+++ /dev/null
-\input texinfo.tex
-
-@c $Id: widget.texi,v 1.99 1997/04/06 20:34:01 abraham Exp $
-
-@c %**start of header
-@setfilename widget
-@settitle The Emacs Widget Library
-@iftex
-@afourpaper
-@headings double
-@end iftex
-@c %**end of header
-
-@node Top, Introduction, (dir), (dir)
-@comment node-name, next, previous, up
-@top The Emacs Widget Library
-
-Version: 1.71
-
-@menu
-* Introduction::
-* User Interface::
-* Programming Example::
-* Setting Up the Buffer::
-* Basic Types::
-* Sexp Types::
-* Widget Properties::
-* Defining New Widgets::
-* Widget Wishlist.::
-@end menu
-
-@node Introduction, User Interface, Top, Top
-@comment node-name, next, previous, up
-@section Introduction
-
-Most graphical user interface toolkits, such as Motif and XView, 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 incredible powerful text ``widget''. On the other
-hand, Emacs does provide the necessary primitives to implement many
-other widgets within a text buffer. The @code{widget} package
-simplifies this task.
-
-The basic widgets are:
-
-@table @code
-@item link
-Areas of text with an associated action. Intended for hypertext links
-embedded in text.
-@item push-button
-Like link, but intended for stand-alone buttons.
-@item editable-field
-An editable text field. It can be either variable or fixed length.
-@item 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.
-@item radio-button-choice
-Allows the user to choose one of multiple options by pushing radio
-buttons. The options are implemented as widgets. All options will be
-visible in the buffer.
-@item item
-A simple constant widget intended to be used in the @code{menu-choice} and
-@code{radio-button-choice} widgets.
-@item choice-item
-An button item only intended for use in choices. When pushed, the user
-will be asked to select another option from the choice widget.
-@item toggle
-A simple @samp{on}/@samp{off} switch.
-@item checkbox
-A checkbox (@samp{[ ]}/@samp{[X]}).
-@item editable-list
-Create an editable list. The user can insert or delete items in the
-list. Each list item is itself a widget.
-@end table
-
-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 @dfn{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 @file{forms}
-package (of course), the customize buffers, the mail and news compose
-modes, and the @sc{html} form support in the @file{w3} browser.
-
-The advantages for a programmer of using the @code{widget} package to
-implement forms are:
-
-@enumerate
-@item
-More complex field than just editable text are supported.
-@item
-You can give the user immediate feedback if he enters invalid data in a
-text field, and sometimes prevent entering invalid data.
-@item
-You can have fixed sized fields, thus allowing multiple field to be
-lined up in columns.
-@item
-It is simple to query or set the value of a field.
-@item
-Editing happens in buffer, not in the mini-buffer.
-@item
-Packages using the library get a uniform look, making them easier for
-the user to learn.
-@item
-As support for embedded graphics improve, the widget library will
-extended to support it. This means that your code using the widget
-library will also use the new graphic features by automatic.
-@end enumerate
-
-In order to minimize the code that is loaded by users who does not
-create any widgets, the code has been split in two files:
-
-@table @file
-@item widget.el
-This will declare the user variables, define the function
-@code{widget-define}, and autoload the function @code{widget-create}.
-@item wid-edit.el
-Everything else is here, there is no reason to load it explicitly, as
-it will be autoloaded when needed.
-@end table
-
-@node User Interface, Programming Example, Introduction, Top
-@comment node-name, next, previous, up
-@section User Interface
-
-A form consist of read only text for documentation and some fields,
-where each the fields contain two parts, as 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 @samp{Foo}. Here is an example
-form:
-
-@example
-Here is some documentation.
-
-Name: @i{My Name} @strong{Choose}: This option
-Address: @i{Some Place
-In some City
-Some country.}
-
-See also @b{_other work_} for more information.
-
-Numbers: count to three below
-@b{[INS]} @b{[DEL]} @i{One}
-@b{[INS]} @b{[DEL]} @i{Eh, two?}
-@b{[INS]} @b{[DEL]} @i{Five!}
-@b{[INS]}
-
-Select multiple:
-
-@b{[X]} This
-@b{[ ]} That
-@b{[X]} Thus
-
-Select one:
-
-@b{(*)} One
-@b{( )} Another One.
-@b{( )} A Final One.
-
-@b{[Apply Form]} @b{[Reset Form]}
-@end example
-
-The top level widgets in is example are tagged @samp{Name},
-@samp{Choose}, @samp{Address}, @samp{_other work_}, @samp{Numbers},
-@samp{Select multiple}, @samp{Select one}, @samp{[Apply Form]}, and
-@samp{[Reset Form]}. There are basically two thing the user can do within
-a form, namely editing the editable text fields and activating the
-buttons.
