use the minibuffer.

User Option: widget-menu-minibuffer-flag = ¶

Whether to use the minibuffer to ask for a choice.

If nil, the default, read a single = character.

Next: GNU Free Documentation License, Previous: Customization, = Up: The Emacs Widget = Library   [Contents][Index]

14 Wishlist

  • It should be possible to add or remove items from a list with C-k and C-o (suggested by RMS).
  • The ‘[INS]’ and = ‘[DEL]’ buttons should be = replaced by a single dash (‘-’). The dash should be = a button that, when invoked, asks whether you want to add or delete an item (RMS= wanted to git rid of the ugly buttons, the dash is my idea).
  • The menu-choice tag should be = prettier, something like the abbreviated menus in Open Look.
  • Finish :tab-order.
  • Make indentation work with glyphs and proportional fonts.
  • Add commands to show overview of object and class hierarchies = to the browser.
  • Find a way to disable mouse highlight for inactive widgets.
  • Find a way to make glyphs look inactive.
  • Add widget widget for editing = widget specifications.
  • Find clean way to implement variable length list. See TeX-printer-list for an explanation.
  • C-h in widget-prompt-value should give type specific = help.
  • Add a mailto widget.

Next: Index, = Previous: Wishlist, Up: The Emacs Widget Library   [Contents][Index]

Appendix = A GNU Free Documentation License

Version 1.3, 3 November 2008 
Copyright © 2000, 2001, 2002, =
2007, 2008 Free Software Foundation, Inc.
https://fsf.org/

Everyone is permitted to copy and distribute verbatim copies
of this license document, but changing it is not allowed.
  1. PREAMBLE

    The purpose of this License is to make a manual, textbook, or other functional and useful document free in the sense = of freedom: to assure everyone the effective freedom to copy and redistribute it, with or without modifying it, either commercially or noncommercially. Secondarily, this License preserves for the author and publisher a way to get credit for their work, while not being considered responsible for modifications made by others.

    This License is a kind of “copyleft”, which means that = derivative works of the document must themselves be free in the same sense. It complements the GNU General Public License, which is a copyleft license designed for free software.

    We have designed this License in order to use it for manuals for free software, because free software needs free documentation: a free program should come with manuals providing the same freedoms that the software does. But this License is not limited to software manuals; it can be used for any textual work, regardless of subject matter or whether it is published as a printed book. We recommend this License principally for works whose purpose is instruction or reference.

  2. APPLICABILITY AND DEFINITIONS

    This License applies to any manual or other work, in any medium, that contains a notice placed by the copyright holder saying it can be distributed under the terms of this License. Such a notice grants a world-wide, royalty-free license, unlimited in duration, to use that work under the conditions stated herein. The “Document”, = below, refers to any such manual or work. Any member of the public is a licensee, and is addressed as “you”. You accept the license = if you copy, modify or distribute the work in a way requiring permission under copyright law.

    A “Modified Version” of the Document means any work = containing the Document or a portion of it, either copied verbatim, or with modifications and/or translated into another language.

    A “Secondary Section” is a named appendix or a = front-matter section of the Document that deals exclusively with the relationship of the publishers or authors of the Document to the Document’s overall subject (or to related matters) and contains nothing that could fall directly within that overall subject. (Thus, if the Document is in part a textbook of mathematics, a Secondary Section may not explain any mathematics.) The relationship could be a matter of historical connection with the subject or with related matters, or of legal, commercial, philosophical, ethical or political position regarding them.

    The “Invariant Sections” are certain Secondary Sections = whose titles are designated, as being those of Invariant Sections, in the notice that says that the Document is released under this License. If a section does not fit the above definition of Secondary then it is not allowed to be designated as Invariant. The Document may contain zero Invariant Sections. If the Document does not identify any Invariant Sections then there are none.

    The “Cover Texts” are certain short passages of text that = are listed, as Front-Cover Texts or Back-Cover Texts, in the notice that says that the Document is released under this License. A Front-Cover Text may be at most 5 words, and a Back-Cover Text may be at most 25 words.

