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diff --git a/doc/misc/widget.texi b/doc/misc/widget.texi index 13b37ab5b54..cfb9d2211cf 100644 --- a/doc/misc/widget.texi +++ b/doc/misc/widget.texi @@ -9,7 +9,7 @@ @c %**end of header @copying -Copyright @copyright{} 2000--2023 Free Software Foundation, Inc. +Copyright @copyright{} 2000--2024 Free Software Foundation, Inc. @quotation Permission is granted to copy, distribute and/or modify this document @@ -49,14 +49,16 @@ modify this GNU manual.'' * Introduction:: * User Interface:: * Programming Example:: +* Widgets Basics:: * Setting Up the Buffer:: -* Basic Types:: -* Sexp Types:: -* Widget Properties:: +* Working with Widgets:: +* Widgets and the Buffer:: +* Widget Gallery:: * Defining New Widgets:: -* Widget Browser:: +* Inspecting Widgets:: * Widget Minor Mode:: * Utilities:: +* Customization:: * Widget Wishlist:: * GNU Free Documentation License:: * Index:: @@ -68,7 +70,7 @@ modify this GNU manual.'' 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 +incredibly 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. @@ -85,13 +87,13 @@ 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. +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. @item 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. +buttons. The options are implemented as widgets. All options are +visible in the buffer, with the selected one marked as chosen. @item item A simple constant widget intended to be used in the @code{menu-choice} and @code{radio-button-choice} widgets. @@ -137,9 +139,9 @@ Editing happens in the buffer, not in the mini-buffer. 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 be +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. +Widget library will also use the new graphic features automatically. @end enumerate @node User Interface @@ -201,12 +203,6 @@ middle of another field is prohibited. Editable text fields are created by the @code{editable-field} widget. -@strong{Warning:} In an @code{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 @code{editable-field} widget itself, or insert it with -@code{widget-insert}. - The @code{:format} keyword is useful for generating the necessary text; for instance, if you give it a value of @code{"Name: %v "}, the @samp{Name: } part will provide the necessary separating text @@ -215,17 +211,9 @@ separating text after the field. If you don't include the @code{:size} keyword, the field will extend to the end of the line, and the terminating newline will provide separation after. -@strong{Warning:} In an @code{editable-field} widget, the @samp{%v} escape -must be preceded by some other text in the @code{:format} string -(if specified). - 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 - @section Buttons @cindex widget buttons @@ -233,24 +221,9 @@ Face used for other editing fields. Some portions of the buffer have an associated @dfn{action}, which can be @dfn{invoked} 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} -Invoke the button at @var{pos}, defaulting to point. -If point is not located on a button, invoke the binding in -@code{widget-global-map} (by default the global map). -@end deffn - -@kindex mouse-2 @r{(on button widgets}) -@item mouse-2 -@deffn Command widget-button-click @var{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 -@code{widget-global-map} (by default the global map). -@end deffn -@end table +are @code{widget-button-press} and @code{widget-button-click}. The +user typically interacts with the buttons with a key, like @key{RET}, +or with the mouse buttons. There are several different kind of buttons, all of which are present in the example: @@ -286,33 +259,15 @@ main difference from the @code{link} widget is that the buttons will be displayed as GUI buttons when possible. @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 highlighting a button when the mouse pointer moves across -it. -@end defopt +To make them easier to locate, buttons are emphasized in the buffer +with a distinctive face, like @code{widget-button-face} or +@code{widget-mouse-face}. @section 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 @kbd{M-@key{TAB}} -@itemx @kbd{S-@key{TAB}} -@deffn Command widget-backward &optional count -Move point @var{count} buttons or editing fields backward. -@end deffn -@end table +buffer, plus you will have these additional commands to navigate from +widget to widget: @code{widget-forward} and @code{widget-backward}. @node Programming Example @chapter Programming Example @@ -414,85 +369,598 @@ Interface}). (widget-setup)) @end lisp +@node Widgets Basics +@chapter Widgets Basics +@cindex widget object +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. + +@cindex widget inheritance +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 @dfn{default} +widget. In this manual, when we talk about a default behavior, we +usually mean the behavior as defined by this @code{default} widget. +@xref{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. + +@cindex widget value +One important property of a widget is its @dfn{value}. All widgets +may have a value, which is stored in a so-called @dfn{internal format}. +For the rest of Emacs, the widget presents its value in a so-called +@dfn{external format}. Both formats can be equal or different, and +each widget is responsible for defining how the conversion between +each format should happen. + +@c FIXME: Briefly describe inline widgets? +@c The inline concept is described elsewhere, and it's difficult to +@c describe. + +The value property is an important property for almost all widgets, +and perhaps more important for @code{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. +@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. + +@cindex widget 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 the @code{widget-put} and @code{widget-get} functions. The +property names, as shown, are keywords, so they must begin with a +@samp{:}. + @node Setting Up the Buffer @chapter Setting Up the Buffer +@cindex widget creation, widget conversion +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 @dfn{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 @code{widget-create}, which +gets a widget