-
-@subsection Editable Text Fields
-
-In the example, the value for the @samp{Name} is most likely displayed
-in an editable text field, and so are values for each of the members of
-the @samp{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.
-
-Editing text fields are created by the @code{editable-field} widget.
-
-The editing text fields are highlighted with the
-@code{widget-field-face} face, making them easy to find.
-
-@deffn Face widget-field-face
-Face used for other editing fields.
-@end deffn
-
-@subsection Buttons
-
-Some portions of the buffer have an associated @dfn{action}, which can
-be @dfn{activated} by a standard key or mouse command. These portions
-are called @dfn{buttons}. The default commands for activating a button
-are:
-
-@table @kbd
-@item @key{RET}
-@deffn Command widget-button-press @var{pos} &optional @var{event}
-Activate the button at @var{pos}, defaulting to point.
-If point is not located on a button, activate the binding in
-@code{widget-global-map} (by default the global map).
-@end deffn
-
-@item mouse-2
-@deffn Command widget-button-click @var{event}
-Activate the button at the location of the mouse pointer. If the mouse
-pointer is located in an editable text field, activate the binding in
-@code{widget-global-map} (by default the global map).
-@end deffn
-@end table
-
-There are several different kind of buttons, all of which are present in
-the example:
-
-@table @emph
-@item The Option Field Tags.
-When you activate 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 @code{menu-choice} widget. In
-the example, @samp{@b{Choose}} is an option field tag.
-@item The @samp{@b{[INS]}} and @samp{@b{[DEL]}} buttons.
-Activating these will insert or delete elements from a editable list.
-The list is created by the @code{editable-list} widget.
-@item Embedded Buttons.
-The @samp{@b{_other work_}} is an example of an embedded
-button. Embedded buttons are not associated with a fields, but can serve
-any purpose, such as implementing hypertext references. They are
-usually created by the @code{link} widget.
-@item The @samp{@b{[ ]}} and @samp{@b{[X]}} buttons.
-Activating one of these will convert it to the other. This is useful
-for implementing multiple-choice fields. You can create it wit
-@item The @samp{@b{( )}} and @samp{@b{(*)}} buttons.
-Only one radio button in a @code{radio-button-choice} widget can be selected at any
-time. When you push one of the unselected radio buttons, it will be
-selected and the previous selected radio button will become unselected.
-@item The @samp{@b{[Apply Form]}} @samp{@b{[Reset Form]}} buttons.
-These are explicit buttons made with the @code{push-button} widget. The main
-difference from the @code{link} widget is that the buttons are will be
-displayed as GUI buttons when possible.
-enough.
-@end table
-
-To make them easier to locate, buttons are emphasized in the buffer.
-
-@deffn Face widget-button-face
-Face used for buttons.
-@end deffn
-
-@defopt widget-mouse-face
-Face used for buttons when the mouse pointer is above it.
-@end defopt
-
-@subsection Navigation
-
-You can use all the normal Emacs commands to move around in a form
-buffer, plus you will have these additional commands:
-
-@table @kbd
-@item @key{TAB}
-@deffn Command widget-forward &optional count
-Move point @var{count} buttons or editing fields forward.
-@end deffn
-@item @key{M-TAB}
-@deffn Command widget-backward &optional count
-Move point @var{count} buttons or editing fields backward.
-@end deffn
-@end table
-
-@node Programming Example, Setting Up the Buffer, User Interface, Top
-@comment node-name, next, previous, up
-@section Programming Example
-
-Here is the code to implement the user interface example (see @ref{User
-Interface}).
-
-@lisp
-(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))
- (widget-insert "Here is some documentation.\n\nName: ")
- (widget-create 'editable-field
- :size 13
- "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-insert "Address: ")
- (widget-create 'editable-field
- "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 "Anthor 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))
-@end lisp
-
-@node Setting Up the Buffer, Basic Types, Programming Example, Top
-@comment node-name, next, previous, up
-@section Setting Up the Buffer
-
-Widgets are created with @code{widget-create}, which returns a
-@dfn{widget} object. This object can be queried and manipulated by
-other widget functions, until it is deleted with @code{widget-delete}.
-After the widgets have been created, @code{widget-setup} must be called
-to enable them.
-
-@defun widget-create type [ keyword argument ]@dots{}
-Create and return a widget of type @var{type}.
-The syntax for the @var{type} argument is described in @ref{Basic Types}.
-
-The keyword arguments can be used to overwrite the keyword arguments
-that are part of @var{type}.
-@end defun
-
-@defun widget-delete widget
-Delete @var{widget} and remove it from the buffer.
-@end defun
-
-@defun widget-setup
-Setup a buffer to support widgets.
-
-This should be called after creating all the widgets and before allowing
-the user to edit them.
-@refill
-@end defun
-
-If you want to insert text outside the widgets in the form, the
-recommended way to do that is with @code{widget-insert}.