    A “Transparent” copy of the Document means a = machine-readable copy, represented in a format whose specification is available to the general public, that is suitable for revising the document straightforwardly with generic text editors or (for images composed of pixels) generic paint programs or (for drawings) some widely available drawing editor, and that is suitable for input to text formatters or for automatic translation to a variety of formats suitable for input to text formatters. A copy made in an otherwise Transparent file format whose markup, or absence of markup, has been arranged to thwart or discourage subsequent modification by readers is not Transparent. An image format is not Transparent if used for any substantial amount of text. A copy that is not “Transparent” is called = “Opaque”.

    Examples of suitable formats for Transparent copies include plain ASCII without markup, Texinfo input format, LaTeX input format, SGML or XML using a publicly available DTD, and standard-conforming simple HTML, PostScript or PDF designed for human modification. Examples of transparent image formats include PNG, XCF and JPG. Opaque formats include proprietary formats that can be read and edited only by proprietary word processors, SGML or XML for which the DTD and/or processing tools are not generally available, and the machine-generated HTML, PostScript or PDF produced by some word processors for output purposes only.

    The “Title Page” means, for a printed book, the title = page itself, plus such following pages as are needed to hold, legibly, the material this License requires to appear in the title page. For works in formats which do not have any title page as such, “Title = Page” means the text near the most prominent appearance of the work’s title, preceding the beginning of the body of the text.

    The “publisher” means any person or entity that = distributes copies of the Document to the public.

    A section “Entitled XYZ” means a named subunit of the = Document whose title either is precisely XYZ or contains XYZ in parentheses following text that translates XYZ in another language. (Here XYZ stands for a specific section name mentioned below, such as = “Acknowledgements”, “Dedications”, “Endorsements”, or = “History”.) To “Preserve the Title” of such a section when you modify the Document means that it remains a section “Entitled XYZ” according to this definition.

    The Document may include Warranty Disclaimers next to the notice = which states that this License applies to the Document. These Warranty Disclaimers are considered to be included by reference in this License, but only as regards disclaiming warranties: any other implication that these Warranty Disclaimers may have is void and has no effect on the meaning of this License.

  3. VERBATIM COPYING

    You may copy and distribute the Document in any medium, either commercially or noncommercially, provided that this License, the copyright notices, and the license notice saying this License applies to the Document are reproduced in all copies, and that you add no other conditions whatsoever to those of this License. You may not use technical measures to obstruct or control the reading or further copying of the copies you make or distribute. However, you may accept compensation in exchange for copies. If you distribute a large enough number of copies you must also follow the conditions in section 3.

    You may also lend copies, under the same conditions stated above, and you may publicly display copies.

  4. COPYING IN QUANTITY

    If you publish printed copies (or copies in media that commonly have printed covers) of the Document, numbering more than 100, and the Document’s license notice requires Cover Texts, you must enclose = the copies in covers that carry, clearly and legibly, all these Cover Texts: Front-Cover Texts on the front cover, and Back-Cover Texts on the back cover. Both covers must also clearly and legibly identify you as the publisher of these copies. The front cover must present the full title with all words of the title equally prominent and visible. You may add other material on the covers in addition. Copying with changes limited to the covers, as long as they preserve the title of the Document and satisfy these conditions, can be treated as verbatim copying in other respects.

    If the required texts for either cover are too voluminous to fit legibly, you should put the first ones listed (as many as fit reasonably) on the actual cover, and continue the rest onto adjacent pages.

    If you publish or distribute Opaque copies of the Document numbering more than 100, you must either include a machine-readable Transparent copy along with each Opaque copy, or state in or with each Opaque copy a computer-network location from which the general network-using public has access to download using public-standard network protocols a complete Transparent copy of the Document, free of added material. If you use the latter option, you must take reasonably prudent steps, when you begin distribution of Opaque copies in quantity, to ensure that this Transparent copy will remain thus accessible at the stated location until at least one year after the last time you distribute an Opaque copy (directly or through your agents or retailers) of that edition to the public.

    It is requested, but not required, that you contact the authors of = the Document well before redistributing any large number of copies, to give them a chance to provide you with an updated version of the Document.