specification and returns a widget object. + +@defun widget-create type [ keyword argument ]@dots{} args +Create and return a widget of type @var{type}, converting it. + +@var{type} is a symbol that specifies a widget type. @var{keyword} +may be one of the properties supported by the widget type, and +@var{argument} specify the value for that property. These keyword +arguments can be used to overwrite the keyword arguments that are part +of @var{type} by default, as well as to provide other properties not +present in @var{type} by default. @var{args} holds additional +information for the creation of @var{type} and each widget type is +responsible for handling that information in a specific way. + +The syntax for the @var{type} argument is described in @ref{Widget +Gallery}, and in more detail in every widget where it's relevant. +@end defun + +There are other functions for creating widgets, useful when you work +with composite widgets. That is, widgets that are part of other +widgets. -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-child-and-convert parent type &rest args +Create a widget of type @var{type} as a child of @var{parent}. -@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}. +Before creating it, converts @var{type} using the keyword arguments +provided in @var{args}. +@c FIXME: Is this description useful? +Adds the @code{:indent} property, unless it is already present, and +sets it to the sum of the values of: @code{:indent} and @code{:offset} +from @var{parent} and @code{:extra-offset} from @var{type}. -The keyword arguments can be used to overwrite the keyword arguments -that are part of @var{type}. +Returns a widget object, with the property @code{:parent} set to +@var{PARENT}. @end defun -@defun widget-delete widget -Delete @var{widget} and remove it from the buffer. +@defun widget-create-child parent type +Create a widget of type @var{type} as a child of @var{parent}. + +This function is like @code{widget-create-child-and-convert} but it +doesn't convert @var{type}, so it expects an already converted widget. @end defun +@defun widget-create-child-value parent type value +Create a widget of type @var{type} as a child of @var{parent} with +value @var{value}. + +This function is like @code{widget-create-child}, but it lets you +specify a value for the widget. + +Converts @var{value} to the internal format, as specified by +@var{type}, and stores it into the @code{:value} property of @var{type}. +That means, @var{value} should be in the external format, as +specified by @var{type}. +@end defun + +All these creating functions described here use the function stored in +the @code{:create} property. So, to modify the creation logic for a +widget, you can provide a different @code{:create} function. + +When you're done creating widgets and you're ready for the user to +interact with the buffer, use the function @code{widget-setup}. + @defun 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. @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}. +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. @xref{Working with Widgets}. -@defun widget-insert -Insert the arguments, either strings or characters, at point. -The inserted text will be read-only. +@defun widget-delete widget +Delete the widget @var{widget} and remove it from the buffer. @end defun -There is a standard widget keymap which you might find useful. +@defun widget-children-value-delete widget +Delete all children and buttons in widget @var{widget}. -@findex widget-button-press -@findex widget-button-click +This function does not delete @var{widget} itself, only the widgets +stored in the @code{:children} and @code{:buttons} properties. It +also sets those properties to @code{nil}. +@end defun + +As with the creation mechanism, the function stored in @code{:delete} +controls the deletion mechanism for a widget. + +Additionally, the library provides a way to make a copy of a widget. + +@defun widget-copy widget +Makes a copy of widget @var{widget} and returns it. + +It uses the function stored in the @code{:copy} property of @var{widget} +and returns the widget that that function returns. +@end defun + +As discussed, there is a conversion step when creating a widget. To +do the conversion without actually creating the widget, you can use +the @code{widget-convert} function. + +@defun widget-convert type &rest args +Convert @var{type} to a widget object, using keyword arguments @var{args}. + +Returns a widget object, suitable for creation. It calls the function +stored in the @code{:convert-widget} property, after putting into the +@code{:args} property the arguments that the widget in question needs. +If @var{type} has a @code{:value} property, either originally or after +doing the conversion, this function converts the value stored in +@code{:value} to the internal format, and stores it into @code{:value}. +@end defun + +Apart from only creating widgets in the buffer, It's useful to have +plain text. For inserting text, the recommended way is with the +@code{widget-insert} function. + +@defun widget-insert &rest args +Insert @var{args}, either strings or characters, at point. + +Uses @code{insert} to perform the insertion, passing @var{args} as +argument. @xref{Insertion,,,elisp, the Emacs Lisp Reference Manual}, +for more information about @var{args}. + +The resulting text will be read-only. +@end defun + +@node Working with Widgets +@chapter 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. @xref{Widget Gallery}. + +@defun widgetp widget +Non-@code{nil} if @var{widget} is a widget. +@end defun + +@defun widget-type widget +Return the type of widget @var{widget}, a symbol. + +This function is useful to find out which kind of widget @var{widget} +represents, i.e., the name of the widget type when the widget +was created. +@end defun + +@defun widget-member widget property +Non-@code{nil} if widget @var{widget} has a value (even @code{nil}) for +property @var{property}. +@end defun + +@defun widget-get widget property +For widget @var{widget}, return the value of the property @var{property}. + +@var{property} should be a keyword, and the value is what was last set by +@code{widget-put} for @var{property}. +@end