-
-@defun widget-insert
-Insert the arguments, either strings or characters, at point.
-The inserted text will be read only.
-@end defun
-
-There is a standard widget keymap which you might find useful.
-
-@defvr Const widget-keymap
-A keymap with the global keymap as its parent.@*
-@key{TAB} and @kbd{C-@key{TAB}} are bound to @code{widget-forward} and
-@code{widget-backward}, respectively. @kbd{@key{RET}} and @kbd{mouse-2}
-are bound to @code{widget-button-press} and
-@code{widget-button-}.@refill
-@end defvr
-
-@defvar widget-global-map
-Keymap used by @code{widget-button-press} and @code{widget-button-click}
-when not on a button. By default this is @code{global-map}.
-@end defvar
-
-@node Basic Types, Sexp Types, Setting Up the Buffer, Top
-@comment node-name, next, previous, up
-@section Basic Types
-
-The syntax of a type specification is given below:
-
-@example
-NAME ::= (NAME [KEYWORD ARGUMENT]... ARGS)
- | NAME
-@end example
-
-Where, @var{name} is a widget name, @var{keyword} is the name of a
-property, @var{argument} is the value of the property, and @var{args}
-are interpreted in a widget specific way.
-
-There following keyword arguments that apply to all widgets:
-
-@table @code
-@item :value
-The initial value for widgets of this type.
-
-@item :format
-This string will be inserted in the buffer when you create a widget.
-The following @samp{%} escapes are available:
-
-@table @samp
-@item %[
-@itemx %]
-The text inside will be marked as a button.
-
-@item %@{
-@itemx %@}
-The text inside will be displayed with the face specified by
-@code{:sample-face}.
-
-@item %v
-This will be replaces with the buffer representation of the widgets
-value. What this is depends on the widget type.
-
-@item %d
-Insert the string specified by @code{:doc} here.
-
-@item %h
-Like @samp{%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 @code{:doc} property in the widget, it will
-instead examine the @code{: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.
-
-@item %t
-Insert the string specified by @code{:tag} here, or the @code{princ}
-representation of the value if there is no tag.
-
-@item %%
-Insert a literal @samp{%}.
-@end table
-
-@item :button-face
-Face used to highlight text inside %[ %] in the format.
-
-@item :doc
-The string inserted by the @samp{%d} escape in the format
-string.
-
-@item :tag
-The string inserted by the @samp{%t} escape in the format
-string.
-
-@item :tag-glyph
-Name of image to use instead of the string specified by `:tag' on
-Emacsen that supports it.
-
-@item :help-echo
-Message displayed whenever you move to the widget with either
-@code{widget-forward} or @code{widget-backward}.
-
-@item :indent
-An integer indicating the absolute number of spaces to indent children
-of this widget.
-
-@item :offset
-An integer indicating how many extra spaces to add to the widget's
-grandchildren compared to this widget.
-
-@item :extra-offset
-An integer indicating how many extra spaces to add to the widget's
-children compared to this widget.
-
-@item :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.
-
-@item :menu-tag
-Tag used in the menu when the widget is used as an option in a
-@code{menu-choice} widget.
-
-@item :menu-tag-get
-Function used for finding the tag when the widget is used as an option
-in a @code{menu-choice} widget. By default, the tag used will be either the
-@code{:menu-tag} or @code{:tag} property if present, or the @code{princ}
-representation of the @code{:value} property if not.
-
-@item :match
-Should be a function called with two arguments, the widget and a value,
-and returning non-nil if the widget can represent the specified value.
-
-@item :validate
-A function which takes a widget as an argument, and return nil if the
-widgets current value is valid for the widget. Otherwise, it should
-return the widget containing the invalid data, and set that widgets
-@code{:error} property to a string explaining the error.
-
-@item :tab-order
-Specify the order in which widgets are traversed with
-@code{widget-forward} or @code{widget-backward}. This is only partially
-implemented.
-
-@enumerate a
-@item
-Widgets with tabbing order @code{-1} are ignored.
-
-@item
-(Unimplemented) When on a widget with tabbing order @var{n}, go to the
-next widget in the buffer with tabbing order @var{n+1} or @code{nil},
-whichever comes first.
-
-@item
-When on a widget with no tabbing order specified, go to the next widget
-in the buffer with a positive tabbing order, or @code{nil}
-@end enumerate
-
-@item :parent
-The parent of a nested widget (e.g. a @code{menu-choice} item or an
-element of a @code{editable-list} widget).
-
-@item :sibling-args
-This keyword is only used for members of a @code{radio-button-choice} or
-@code{checklist}. The value should be a list of extra keyword
-arguments, which will be used when creating the @code{radio-button} or
-@code{checkbox} associated with this item.
-
-@end table
-
-@deffn {User Option} widget-glyph-directory
-Directory where glyphs are found.