  5. MODIFICATIONS

    You may copy and distribute a Modified Version of the Document under the conditions of sections 2 and 3 above, provided that you release the Modified Version under precisely this License, with the Modified Version filling the role of the Document, thus licensing distribution and modification of the Modified Version to whoever possesses a copy of it. In addition, you must do these things in the Modified Version:

    1. Use in the Title Page (and on the covers, if any) a title distinct from that of the Document, and from those of previous versions (which should, if there were any, be listed in the History section of the Document). You may use the same title as a previous version if the original publisher of that version gives permission.
    2. List on the Title Page, as authors, one or more persons or = entities responsible for authorship of the modifications in the Modified Version, together with at least five of the principal authors of the Document (all of its principal authors, if it has fewer than five), unless they release you from this requirement.
    3. State on the Title page the name of the publisher of the Modified Version, as the publisher.
    4. Preserve all the copyright notices of the Document.
    5. Add an appropriate copyright notice for your modifications adjacent to the other copyright notices.
    6. Include, immediately after the copyright notices, a license = notice giving the public permission to use the Modified Version under the terms of this License, in the form shown in the Addendum below.
    7. Preserve in that license notice the full lists of Invariant = Sections and required Cover Texts given in the Document’s license notice.
    8. Include an unaltered copy of this License.
    9. Preserve the section Entitled “History”, Preserve = its Title, and add to it an item stating at least the title, year, new authors, and publisher of the Modified Version as given on the Title Page. If there is no section Entitled “History” in the Document, = create one stating the title, year, authors, and publisher of the Document as given on its Title Page, then add an item describing the Modified Version as stated in the previous sentence.
    10. Preserve the network location, if any, given in the Document = for public access to a Transparent copy of the Document, and likewise the network locations given in the Document for previous versions it was based on. These may be placed in the “History” = section. You may omit a network location for a work that was published at least four years before the Document itself, or if the original publisher of the version it refers to gives permission.
    11. For any section Entitled “Acknowledgements” or = “Dedications”, Preserve the Title of the section, and preserve in the section all the substance and tone of each of the contributor acknowledgements and/or dedications given therein.
    12. Preserve all the Invariant Sections of the Document, unaltered in their text and in their titles. Section numbers or the equivalent are not considered part of the section titles.
    13. Delete any section Entitled “Endorsements”. Such = a section may not be included in the Modified Version.
    14. Do not retitle any existing section to be Entitled = “Endorsements” or to conflict in title with any Invariant Section.
    15. Preserve any Warranty Disclaimers.

    If the Modified Version includes new front-matter sections or appendices that qualify as Secondary Sections and contain no material copied from the Document, you may at your option designate some or all of these sections as invariant. To do this, add their titles to the list of Invariant Sections in the Modified Version’s license = notice. These titles must be distinct from any other section titles.

    You may add a section Entitled “Endorsements”, provided = it contains nothing but endorsements of your Modified Version by various parties—for example, statements of peer review or that the text = has been approved by an organization as the authoritative definition of a standard.

    You may add a passage of up to five words as a Front-Cover Text, and = a passage of up to 25 words as a Back-Cover Text, to the end of the list of Cover Texts in the Modified Version. Only one passage of Front-Cover Text and one of Back-Cover Text may be added by (or through arrangements made by) any one entity. If the Document already includes a cover text for the same cover, previously added by you or by arrangement made by the same entity you are acting on behalf of, you may not add another; but you may replace the old one, on explicit permission from the previous publisher that added the old one.

    The author(s) and publisher(s) of the Document do not by this License give permission to use their names for publicity for or to assert or imply endorsement of any Modified Version.

  6. COMBINING DOCUMENTS

    You may combine the Document with other documents released under this License, under the terms defined in section 4 above for modified versions, provided that you include in the combination all of the Invariant Sections of all of the original documents, unmodified, and list them all as Invariant Sections of your combined work in its license notice, and that you preserve all their Warranty Disclaimers.

    The combined work need only contain one copy of this License, and multiple identical Invariant Sections may be replaced with a single copy. If there are multiple Invariant Sections with the same name but different contents, make the title of each such section unique by adding at the end of it, in parentheses, the name of the original author or publisher of that section if known, or else a unique number. Make the same adjustment to the section titles in the list of Invariant Sections in the license notice of the combined work.

