* Re: [External] : Editions to the Widget Manual
2023-08-21 15:42 ` Drew Adams
@ 2023-08-21 16:52 ` Corwin Brust
2023-08-21 16:55 ` Drew Adams
0 siblings, 1 reply; 13+ messages in thread
From: Corwin Brust @ 2023-08-21 16:52 UTC (permalink / raw)
To: Drew Adams; +Cc: emacs-devel
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On Mon, Aug 21, 2023 at 10:42 AM Drew Adams <drew.adams@oracle.com> wrote:
>
> Even a plain-text diff/patch would be more helpful
I've attached plain text versions (makeinfo --plaintext) with and
without the patch as well as a diff -u contrasting them. hth
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The Emacs Widget Library
1 Introduction
2 User Interface
2.1 Editable Text Fields
2.2 Buttons
2.3 Navigation
3 Programming Example
4 Setting Up the Buffer
5 Basic Types
5.1 The ‘link’ Widget
5.2 The ‘url-link’ Widget
5.3 The ‘info-link’ Widget
5.4 The ‘push-button’ Widget
5.5 The ‘editable-field’ Widget
5.6 The ‘text’ Widget
5.7 The ‘menu-choice’ Widget
5.8 The ‘radio-button-choice’ Widget
5.9 The ‘item’ Widget
5.10 The ‘choice-item’ Widget
5.11 The ‘toggle’ Widget
5.12 The ‘checkbox’ Widget
5.13 The ‘checklist’ Widget
5.14 The ‘editable-list’ Widget
5.15 The ‘group’ Widget
6 Sexp Types
6.1 The Constant Widgets
6.2 Generic Sexp Widget
6.3 Atomic Sexp Widgets
6.4 Composite Sexp Widgets
7 Properties
8 Defining New Widgets
9 Widget Browser
10 Widget Minor Mode
11 Utilities
12 Wishlist
Appendix A GNU Free Documentation License
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.”
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.
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.
3 Programming Example
*********************
Here is the code to implement the user interface example (*note 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 (= (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))
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 *note 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’.
5 Basic Types
*************
This is the general syntax of a type specification:
NAME ::= (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 (*note 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. *Note
Defining Clickable Text: (elisp)Clickable Text.
‘: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.
a. Widgets with tabbing order ‘-1’ are ignored.
b. (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.
c. 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.
5.1 The ‘link’ Widget
=====================
Syntax:
TYPE ::= (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.
5.2 The ‘url-link’ Widget
=========================
Syntax:
TYPE ::= (url-link [KEYWORD ARGUMENT]... URL)
When this link is invoked, the WWW browser specified by
‘browse-url-browser-function’ will be called with URL.
5.3 The ‘info-link’ Widget
==========================
Syntax:
TYPE ::= (info-link [KEYWORD ARGUMENT]... ADDRESS)
When this link is invoked, the built-in Info reader is started on
ADDRESS.
5.4 The ‘push-button’ Widget
============================
Syntax:
TYPE ::= (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.
5.5 The ‘editable-field’ Widget
===============================
Syntax:
TYPE ::= (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 *note 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’.
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.
5.7 The ‘menu-choice’ Widget
============================
Syntax:
TYPE ::= (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.
5.8 The ‘radio-button-choice’ Widget
====================================
Syntax:
TYPE ::= (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’.
5.9 The ‘item’ Widget
=====================
Syntax:
ITEM ::= (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.
5.10 The ‘choice-item’ Widget
=============================
Syntax:
ITEM ::= (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.
5.11 The ‘toggle’ Widget
========================
Syntax:
TYPE ::= (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.
5.12 The ‘checkbox’ Widget
==========================
This widget has two possible states, ‘selected’ and ‘unselected’, which
corresponds to a ‘t’ or ‘nil’ value.
Syntax:
TYPE ::= (checkbox [KEYWORD ARGUMENT]...)
5.13 The ‘checklist’ Widget
===========================
Syntax:
TYPE ::= (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.
5.14 The ‘editable-list’ Widget
===============================
Syntax:
TYPE ::= (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.
5.15 The ‘group’ Widget
=======================
This widget simply group other widgets together.
Syntax:
TYPE ::= (group [KEYWORD ARGUMENT]... TYPE...)
The value is a list, with one member for each TYPE.
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.
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 ::= (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.
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 ::= (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. *Note editable-field::.
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 ::= (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. *Note editable-field::.
-- 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.
6.4 Composite Sexp Widgets
==========================
The syntax for the composite widget construct is:
TYPE ::= (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 ::= (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 ::= (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 ::= (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 ::= (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 ::= (repeat [KEYWORD ARGUMENT]... TYPE)
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.
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.
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.
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’.
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.
*Note Defining Menus: (elisp)Defining Menus. 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’ (*note
(elisp)Changing Key Bindings::). 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.
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.
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.
0. PREAMBLE
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This License is a kind of “copyleft”, which means that derivative
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We have designed this License in order to use it for manuals for
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====================================================
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Index
*****
This is an alphabetical listing of all concepts, functions, commands,
variables, and widgets described in this manual.
* Menu:
* action keyword: Defining New Widgets.
(line 1333)
* activate a widget: Widget Properties. (line 1181)
* active widget: Widget Properties. (line 1181)
* append-button-args keyword: editable-list. (line 919)
* args keyword: menu-choice. (line 731)
* args keyword <1>: radio-button-choice.
(line 771)
* args keyword <2>: checklist. (line 885)
* args keyword <3>: editable-list. (line 928)
* atomic sexp widget: atoms. (line 999)
* basic widgets: Introduction. (line 63)
* boolean: atoms. (line 1052)
* browse-url-browser-function, and url-link widget: url-link.
(line 629)
* button widgets: User Interface. (line 200)
* button-args keyword: radio-button-choice.
(line 758)
* button-args keyword <1>: checklist. (line 875)
* button-face keyword: Basic Types. (line 486)
* button-prefix keyword: Basic Types. (line 489)
* button-suffix keyword: Basic Types. (line 489)
* buttons keyword: radio-button-choice.
(line 762)
* buttons keyword <1>: checklist. (line 879)
* buttons keyword <2>: editable-list. (line 922)
* case-fold keyword: menu-choice. (line 720)
* character: atoms. (line 1021)
* checkbox widget: checkbox. (line 837)
* checklist widget: checklist. (line 847)
* children keyword: menu-choice. (line 724)
* children keyword <1>: radio-button-choice.
(line 765)
* children keyword <2>: checklist. (line 882)
* children keyword <3>: editable-list. (line 925)
* choice: composite. (line 1072)
* choice keyword: menu-choice. (line 728)
* choice keyword <1>: radio-button-choice.
(line 768)
* choice-item widget: choice-item. (line 800)
* composite sexp widgets: composite. (line 1059)
* cons: composite. (line 1066)
* const: constants. (line 963)
* constant widgets: constants. (line 952)
* convert-widget keyword: Defining New Widgets.
(line 1243)
* copy keyword: Defining New Widgets.
(line 1258)
* create keyword: Defining New Widgets.
(line 1281)
* deactivate a widget: Widget Properties. (line 1181)
* default: Defining New Widgets.
(line 1355)
* define-widget: Defining New Widgets.
(line 1219)
* defining new widgets: Defining New Widgets.
(line 1215)
* delete keyword: Defining New Widgets.
(line 1286)
* delete-button-args keyword: editable-list. (line 916)
* directory: atoms. (line 1032)
* doc keyword: Basic Types. (line 503)
* editable-field widget: editable-field. (line 663)
* editable-list widget: editable-list. (line 891)
* embedded buttons: User Interface. (line 227)
* entry-format keyword: radio-button-choice.
(line 748)
* entry-format keyword <1>: checklist. (line 858)
* entry-format keyword <2>: editable-list. (line 900)
* example of using widgets: Programming Example.
(line 273)
* external format: Basic Types. (line 422)
* extra-offset keyword: Basic Types. (line 533)
* file: atoms. (line 1024)
* follow-link keyword: Basic Types. (line 521)
* format keyword: Basic Types. (line 435)
* format-handler keyword: Defining New Widgets.
(line 1323)
* function: atoms. (line 1039)
* function-item: constants. (line 976)
* generic sexp widget: generic. (line 982)
* greedy keyword: checklist. (line 868)
* group widget: group. (line 934)
* help-echo keyword: Basic Types. (line 513)
* inactive widget: Widget Properties. (line 1181)
* indent keyword: Basic Types. (line 525)
* info-link widget: info-link. (line 635)
* insert-button-args keyword: editable-list. (line 913)
* integer: atoms. (line 1046)
* internal format: Basic Types. (line 422)
* item widget: item. (line 789)
* keymap keyword: editable-field. (line 691)
* keyword arguments: Basic Types. (line 420)
* link widget: link. (line 607)
* list: composite. (line 1081)
* match keyword: Basic Types. (line 554)
* menu-choice widget: menu-choice. (line 708)
* menu-tag keyword: Basic Types. (line 544)
* menu-tag-get keyword: Basic Types. (line 548)
* mouse-2 (on button widgets): User Interface. (line 210)
* must-match keyword: atoms. (line 1028)
* new widgets: Defining New Widgets.
(line 1215)
* notify keyword: Basic Types. (line 537)
* number: atoms. (line 1049)
* off-glyph keyword: toggle. (line 829)
* offset keyword: Basic Types. (line 529)
* on-glyph keyword: toggle. (line 826)
* option field tag: User Interface. (line 220)
* parent keyword: Basic Types. (line 585)
* prompt-value keyword: Defining New Widgets.
(line 1343)
* properties of widgets: Widget Properties. (line 1136)
* push-button widget: push-button. (line 645)
* radio-button-choice widget: radio-button-choice.