-Widget will look here for a file with the same name as specified for the
-image, with either a @samp{.xpm} (if supported) or @samp{.xbm} extension.
-@end deffn
-
-@deffn{User Option} widget-glyph-enable
-If non-nil, allow glyphs to appear on displayes where they are supported.
-@end deffn
-
-
-@menu
-* link::
-* url-link::
-* info-link::
-* push-button::
-* editable-field::
-* text::
-* menu-choice::
-* radio-button-choice::
-* item::
-* choice-item::
-* toggle::
-* checkbox::
-* checklist::
-* editable-list::
-@end menu
-
-@node link, url-link, Basic Types, Basic Types
-@comment node-name, next, previous, up
-@subsection The @code{link} Widget
-
-Syntax:
-
-@example
-TYPE ::= (link [KEYWORD ARGUMENT]... [ VALUE ])
-@end example
-
-The @var{value}, if present, is used to initialize the @code{:value}
-property. The value should be a string, which will be inserted in the
-buffer.
-
-@node url-link, info-link, link, Basic Types
-@comment node-name, next, previous, up
-@subsection The @code{url-link} Widget
-
-Syntax:
-
-@example
-TYPE ::= (url-link [KEYWORD ARGUMENT]... URL)
-@end example
-
-When this link is activated, the @sc{www} browser specified by
-@code{browse-url-browser-function} will be called with @var{url}.
-
-@node info-link, push-button, url-link, Basic Types
-@comment node-name, next, previous, up
-@subsection The @code{info-link} Widget
-
-Syntax:
-
-@example
-TYPE ::= (info-link [KEYWORD ARGUMENT]... ADDRESS)
-@end example
-
-When this link is activated, the build-in info browser is started on
-@var{address}.
-
-@node push-button, editable-field, info-link, Basic Types
-@comment node-name, next, previous, up
-@subsection The @code{push-button} Widget
-
-Syntax:
-
-@example
-TYPE ::= (push-button [KEYWORD ARGUMENT]... [ VALUE ])
-@end example
-
-The @var{value}, if present, is used to initialize the @code{:value}
-property. The value should be a string, which will be inserted in the
-buffer.
-
-@node editable-field, text, push-button, Basic Types
-@comment node-name, next, previous, up
-@subsection The @code{editable-field} Widget
-
-Syntax:
-
-@example
-TYPE ::= (editable-field [KEYWORD ARGUMENT]... [ VALUE ])
-@end example
-
-The @var{value}, if present, is used to initialize the @code{:value}
-property. The value should be a string, which will be inserted in
-field. This widget will match all string values.
-
-The following extra properties are recognized.
-
-@table @code
-@item :size
-The width of the editable field.@*
-By default the field will reach to the end of the line.
-
-@item :value-face
-Face used for highlighting the editable field. Default is
-@code{widget-field-face}.
-
-@item :secret
-Character used to display the value. You can set this to e.g. @code{?*}
-if the field contains a password or other secret information. By
-default, the value is not secret.
-
-@item :valid-regexp
-By default the @code{:validate} function will match the content of the
-field with the value of this attribute. The default value is @code{""}
-which matches everything.
-
-@item :keymap
-Keymap used in the editable field. The default value is
-@code{widget-field-keymap}, which allows you to use all the normal
-editing commands, even if the buffers major mode supress some of them.
-Pressing return activates the function specified by @code{:activate}.
-
-@item :hide-front-space
-@itemx :hide-rear-space
-In order to keep track of the editable field, emacs places an invisible
-space character in front of the field, and for fixed sized fields also
-in the rear end of the field. For fields that extent to the end of the
-line, the terminating linefeed serves that purpose instead.
-
-Emacs will try to make the spaces intangible when it is safe to do so.
-Intangible means that the cursor motion commands will skip over the
-character as if it didn't exist. This is safe to do when the text
-preceding or following the widget cannot possible change during the
-lifetime of the @code{editable-field} widget. The preferred way to tell
-Emacs this, is to add text to the @code{:format} property around the
-value. For example @code{:format "Tag: %v "}.
-
-You can overwrite the internal safety check by setting the
-@code{:hide-front-space} or @code{:hide-rear-space} properties to
-non-nil. This is not recommended. For example, @emph{all} text that
-belongs to a widget (i.e. is created from its @code{:format} string) will
-change whenever the widget changes its value.
-
-@end table
-
-@node text, menu-choice, editable-field, Basic Types
-@comment node-name, next, previous, up
-@subsection The @code{text} Widget
-
-This is just like @code{editable-field}, but intended for multiline text
-fields. The default @code{:keymap} is @code{widget-text-keymap}, which
-does not rebind the return key.