defun + +@defun widget-put widget property value +For widget @var{widget}, set the property @var{property} to @var{value}. +@var{property} should be a keyword, while @var{value} can be anything. +@end defun + +@defun widget-at &optional pos +Return the widget at position @var{pos}, or at point if @var{pos} is @code{nil}. +@end defun + +@defun widget-field-at pos +Return the widget field at position POS, or @code{nil} if there is none. +@end defun + +@defun widget-apply widget property &rest args +Apply the function stored in @var{property} to @var{widget}, passing @var{args} +as additional arguments to the function. + +Returns the result of that function call. +@end defun + +@defun widget-value widget +Return the current value contained in @var{widget}. + +Note that the value returned by this function might differ from what's +stored in the @code{:value} property of @var{widget}. This is because +this function extracts the current value of @var{widget} from the +buffer, taking editions into account. + +The value returned is in the external format, after getting it with +the @code{:value-get} function. + +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}. + +Converts @var{value} to the internal format, and then sets it by +applying the @code{:value-set} function. + +It is an error to call this function with an invalid @var{value}, that +is, a value that @var{widget} cannot represent. +@end defun + +@defun widget-default-get widget +Return the default external value of widget @var{widget}. + +The default value is the one stored in @code{:value} or the result of +applying the @code{:default-get} function to the arguments of +@var{widget}, as stored in @code{:args}. A value of @code{nil} is +ignored by default, so in order for a widget to respect @code{nil} as +a value, it has to override the @code{:default-get} function. +@end defun + +@defun widget-type-default-get widget +Convert the @code{:type} attribute in @var{widget} and return its +default value. +@end defun + +@defun widget-child-value-get widget +Return the value of the first member of @code{:children} in +@var{widget}. +@end defun + +@defun widget-child-value-inline widget +Return the inline value of the first member of @code{:children} in +@var{widget}. + +The inline value is whatever the function stored in +@code{:value-inline} returns. +@end defun + +@defun widget-type-value-create widget +Create a child widget for @var{widget}, of type stored in +@code{:type}. + +Creates the child widget taking the value from the @code{:value} +property and stores the newly created widget in the @code{:children} +property of @var{widget}. + +The value stored in @code{:type} should be an unconverted widget +type. +@end defun + +@defun widget-value-convert-widget widget +Initializes the @code{:value} property of @var{widget} from +@code{:args}. + +Sets @code{:args} to @code{nil} and returns the modified widget +@var{widget}. +@end defun + +@defun widget-value-value-get widget +Return the value stored in @code{:value} for widget @var{widget}. + +This is different to getting the current value for @var{widget} with +@code{widget-value}, since that function extracts the value from the +buffer. +@end defun + +@defun widget-apply-action widget &optional event +Apply the function stored in @code{:action} to @var{widget}, in +response to @var{event}. + +It is an error to call this function with an inactive widget. +@end defun + +@defun widget-parent-action widget &optional event +Tell @code{:parent} of @var{widget} to handle @var{event}. + +Optional @var{event} is the event that triggered the action. +@end defun + +@defun widget-child-validate widget +Check that the first member of @code{:children} in @var{widget} is valid. + +To be valid means that the widget value passes the checks that the +function stored in @code{:validate} makes. +@end defun + +@defun widget-children-validate widget +Check that all @code{:children} in @var{widget} are valid. + +Returns @code{nil} on success, or the first child that isn't valid. +@end defun + +@defun widget-type-match widget value +Return non-@code{nil} if @var{VALUE} matches the value for the +@code{:type} widget. + +As with the other type functions, the widget stored in @code{:type} +should be an unconverted widget. +@end defun + +@defun widget-types-copy widget +Copy the @code{:args} value in @var{widget} and store them in @code{:args}. + +Makes the copies by calling @code{widget-copy} on each element present +in @code{:args}. Returns the modified widget @var{widget}. +@end defun + +@defun widget-types-convert-widget widget +Convert the @code{:args} value in @var{widget} and store them in +@code{args}. + +Returns the modified widget @var{widget}. +@end defun + +@node Widgets and the Buffer +@chapter Widgets and the Buffer +This chapter describes commands that are specific to buffers that +contain widgets. + +@cindex widget keybindings @defvr Const widget-keymap -@key{TAB} and @kbd{C-@key{TAB}} are bound to @code{widget-forward} and -@code{widget-backward}, respectively. @key{RET} and @kbd{mouse-2} -are bound to @code{widget-button-press} and -@code{widget-button-click}. +Keymap containing useful bindings for buffers containing widgets. + +Binds @key{TAB} and @kbd{C-@key{TAB}} to @code{widget-forward} and +@code{widget-backward}, respectively. It also binds @key{RET} to +@code{widget-button-press} and @kbd{down-mouse-1} and +@kbd{down-mouse-2} to @code{widget-button-click}. @end defvr +There's also a keymap for events that the Widget library doesn't need +to handle. + @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 -@chapter Basic Types +In addition to these two keymaps, each widget might define a keymap of +its own, active when events happen at that widget. + +@cindex widget navigation +The following navigation commands are available: + +@table @kbd +@item @key{TAB} +@deffn Command widget-forward &optional count +Move point @var{count} buttons or editing fields forward. +@end deffn +@item @kbd{M-@key{TAB}} +@itemx @kbd{S-@key{TAB}} +@deffn Command widget-backward &optional count +Move point @var{count} buttons or editing fields backward. +@end deffn +@end table + + +When editing an @code{editable-field} widget, the