(line 737)
* regexp: atoms. (line 1018)
* repeat: composite. (line 1128)
* secret keyword: editable-field. (line 681)
* set: composite. (line 1118)
* sexp: generic. (line 989)
* sexp types: Sexp Types. (line 945)
* sibling-args keyword: Basic Types. (line 589)
* size keyword: editable-field. (line 673)
* string: atoms. (line 1015)
* symbol: atoms. (line 1036)
* tab-order keyword: Basic Types. (line 570)
* tag keyword: Basic Types. (line 506)
* tag-glyph keyword: Basic Types. (line 509)
* text widget: text. (line 701)
* todo: Widget Wishlist. (line 1429)
* toggle widget: toggle. (line 813)
* url-link widget: url-link. (line 625)
* utility functions for widgets: Utilities. (line 1398)
* valid-regexp keyword: editable-field. (line 686)
* validate keyword: Basic Types. (line 559)
* value keyword: Basic Types. (line 422)
* value-create keyword: Defining New Widgets.
(line 1299)
* value-delete keyword: Defining New Widgets.
(line 1307)
* value-face keyword: editable-field. (line 677)
* value-get keyword: Defining New Widgets.
(line 1314)
* value-to-external keyword: Defining New Widgets.
(line 1276)
* value-to-internal keyword: Defining New Widgets.
(line 1269)
* variable: atoms. (line 1043)
* variable-item: constants. (line 973)
* vector: composite. (line 1090)
* void keyword: menu-choice. (line 716)
* widget browser: Widget Browser. (line 1364)
* widget buttons: User Interface. (line 200)
* widget library, why use it: Introduction. (line 103)
* widget minor mode: Widget Minor Mode. (line 1384)
* widget properties: Widget Properties. (line 1136)
* widget-apply: Widget Properties. (line 1170)
* widget-backward: User Interface. (line 267)
* widget-browse: Widget Browser. (line 1369)
* widget-browse-at: Widget Browser. (line 1377)
* widget-browse-other-window: Widget Browser. (line 1373)
* widget-button-click: User Interface. (line 211)
* widget-button-click <1>: Setting Up the Buffer.
(line 399)
* widget-button-face: User Interface. (line 249)
* widget-button-prefix: Basic Types. (line 446)
* widget-button-press: User Interface. (line 205)
* widget-button-press <1>: Setting Up the Buffer.
(line 399)
* widget-button-suffix: Basic Types. (line 449)
* widget-children-validate: Basic Types. (line 567)
* widget-choose: Utilities. (line 1406)
* widget-create: Setting Up the Buffer.
(line 374)
* widget-default-delete: Defining New Widgets.
(line 1292)
* widget-default-format-handler: Defining New Widgets.
(line 1329)
* widget-delete: Setting Up the Buffer.
(line 381)
* widget-field-face: User Interface. (line 194)
* widget-field-keymap: editable-field. (line 691)
* widget-forward: User Interface. (line 263)
* widget-get: Widget Properties. (line 1162)
* widget-get-sibling: Utilities. (line 1402)
* widget-global-map: Setting Up the Buffer.
(line 404)
* widget-image-directory: Basic Types. (line 595)
* widget-image-enable: Basic Types. (line 600)
* widget-insert: Setting Up the Buffer.
(line 393)
* widget-keymap: Setting Up the Buffer.
(line 399)
* widget-link-prefix: link. (line 616)
* widget-link-suffix: link. (line 619)
* widget-member: Widget Properties. (line 1167)
* widget-minor-mode: Widget Minor Mode. (line 1388)
* widget-minor-mode-keymap: Widget Minor Mode. (line 1392)
* widget-mouse-face: User Interface. (line 252)
* widget-parent-action: Defining New Widgets.
(line 1339)
* widget-prompt-value: Utilities. (line 1398)
* widget-push-button-prefix: push-button. (line 654)
* widget-push-button-suffix: push-button. (line 657)
* widget-put: Widget Properties. (line 1158)
* widget-radio-add-item: radio-button-choice.
(line 778)
* widget-setup: Setting Up the Buffer.
(line 384)
* widget-text-keymap: text. (line 701)
* widget-type: Widget Properties. (line 1178)
* widget-types-convert-widget: Defining New Widgets.
(line 1252)
* widget-types-copy: Defining New Widgets.
(line 1266)
* widget-value: Widget Properties. (line 1139)
* widget-value-convert-widget: Defining New Widgets.
(line 1255)
* widget-value-set: Widget Properties. (line 1143)
* widget-value-value-get: Defining New Widgets.
(line 1320)
* widgets, basic types: Introduction. (line 63)
* widgets, programming example: Programming Example.
(line 273)
[-- Attachment #3: widget.txt.patch --]
[-- Type: application/octet-stream, Size: 141634 bytes --]
--- widget.orig_texi.txt 2023-08-21 11:45:19.141060600 -0500
+++ widget.texi.txt 2023-08-21 11:43:40.847561200 -0500
@@ -5,34 +5,46 @@
2.2 Buttons
2.3 Navigation
3 Programming Example
-4 Setting Up the Buffer
-5 Basic Types
- 5.1 The ‘link’ Widget
- 5.2 The ‘url-link’ Widget
- 5.3 The ‘info-link’ Widget
- 5.4 The ‘push-button’ Widget
- 5.5 The ‘editable-field’ Widget
- 5.6 The ‘text’ Widget
- 5.7 The ‘menu-choice’ Widget
- 5.8 The ‘radio-button-choice’ Widget
- 5.9 The ‘item’ Widget
- 5.10 The ‘choice-item’ Widget
- 5.11 The ‘toggle’ Widget
- 5.12 The ‘checkbox’ Widget
- 5.13 The ‘checklist’ Widget
- 5.14 The ‘editable-list’ Widget
- 5.15 The ‘group’ Widget
-6 Sexp Types
- 6.1 The Constant Widgets
- 6.2 Generic Sexp Widget
- 6.3 Atomic Sexp Widgets
- 6.4 Composite Sexp Widgets
-7 Properties
-8 Defining New Widgets
-9 Widget Browser
-10 Widget Minor Mode
-11 Utilities
-12 Wishlist
+4 Widgets Basics
+5 Setting Up the Buffer
+6 Working with Widgets
+7 Widgets and the Buffer
+8 Widget Gallery
+ 8.1 Basic Types
+ 8.1.1 The ‘item’ Widget
+ 8.1.2 The ‘link’ Widget
+ 8.1.3 The ‘url-link’ Widget
+ 8.1.4 The ‘info-link’ Widget
+ 8.1.5 The ‘function-link’ Widget
+ 8.1.6 The ‘variable-link’ Widget
+ 8.1.7 The ‘face-link’ Widget
+ 8.1.8 The ‘file-link’ Widget
+ 8.1.9 The ‘emacs-library-link’ Widget
+ 8.1.10 The ‘emacs-commentary-link’ Widget
+ 8.1.11 The ‘push-button’ Widget
+ 8.1.12 The ‘editable-field’ Widget
+ 8.1.13 The ‘text’ Widget
+ 8.1.14 The ‘menu-choice’ Widget
+ 8.1.15 The ‘radio-button-choice’ Widget
+ 8.1.16 The ‘choice-item’ Widget
+ 8.1.17 The ‘toggle’ Widget
+ 8.1.18 The ‘radio-button-toggle’ Widget
+ 8.1.19 The ‘checkbox’ Widget
+ 8.1.20 The ‘checklist’ Widget
+ 8.1.21 The ‘editable-list’ Widget
+ 8.1.22 The ‘group’ Widget
+ 8.1.23 The ‘documentation-string’ Widget
+ 8.2 Sexp Types
+ 8.2.1 The Constant Widgets
+ 8.2.2 Generic Sexp Widget
+ 8.2.3 Atomic Sexp Widgets
+ 8.2.4 Composite Sexp Widgets
+9 Defining New Widgets
+10 Inspecting Widgets
+11 Widget Minor Mode
+12 Utilities
+13 Customization
+14 Wishlist
Appendix A GNU Free Documentation License
Index
The Emacs Widget Library
@@ -57,7 +69,7 @@
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
+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.
@@ -71,13 +83,14 @@
‘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
+ 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 will be visible in the buffer.
+ 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.
@@ -174,11 +187,6 @@
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
@@ -186,34 +194,18 @@
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).
+“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:
@@ -245,28 +237,16 @@
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.
+ 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:
-
-‘<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.
+buffer, plus you will have these additional commands to navigate from
+widget to widget: ‘widget-forward’ and ‘widget-backward’.
3 Programming Example
*********************
@@ -364,68 +344,474 @@
(use-local-map widget-keymap)
(widget-setup))
-4 Setting Up the Buffer
-***********************
+4 Widgets Basics
+****************
-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 *note Basic Types::.
+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. *Note
+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.
- The keyword arguments can be used to overwrite the keyword
- arguments that are part of TYPE.
+ 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 ‘:’.
- -- Function: widget-delete widget
- Delete WIDGET and remove it from the buffer.
+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 *note 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
- Set up a buffer to support widgets.
+ 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.
- If you want to insert text outside the widgets in the form, the
-recommended way to do that is with ‘widget-insert’.
+ 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. *Note
+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.
+ *Note (elisp)Insertion::, for more information about ARGS.
+
+ The resulting text will be read-only.
+
+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. *Note 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-insert
- Insert the arguments, either strings or characters, at point. The
- inserted text will be read-only.
+ -- Function: widget-value-convert-widget widget
+ Initializes the ‘:value’ property of WIDGET from ‘:args’.
- There is a standard widget keymap which you might find useful.
+ 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.
+
+7 Widgets and the Buffer
+************************
+
+This chapter describes commands that are specific to buffers that
+contain widgets.
-- 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’.
+ 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’.
-5 Basic Types
-*************
+ 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.
-This is the general syntax of a type specification:
+ 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.
+
+8 Widget Gallery
+****************
+
+All widgets can be created from a type specification. The general
+syntax of a type specification is:
NAME ::= (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.
+ 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. *Note 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.
+ 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
@@ -433,6 +819,59 @@
widget or defining a new one (*note 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:
@@ -444,12 +883,6 @@
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
@@ -459,10 +892,6 @@
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.