-
-@node menu-choice, radio-button-choice, text, Basic Types
-@comment node-name, next, previous, up
-@subsection The @code{menu-choice} Widget
-
-Syntax:
-
-@example
-TYPE ::= (menu-choice [KEYWORD ARGUMENT]... TYPE ... )
-@end example
-
-The @var{type} arguments represents each possible choice. The widgets
-value of will be the value of the chosen @var{type} argument. This
-widget will match any value that matches at least one of the specified
-@var{type} arguments.
-
-@table @code
-@item :void
-Widget type used as a fallback when the value does not match any of the
-specified @var{type} arguments.
-
-@item :case-fold
-Set this to nil if you don't want to ignore case when prompting for a
-choice through the minibuffer.
-
-@item :children
-A list whose car is the widget representing the currently chosen type in
-the buffer.
-
-@item :choice
-The current chosen type
-
-@item :args
-The list of types.
-@end table
-
-@node radio-button-choice, item, menu-choice, Basic Types
-@comment node-name, next, previous, up
-@subsection The @code{radio-button-choice} Widget
-
-Syntax:
-
-@example
-TYPE ::= (radio-button-choice [KEYWORD ARGUMENT]... TYPE ... )
-@end example
-
-The @var{type} arguments represents each possible choice. The widgets
-value of will be the value of the chosen @var{type} argument. This
-widget will match any value that matches at least one of the specified
-@var{type} arguments.
-
-The following extra properties are recognized.
-
-@table @code
-@item :entry-format
-This string will be inserted for each entry in the list.
-The following @samp{%} escapes are available:
-@table @samp
-@item %v
-Replaced with the buffer representation of the @var{type} widget.
-@item %b
-Replace with the radio button.
-@item %%
-Insert a literal @samp{%}.
-@end table
-
-@item button-args
-A list of keywords to pass to the radio buttons. Useful for setting
-e.g. the @samp{:help-echo} for each button.
-
-@item :buttons
-The widgets representing the radio buttons.
-
-@item :children
-The widgets representing each type.
-
-@item :choice
-The current chosen type
-
-@item :args
-The list of types.
-@end table
-
-You can add extra radio button items to a @code{radio-button-choice}
-widget after it has been created with the function
-@code{widget-radio-add-item}.
-
-@defun widget-radio-add-item widget type
-Add to @code{radio-button-choice} widget @var{widget} a new radio button item of type
-@var{type}.
-@end defun
-
-Please note that such items added after the @code{radio-button-choice}
-widget has been created will @strong{not} be properly destructed when
-you call @code{widget-delete}.
-
-@node item, choice-item, radio-button-choice, Basic Types
-@comment node-name, next, previous, up
-@subsection The @code{item} Widget
-
-Syntax:
-
-@example
-ITEM ::= (item [KEYWORD ARGUMENT]... VALUE)
-@end example
-
-The @var{value}, if present, is used to initialize the @code{:value}
-property. The value should be a string, which will be inserted in the
-buffer. This widget will only match the specified value.
-
-@node choice-item, toggle, item, Basic Types
-@comment node-name, next, previous, up
-@subsection The @code{choice-item} Widget
-
-Syntax:
-
-@example
-ITEM ::= (choice-item [KEYWORD ARGUMENT]... VALUE)
-@end example
-
-The @var{value}, if present, is used to initialize the @code{:value}
-property. The value should be a string, which will be inserted in the
-buffer as a button. Activating the button of a @code{choice-item} is
-equivalent to activating the parent widget. This widget will only match
-the specified value.
-
-@node toggle, checkbox, choice-item, Basic Types
-@comment node-name, next, previous, up
-@subsection The @code{toggle} Widget
-
-Syntax:
-
-@example
-TYPE ::= (toggle [KEYWORD ARGUMENT]...)
-@end example
-
-The widget has two possible states, `on' and `off', which corresponds to
-a @code{t} or @code{nil} value.
-
-The following extra properties are recognized.
-
-@table @code
-@item :on
-String representing the `on' state. By default the string @samp{on}.
-@item :off
-String representing the `off' state. By default the string @samp{off}.
-@item :on-glyph
-Name of a glyph to be used instead of the `:on' text string, on emacsen
-that supports it.
-@item :off-glyph
-Name of a glyph to be used instead of the `:off' text string, on emacsen
-that supports it.
-@end table
-
-@node checkbox, checklist, toggle, Basic Types
-@comment node-name, next, previous, up
-@subsection The @code{checkbox} Widget
-
-The widget has two possible states, `selected' and `unselected', which
-corresponds to a @code{t} or @code{nil} value.
-
-Syntax:
-
-@example
-TYPE ::= (checkbox [KEYWORD ARGUMENT]...)
-@end example
-
-@node checklist, editable-list, checkbox, Basic Types
-@comment node-name, next, previous, up
-@subsection The @code{checklist} Widget
-
-Syntax:
-
-@example
-TYPE ::= (checklist [KEYWORD ARGUMENT]... TYPE ... )
-@end example
-
-The @var{type} arguments represents each checklist item. The widgets
-value of will be a list containing the value of each ticked @var{type}
-argument. The checklist widget will match a list whose elements all
-matches at least one of the specified @var{type} arguments.
