From: Dave Love Date: Fri, 27 Oct 2000 22:05:48 +0000 (+0000) Subject: *** empty log message *** X-Git-Tag: emacs-pretest-21.0.90~483 X-Git-Url: http://git.eshelyaron.com/gitweb/?a=commitdiff_plain;h=b01c997e2b7319b27bf1a57c65bc484178f6772e;p=emacs.git *** empty log message *** --- diff --git a/etc/widget.texi b/etc/widget.texi deleted file mode 100644 index c4761748105..00000000000 --- a/etc/widget.texi +++ /dev/null @@ -1,1422 +0,0 @@ -\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