@@ -489,6 +918,11 @@
‘: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
@@ -514,10 +948,11 @@
‘: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.
+ 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. *Note
@@ -525,7 +960,12 @@
‘:indent’
An integer indicating the absolute number of spaces to indent
- children of this widget.
+ 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
@@ -535,22 +975,17 @@
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.
+ 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
@@ -559,20 +994,18 @@
‘: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.
+ if the widget’s current value is valid for the widget.
- The following predefined function can be used:
+ Otherwise, it should return the widget containing the invalid data,
+ and set that widget’s ‘:error’ property to a string explaining the
+ error.
- -- Function: widget-children-validate widget
- All the ‘:children’ of WIDGET must be valid.
+ 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.
-
a. Widgets with tabbing order ‘-1’ are ignored.
b. (Unimplemented) When on a widget with tabbing order N, go to
@@ -593,134 +1026,508 @@
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.
+‘:completions-function’
+ Function that takes a widget and returns completion data for that
+ widget, like ‘completion-at-point-functions’ would. *Note
+ (elisp)Completion::. 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.
- -- User Option: widget-image-enable
- If non-‘nil’, allow images to appear on displays where they are
- supported.
+‘: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.
+
+8.1 Basic Types
+===============
+
+8.1.1 The ‘item’ Widget
+-----------------------
+
+Syntax:
+
+ TYPE ::= (item [KEYWORD ARGUMENT]... VALUE)
-5.1 The ‘link’ Widget
-=====================
+ 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.
+
+8.1.2 The ‘link’ Widget
+-----------------------
Syntax:
TYPE ::= (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 the link will be shown in brackets.
+ By default, it has the following properties:
- -- User Option: widget-link-prefix
- String to prefix links.
+‘:button-prefix’
+ The value of ‘widget-link-prefix’.
- -- User Option: widget-link-suffix
- String to suffix links.
+‘: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’. *Note (elisp)Clickable Text::.
+
+‘: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.
-5.2 The ‘url-link’ Widget
-=========================
+8.1.3 The ‘url-link’ Widget
+---------------------------
Syntax:
TYPE ::= (url-link [KEYWORD ARGUMENT]... URL)
- When this link is invoked, the WWW browser specified by
-‘browse-url-browser-function’ will be called with 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.
-5.3 The ‘info-link’ Widget
-==========================
+8.1.4 The ‘info-link’ Widget
+----------------------------
Syntax:
TYPE ::= (info-link [KEYWORD ARGUMENT]... ADDRESS)
- When this link is invoked, the built-in Info reader is started on
-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.
-5.4 The ‘push-button’ Widget
-============================
+8.1.5 The ‘function-link’ Widget
+--------------------------------
+
+Syntax:
+
+ TYPE ::= (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.
+
+8.1.6 The ‘variable-link’ Widget
+--------------------------------
+
+Syntax:
+
+ TYPE ::= (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.
+
+8.1.7 The ‘face-link’ Widget
+----------------------------
+
+Syntax:
+
+ TYPE ::= (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.
+
+8.1.8 The ‘file-link’ Widget
+----------------------------
+
+Syntax:
+
+ TYPE ::= (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.
+
+8.1.9 The ‘emacs-library-link’ Widget
+-------------------------------------
+
+Syntax:
+
+ TYPE ::= (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.
+
+8.1.10 The ‘emacs-commentary-link’ Widget
+-----------------------------------------
+
+Syntax:
+
+ TYPE ::= (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.
+
+8.1.11 The ‘push-button’ Widget
+-------------------------------
Syntax:
TYPE ::= (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 the tag will be shown in brackets.
+ By default, it has the following properties:
+‘:button-prefix’
+ The empty string.
- -- User Option: widget-push-button-prefix
- String to prefix push buttons.
+‘:button-suffix’
+ The empty string.
- -- User Option: widget-push-button-suffix
- String to suffix push buttons.
+‘: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’. *Note
+ Customization::.
-5.5 The ‘editable-field’ Widget
-===============================
+‘:format’
+ Buttonizes the widget, to make it clickable.
+
+8.1.12 The ‘editable-field’ Widget
+----------------------------------
Syntax:
TYPE ::= (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. This
-widget will match all string values.
+The value should be a string, which will be inserted in the field. If
+not present, ‘:value’ is the empty string.
- The following extra properties are recognized:
+ *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 *note User Interface::.
+ Face used for highlighting the editable field.
+
+ Default is ‘widget-field-face’, *note 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.
+ 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.
+ 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.
+
+8.1.13 The ‘text’ Widget
+------------------------
+
+Syntax:
+
+ TYPE ::= (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’
- 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’.
-
-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.
+ The default is ‘widget-text-keymap’, which does not rebind the
+ <RET> key.
-5.7 The ‘menu-choice’ Widget
-============================
+8.1.14 The ‘menu-choice’ Widget
+-------------------------------
Syntax:
TYPE ::= (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. This widget will match
-any value matching at least one of the specified TYPE arguments.
+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’
- Set this to ‘nil’ if you don’t want to ignore case when prompting
- for a choice through the minibuffer.
+ 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
@@ -732,19 +1539,77 @@
‘:args’
The list of types.
-5.8 The ‘radio-button-choice’ Widget
-====================================
+‘: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.
+
+8.1.15 The ‘radio-button-choice’ Widget
+---------------------------------------
Syntax:
TYPE ::= (radio-button-choice [KEYWORD ARGUMENT]... TYPE ... )
- The component types specify the choices, with one radio button for
+ 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.
-This widget matches any value that matches at least one of the specified
-TYPE arguments.
- The following extra properties are recognized.
+ 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
@@ -756,6 +1621,9 @@
‘%%’
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.
@@ -767,11 +1635,37 @@
The widgets representing each type.
‘:choice’
- The current chosen type
+ 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’.
@@ -784,77 +1678,172 @@
widget has been created will *not* be properly destructed when you call
‘widget-delete’.
-5.9 The ‘item’ Widget
-=====================
+8.1.16 The ‘choice-item’ Widget
+-------------------------------
Syntax:
- ITEM ::= (item [KEYWORD ARGUMENT]... VALUE)
+ ITEM ::= (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.
-This widget will only match the specified value.
+ A widget to represent a choice in a ‘menu-choice’ widget. Its super
+is the ‘item’ widget.
-5.10 The ‘choice-item’ Widget
-=============================
+ The VALUE, if present, is used to initialize the ‘:value’ property.
-Syntax:
+ It overrides the following properties:
- ITEM ::= (choice-item [KEYWORD ARGUMENT]... VALUE)
+‘:action’
+ Activating the button of a ‘choice-item’ is equivalent to
+ activating the parent 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 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.
+‘:format’
+ By default, it buttonizes the tag (i.e., its value) and adds a
+ newline character at the end of the widget.
-5.11 The ‘toggle’ Widget
-========================
+8.1.17 The ‘toggle’ Widget
+--------------------------
Syntax:
TYPE ::= (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.
- The following extra properties are recognized:
+ 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.
-5.12 The ‘checkbox’ Widget
-==========================
+‘: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.
+
+8.1.18 The ‘radio-button-toggle’ Widget
+---------------------------------------
+
+Syntax:
+
+ TYPE ::= (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.
-This widget has two possible states, ‘selected’ and ‘unselected’, which
-corresponds to a ‘t’ or ‘nil’ value.
+8.1.19 The ‘checkbox’ Widget
+----------------------------
- Syntax:
+Syntax:
TYPE ::= (checkbox [KEYWORD ARGUMENT]...)
-5.13 The ‘checklist’ Widget
-===========================
+ 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.
+
+8.1.20 The ‘checklist’ Widget
+-----------------------------
Syntax:
TYPE ::= (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. The
-checklist widget will match a list whose elements all match at least one
-of the specified TYPE arguments.
+will be a list containing the values of all checked TYPE arguments.
- The following extra properties are recognized:
+ 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
@@ -866,13 +1855,6 @@
‘%%’
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.
@@ -886,17 +1868,48 @@
‘:args’
The list of types.
-5.14 The ‘editable-list’ Widget
-===============================
+‘: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.
+
+8.1.21 The ‘editable-list’ Widget
+---------------------------------
Syntax:
TYPE ::= (editable-list [KEYWORD ARGUMENT]... TYPE)
- The value is a list, where each member represents one widget of type
-TYPE.
+ A widget that can hold a variable list of widgets of the same type,
+represented by TYPE. Its super is the ‘default’ widget.
- The following extra properties are recognized:
+ 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
@@ -905,9 +1918,9 @@
This will be replaced with the buffer representation of the
TYPE widget.
‘%i’
- Insert the [INS] button.
+ Insert the [INS] button, a widget of type ‘insert-button’.
‘%d’
- Insert the [DEL] button.
+ Insert the [DEL] button, a widget of type ‘delete-button’.
‘%%’
Insert a literal ‘%’.
@@ -923,32 +1936,138 @@
‘: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.
-5.15 The ‘group’ Widget
-=======================
+‘: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.
-This widget simply group other widgets together.
+‘: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.
- Syntax:
+8.1.22 The ‘group’ Widget
+-------------------------
+
+Syntax:
TYPE ::= (group [KEYWORD ARGUMENT]... TYPE...)
- The value is a list, with one member for each TYPE.
+ A widget to group other widgets. Its super is the ‘default’ widget.
-6 Sexp Types
-************
+ 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.
+
+8.1.23 The ‘documentation-string’ Widget
+----------------------------------------
+
+Syntax:
+
+ TYPE ::= (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’.
+
+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.
-6.1 The Constant Widgets
-========================
+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
@@ -958,18 +2077,24 @@
TYPE ::= (const [KEYWORD ARGUMENT]... [ VALUE ])
- The VALUE, if present, is used to initialize the ‘:value’ property
-and can be any s-expression.
+ 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. The major difference from the ‘const’
-widget is that they will allow the user to see the variable or function
-documentation for the symbol.
+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.