following commands +are available: + +@table @kbd +@item @key{C-e} +@deffn Command widget-end-of-line +Move point to the end of field or end of line, whichever is first. +@end deffn + +@item @kbd{C-k} +@deffn Command widget-kill-line +Kill to end of field or end of line, whichever is first. +@end deffn + +@item @kbd{M-TAB} +@deffn Command widget-complete +Complete the content of the editable field at point. +@end deffn + +@item @kbd{C-m} +@deffn Command widget-field-activate +Invoke the editable field at point. +@end deffn +@end table + +The following two are commands that can execute widget actions. +@table @kbd +@item @key{RET} +@findex widget-button-press +@deffn Command widget-button-press @var{pos} &optional @var{event} +Invoke the button at @var{pos}, defaulting to point. + +Invocation means to run the function stored in the @code{:action} +property. + +If point is not located on a button, invoke the binding in +@code{widget-global-map} (by default the global map). +@end deffn + +@kindex mouse-2 @r{(on button widgets}) +@item mouse-2 +@findex widget-button-click +@deffn Command widget-button-click @var{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 @code{widget-global-map} (by default the global map). + +In case the mouse-click is on a widget, calls the function stored in +the @code{:mouse-down-action} property. +@end deffn +@end table -This is the general syntax of a type specification: +@node Widget Gallery +@chapter Widget Gallery +@cindex widget syntax +All widgets can be created from a type specification. The general +syntax of a type specification is: +@c FIXME: Add BNF reference here? If yes, what reference? @example @var{name} ::= (@var{name} [@var{keyword} @var{argument}]... @var{args}) | @var{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. +Where @var{name} is a widget name, as defined with +@code{define-widget}, @var{keyword} is the name of a property and +@var{argument} is the value for that property, and @var{args} are +interpreted in a widget specific way. @xref{Defining New Widgets}. + +@menu +* Basic Types:: +* Sexp Types:: +@end menu + +@node Basic Types +@section Basic Types + +@menu +* default:: +* item:: +* link:: +* url-link:: +* info-link:: +* function-link:: +* variable-link:: +* face-link:: +* file-link:: +* emacs-library-link:: +* emacs-commentary-link:: +* push-button:: +* editable-field:: +* text:: +* menu-choice:: +* radio-button-choice:: +* choice-item:: +* toggle:: +* radio-button-toggle:: +* checkbox:: +* checklist:: +* editable-list:: +* group:: +* documentation-string:: +@end menu + +@node default +@subsection The @code{default} Widget +@findex default@r{ widget} +The most basic widget in the Widget Library is the @dfn{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. + +@deffn 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 @code{default} widget as its base. +@end deffn @cindex keyword arguments The following keyword arguments apply to all widgets: @table @code +@vindex create@r{ keyword} +@item :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 @code{:format} property. + +@vindex delete@r{ keyword} +@item :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: + +@defun widget-default-delete widget +Remove @var{widget} from the buffer. +Delete all @code{:children} and @code{:buttons} in @var{widget}. +@end defun + +In most cases you should not change this value, but instead use +@code{:value-delete} to make any additional cleanup. + @cindex internal format @cindex external format @vindex value@r{ keyword} @item :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 @@ -500,6 +968,68 @@ stored in the @code{:value} property has. However, when creating a widget or defining a new one (@pxref{Defining New Widgets}), the @code{:value} should be in the external format. +@vindex value-to-internal@r{ keyword} +@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}. + +@vindex value-to-external@r{ keyword} +@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 value in the external format. + +@vindex value-create@r{ keyword} +@item :value-create +Function to expand the @samp{%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. + +@vindex value-delete@r{ keyword} +@item :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 @code{:children} or @code{:buttons}. + +By default, it's a no-op. + +@vindex value-get@r{ keyword} +@item :value-get +Function to extract the value of a widget, as it is displayed in the +buffer. + +@vindex value-set@r{ keyword} +@item :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 @code{:delete} function and +creates it again with the @code{:create} function. + +@vindex value-inline@r{ keyword} +@item :value-inline +Function that takes a widget and returns its value, inlined. + +Inlined means that if the widget is not inline (i.e., its +@code{:inline} property is @code{nil}), the return value is wrapped in +a list. + +@vindex default-get@r{ keyword} +@item :default-get +Function that takes a widget and returns its default value. + +By default, it just returns the value stored in @code{:value}. + @vindex format@r{ keyword} @item :format This string will be inserted in the buffer when you create a widget. @@ -513,14 +1043,6 @@ The text inside will be marked as a button. By default, the text will be shown in @code{widget-button-face}, and surrounded by brackets. -@defopt widget-button-prefix -String to prefix buttons. -@end defopt - -@defopt widget-button-suffix -String to suffix buttons. -@end defopt - @item %@{ @itemx %@} The text inside will be displayed with the face specified by @@ -530,9 +1052,6 @@ The text inside will be displayed with the face specified by This will be replaced with the buffer representation of the widget's value. What this is depends on the widget type. -@strong{Warning:} In an @code{editable-field} widget, the @samp{%v} escape -must be preceded by some other text in the format string (if specified). - @item %d Insert the string specified by @code{:doc} here. @@ -561,6 +1080,11 @@ Face used to highlight text inside %[ %] in the format. @vindex button-suffix@r{ keyword} @item :button-prefix @itemx :button-suffix +Strings used as prefix and suffix for widgets that are buttons. + +By