-
-The following extra properties are recognized.
-
-@table @code
-@item :entry-format
-This string will be inserted for each entry in the list.
-The following @samp{%} escapes are available:
-@table @samp
-@item %v
-Replaced with the buffer representation of the @var{type} widget.
-@item %b
-Replace with the checkbox.
-@item %%
-Insert a literal @samp{%}.
-@end table
-
-@item button-args
-A list of keywords to pass to the checkboxes. Useful for setting
-e.g. the @samp{:help-echo} for each checkbox.
-
-@item :buttons
-The widgets representing the checkboxes.
-
-@item :children
-The widgets representing each type.
-
-@item :args
-The list of types.
-@end table
-
-@node editable-list, , checklist, Basic Types
-@comment node-name, next, previous, up
-@subsection The @code{editable-list} Widget
-
-Syntax:
-
-@example
-TYPE ::= (editable-list [KEYWORD ARGUMENT]... TYPE)
-@end example
-
-The value is a list, where each member represent one widget of type
-@var{type}.
-
-The following extra properties are recognized.
-
-@table @code
-@item :entry-format
-This string will be inserted for each entry in the list.
-The following @samp{%} escapes are available:
-@table @samp
-@item %v
-This will be replaced with the buffer representation of the @var{type}
-widget.
-@item %i
-Insert the @b{[INS]} button.
-@item %d
-Insert the @b{[DEL]} button.
-@item %%
-Insert a literal @samp{%}.
-@end table
-
-@item :insert-button-args
-A list of keyword arguments to pass to the insert buttons.
-
-@item :delete-button-args
-A list of keyword arguments to pass to the delete buttons.
-
-@item :append-button-args
-A list of keyword arguments to pass to the trailing insert button.
-
-
-@item :buttons
-The widgets representing the insert and delete buttons.
-
-@item :children
-The widgets representing the elements of the list.
-
-@item :args
-List whose car is the type of the list elements.
-
-@end table
-
-@node Sexp Types, Widget Properties, Basic Types, Top
-@comment
-@section Sexp Types
-
-A number of widgets for editing s-expressions (lisp types) are also
-available. These basically fall in three categories: @dfn{atoms},
-@dfn{composite types}, and @dfn{generic}.
-
-@menu
-* generic::
-* atoms::
-* composite::
-@end menu
-
-@node generic, atoms, Sexp Types, Sexp Types
-@comment node-name, next, previous, up
-@subsection The Generic Widget.
-
-The @code{const} and @code{sexp} widgets can contain any lisp
-expression. In the case of the @code{const} widget the user is
-prohibited from editing edit it, which is mainly useful as a component
-of one of the composite widgets.
-
-The syntax for the generic widgets is
-
-@example
-TYPE ::= (const [KEYWORD ARGUMENT]... [ VALUE ])
-@end example
-
-The @var{value}, if present, is used to initialize the @code{:value}
-property and can be any s-expression.
-
-@deffn Widget const
-This will display any valid s-expression in an immutable part of the
-buffer.
-@end deffn
-
-@deffn Widget sexp
-This will allow you to edit any valid s-expression in an editable buffer
-field.
-
-The @code{sexp} widget takes the same keyword arguments as the
-@code{editable-field} widget.
-@end deffn
-
-@node atoms, composite, generic, Sexp Types
-@comment node-name, next, previous, up
-@subsection Atomic Sexp Widgets.
-
-The atoms are s-expressions that does not consist of other
-s-expressions. A string is an atom, 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
-
-@example
-TYPE ::= (NAME [KEYWORD ARGUMENT]... [ VALUE ])
-@end example
-
-The @var{value}, if present, is used to initialize the @code{:value}
-property and must be an expression of the same type as the widget.
-I.e. the string widget can only be initialized with a string.
-
-All the atom widgets take the same keyword arguments as the @code{editable-field}
-widget.
-
-@deffn Widget string
-Allows you to edit a string in an editable field.
-@end deffn
-
-@deffn Widget file
-Allows you to edit a file name in an editable field. You you activate
-the tag button, you can edit the file name in the mini-buffer with
-completion.
-
-Keywords:
-@table @code
-@item :must-match
-If this is set to non-nil, only existing file names will be allowed in
-the minibuffer.
-@end table
-@end deffn
-
-@deffn Widget directory
-Allows you to edit a directory name in an editable field.
-Similar to the @code{file} widget.
-@end deffn
-
-@deffn Widget symbol
-Allows you to edit a lisp symbol in an editable field.
-@end deffn
-
-@deffn Widget integer
-Allows you to edit an integer in an editable field.