@@ -977,8 +2102,8 @@
-- Widget: function-item
An immutable symbol that is bound as a function.
-6.2 Generic Sexp Widget
-=======================
+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.
@@ -988,74 +2113,165 @@
TYPE ::= (sexp [KEYWORD ARGUMENT]... [ VALUE ])
-- Widget: sexp
- This will allow you to edit any valid s-expression in an editable
- buffer field.
+ 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. *Note editable-field::.
-6.3 Atomic Sexp Widgets
-=======================
+ 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)’.
+
+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
-following widgets.
+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 are:
+ The syntax for all the atoms is:
TYPE ::= (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.
+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. *Note editable-field::.
-- Widget: string
- Allows you to edit a string in an editable field.
+ An editable field widget that can represent any Lisp string.
+
+ It offers completion via the ispell library and the ‘:complete’
+ property.
-- Widget: regexp
- Allows you to edit a regular expression in an editable field.
+ 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
- Allows you to enter a character in an editable field.
+ 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
- Allows you to edit a file name in an editable field.
+ 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 will be
- allowed in the minibuffer.
+ 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
- Allows you to edit a directory name in an editable field. Similar
- to the ‘file’ widget.
+ 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
- Allows you to edit a Lisp symbol in an editable field.
+ A widget for editing a Lisp symbol.
+
+ Its value by default is ‘nil’.
-- Widget: function
- Allows you to edit a lambda expression, or a function name with
- completion.
+ A widget for editing a lambda expression, or a function name,
+ offering completion. Its super is the ‘restricted-sexp’ widget.
-- Widget: variable
- Allows you to edit a variable name, with completion.
+ A widget for editing variable names, offering completion. Its
+ super is the ‘symbol’ widget.
-- Widget: integer
- Allows you to edit an integer in an editable field.
+ 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
- Allows you to edit a number in an editable field.
+ 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
- Allows you to edit a boolean. In Lisp this means a variable which
- is either ‘nil’ meaning false, or non-‘nil’ meaning true.
+ 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. *Note (elisp)Coding Systems::. 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’.
-6.4 Composite Sexp Widgets
-==========================
+8.2.4 Composite Sexp Widgets
+----------------------------
The syntax for the composite widget construct is:
@@ -1065,34 +2281,50 @@
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 ::= (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:
+ 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 ::= (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 ::= (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.
+ 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, ‘(vector string number)’ matches vectors
- of two elements, the first being a string and the second being a
- number.
+ 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
@@ -1117,9 +2349,13 @@
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:
+ 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 ::= (set [KEYWORD ARGUMENT]... PERMITTED-ELEMENT ... )
@@ -1128,89 +2364,47 @@
-- Widget: repeat
Specifies a list of any number of elements that fit a certain type.
+ Its super is the ‘editable-list’ widget.
TYPE ::= (repeat [KEYWORD ARGUMENT]... TYPE)
-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.
+ -- Widget: plist
+ A widget to edit property lists. Its super is the ‘list’ widget.
- *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.
+ It recognizes the following properties:
- 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 ‘:’.
+ ‘:options’
+ A given set of recommended key-value values for the ‘plist’
+ widget. Each option shows up as a checklist item.
- -- Function: widget-put widget property value
- In WIDGET set PROPERTY to VALUE. PROPERTY should be a symbol,
- while VALUE can be anything.
+ ‘:key-type’
+ The widget type to use for the plist keys. By default, it
+ uses the ‘symbol’ widget.
- -- 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.
+ ‘:value-type’
+ The widget type to use for the plist values. By default, it
+ uses the ‘sexp’ widget.
- -- Function: widget-member widget property
- Non-‘nil’ if WIDGET has a value (even ‘nil’) for property PROPERTY.
+ -- Widget: alist
+ A widget to edit association lists. Its super is the ‘list’
+ widget.
- -- 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.
+ It recognizes the same properties that the ‘plist’ widget, with the
+ difference that the ‘:key-type’ uses by default a ‘sexp’ widget.
- 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.
+ 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.
- -- Function: widget-type widget
- Return the name of WIDGET, a symbol.
+ -- Widget: lazy
+ A base widget for recursive data structures. Its super is the
+ ‘default’ widget.
- 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.
+ 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.
-8 Defining New Widgets
+9 Defining New Widgets
**********************
You can define specialized widgets with ‘define-widget’. It allows you
@@ -1218,15 +2412,24 @@
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’.
+ Define a new widget type named NAME that derives from CLASS.
- NAME and class should both be symbols, ‘class’ should be one of the
- existing widget types.
+ 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.
- After the new widget has been defined, the following two calls will
- create identical widgets:
+ 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)
@@ -1239,147 +2442,61 @@
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:
+ 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 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’.
+ type.
-‘: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.
+ 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 function can be used here:
+ The predefined functions ‘widget-types-convert-widget’ and
+ ‘widget-value-convert-widget’ 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.
+10 Inspecting Widgets
+*********************
- The following predefined function can be used here:
+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.
- -- Function: widget-parent-action widget &optional event
- Tell ‘:parent’ of WIDGET to handle the ‘:action’. Optional
- EVENT is the event that triggered the action.
+ -- Command: widget-browse WIDGET
+ Create a widget browser for WIDGET.
-‘: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.
+ When called interactively, prompt for WIDGET.
- If you want to define a new widget from scratch, use the ‘default’
-widget as its base.
+ -- Command: widget-browse-other-window WIDGET
+ Create a widget browser for WIDGET and show it in another window.
- -- Widget: default
- Widget used as a base for other widgets.
+ When called interactively, prompt for WIDGET.
- It provides most of the functionality that is referred to as “by
- default” in this text.
+ -- Command: widget-browse-at POS
+ Create a widget browser for the widget at POS.
-9 Widget Browser
-****************
+ When called interactively, use the position of point.
-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.
+ In addition, there’s a function to describe the widget at point.
- -- Command: widget-browse WIDGET
- Create a widget browser for WIDGET. When called interactively,
- prompt for WIDGET.
+ -- Command: widget-describe &optional widget-or-pos
+ Describe the widget at point.
- -- Command: widget-browse-other-window WIDGET
- Create a widget browser for WIDGET and show it in another window.
- When called interactively, prompt for WIDGET.
+ 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.
- -- Command: widget-browse-at POS
- Create a widget browser for the widget at POS. When called
- interactively, use the position of 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.
-10 Widget Minor Mode
+11 Widget Minor Mode
********************
There is a minor mode for manipulating widgets in major modes that don’t
@@ -1393,16 +2510,26 @@
-- Variable: widget-minor-mode-keymap
Keymap used in ‘widget-minor-mode’.
-11 Utilities
+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 is assumed to toggle. This is only
- meaningful for radio buttons or checkboxes in a list.
+ 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.
@@ -1424,7 +2551,124 @@
simplified format), then the return value is the VALUE of the
chosen element.
-12 Wishlist
+ -- 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 ‘eval’s it.
+
+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.
+
+14 Wishlist
***********
• It should be possible to add or remove items from a list with ‘C-k’
@@ -1449,12 +2693,6 @@
• 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
@@ -1951,229 +3189,318 @@
* Menu:
-* action keyword: Defining New Widgets.
- (line 1333)
-* activate a widget: Widget Properties. (line 1181)
-* active widget: Widget Properties. (line 1181)
-* append-button-args keyword: editable-list. (line 919)
-* args keyword: menu-choice. (line 731)
+* action keyword: Widget Gallery. (line 1124)
+* activate a widget: Widget Gallery. (line 1083)
+* activate keyword: Widget Gallery. (line 1116)
+* active keyword: Widget Gallery. (line 1077)
+* active widget: Widget Gallery. (line 1083)
+* alist: composite. (line 2387)
+* append-button-args keyword: editable-list. (line 1932)
+* args keyword: menu-choice. (line 1538)
* args keyword <1>: radio-button-choice.
- (line 771)
-* args keyword <2>: checklist. (line 885)
-* args keyword <3>: editable-list. (line 928)
-* atomic sexp widget: atoms. (line 999)
-* basic widgets: Introduction. (line 63)
-* boolean: atoms. (line 1052)
-* browse-url-browser-function, and url-link widget: url-link.
- (line 629)
-* button widgets: User Interface. (line 200)
+ (line 1639)
+* args keyword <2>: checklist. (line 1867)
+* args keyword <3>: editable-list. (line 1954)
+* atomic sexp widget: atoms. (line 2142)
+* basic widgets: Introduction. (line 75)
+* boolean: atoms. (line 2242)
+* button widgets: User Interface. (line 202)
* button-args keyword: radio-button-choice.
- (line 758)
-* button-args keyword <1>: checklist. (line 875)
-* button-face keyword: Basic Types. (line 486)
-* button-prefix keyword: Basic Types. (line 489)
-* button-suffix keyword: Basic Types. (line 489)
+ (line 1626)
+* button-args keyword <1>: checklist. (line 1857)
+* button-face keyword: Widget Gallery. (line 915)
+* button-face-get keyword: Widget Gallery. (line 1050)
+* button-prefix keyword: Widget Gallery. (line 918)
+* button-suffix keyword: Widget Gallery. (line 918)
* buttons keyword: radio-button-choice.
- (line 762)
-* buttons keyword <1>: checklist. (line 879)
-* buttons keyword <2>: editable-list. (line 922)
-* case-fold keyword: menu-choice. (line 720)
-* character: atoms. (line 1021)
-* checkbox widget: checkbox. (line 837)
-* checklist widget: checklist. (line 847)
-* children keyword: menu-choice. (line 724)
+ (line 1630)
+* buttons keyword <1>: checklist. (line 1861)
+* buttons keyword <2>: editable-list. (line 1935)
+* case-fold keyword: menu-choice. (line 1525)
+* character: atoms. (line 2170)
+* checkbox widget: checkbox. (line 1785)
+* checklist widget: checklist. (line 1825)
+* children keyword: menu-choice. (line 1531)
* children keyword <1>: radio-button-choice.