    In the combination, you must combine any sections Entitled = “History” in the various original documents, forming one section Entitled “History”; likewise combine any sections Entitled = “Acknowledgements”, and any sections Entitled “Dedications”. You must delete = all sections Entitled “Endorsements.”

  7. COLLECTIONS OF DOCUMENTS

    You may make a collection consisting of the Document and other = documents released under this License, and replace the individual copies of this License in the various documents with a single copy that is included in the collection, provided that you follow the rules of this License for verbatim copying of each of the documents in all other respects.

    You may extract a single document from such a collection, and = distribute it individually under this License, provided you insert a copy of this License into the extracted document, and follow this License in all other respects regarding verbatim copying of that document.

  8. AGGREGATION WITH INDEPENDENT WORKS

    A compilation of the Document or its derivatives with other separate and independent documents or works, in or on a volume of a storage or distribution medium, is called an “aggregate” if the = copyright resulting from the compilation is not used to limit the legal rights of the compilation’s users beyond what the individual works = permit. When the Document is included in an aggregate, this License does not apply to the other works in the aggregate which are not themselves derivative works of the Document.

    If the Cover Text requirement of section 3 is applicable to these copies of the Document, then if the Document is less than one half of the entire aggregate, the Document’s Cover Texts may be placed on covers that bracket the Document within the aggregate, or the electronic equivalent of covers if the Document is in electronic form. Otherwise they must appear on printed covers that bracket the whole aggregate.

  9. TRANSLATION

    Translation is considered a kind of modification, so you may distribute translations of the Document under the terms of section 4. Replacing Invariant Sections with translations requires special permission from their copyright holders, but you may include translations of some or all Invariant Sections in addition to the original versions of these Invariant Sections. You may include a translation of this License, and all the license notices in the Document, and any Warranty Disclaimers, provided that you also include the original English version of this License and the original versions of those notices and disclaimers. In case of a disagreement between the translation and the original version of this License or a notice or disclaimer, the original version will prevail.

    If a section in the Document is Entitled = “Acknowledgements”, “Dedications”, or “History”, the requirement = (section 4) to Preserve its Title (section 1) will typically require changing the actual title.

  10. TERMINATION

    You may not copy, modify, sublicense, or distribute the Document except as expressly provided under this License. Any attempt otherwise to copy, modify, sublicense, or distribute it is void, and will automatically terminate your rights under this License.

    However, if you cease all violation of this License, then your = license from a particular copyright holder is reinstated (a) provisionally, unless and until the copyright holder explicitly and finally terminates your license, and (b) permanently, if the copyright holder fails to notify you of the violation by some reasonable means prior to 60 days after the cessation.

    Moreover, your license from a particular copyright holder is reinstated permanently if the copyright holder notifies you of the violation by some reasonable means, this is the first time you have received notice of violation of this License (for any work) from that copyright holder, and you cure the violation prior to 30 days after your receipt of the notice.

    Termination of your rights under this section does not terminate the licenses of parties who have received copies or rights from you under this License. If your rights have been terminated and not permanently reinstated, receipt of a copy of some or all of the same material does not give you any rights to use it.

  11. FUTURE REVISIONS OF THIS LICENSE

    The Free Software Foundation may publish new, revised versions of the GNU Free Documentation License from time to time. Such new versions will be similar in spirit to the present version, but may differ in detail to address new problems or concerns. See https://www.gnu.org/licenses/.

    Each version of the License is given a distinguishing version number. If the Document specifies that a particular numbered version of this License “or any later version” applies to it, you have the = option of following the terms and conditions either of that specified version or of any later version that has been published (not as a draft) by the Free Software Foundation. If the Document does not specify a version number of this License, you may choose any version ever published (not as a draft) by the Free Software Foundation. If the Document specifies that a proxy can decide which future versions of this License can be used, that proxy’s public statement of acceptance = of a version permanently authorizes you to choose that version for the Document.