-@end deffn
-
-@deffn Widget number
-Allows you to edit a number in an editable field.
-@end deffn
-
-@deffn 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.
-@end deffn
-
-
-@node composite, , atoms, Sexp Types
-@comment node-name, next, previous, up
-@subsection Composite Sexp Widgets.
-
-The syntax for the composite are
-
-@example
-TYPE ::= (NAME [KEYWORD ARGUMENT]... COMPONENT...)
-@end example
-
-Where each @var{component} must be a widget type. Each component widget
-will be displayed in the buffer, and be editable to the user.
-
-@deffn Widget cons
-The value of a @code{cons} widget is a cons-cell where the car is the
-value of the first component and the cdr is the value of the second
-component. There must be exactly two components.
-@end deffn
-
-@deffn Widget lisp
-The value of a @code{lisp} widget is a list containing the value of
-each of its component.
-@end deffn
-
-@deffn Widget vector
-The value of a @code{vector} widget is a vector containing the value of
-each of its component.
-@end deffn
-
-The above suffice for specifying fixed size lists and vectors. To get
-variable length lists and vectors, you can use a @code{choice},
-@code{set} or @code{repeat} widgets together with the @code{:inline}
-keywords. If any component of a composite widget has the @code{: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 arguments should either by the
-symbol @code{t} or two files, you can use the following widget
-specification:
-
-@example
-(list file
- (choice (const t)
- (list :inline t
- :value ("foo" "bar")
- string string)))
-@end example
-
-The value of a widget of this type will either have the form
-@samp{(file t)} or @code{(file string string)}.
-
-This concept of inline is probably hard to understand. It was certainly
-hard to implement so instead of confuse you more by trying to explain it
-here, I'll just suggest you meditate over it for a while.
-
-@deffn Widget choice
-Allows you to edit a sexp which may have one of fixed set of types. It
-is currently implemented with the @code{choice-menu} basic widget, and
-has a similar syntax.
-@end deffn
-
-@deffn Widget set
-Allows you to specify a type which must be a list whose elements all
-belong to given set. The elements of the list is not significant. This
-is implemented on top of the @code{checklist} basic widget, and has a
-similar syntax.
-@end deffn
-
-@deffn Widget repeat
-Allows you to specify a variable length list whose members are all of
-the same type. Implemented on top of the `editable-list' basic widget,
-and has a similar syntax.
-@end deffn
-
-@node Widget Properties, Defining New Widgets, Sexp Types, Top
-@comment node-name, next, previous, up
-@section Properties
-
-You can examine or set the value of a widget by using the widget object
-that was returned by @code{widget-create}.
-
-@defun widget-value widget
-Return the current value contained in @var{widget}.
-It is an error to call this function on an uninitialized widget.
-@end defun
-
-@defun widget-value-set widget value
-Set the value contained in @var{widget} to @var{value}.
-It is an error to call this function with an invalid @var{value}.
-@end defun
-
-@strong{Important:} You @emph{must} call @code{widget-setup} after
-modifying the value of a widget before the user is allowed to edit the
-widget again. It is enough to call @code{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 @code{widget-put} and @code{widget-get}. The property names
-must begin with a @samp{:}.
-
-@defun widget-put widget property value
-In @var{widget} set @var{property} to @var{value}.
-@var{property} should be a symbol, while @var{value} can be anything.
-@end defun
-
-@defun widget-get widget property
-In @var{widget} return the value for @var{property}.
-@var{property} should be a symbol, the value is what was last set by
-@code{widget-put} for @var{property}.
-@end defun
-
-@defun widget-member widget property
-Non-nil if @var{widget} has a value (even nil) for property @var{property}.
-@end defun
-
-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.
-
-@defun widget-type widget
-Return the name of @var{widget}, a symbol.
-@end defun
-
-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:
-
-@lisp
-;; Examine if @var{widget} is active or not.
-(if (widget-apply @var{widget} :active)
- (message "Widget is active.")
- (message "Widget is inactive.")
-
-;; Make @var{widget} inactive.
-(widget-apply @var{widget} :deactivate)
-
-;; Make @var{widget} active.
-(widget-apply @var{widget} :activate)
-@end lisp
-
-A widget is inactive if itself, or any of its ancestors (found by
-following the @code{:parent} link) have been deactivated. To make sure
-a widget is really active, you must therefore activate both itself, and
-all its ancestors.
-
-@lisp
-(while widget
- (widget-apply widget :activate)
- (setq widget (widget-get widget :parent)))
-@end lisp
-
-You can check if a widget has been made inactive by examining the value
-of @code{:inactive} keyword. If this is non-nil, the widget itself has
-been deactivated. This is different from using the @code{:active}
-keyword, in that the later tell you if the widget @strong{or} any of its
-ancestors have been deactivated. Do not attempt to set the
-@code{:inactive} keyword directly. Use the @code{:activate}
-@code{:deactivated} keywords instead.