- (line 765)
-* children keyword <2>: checklist. (line 882)
-* children keyword <3>: editable-list. (line 925)
-* choice: composite. (line 1072)
-* choice keyword: menu-choice. (line 728)
+ (line 1633)
+* children keyword <2>: checklist. (line 1864)
+* children keyword <3>: editable-list. (line 1951)
+* choice: composite. (line 2291)
+* choice keyword: menu-choice. (line 1535)
* choice keyword <1>: radio-button-choice.
- (line 768)
-* choice-item widget: choice-item. (line 800)
-* composite sexp widgets: composite. (line 1059)
-* cons: composite. (line 1066)
-* const: constants. (line 963)
-* constant widgets: constants. (line 952)
+ (line 1636)
+* choice-item widget: choice-item. (line 1683)
+* coding-system: atoms. (line 2260)
+* color: atoms. (line 2248)
+* completions-function keyword: Widget Gallery. (line 1028)
+* composite sexp widgets: composite. (line 2275)
+* cons: composite. (line 2282)
+* const: constants. (line 2082)
+* constant widgets: constants. (line 2071)
* convert-widget keyword: Defining New Widgets.
- (line 1243)
-* copy keyword: Defining New Widgets.
- (line 1258)
-* create keyword: Defining New Widgets.
- (line 1281)
-* deactivate a widget: Widget Properties. (line 1181)
-* default: Defining New Widgets.
- (line 1355)
+ (line 2447)
+* copy keyword: Widget Gallery. (line 1067)
+* create keyword: Widget Gallery. (line 782)
+* deactivate a widget: Widget Gallery. (line 1083)
+* deactivate keyword: Widget Gallery. (line 1120)
+* default: Widget Gallery. (line 773)
+* default-get keyword: Widget Gallery. (line 869)
* define-widget: Defining New Widgets.
- (line 1219)
+ (line 2413)
* defining new widgets: Defining New Widgets.
- (line 1215)
-* delete keyword: Defining New Widgets.
- (line 1286)
-* delete-button-args keyword: editable-list. (line 916)
-* directory: atoms. (line 1032)
-* doc keyword: Basic Types. (line 503)
-* editable-field widget: editable-field. (line 663)
-* editable-list widget: editable-list. (line 891)
-* embedded buttons: User Interface. (line 227)
+ (line 2409)
+* delete keyword: Widget Gallery. (line 792)
+* delete-button-args keyword: editable-list. (line 1929)
+* directory: atoms. (line 2199)
+* doc keyword: Widget Gallery. (line 937)
+* documentation-string widget: documentation-string.
+ (line 2034)
+* editable-field widget: editable-field. (line 1378)
+* editable-list widget: editable-list. (line 1897)
+* emacs-commentary-link widget: emacs-commentary-link.
+ (line 1332)
+* emacs-library-link widget: emacs-library-link. (line 1319)
+* embedded buttons: User Interface. (line 219)
* entry-format keyword: radio-button-choice.
- (line 748)
-* entry-format keyword <1>: checklist. (line 858)
-* entry-format keyword <2>: editable-list. (line 900)
+ (line 1613)
+* entry-format keyword <1>: checklist. (line 1847)
+* entry-format keyword <2>: editable-list. (line 1913)
* example of using widgets: Programming Example.
- (line 273)
-* external format: Basic Types. (line 422)
-* extra-offset keyword: Basic Types. (line 533)
-* file: atoms. (line 1024)
-* follow-link keyword: Basic Types. (line 521)
-* format keyword: Basic Types. (line 435)
-* format-handler keyword: Defining New Widgets.
- (line 1323)
-* function: atoms. (line 1039)
-* function-item: constants. (line 976)
-* generic sexp widget: generic. (line 982)
-* greedy keyword: checklist. (line 868)
-* group widget: group. (line 934)
-* help-echo keyword: Basic Types. (line 513)
-* inactive widget: Widget Properties. (line 1181)
-* indent keyword: Basic Types. (line 525)
-* info-link widget: info-link. (line 635)
-* insert-button-args keyword: editable-list. (line 913)
-* integer: atoms. (line 1046)
-* internal format: Basic Types. (line 422)
-* item widget: item. (line 789)
-* keymap keyword: editable-field. (line 691)
-* keyword arguments: Basic Types. (line 420)
-* link widget: link. (line 607)
-* list: composite. (line 1081)
-* match keyword: Basic Types. (line 554)
-* menu-choice widget: menu-choice. (line 708)
-* menu-tag keyword: Basic Types. (line 544)
-* menu-tag-get keyword: Basic Types. (line 548)
-* mouse-2 (on button widgets): User Interface. (line 210)
-* must-match keyword: atoms. (line 1028)
+ (line 253)
+* external format: Widget Gallery. (line 807)
+* extra-offset keyword: Widget Gallery. (line 973)
+* face-link widget: face-link. (line 1294)
+* file: atoms. (line 2177)
+* file-link widget: file-link. (line 1306)
+* float: atoms. (line 2230)
+* follow-link keyword: Widget Gallery. (line 956)
+* format keyword: Widget Gallery. (line 874)
+* format-handler keyword: Widget Gallery. (line 1039)
+* function: atoms. (line 2210)
+* function-item: constants. (line 2101)
+* function-link widget: function-link. (line 1269)
+* generic sexp widget: generic. (line 2107)
+* greedy keyword: checklist. (line 1887)
+* group widget: group. (line 1991)
+* help-echo keyword: Widget Gallery. (line 947)
+* inactive widget: Widget Gallery. (line 1083)
+* indent keyword: Widget Gallery. (line 960)
+* info-link widget: info-link. (line 1256)
+* insert-button-args keyword: editable-list. (line 1926)
+* integer: atoms. (line 2218)
+* internal format: Widget Gallery. (line 807)
+* item widget: item. (line 1168)
+* key: atoms. (line 2267)
+* keymap keyword: editable-field. (line 1400)
+* keyword arguments: Widget Gallery. (line 780)
+* lazy: composite. (line 2398)
+* link widget: link. (line 1207)
+* list: composite. (line 2309)
+* match keyword: Widget Gallery. (line 989)
+* menu-choice widget: menu-choice. (line 1498)
+* menu-tag keyword: Widget Gallery. (line 977)
+* menu-tag-get keyword: Widget Gallery. (line 981)
+* mouse-2 (on button widgets): Widgets and the Buffer.
+ (line 740)
+* mouse-down-action keyword: Widget Gallery. (line 1131)
+* mouse-face-get keyword: Widget Gallery. (line 1058)
+* must-match keyword: atoms. (line 2187)
+* natnum: atoms. (line 2224)
* new widgets: Defining New Widgets.
- (line 1215)
-* notify keyword: Basic Types. (line 537)
-* number: atoms. (line 1049)
-* off-glyph keyword: toggle. (line 829)
-* offset keyword: Basic Types. (line 529)
-* on-glyph keyword: toggle. (line 826)
-* option field tag: User Interface. (line 220)
-* parent keyword: Basic Types. (line 585)
-* prompt-value keyword: Defining New Widgets.
- (line 1343)
-* properties of widgets: Widget Properties. (line 1136)
-* push-button widget: push-button. (line 645)
+ (line 2409)
+* notify keyword: Widget Gallery. (line 1137)
+* number: atoms. (line 2236)
+* off-glyph keyword: toggle. (line 1732)
+* offset keyword: Widget Gallery. (line 969)
+* on-glyph keyword: toggle. (line 1728)
+* option field tag: User Interface. (line 212)
+* other: atoms. (line 2253)
+* parent keyword: Widget Gallery. (line 1018)
+* plist: composite. (line 2370)
+* prompt-value keyword: Widget Gallery. (line 1148)
+* push-button widget: push-button. (line 1345)
+* radio: composite. (line 2305)
* radio-button-choice widget: radio-button-choice.
- (line 737)
-* regexp: atoms. (line 1018)
-* repeat: composite. (line 1128)
-* secret keyword: editable-field. (line 681)
-* set: composite. (line 1118)
-* sexp: generic. (line 989)
-* sexp types: Sexp Types. (line 945)
-* sibling-args keyword: Basic Types. (line 589)
-* size keyword: editable-field. (line 673)
-* string: atoms. (line 1015)
-* symbol: atoms. (line 1036)
-* tab-order keyword: Basic Types. (line 570)
-* tag keyword: Basic Types. (line 506)
-* tag-glyph keyword: Basic Types. (line 509)
-* text widget: text. (line 701)
-* todo: Widget Wishlist. (line 1429)
-* toggle widget: toggle. (line 813)
-* url-link widget: url-link. (line 625)
-* utility functions for widgets: Utilities. (line 1398)
-* valid-regexp keyword: editable-field. (line 686)
-* validate keyword: Basic Types. (line 559)
-* value keyword: Basic Types. (line 422)
-* value-create keyword: Defining New Widgets.
- (line 1299)
-* value-delete keyword: Defining New Widgets.
- (line 1307)
-* value-face keyword: editable-field. (line 677)
-* value-get keyword: Defining New Widgets.
- (line 1314)
-* value-to-external keyword: Defining New Widgets.
- (line 1276)
-* value-to-internal keyword: Defining New Widgets.
- (line 1269)
-* variable: atoms. (line 1043)
-* variable-item: constants. (line 973)
-* vector: composite. (line 1090)
-* void keyword: menu-choice. (line 716)
-* widget browser: Widget Browser. (line 1364)
-* widget buttons: User Interface. (line 200)
-* widget library, why use it: Introduction. (line 103)
-* widget minor mode: Widget Minor Mode. (line 1384)
-* widget properties: Widget Properties. (line 1136)
-* widget-apply: Widget Properties. (line 1170)
-* widget-backward: User Interface. (line 267)
-* widget-browse: Widget Browser. (line 1369)
-* widget-browse-at: Widget Browser. (line 1377)
-* widget-browse-other-window: Widget Browser. (line 1373)
-* widget-button-click: User Interface. (line 211)
-* widget-button-click <1>: Setting Up the Buffer.