  12. RELICENSING

    “Massive Multiauthor Collaboration Site” (or “MMC = Site”) means any World Wide Web server that publishes copyrightable works and also provides prominent facilities for anybody to edit those works. A public wiki that anybody can edit is an example of such a server. A “Massive Multiauthor Collaboration” (or “MMC”) = contained in the site means any set of copyrightable works thus published on the MMC site.

    “CC-BY-SA” means the Creative Commons Attribution-Share = Alike 3.0 license published by Creative Commons Corporation, a not-for-profit corporation with a principal place of business in San Francisco, California, as well as future copyleft versions of that license published by that same organization.

    “Incorporate” means to publish or republish a Document, = in whole or in part, as part of another Document.

    An MMC is “eligible for relicensing” if it is licensed = under this License, and if all works that were first published under this License somewhere other than this MMC, and subsequently incorporated in whole or in part into the MMC, (1) had no cover texts or invariant sections, and (2) were thus incorporated prior to November 1, 2008.

    The operator of an MMC Site may republish an MMC contained in the = site under CC-BY-SA on the same site at any time before August 1, 2009, provided the MMC is eligible for relicensing.

ADDENDUM: = How to use this License for your documents

To use this License in a document you have written, include a copy of the License in the document and put the following copyright and license notices just after the title page: 

  Copyright (C) =
 year  your name.
  Permission is granted to copy, distribute and/or modify this document
  under the terms of the GNU Free Documentation License, Version 1.3
  or any later version published by the Free Software Foundation;
  with no Invariant Sections, no Front-Cover Texts, and no Back-Cover
  Texts.  A copy of the license is included in the section entitled =
``GNU
  Free Documentation License''.

If you have Invariant Sections, Front-Cover Texts and Back-Cover = Texts, replace the “with…Texts.” line with this: 

    with the =
Invariant Sections being list their titles, =
with
    the Front-Cover Texts being list, and with =
the Back-Cover Texts
    being list.

If you have Invariant Sections without Cover Texts, or some other combination of the three, merge those two alternatives to suit the situation.

If your document contains nontrivial examples of program code, we recommend releasing these examples in parallel under your choice of free software license, such as the GNU General Public License, to permit their use in free software.

Previous: GNU Free Documentation License, Up: The Emacs Widget Library   [Contents][Index]

Index

This is an alphabetical listing of all concepts, functions, commands, variables, and widgets described in this manual.