-
-
-@node Defining New Widgets, Widget Wishlist., Widget Properties, Top
-@comment node-name, next, previous, up
-@section Defining New Widgets
-
-You can define specialized widgets with @code{define-widget}. It allows
-you to create a shorthand for more complex widgets, including specifying
-component widgets and default new default values for the keyword
-arguments.
-
-@defun widget-define name class doc &rest args
-Define a new widget type named @var{name} from @code{class}.
-
-@var{name} and class should both be symbols, @code{class} should be one
-of the existing widget types.
-
-The third argument @var{DOC} is a documentation string for the widget.
-
-After the new widget has been defined, the following two calls will
-create identical widgets:
-
-@itemize @bullet
-@item
-@lisp
-(widget-create @var{name})
-@end lisp
-
-@item
-@lisp
-(apply widget-create @var{class} @var{args})
-@end lisp
-@end itemize
-
-@end defun
-
-Using @code{widget-define} does just store the definition of the widget
-type in the @code{widget-type} property of @var{name}, which is what
-@code{widget-create} uses.
-
-If you just want to specify defaults for keywords with no complex
-conversions, you can use @code{identity} as your conversion function.
-
-The following additional keyword arguments are useful when defining new
-widgets:
-@table @code
-@item :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 widgets parent types, most derived first.
-
-@item :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 @code{:value}
-when the widget is created, and on any value set later with
-@code{widget-value-set}.
-
-@item :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
-internal value. The function is called on the present @code{:value}
-when the widget is created, and on any value set later with
-@code{widget-value-set}.
-
-@item :create
-Function to create a widget from scratch. The function takes one
-argument, a widget type, and create a widget of that type, insert it in
-the buffer, and return a widget object.
-
-@item :delete
-Function to delete a widget. The function takes one argument, a widget,
-and should remove all traces of the widget from the buffer.
-
-@item :value-create
-Function to expand the @samp{%v} escape in the format string. It will
-be called with the widget as its argument. Should
-insert a representation of the widgets value in the buffer.
-
-@item :value-delete
-Should remove the representation of the widgets 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 such has been used.
-
-@item :format-handler
-Function to handle unknown @samp{%} escapes in the format string. It
-will be called with the widget and the escape character as arguments.
-You can set this to allow your widget to handle non-standard escapes.
-
-You should end up calling @code{widget-default-format-handler} to handle
-unknown escape sequences, which will handle the @samp{%h} and any future
-escape sequences, as well as give an error for unknown escapes.
-@end table
-
-If you want to define a new widget from scratch, use the @code{default}
-widget as its base.
-
-@deffn Widget default [ keyword argument ]
-Widget used as a base for other widgets.
-
-It provides most of the functionality that is referred to as ``by
-default'' in this text.
-@end deffn
-
-@node Widget Wishlist., , Defining New Widgets, Top
-@comment node-name, next, previous, up
-@section Wishlist.
-
-@itemize @bullet
-@item
-It should be possible to add or remove items from a list with @kbd{C-k}
-and @kbd{C-o} (suggested by @sc{rms}).
-
-@item
-The @samp{[INS]} and @samp{[DEL]} buttons should be replaced by a single
-dash (@samp{-}). The dash should be a button that, when activated, ask
-whether you want to add or delete an item (@sc{rms} wanted to git rid of
-the ugly buttons, the dash is my idea).
-
-@item
-Widgets such as @code{file} and @code{symbol} should prompt with completion.
-
-@item
-The @code{menu-choice} tag should be prettier, something like the abbreviated
-menus in Open Look.
-
-@item
-The functions used in many widgets, like
-@code{widget-item-convert-widget}, should not have names that are
-specific to the first widget where I happended to use them.
-
-@item
-Flag to make @code{widget-move} skip a specified button.
-
-@item
-Document `helper' functions for defining new widgets.
-
-@item
-Activate the item this is below the mouse when the button is
-released, not the item this is below the mouse when the button is
-pressed. Dired and grep gets this right. Give feedback if possible.
-
-@item
-Use @samp{@@deffn Widget} to document widgets.
-
-@item
-Document global keywords in one place.
-
-Document keywords particular to a specific widget in the widget
-definition.
-
-Document the `default' widget first.
-
-Split, when needed, keywords into those useful for normal
-customization, those primarily useful when deriving, and those who
-represent runtime information.
-
-@item
-Figure out terminology and @sc{api} for the class/type/object/super
-stuff.
-
-Perhaps the correct model is delegation?
-
-@item
-Document @code{widget-browse}.
-
-@item
-Make indentation work with glyphs and propertional fonts.
-
-@item
-Add object and class hierarchies to the browser.
-
-@end itemize
-
-@contents
-@bye
projects / emacs.git / commitdiff