- (line 399)
-* widget-button-face: User Interface. (line 249)
-* widget-button-prefix: Basic Types. (line 446)
-* widget-button-press: User Interface. (line 205)
-* widget-button-press <1>: Setting Up the Buffer.
+ (line 1589)
+* radio-button-toggle widget: radio-button-toggle.
+ (line 1750)
+* regexp: atoms. (line 2164)
+* repeat: composite. (line 2364)
+* restricted-sexp: generic. (line 2123)
+* secret keyword: editable-field. (line 1424)
+* set: composite. (line 2350)
+* sexp: generic. (line 2114)
+* sexp types: Sexp Types. (line 2064)
+* sibling-args keyword: Widget Gallery. (line 1022)
+* size keyword: editable-field. (line 1414)
+* string: atoms. (line 2158)
+* symbol: atoms. (line 2205)
+* tab-order keyword: Widget Gallery. (line 1004)
+* tag keyword: Widget Gallery. (line 940)
+* tag-glyph keyword: Widget Gallery. (line 943)
+* text widget: text. (line 1479)
+* todo: Widget Wishlist. (line 2673)
+* toggle widget: toggle. (line 1705)
+* url-link widget: url-link. (line 1244)
+* utility functions for widgets: Utilities. (line 2515)
+* valid-regexp keyword: editable-field. (line 1431)
+* validate keyword: Widget Gallery. (line 994)
+* value keyword: Widget Gallery. (line 807)
+* value-create keyword: Widget Gallery. (line 835)
+* value-delete keyword: Widget Gallery. (line 841)
+* value-face keyword: editable-field. (line 1419)
+* value-get keyword: Widget Gallery. (line 851)
+* value-inline keyword: Widget Gallery. (line 863)
+* value-set keyword: Widget Gallery. (line 855)
+* value-to-external keyword: Widget Gallery. (line 829)
+* value-to-internal keyword: Widget Gallery. (line 821)
+* variable: atoms. (line 2214)
+* variable-item: constants. (line 2098)
+* variable-link widget: variable-link. (line 1282)
+* vector: composite. (line 2320)
+* void keyword: menu-choice. (line 1519)
+* widget browser: Inspecting Widgets. (line 2462)
+* widget buttons: User Interface. (line 202)
+* widget creation, widget conversion: Setting Up the Buffer.
(line 399)
-* widget-button-suffix: Basic Types. (line 449)
-* widget-children-validate: Basic Types. (line 567)
-* widget-choose: Utilities. (line 1406)
+* widget inheritance: Widgets Basics. (line 355)
+* widget library, why use it: Introduction. (line 116)
+* widget minor mode: Widget Minor Mode. (line 2501)
+* widget object: Widgets Basics. (line 349)
+* widget properties: Widgets Basics. (line 391)
+* widget syntax: Widget Gallery. (line 754)
+* widget value: Widgets Basics. (line 374)
+* widget-apply: Working with Widgets.
+ (line 564)
+* widget-apply-action: Working with Widgets.
+ (line 636)
+* widget-at: Working with Widgets.
+ (line 558)
+* widget-backward: Widgets and the Buffer.
+ (line 706)
+* widget-browse: Inspecting Widgets. (line 2468)
+* widget-browse-at: Inspecting Widgets. (line 2478)
+* widget-browse-other-window: Inspecting Widgets. (line 2473)
+* widget-button-click: Widgets and the Buffer.
+ (line 741)
+* widget-button-click <1>: Widgets and the Buffer.
+ (line 741)
+* widget-button-face: Customization. (line 2582)
+* widget-button-prefix: Customization. (line 2610)
+* widget-button-press: Widgets and the Buffer.
+ (line 731)
+* widget-button-press <1>: Widgets and the Buffer.
+ (line 731)
+* widget-button-suffix: Customization. (line 2613)
+* widget-child-validate: Working with Widgets.
+ (line 647)
+* widget-child-value-get: Working with Widgets.
+ (line 605)
+* widget-child-value-inline: Working with Widgets.
+ (line 608)
+* widget-children-validate: Working with Widgets.
+ (line 653)
+* widget-children-value-delete: Setting Up the Buffer.
+ (line 482)
+* widget-choice-toggle: Customization. (line 2628)
+* widget-choose: Utilities. (line 2533)
+* widget-complete: Widgets and the Buffer.
+ (line 722)
+* widget-convert: Setting Up the Buffer.
+ (line 504)
+* widget-copy: Setting Up the Buffer.
+ (line 494)
* widget-create: Setting Up the Buffer.
- (line 374)
-* widget-default-delete: Defining New Widgets.
- (line 1292)
-* widget-default-format-handler: Defining New Widgets.
- (line 1329)
+ (line 414)
+* widget-create-child: Setting Up the Buffer.
+ (line 443)
+* widget-create-child-and-convert: Setting Up the Buffer.
+ (line 433)
+* widget-create-child-value: Setting Up the Buffer.
+ (line 449)
+* widget-default-delete: Widget Gallery. (line 800)
+* widget-default-format-handler: Widget Gallery. (line 1046)
+* widget-default-get: Working with Widgets.
+ (line 592)
* widget-delete: Setting Up the Buffer.
- (line 381)
-* widget-field-face: User Interface. (line 194)
-* widget-field-keymap: editable-field. (line 691)
-* widget-forward: User Interface. (line 263)
-* widget-get: Widget Properties. (line 1162)
-* widget-get-sibling: Utilities. (line 1402)
-* widget-global-map: Setting Up the Buffer.
- (line 404)
-* widget-image-directory: Basic Types. (line 595)
-* widget-image-enable: Basic Types. (line 600)
+ (line 479)
+* widget-describe: Inspecting Widgets. (line 2485)
+* widget-documentation-link-p: Customization. (line 2640)
+* widget-documentation-link-regexp: Customization. (line 2636)
+* widget-documentation-link-type: Customization. (line 2647)
+* widget-documentation-links: Customization. (line 2633)
+* widget-echo-help: Utilities. (line 2567)
+* widget-end-of-line: Widgets and the Buffer.
+ (line 713)
+* widget-field-activate: Widgets and the Buffer.
+ (line 726)
+* widget-field-at: Working with Widgets.
+ (line 561)
+* widget-field-face: Customization. (line 2579)
+* widget-field-keymap: editable-field. (line 1400)
+* widget-forward: Widgets and the Buffer.
+ (line 702)
+* widget-get: Working with Widgets.
+ (line 548)
+* widget-get-sibling: Utilities. (line 2529)
+* widget-global-map: Widgets and the Buffer.
+ (line 692)
+* widget-image-conversion: Customization. (line 2602)
+* widget-image-directory: Customization. (line 2591)
+* widget-image-enable: Customization. (line 2598)
+* widget-image-find: Utilities. (line 2553)
+* widget-image-insert: Utilities. (line 2561)
* widget-insert: Setting Up the Buffer.
- (line 393)
-* widget-keymap: Setting Up the Buffer.
- (line 399)
-* widget-link-prefix: link. (line 616)
-* widget-link-suffix: link. (line 619)
-* widget-member: Widget Properties. (line 1167)
-* widget-minor-mode: Widget Minor Mode. (line 1388)
-* widget-minor-mode-keymap: Widget Minor Mode. (line 1392)
-* widget-mouse-face: User Interface. (line 252)
-* widget-parent-action: Defining New Widgets.
- (line 1339)
-* widget-prompt-value: Utilities. (line 1398)
-* widget-push-button-prefix: push-button. (line 654)
-* widget-push-button-suffix: push-button. (line 657)
-* widget-put: Widget Properties. (line 1158)
+ (line 518)
+* widget-keymap: Widgets and the Buffer.
+ (line 681)
+* widget-kill-line: Widgets and the Buffer.
+ (line 718)
+* widget-link-prefix: Customization. (line 2622)
+* widget-link-suffix: Customization. (line 2625)
+* widget-member: Working with Widgets.
+ (line 544)
+* widget-menu-max-shortcuts: Customization. (line 2659)
+* widget-menu-max-size: Customization. (line 2653)
+* widget-menu-minibuffer-flag: Customization. (line 2665)
+* widget-minor-mode: Widget Minor Mode. (line 2505)
+* widget-minor-mode-keymap: Widget Minor Mode. (line 2509)
+* widget-mouse-face: Customization. (line 2585)
+* widget-parent-action: Working with Widgets.
+ (line 642)
+* widget-prompt-value: Utilities. (line 2518)
+* widget-push-button-prefix: Customization. (line 2616)
+* widget-push-button-suffix: Customization. (line 2619)
+* widget-put: Working with Widgets.
+ (line 554)
* widget-radio-add-item: radio-button-choice.
- (line 778)
+ (line 1672)
* widget-setup: Setting Up the Buffer.
- (line 384)
-* widget-text-keymap: text. (line 701)
-* widget-type: Widget Properties. (line 1178)
-* widget-types-convert-widget: Defining New Widgets.
- (line 1252)
-* widget-types-copy: Defining New Widgets.
- (line 1266)
-* widget-value: Widget Properties. (line 1139)
-* widget-value-convert-widget: Defining New Widgets.
- (line 1255)
-* widget-value-set: Widget Properties. (line 1143)
-* widget-value-value-get: Defining New Widgets.
- (line 1320)
-* widgets, basic types: Introduction. (line 63)
+ (line 466)
+* widget-text-keymap: text. (line 1491)
+* widget-type: Working with Widgets.
+ (line 537)
+* widget-type-default-get: Working with Widgets.
+ (line 601)
+* widget-type-match: Working with Widgets.
+ (line 658)
+* widget-type-value-create: Working with Widgets.
+ (line 615)
+* widget-types-convert-widget: Working with Widgets.
+ (line 670)
+* widget-types-copy: Working with Widgets.
+ (line 664)
+* widget-value: Working with Widgets.
+ (line 570)
+* widget-value-convert-widget: Working with Widgets.