Jump to:   = A  =20 B  =20 C  =20 D  =20 E  =20 F  =20 G  =20 H  =20 I  =20 K  =20 L  =20 M  =20 N  =20 O  =20 P  =20 R  =20 S  =20 T  =20 U  =20 V  =20 W  =20
<= td class=3D"printindex-index-section">atoms<= td class=3D"printindex-index-section">atomsatoms= = atoms= = =  =  
Index = Entry  = Section
A
action = keyword: Widget = Gallery
activate a = widget: Widget Gallery
activate = keyword: Widget = Gallery
active = keyword: Widget = Gallery
active widget: Widget = Gallery
alist: composite
append-button-arg= s keyword: editable-list
args = keyword: menu-choice
args = keyword: radio-button-choice
args = keyword: checklist
args = keyword: editable-list
atomic sexp = widget: atoms
B
basic widgets: Introduction
boolean: atoms
button = widgets: User Interface
button-args keyword: radio-button-choice
button-args keyword: checklist
button-face keyword: Widget = Gallery
button-face-get keyword: Widget = Gallery
button-prefix keyword: Widget = Gallery
button-suffix keyword: Widget = Gallery
buttons = keyword: radio-button-choice
buttons = keyword: checklist
buttons = keyword: editable-list
C
case-fold = keyword: menu-choice
character: 
checkbox = widget: checkbox
checklist = widget: checklist
children = keyword: menu-choice
children = keyword: radio-button-choice
children = keyword: checklist
children = keyword: editable-list
choice: composite
choice = keyword: menu-choice
choice = keyword: radio-button-choice
choice-item= widget: choice-item
coding-system:=  atoms
color: atoms
completions-functio= n keyword: Widget = Gallery
composite sexp = widgets: composite
cons: composite
const: constants
constant = widgets: constants
convert-widget keyword: Defining New Widgets
copy = keyword: Widget = Gallery
create = keyword: Widget = Gallery
D
deactivate a = widget: Widget Gallery
deactivate = keyword: Widget = Gallery
default: Widget = Gallery
default-get keyword: Widget = Gallery
define-widget:=  Defining New Widgets
defining new = widgets: Defining New Widgets
delete = keyword: Widget = Gallery
delete-button-arg= s keyword: editable-list
directory: 
doc = keyword: Widget = Gallery
documentation-string= widget: documentation-string
E
editable-field widget: editable-field
editable-list widget: editable-list
emacs-commentar= y-link = widget: emacs-commentary-link
emacs-library-link= widget: emacs-library-link
embedded = buttons: User Interface
entry-format keyword: radio-button-choice
entry-format keyword: checklist
entry-format keyword: editable-list
example of using = widgets: Programming Example
external = format: Widget Gallery
extra-offset keyword: Widget = Gallery
F
face-link = widget: face-link
file: atoms
file-link = widget: file-link
float: atoms
follow-link keyword: Widget = Gallery
format = keyword: Widget = Gallery
format-handler keyword: Widget = Gallery
function: 
function-item:=  constants
function-link widget: function-link
G
generic sexp = widget: generic
greedy = keyword: checklist
group = widget: group
H
help-echo = keyword: Widget = Gallery
I
inactive = widget: Widget Gallery
indent = keyword: Widget = Gallery
info-link = widget: info-link
insert-button-arg= s keyword: editable-list
integer: atoms
internal = format: Widget Gallery
item = widget: item
K
key: atoms
keymap = keyword: editable-field
keyword = arguments: Widget = Gallery
L
lazy: composite
link = widget: link
list: composite
M
match = keyword: Widget = Gallery
menu-choice= widget: menu-choice
menu-tag = keyword: Widget = Gallery
menu-tag-get keyword: Widget = Gallery
mouse-2 = (on button = widgets): Widgets and the Buffer
mouse-down-action<= span class=3D"r"> keyword: Widget = Gallery
mouse-face-get keyword: Widget = Gallery
must-match = keyword: atoms
N
natnum: atoms
new widgets: Defining New Widgets
notify = keyword: Widget = Gallery
number: atoms
O
off-glyph = keyword: toggle
offset = keyword: Widget = Gallery
on-glyph = keyword: toggle
option field = tag: User Interface
other: atoms
P
parent = keyword: Widget = Gallery
plist: composite
prompt-value keyword: Widget = Gallery
push-button= widget: push-button
R
radio: composite
radio-button-choi= ce widget: radio-button-choice
radio-button-togg= le widget: radio-button-toggle
regexp: atoms
repeat: composite
restricted-sexp: generic
S
secret = keyword: editable-field
set: composite
sexp: generic
sexp types: Sexp = Types
sibling-args keyword: Widget = Gallery
size = keyword: editable-field
string: atoms
symbol: atoms
T
tab-order = keyword: Widget = Gallery
tag = keyword: Widget = Gallery
tag-glyph = keyword: Widget = Gallery
text = widget: text
todo: Widget = Wishlist
toggle = widget: toggle
U
url-link = widget: url-link
utility functions for = widgets: Utilities
V
valid-regexp keyword: editable-field
validate = keyword: Widget = Gallery
value = keyword: Widget = Gallery
value-create keyword: Widget = Gallery
value-delete keyword: Widget = Gallery
value-face = keyword: editable-field
value-get = keyword: Widget = Gallery
value-inline keyword: Widget = Gallery
value-set = keyword: Widget = Gallery
value-to-external<= span class=3D"r"> keyword: Widget = Gallery
value-to-internal<= span class=3D"r"> keyword: Widget = Gallery
variable: 
variable-item:=  constants
variable-link widget: variable-link
vector: composite
void = keyword: menu-choice
W
widget = browser: Inspecting Widgets
widget = buttons: User Interface
widget creation, = widget conversion: Setting Up the Buffer
widget = inheritance: Widgets = Basics
widget library, why use = it: Introduction
widget minor = mode: Widget Minor Mode
widget object: Widgets = Basics
widget = properties: Widgets = Basics
widget syntax: Widget = Gallery
widget value: Widgets = Basics
widget-apply:&n= bsp;Working with Widgets
widget-apply-action: Working with Widgets
widget-at: Working with Widgets
widget-backward: Widgets and the Buffer
widget-browse:=  Inspecting Widgets
widget-browse-at= : Inspecting Widgets
widget-browse= -other-window: Inspecting Widgets
widget-button-click: Widgets and the Buffer
widget-button-click: Widgets and the Buffer
widget-button-face= : Customization
widget-button-prefix: Customization
widget-button-press: Widgets and the Buffer
widget-button-press: Widgets and the Buffer
widget-button-suffix: Customization
widget-child-validate<= /code>: Working with Widgets
widget-child-valu= e-get: Working with Widgets
widget-child-v= alue-inline: Working with Widgets
widget-children-val= idate: Working with Widgets
widget-chil= dren-value-delete: Setting Up the Buffer
widget-choice-toggle: Customization
widget-choose:=  Utilities
widget-complete: Widgets and the Buffer
widget-convert:Setting Up the Buffer
widget-copy:&nbs= p;Setting Up the Buffer
widget-create:=  Setting Up the Buffer
widget-create-child: Setting Up the Buffer
widg= et-create-child-and-convert: Setting Up the Buffer
widget-create-= child-value: Setting Up the Buffer
widget-default-delete<= /code>: Widget Gallery
widget-def= ault-format-handler: Widget = Gallery
widget-default-get= : Working with Widgets
widget-delete:=  Setting Up the Buffer
widget-describe: Inspecting Widgets
widget-docum= entation-link-p: Customization
widget-= documentation-link-regexp: Customization
widget-do= cumentation-link-type: Customization
widget-documentat= ion-links: Customization
widget-echo-help= : Utilities
widget-end-of-line: Widgets and the Buffer
widget-field-activate<= /code>: Widgets and the Buffer
widget-field-at:<= /td> Working with Widgets
widget-field-face: Customization
widget-field-keymap: editable-field
widget-forward:Widgets and the Buffer
widget-get: = Working with Widgets
widget-get-sibling= : Utilities
widget-global-map: Widgets and the Buffer
widget-image-convers= ion: Customization
widget-image-director= y: Customization
widget-image-enable: Customization
widget-image-find: Utilities
widget-image-insert: Utilities
widget-insert:=  Setting Up the Buffer
widget-keymap:=  Widgets and the Buffer
widget-kill-line= : Widgets and the Buffer
widget-link-prefix= : Customization
widget-link-suffix= : Customization
widget-member:=  Working with Widgets
widget-menu-ma= x-shortcuts: Customization
widget-menu-max-siz= e: Customization
widget-menu-= minibuffer-flag: Customization
widget-minor-mode: Widget Minor Mode
widget-minor-mo= de-keymap: Widget = Minor Mode
widget-mouse-face: Customization
widget-parent-action: Working with Widgets
widget-prompt-value: Utilities
widget-push-bu= tton-prefix: Customization
widget-push-bu= tton-suffix: Customization
widget-put: = Working with Widgets
widget-radio-add-i= tem: radio-button-choice
widget-setup:&n= bsp;Setting Up the Buffer
widget-text-keymap= : text
widget-type:&nbs= p;Working with Widgets
widget-type-defa= ult-get: Working with Widgets
widget-type-match: Working with Widgets
widget-type-val= ue-create: Working with Widgets
widget-types= -convert-widget: Working with Widgets
widget-types-copy: Working with Widgets
widget-value:&n= bsp;Working with Widgets
widget-value= -convert-widget: Working with Widgets
widget-value-set= : Working with Widgets
widget-value-valu= e-get: Working with Widgets
widgetp: Working with Widgets
widgets, basic = types: Introduction
widgets, programming = example: Programming Example
Jump to:   = A  =20 B  =20 C  =20 D  =20 E  =20 F  =20 G  =20 H  =20 I  =20 K  =20 L  =20 M  =20 N  =20 O  =20 P  =20 R  =20 S  =20 T  =20 U  =20 V  =20 W  =20
--Apple-Mail=_10F3A5D0-319C-48D1-A362-8270E462F228--