+ (line 624)
+* widget-value-set: Working with Widgets.
+ (line 583)
+* widget-value-value-get: Working with Widgets.
+ (line 629)
+* widgetp: Working with Widgets.
+ (line 534)
+* widgets, basic types: Introduction. (line 75)
* widgets, programming example: Programming Example.
- (line 273)
+ (line 253)
[-- Attachment #4: widget.texi.txt --]
[-- Type: text/plain, Size: 141967 bytes --]
The Emacs Widget Library
1 Introduction
2 User Interface
2.1 Editable Text Fields
2.2 Buttons
2.3 Navigation
3 Programming Example
4 Widgets Basics
5 Setting Up the Buffer
6 Working with Widgets
7 Widgets and the Buffer
8 Widget Gallery
8.1 Basic Types
8.1.1 The ‘item’ Widget
8.1.2 The ‘link’ Widget
8.1.3 The ‘url-link’ Widget
8.1.4 The ‘info-link’ Widget
8.1.5 The ‘function-link’ Widget
8.1.6 The ‘variable-link’ Widget
8.1.7 The ‘face-link’ Widget
8.1.8 The ‘file-link’ Widget
8.1.9 The ‘emacs-library-link’ Widget
8.1.10 The ‘emacs-commentary-link’ Widget
8.1.11 The ‘push-button’ Widget
8.1.12 The ‘editable-field’ Widget
8.1.13 The ‘text’ Widget
8.1.14 The ‘menu-choice’ Widget
8.1.15 The ‘radio-button-choice’ Widget
8.1.16 The ‘choice-item’ Widget
8.1.17 The ‘toggle’ Widget
8.1.18 The ‘radio-button-toggle’ Widget
8.1.19 The ‘checkbox’ Widget
8.1.20 The ‘checklist’ Widget
8.1.21 The ‘editable-list’ Widget
8.1.22 The ‘group’ Widget
8.1.23 The ‘documentation-string’ Widget
8.2 Sexp Types
8.2.1 The Constant Widgets
8.2.2 Generic Sexp Widget
8.2.3 Atomic Sexp Widgets
8.2.4 Composite Sexp Widgets
9 Defining New Widgets
10 Inspecting Widgets
11 Widget Minor Mode
12 Utilities
13 Customization
14 Wishlist
Appendix A GNU Free Documentation License
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.”
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.
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’.
3 Programming Example
*********************
Here is the code to implement the user interface example (*note 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 (= (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))
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. *Note
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 ‘:’.
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 *note 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. *Note
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.
*Note (elisp)Insertion::, for more information about ARGS.
The resulting text will be read-only.
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. *Note 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.
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.
8 Widget Gallery
****************
All widgets can be created from a type specification. The general
syntax of a type specification is:
NAME ::= (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. *Note 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 (*note 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. *Note
Defining Clickable Text: (elisp)Clickable Text.
‘: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.
a. Widgets with tabbing order ‘-1’ are ignored.
b. (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.
c. 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. *Note
(elisp)Completion::. 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.
8.1 Basic Types
===============
8.1.1 The ‘item’ Widget
-----------------------
Syntax:
TYPE ::= (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.
8.1.2 The ‘link’ Widget
-----------------------
Syntax:
TYPE ::= (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’. *Note (elisp)Clickable Text::.
‘: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.
8.1.3 The ‘url-link’ Widget
---------------------------
Syntax:
TYPE ::= (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.
8.1.4 The ‘info-link’ Widget
----------------------------
Syntax:
TYPE ::= (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.
8.1.5 The ‘function-link’ Widget
--------------------------------
Syntax:
TYPE ::= (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.
8.1.6 The ‘variable-link’ Widget
--------------------------------
Syntax:
TYPE ::= (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.
8.1.7 The ‘face-link’ Widget
----------------------------
Syntax:
TYPE ::= (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.
8.1.8 The ‘file-link’ Widget
----------------------------
Syntax:
TYPE ::= (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.
8.1.9 The ‘emacs-library-link’ Widget
-------------------------------------
Syntax:
TYPE ::= (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.
8.1.10 The ‘emacs-commentary-link’ Widget
-----------------------------------------
Syntax:
TYPE ::= (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.
8.1.11 The ‘push-button’ Widget
-------------------------------
Syntax:
TYPE ::= (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’. *Note
Customization::.
‘:format’
Buttonizes the widget, to make it clickable.
8.1.12 The ‘editable-field’ Widget
----------------------------------
Syntax:
TYPE ::= (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’, *note 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.
8.1.13 The ‘text’ Widget
------------------------
Syntax:
TYPE ::= (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.
8.1.14 The ‘menu-choice’ Widget
-------------------------------
Syntax:
TYPE ::= (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.
8.1.15 The ‘radio-button-choice’ Widget
---------------------------------------
Syntax:
TYPE ::= (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’.
8.1.16 The ‘choice-item’ Widget
-------------------------------
Syntax:
ITEM ::= (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.
8.1.17 The ‘toggle’ Widget
--------------------------
Syntax:
TYPE ::= (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.
8.1.18 The ‘radio-button-toggle’ Widget
---------------------------------------
Syntax:
TYPE ::= (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.
8.1.19 The ‘checkbox’ Widget
----------------------------
Syntax:
TYPE ::= (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.
8.1.20 The ‘checklist’ Widget
-----------------------------
Syntax:
TYPE ::= (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.
8.1.21 The ‘editable-list’ Widget
---------------------------------
Syntax:
TYPE ::= (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.
8.1.22 The ‘group’ Widget
-------------------------
Syntax:
TYPE ::= (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.
8.1.23 The ‘documentation-string’ Widget
----------------------------------------
Syntax:
TYPE ::= (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’.
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.
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 ::= (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.
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 ::= (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. *Note editable-field::.
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)’.
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 ::= (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. *Note editable-field::.
-- 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. *Note (elisp)Coding Systems::. 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’.
8.2.4 Composite Sexp Widgets
----------------------------
The syntax for the composite widget construct is:
TYPE ::= (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 ::= (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 ::= (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 ::= (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 ::= (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 ::= (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.
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.
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.
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’.
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.
*Note Defining Menus: (elisp)Defining Menus. 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’ (*note
(elisp)Changing Key Bindings::). 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 ‘eval’s it.
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.
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.
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.
0. PREAMBLE
The purpose of this License is to make a manual, textbook, or other
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This License is a kind of “copyleft”, which means that derivative
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It complements the GNU General Public License, which is a copyleft
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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
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11. RELICENSING
“Massive Multiauthor Collaboration Site” (or “MMC Site”) means any
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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.
Index
*****
This is an alphabetical listing of all concepts, functions, commands,
variables, and widgets described in this manual.
* Menu:
* action keyword: Widget Gallery. (line 1124)
* activate a widget: Widget Gallery. (line 1083)
* activate keyword: Widget Gallery. (line 1116)
* active keyword: Widget Gallery. (line 1077)
* active widget: Widget Gallery. (line 1083)
* alist: composite. (line 2387)
* append-button-args keyword: editable-list. (line 1932)
* args keyword: menu-choice. (line 1538)
* args keyword <1>: radio-button-choice.
(line 1639)
* args keyword <2>: checklist. (line 1867)
* args keyword <3>: editable-list. (line 1954)
* atomic sexp widget: atoms. (line 2142)
* basic widgets: Introduction. (line 75)
* boolean: atoms. (line 2242)
* button widgets: User Interface. (line 202)
* button-args keyword: radio-button-choice.
(line 1626)
* button-args keyword <1>: checklist. (line 1857)
* button-face keyword: Widget Gallery. (line 915)
* button-face-get keyword: Widget Gallery. (line 1050)
* button-prefix keyword: Widget Gallery. (line 918)
* button-suffix keyword: Widget Gallery. (line 918)
* buttons keyword: radio-button-choice.
(line 1630)
* buttons keyword <1>: checklist. (line 1861)
* buttons keyword <2>: editable-list. (line 1935)
* case-fold keyword: menu-choice. (line 1525)
* character: atoms. (line 2170)
* checkbox widget: checkbox. (line 1785)
* checklist widget: checklist. (line 1825)
* children keyword: menu-choice. (line 1531)
* children keyword <1>: radio-button-choice.
(line 1633)
* children keyword <2>: checklist. (line 1864)
* children keyword <3>: editable-list. (line 1951)
* choice: composite. (line 2291)
* choice keyword: menu-choice. (line 1535)
* choice keyword <1>: radio-button-choice.
(line 1636)
* choice-item widget: choice-item. (line 1683)
* coding-system: atoms. (line 2260)
* color: atoms. (line 2248)
* completions-function keyword: Widget Gallery. (line 1028)
* composite sexp widgets: composite. (line 2275)
* cons: composite. (line 2282)
* const: constants. (line 2082)
* constant widgets: constants. (line 2071)
* convert-widget keyword: Defining New Widgets.
(line 2447)
* copy keyword: Widget Gallery. (line 1067)
* create keyword: Widget Gallery. (line 782)
* deactivate a widget: Widget Gallery. (line 1083)
* deactivate keyword: Widget Gallery. (line 1120)
* default: Widget Gallery. (line 773)
* default-get keyword: Widget Gallery. (line 869)
* define-widget: Defining New Widgets.
(line 2413)
* defining new widgets: Defining New Widgets.
(line 2409)
* delete keyword: Widget Gallery. (line 792)
* delete-button-args keyword: editable-list. (line 1929)
* directory: atoms. (line 2199)
* doc keyword: Widget Gallery. (line 937)
* documentation-string widget: documentation-string.
(line 2034)
* editable-field widget: editable-field. (line 1378)
* editable-list widget: editable-list. (line 1897)
* emacs-commentary-link widget: emacs-commentary-link.
(line 1332)
* emacs-library-link widget: emacs-library-link. (line 1319)
* embedded buttons: User Interface. (line 219)
* entry-format keyword: radio-button-choice.
(line 1613)
* entry-format keyword <1>: checklist. (line 1847)
* entry-format keyword <2>: editable-list. (line 1913)
* example of using widgets: Programming Example.
(line 253)
* external format: Widget Gallery. (line 807)
* extra-offset keyword: Widget Gallery. (line 973)
* face-link widget: face-link. (line 1294)
* file: atoms. (line 2177)
* file-link widget: file-link. (line 1306)
* float: atoms. (line 2230)
* follow-link keyword: Widget Gallery. (line 956)
* format keyword: Widget Gallery. (line 874)
* format-handler keyword: Widget Gallery. (line 1039)
* function: atoms. (line 2210)
* function-item: constants. (line 2101)
* function-link widget: function-link. (line 1269)
* generic sexp widget: generic. (line 2107)
* greedy keyword: checklist. (line 1887)
* group widget: group. (line 1991)
* help-echo keyword: Widget Gallery. (line 947)
* inactive widget: Widget Gallery. (line 1083)
* indent keyword: Widget Gallery. (line 960)
* info-link widget: info-link. (line 1256)
* insert-button-args keyword: editable-list. (line 1926)
* integer: atoms. (line 2218)
* internal format: Widget Gallery. (line 807)
* item widget: item. (line 1168)
* key: atoms. (line 2267)
* keymap keyword: editable-field. (line 1400)
* keyword arguments: Widget Gallery. (line 780)
* lazy: composite. (line 2398)
* link widget: link. (line 1207)
* list: composite. (line 2309)
* match keyword: Widget Gallery. (line 989)
* menu-choice widget: menu-choice. (line 1498)
* menu-tag keyword: Widget Gallery. (line 977)
* menu-tag-get keyword: Widget Gallery. (line 981)
* mouse-2 (on button widgets): Widgets and the Buffer.
(line 740)
* mouse-down-action keyword: Widget Gallery. (line 1131)
* mouse-face-get keyword: Widget Gallery. (line 1058)
* must-match keyword: atoms. (line 2187)
* natnum: atoms. (line 2224)
* new widgets: Defining New Widgets.
(line 2409)
* notify keyword: Widget Gallery. (line 1137)
* number: atoms. (line 2236)
* off-glyph keyword: toggle. (line 1732)
* offset keyword: Widget Gallery. (line 969)
* on-glyph keyword: toggle. (line 1728)
* option field tag: User Interface. (line 212)
* other: atoms. (line 2253)
* parent keyword: Widget Gallery. (line 1018)
* plist: composite. (line 2370)
* prompt-value keyword: Widget Gallery. (line 1148)
* push-button widget: push-button. (line 1345)
* radio: composite. (line 2305)
* radio-button-choice widget: radio-button-choice.
(line 1589)
* radio-button-toggle widget: radio-button-toggle.
(line 1750)
* regexp: atoms. (line 2164)
* repeat: composite. (line 2364)
* restricted-sexp: generic. (line 2123)
* secret keyword: editable-field. (line 1424)
* set: composite. (line 2350)
* sexp: generic. (line 2114)
* sexp types: Sexp Types. (line 2064)
* sibling-args keyword: Widget Gallery. (line 1022)
* size keyword: editable-field. (line 1414)
* string: atoms. (line 2158)
* symbol: atoms. (line 2205)
* tab-order keyword: Widget Gallery. (line 1004)
* tag keyword: Widget Gallery. (line 940)
* tag-glyph keyword: Widget Gallery. (line 943)
* text widget: text. (line 1479)
* todo: Widget Wishlist. (line 2673)
* toggle widget: toggle. (line 1705)
* url-link widget: url-link. (line 1244)
* utility functions for widgets: Utilities. (line 2515)
* valid-regexp keyword: editable-field. (line 1431)
* validate keyword: Widget Gallery. (line 994)
* value keyword: Widget Gallery. (line 807)
* value-create keyword: Widget Gallery. (line 835)
* value-delete keyword: Widget Gallery. (line 841)
* value-face keyword: editable-field. (line 1419)
* value-get keyword: Widget Gallery. (line 851)
* value-inline keyword: Widget Gallery. (line 863)
* value-set keyword: Widget Gallery. (line 855)
* value-to-external keyword: Widget Gallery. (line 829)
* value-to-internal keyword: Widget Gallery. (line 821)
* variable: atoms. (line 2214)
* variable-item: constants. (line 2098)
* variable-link widget: variable-link. (line 1282)
* vector: composite. (line 2320)
* void keyword: menu-choice. (line 1519)
* widget browser: Inspecting Widgets. (line 2462)
* widget buttons: User Interface. (line 202)
* widget creation, widget conversion: Setting Up the Buffer.
(line 399)
* widget inheritance: Widgets Basics. (line 355)
* widget library, why use it: Introduction. (line 116)
* widget minor mode: Widget Minor Mode. (line 2501)
* widget object: Widgets Basics. (line 349)
* widget properties: Widgets Basics. (line 391)
* widget syntax: Widget Gallery. (line 754)
* widget value: Widgets Basics. (line 374)
* widget-apply: Working with Widgets.
(line 564)
* widget-apply-action: Working with Widgets.
(line 636)
* widget-at: Working with Widgets.
(line 558)
* widget-backward: Widgets and the Buffer.
(line 706)
* widget-browse: Inspecting Widgets. (line 2468)
* widget-browse-at: Inspecting Widgets. (line 2478)
* widget-browse-other-window: Inspecting Widgets. (line 2473)
* widget-button-click: Widgets and the Buffer.
(line 741)
* widget-button-click <1>: Widgets and the Buffer.
(line 741)
* widget-button-face: Customization. (line 2582)
* widget-button-prefix: Customization. (line 2610)
* widget-button-press: Widgets and the Buffer.
(line 731)
* widget-button-press <1>: Widgets and the Buffer.
(line 731)
* widget-button-suffix: Customization. (line 2613)
* widget-child-validate: Working with Widgets.
(line 647)
* widget-child-value-get: Working with Widgets.
(line 605)
* widget-child-value-inline: Working with Widgets.
(line 608)
* widget-children-validate: Working with Widgets.
(line 653)
* widget-children-value-delete: Setting Up the Buffer.
(line 482)
* widget-choice-toggle: Customization. (line 2628)
* widget-choose: Utilities. (line 2533)
* widget-complete: Widgets and the Buffer.
(line 722)
* widget-convert: Setting Up the Buffer.
(line 504)
* widget-copy: Setting Up the Buffer.
(line 494)
* widget-create: Setting Up the Buffer.
(line 414)
* widget-create-child: Setting Up the Buffer.
(line 443)
* widget-create-child-and-convert: Setting Up the Buffer.
(line 433)
* widget-create-child-value: Setting Up the Buffer.
(line 449)
* widget-default-delete: Widget Gallery. (line 800)
* widget-default-format-handler: Widget Gallery. (line 1046)
* widget-default-get: Working with Widgets.
(line 592)
* widget-delete: Setting Up the Buffer.
(line 479)
* widget-describe: Inspecting Widgets. (line 2485)
* widget-documentation-link-p: Customization. (line 2640)
* widget-documentation-link-regexp: Customization. (line 2636)
* widget-documentation-link-type: Customization. (line 2647)
* widget-documentation-links: Customization. (line 2633)
* widget-echo-help: Utilities. (line 2567)
* widget-end-of-line: Widgets and the Buffer.
(line 713)
* widget-field-activate: Widgets and the Buffer.
(line 726)
* widget-field-at: Working with Widgets.
(line 561)
* widget-field-face: Customization. (line 2579)
* widget-field-keymap: editable-field. (line 1400)
* widget-forward: Widgets and the Buffer.
(line 702)
* widget-get: Working with Widgets.
(line 548)
* widget-get-sibling: Utilities. (line 2529)
* widget-global-map: Widgets and the Buffer.
(line 692)
* widget-image-conversion: Customization. (line 2602)
* widget-image-directory: Customization. (line 2591)
* widget-image-enable: Customization. (line 2598)
* widget-image-find: Utilities. (line 2553)
* widget-image-insert: Utilities. (line 2561)
* widget-insert: Setting Up the Buffer.
(line 518)
* widget-keymap: Widgets and the Buffer.
(line 681)
* widget-kill-line: Widgets and the Buffer.
(line 718)
* widget-link-prefix: Customization. (line 2622)
* widget-link-suffix: Customization. (line 2625)
* widget-member: Working with Widgets.
(line 544)
* widget-menu-max-shortcuts: Customization. (line 2659)
* widget-menu-max-size: Customization. (line 2653)
* widget-menu-minibuffer-flag: Customization. (line 2665)
* widget-minor-mode: Widget Minor Mode. (line 2505)
* widget-minor-mode-keymap: Widget Minor Mode. (line 2509)
* widget-mouse-face: Customization. (line 2585)
* widget-parent-action: Working with Widgets.
(line 642)
* widget-prompt-value: Utilities. (line 2518)
* widget-push-button-prefix: Customization. (line 2616)
* widget-push-button-suffix: Customization. (line 2619)
* widget-put: Working with Widgets.
(line 554)
* widget-radio-add-item: radio-button-choice.
(line 1672)
* widget-setup: Setting Up the Buffer.
(line 466)
* widget-text-keymap: text. (line 1491)
* widget-type: Working with Widgets.
(line 537)
* widget-type-default-get: Working with Widgets.
(line 601)
* widget-type-match: Working with Widgets.
(line 658)
* widget-type-value-create: Working with Widgets.
(line 615)
* widget-types-convert-widget: Working with Widgets.
(line 670)
* widget-types-copy: Working with Widgets.
(line 664)
* widget-value: Working with Widgets.
(line 570)
* widget-value-convert-widget: Working with Widgets.
(line 624)
* widget-value-set: Working with Widgets.
(line 583)
* widget-value-value-get: Working with Widgets.
(line 629)
* widgetp: Working with Widgets.
(line 534)
* widgets, basic types: Introduction. (line 75)
* widgets, programming example: Programming Example.
(line 253)
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