default, the values are @code{widget-button-prefix} and +@code{widget-button-suffix}. + Text around %[ %] in the format. These can be @@ -594,10 +1118,11 @@ Emacsen that supports it. @item :help-echo Specifies how to display a message whenever you move to the widget with either @code{widget-forward} or @code{widget-backward} or move the mouse -over it (using the standard @code{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 @code{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. @vindex follow-link@r{ keyword} @item :follow-link @@ -607,7 +1132,12 @@ Specifies how to interpret a @key{mouse-1} click on the widget. @vindex indent@r{ keyword} @item :indent An integer indicating the absolute number of spaces to indent children -of this widget. +of this widget. Its value might be @code{nil} too, which corresponds +to a value of 0. + +The default @code{:create} functions and the functions that create the +value per se use this property as a rudimentary layout mechanism for +the widgets. @vindex offset@r{ keyword} @item :offset @@ -619,14 +1149,6 @@ grandchildren compared to this widget. An integer indicating how many extra spaces to add to the widget's children compared to this widget. -@vindex notify@r{ keyword} -@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. - @vindex menu-tag@r{ keyword} @item :menu-tag Tag used in the menu when the widget is used as an option in a @@ -634,10 +1156,12 @@ Tag used in the menu when the widget is used as an option in a @vindex menu-tag-get@r{ keyword} @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. +Function that takes a widget and returns 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. @vindex match@r{ keyword} @item :match @@ -648,22 +1172,19 @@ represent the specified value. @vindex validate@r{ keyword} @item :validate A function which takes a widget as an argument, and returns @code{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 @code{: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 @code{:error} property to a string explaining +the error. -@defun widget-children-validate widget -All the @code{:children} of @var{widget} must be valid. -@end defun +By default, it always returns @code{nil}. @vindex tab-order@r{ keyword} @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. @@ -690,39 +1211,217 @@ This keyword is only used for members of a @code{radio-button-choice} or arguments, which will be used when creating the @code{radio-button} or @code{checkbox} associated with this item. +@vindex completions-function@r{ keyword} +@item :completions-function +Function that takes a widget and returns completion data for that +widget, like @code{completion-at-point-functions} would. +@xref{Completion,,,elisp, the Emacs Lisp Reference Manual}. It's +used by @code{editable-field} widgets to provide completions. + +By default, it looks into the property @code{:completions}, which +should be a completion table. If @code{:completions} is @code{nil}, +then it calls the function stored either in the @code{:complete} or +@code{:complete-function} property. + +@vindex format-handler@r{ keyword} +@item :format-handler +Function to handle unknown @samp{%} escapes in the format string. + +It takes a widget and the character that follows the @samp{%} as +arguments. You can set this to allow your widget to handle +non-standard escapes in your own specialized widgets. + +@findex widget-default-format-handler +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. + +@vindex button-face-get@r{ keyword} +@item :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 @code{:button-face} +property, or calls the @code{:button-face-get} function from the +parent of the widget, if it has one. + +@vindex mouse-face-get@r{ keyword} +@item :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 @code{:mouse-face} property, or calls +the @code{:button-face-get} function from the parent of the widget, if +it has one. + +@vindex copy@r{ keyword} +@item :copy +Function to deep copy a widget type. + +It takes a shallow copy of the widget type as an argument (made by +@code{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 @code{identity}. + +@vindex active@r{ keyword} +@item :active +Function that takes a widget and returns @code{t} if it is active. + +A widget might be effectively always active, if its +@code{:always-active} property is @code{t}. + +@cindex active widget +@cindex inactive widget +@cindex activate a widget +@cindex deactivate a 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: + +@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 it, 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 it 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 the @code{:inactive} keyword. If this is non-@code{nil}, the widget itself +has been deactivated. This is different from using the @code{:active} +keyword, in that the latter tells 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{:deactivate} functions instead. + +@vindex activate@r{ keyword} +@item :activate +Function that takes a widget and makes it active for user +modifications. + +@vindex deactivate@r{ keyword} +@item :deactivate +Function that takes a widget and makes it inactive for user +modifications. + +@vindex action@r{ keyword} +@item :action +Function that takes a widget and optionally an event, and handles a +user initiated event. + +By default, uses the @code{:notify} function to notify the widget's +parent about the event. + +@vindex mouse-down-action@r{ keyword} +@item :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. + +@vindex notify@r{ keyword} +@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. + +By default, it passes the notification to the widget's parent. + +@vindex prompt-value@r{ keyword} +@item :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-@code{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. @end table -@deffn {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 @file{.xpm} (if supported) or @file{.xbm} extension. -@end deffn +@node item +@subsection The @code{item} Widget +@findex item@r{ widget} -@deffn{User Option} widget-image-enable -If non-@code{nil}, allow images to appear on displays where they are supported. -@end deffn +Syntax: +@example +@var{type} ::= (item [@var{keyword} @var{argument}]... @var{value}) +@end example -@menu -* link:: -* url-link:: -* info-link:: -* push-button:: -* editable-field:: -* text:: -* menu-choice:: -* radio-button-choice:: -* item:: -* choice-item:: -* toggle:: -* checkbox:: -* checklist:: -* editable-list:: -* group:: -@end menu +A useful widget that holds a constant value, and can be included in +other widgets. Its super is the @code{default} widget. + +As can be seen in the syntax, the @code{item} widget is one of the +widget that handles the @var{args} argument to @code{widget-create} in +a specific way. If present, @var{value} is used to initialize the +@code{:value} property. When created, it inserts the value as a +string in the buffer. + +@noindent +Example: + +@lisp +(widget-create 'item :tag "Today is" :format "%t: %v\n" + (format-time-string "%d-%m-%Y")) +@end lisp + + +By default, it has the following properties: + +@table @code +@item :convert-widget +The function that allows it to handle @var{value}. + +@item :value-create +Prints the representation of @code{:value} in the buffer. + +@item :value-get +Returns the value stored in @code{:value}. + +@item :match +A value matches the @code{item} widget if it's @code{equal} to its +@code{:value}. + +@item :match-inline +Inline values match the @code{item} widget if @code{:value} is a +sublist of values. + +@item :action +The @code{item} widget notifies itself of an event. + +@item :format +By default, the @code{item} widget inserts its tag in the buffer. +@end table @node link -@section The @code{link} Widget +@subsection The @code{link} Widget @findex link@r{ widget} Syntax: @@ -731,22 +1430,56 @@ Syntax: @var{type} ::= (link [@var{keyword} @var{argument}]... [ @var{value} ]) @end example +A widget to represent an embedded link. Its super is the @code{item} +widget. + 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. -By default the link will be shown in brackets. +@noindent +Example: -@defopt widget-link-prefix -String to prefix links. -@end defopt +@lisp +(widget-create 'link + :button-prefix "" + :button-suffix "" + :tag "Mail yourself" + :action #'(lambda (widget &optional _event) + (compose-mail-other-window (widget-value widget))) + user-mail-address) +@end lisp -@defopt widget-link-suffix -String to suffix links. -@end defopt + +By default, it has the following properties: + +@table @code +@item :button-prefix +The value of @code{widget-link-prefix}. + +@item :button-suffix +The value of @code{widget-link-suffix}. + +@item :keymap +A custom keymap for the link widget, so that it can respond to mouse clicks. + +@item :follow-link +This property allows the link to respect the value of +@code{mouse-1-click-follows-link}. @xref{Clickable Text,,,elisp, the Emacs Lisp Reference Manual}. + +@item :format +Buttonizes the link, to make it clickable. + +If you override this property, you should make sure to provide the +@samp{%[} and @samp{%]} escape sequences, so that the link is +clickable. + +@end table + +By default the link will be shown in brackets. @node url-link -@section The @code{url-link} Widget +@subsection The @code{url-link} Widget @findex url-link@r{ widget} Syntax: @@ -755,12 +1488,39 @@ Syntax: @var{type} ::= (url-link [@var{keyword} @var{argument}]... @var{url}) @end example -@findex browse-url-browser-function@r{, and @code{url-link} widget} -When this link is invoked, the @acronym{WWW} browser specified by -@code{browse-url-browser-function} will be called with @var{url}. +A widget to represent a link to a web page. Its super is the +@code{link} widget. + +It overrides the @code{:action} property to open up the @var{url} +specified. + +@noindent +Example: + +@lisp +@group +(widget-create 'url-link + :button-prefix "" + :button-suffix "" + ;; Return appropriate face. + :button-face-get (lambda (widget) + (if (widget-get widget :visited) + 'link-visited + 'link)) + :format "%[%t%]" + :tag "Browse this manual" + :action (lambda (widget &optional _event) + (widget-put widget :visited t) + ;; Takes care of redrawing the widget. + (widget-value-set widget (widget-value widget)) + ;; And then call the original function. + (widget-url-link-action widget)) + "https://www.gnu.org/software/emacs/manual/html_mono/widget.html") +@end group +@end lisp @node info-link -@section The @code{info-link} Widget +@subsection The @code{info-link} Widget @findex info-link@r{ widget} Syntax: @@ -769,11 +1529,183 @@ Syntax: @var{type} ::= (info-link [@var{keyword} @var{argument}]... @var{address}) @end example -When this link is invoked, the built-in Info reader is started on -@var{address}. +A widget to represent a link to an info file. Its super is the +@code{link} widget. + +It overrides the @code{:action} property, to a function to start the +built-in Info reader on @var{address}, when invoked. + +@noindent +Example: + +@lisp +(widget-create 'info-link + :button-prefix "" + :button-suffix "" + :tag "Browse this manual" + "(widget) info-link"))) +@end lisp + +@node function-link +@subsection The @code{function-link} Widget +@findex function-link@r{ widget} +Syntax: + +@example +@var{type} ::= (function-link [@var{keyword} @var{argument}]... @var{function}) +@end example + +A widget to represent a link to an Emacs function. Its super is the +@code{link} widget. + +It overrides the @code{:action} property, to a function to describe +@var{function}. + +@noindent +Example: + +@lisp +(widget-create 'function-link + :button-prefix "" + :button-suffix "" + :tag "Describe the function that gets called" + #'widget-function-link-action) +@end lisp + +@node variable-link +@subsection The @code{variable-link} Widget +@findex variable-link@r{ widget} +Syntax: + +@example +@var{type} ::= (variable-link [@var{keyword} @var{argument}]... @var{var}) +@end example + +A widget to represent a link to an Emacs variable. Its super is the +@code{link} widget. + +It overrides the @code{:action} property, to a function to describe +@var{var}. + +@noindent +Example: + +@lisp +(widget-create 'variable-link + :button-prefix "" + :button-suffix "" + :tag "What setting controls button-prefix?" + 'widget-button-prefix) +@end lisp + +@node face-link +@subsection The @code{face-link} Widget +@findex face-link@r{ widget} +Syntax: + +@example +@var{type} ::= (face-link [@var{keyword} @var{argument}]... @var{face}) +@end example + +A widget to represent a link to an Emacs face. Its super is the +@code{link} widget. + +It overrides the @code{:action} property, to a function to describe +@var{face}. + +@noindent +Example: + +@lisp +(widget-create 'face-link + :button-prefix "" + :button-suffix "" + :tag "Which face is this one?" + 'widget-button) +@end lisp + +@node file-link +@subsection The @code{file-link} Widget +@findex file-link@r{ widget} +Syntax: + +@example +@var{type} ::= (file-link [@var{keyword} @var{argument}]... @var{file}) +@end example + +A widget to represent a link to a file. Its super is the +@code{link} widget. + +It overrides the @code{:action} property, to a function to find the file +@var{file}. + +@noindent +Example: + +@lisp +(let ((elisp-files (directory-files user-emacs-directory t ".el$"))) + (dolist (file elisp-files) + (widget-create 'file-link + :button-prefix "" + :button-suffix "" + file) + (widget-insert "\n"))) +@end lisp + +@node emacs-library-link +@subsection The @code{emacs-library-link} Widget +@findex emacs-library-link@r{ widget} +Syntax: + +@example +@var{type} ::= (emacs-library-link [@var{keyword} @var{argument}]... @var{file}) +@end example + +A widget to represent a link to an Emacs Lisp file. Its super is the +@code{link} widget. + +It overrides the @code{:action} property, to a function to find the file +@var{file}. + +@noindent +Example: + +@lisp +(widget-create 'emacs-library-link + :button-prefix "" + :button-suffix "" + :tag "Show yourself, Widget Library!" + "wid-edit.el") +@end lisp + +@node emacs-commentary-link +@subsection The @code{emacs-commentary-link} Widget +@findex emacs-commentary-link@r{ widget} +Syntax: + +@example +@var{type} ::= (emacs-commentary-link [@var{keyword} @var{argument}]... @var{file}) +@end example + +A widget to represent a link to the Comment section of an Emacs Lisp +file. Its super is the @code{link} widget. + +It overrides the @code{:action} property, to a function to find the file +@var{file} and put point in the Comment section. + +@noindent +Example: + +@lisp +(widget-create 'emacs-commentary-link + :button-prefix "" + :button-suffix "" + :tag "Check our good friend Customize" + "cus-edit.el") +@end lisp @node push-button -@section The @code{push-button} Widget +@subsection The @code{push-button} Widget @findex push-button@r{ widget} Syntax: @@ -782,22 +1714,37 @@ Syntax: @var{type} ::= (push-button [@var{keyword} @var{argument}]... [ @var{value} ]) @end example +A widget that acts as a pushable button. Its super is the @code{item} +widget. + 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. -By default the tag will be shown in brackets. +By default, it has the following properties: +@table @code +@item :button-prefix +The empty string. -@defopt widget-push-button-prefix -String to prefix push buttons. -@end defopt +@item :button-suffix +The empty string. -@defopt widget-push-button-suffix -String to suffix push buttons. -@end defopt +@item :value-create +Inserts a representation of the ``on'' and ``off'' states for the push +button. + +The representation might be an image, stored in the @code{:tag-glyph} +property, or text. If it is text, it might be the value of the +@code{:tag} property, or the @code{:value} of the widget, surrounded +with @code{widget-push-button-prefix} and +@code{widget-push-button-suffix}. @xref{Customization}. + +@item :format +Buttonizes the widget, to make it clickable. +@end table @node editable-field -@section The @code{editable-field} Widget +@subsection The @code{editable-field} Widget @findex editable-field@r{ widget} Syntax: @@ -806,56 +1753,137 @@ Syntax: @var{type} ::= (editable-field [@var{keyword} @var{argument}]... [ @var{value} ]) @end example +A widget that can be edited by the user. Its super is the +@code{default} widget. + 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 -field. This widget will match all string values. +field. If not present, @code{:value} is the empty string. -The following extra properties are recognized: +@strong{Warning:} In an @code{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 @code{editable-field} widget itself, or insert it with +@code{widget-insert}. + +This widget either overrides or adds the following properties: @table @code +@item :convert-widget +Just like the @code{item} widget, this function allows it to +initialize @code{:value} from @var{value}. + +@vindex keymap@r{ keyword} +@vindex widget-field-keymap +@item :keymap +Keymap used in the editable field. + +The default value is @code{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 @key{RET} invokes the function +specified by @code{:action}. + +@item :format +By default, it specifies to insert only the widget's value. + +@strong{Warning:} In an @code{editable-field} widget, the @samp{%v} escape +must be preceded by some other text in the @code{:format} string (if +specified). + @vindex size@r{ keyword} @item :size -The width of the editable field.@* +The width of the editable field. + By default the field will reach to the end of the line. @vindex value-face@r{ keyword} @item :value-face -Face used for highlighting the editable field. Default is -@code{widget-field-face}, see @ref{User Interface}. +Face used for highlighting the editable field. + +Default is @code{widget-field-face}, @pxref{User Interface}. @vindex secret@r{ keyword} @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, this is @code{nil}, and the value is not 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, this is @code{nil}, and the +value is not secret. @vindex valid-regexp@r{ keyword} @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. +field with the value of this attribute. -@vindex keymap@r{ keyword} -@vindex widget-field-keymap -@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 buffer's major mode suppresses some of -them. Pressing @key{RET} invokes the function specified by -@code{:action}. +The default value is @code{""} which matches everything. + +@item :validate +Returns @code{nil} if the current value of the widget matches the +@code{:valid-regexp} value. + +@item :prompt-internal +A function to read a value for widget, used by the +@code{:prompt-value} function. + +@item :prompt-history +A variable that holds the history of field minibuffer edits. + +@item :prompt-value +A function that uses the @code{:prompt-internal} function and the +@code{:prompt-history} value to prompt for a string, and return the +user response in the external format. + +@item :action +When invoked, moves point to the next field. + +@item :value-create +Function that takes care of creating the widget, respecting its +@code{:size} and @code{:value}. + +@item :value-set +Function to use to modify programmatically the current value of the +widget. + +@item :value-delete +Function that removes the widget so it cannot be edited anymore. + +@item :value-get +Function to return the current text in the widget. + +It takes an optional argument, @var{no-truncate}. If +@var{no-truncate} is nil, truncates trailing spaces. + +@item :match +Function that makes the widget match any string value. @end table @node text -@section The @code{text} Widget +@subsection The @code{text} Widget @findex text@r{ widget} +Syntax: + +@example +@var{type} ::= (text [@var{keyword} @var{argument}]... [ @var{value} ]) +@end example + +A widget just like the @code{editable-field} widget, but intended for +multiline text fields. Its super is the @code{editable-field} widget. + +It overrides the following properties: + +@table @code +@item :format +By default, prints a tag and the value. + @vindex widget-text-keymap -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 @key{RET} key. +@item :keymap +The default is @code{widget-text-keymap}, which does not rebind the +@key{RET} key. +@end table @node menu-choice -@section The @code{menu-choice} Widget +@subsection The @code{menu-choice} Widget @findex menu-choice@r{ widget} Syntax: @@ -864,21 +1892,37 @@ Syntax: @var{type} ::= (menu-choice [@var{keyword} @var{argument}]... @var{type} ... ) @end example +A widget to represent a menu of options. Its super is the +@code{default} widget. + The @var{type} argument represents each possible choice. The widget's -value will be that of the chosen @var{type} argument. This widget will -match any value matching at least one of the specified @var{type} -arguments. +value will be that of the chosen @var{type} argument. + +It either overrides or adds the following properties: @table @code +@item :convert-widget +A function that takes care of converting each possible choice. + +@item :copy +A function to copy each possible choice. + +@item :format +By default, buttonize the tag and show the value. + @vindex void@r{ keyword} @item :void Widget type used as a fallback when the value does not match any of the specified @var{type} arguments. +By default this is an @code{item} widget. + @vindex case-fold@r{ keyword} @item :case-fold -Set this to @code{nil} if you don't want to ignore case when prompting for a -choice through the minibuffer. +If @code{nil} don't ignore case when prompting for a choice through +the minibuffer. + +By default, its value is @code{t}. @vindex children@r{ keyword} @item :children @@ -892,10 +1936,54 @@ The current chosen type. @vindex args@r{ keyword} @item :args The list of types. + +@item :value-create +The function that inserts the current value for the widget. + +It inserts the first choice that matches, as with the @code{:match} +function, the value of the widget. + +@item :value-get +Returns the value of the first child for the widget (see the +description for @code{:children} above). + +@item :value-inline +Returns the inline value of the first child for the widget. + +@item :default-get +The default value for this widget is the default value for the first +choice, in case @code{:value} is missing. + +This means that if you want a specific default value for the +@code{menu-choice} widget, you should either pass a @code{:value} +property when creating it, or arrange the choices so that the first +one can hold your desired default value. + +@item :mouse-down-action +A function that takes care of showing a menu, if possible and desired. + +@item :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. + +@item :validate +Returns @code{nil} if the widget's value is a valid choice. + +@item :match +This widget will match any value matching at least one of the +specified @var{type} arguments. + +@item :match-inline +A function that returns non-@code{nil} if the values match the widget, +taking into account the @code{:inline} property. @end table @node radio-button-choice -@section The @code{radio-button-choice} Widget +@subsection The @code{radio-button-choice} Widget @findex radio-button-choice@r{ widget} Syntax: @@ -904,14 +1992,28 @@ Syntax: @var{type} ::= (radio-button-choice [@var{keyword} @var{argument}]... @var{type} ... ) @end example -The component types specify the choices, with one radio button for +A widget to represent a choice from multiple options. Its super is +the @code{default} widget. + +The component @var{types} specify the choices, with one radio button for each. The widget's value will be that of the chosen @var{type} -argument. This widget matches any value that matches at least one of -the specified @var{type} arguments. +argument. -The following extra properties are recognized. +It overrides the following properties: @table @code +@item :convert-widget +As other composite widgets, a function that takes care of converting +each available choice. + +@item :copy +A function to copy each available choice. + +@item :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. + @vindex entry-format@r{ keyword} @item :entry-format This string will be inserted for each entry in the list. @@ -925,6 +2027,9 @@ Replace with the radio button. Insert a literal @samp{%}. @end table +@item :format +By default, it inserts its value. + @vindex button-args@r{ keyword} @item :button-args A list of keywords to pass to the radio buttons. Useful for setting, @@ -940,11 +2045,38 @@ The widgets representing each type. @vindex choice@r{ keyword} @item :choice -The current chosen type +The current chosen type. @vindex args@r{ keyword} @item :args The list of types. + +@item :value-create +A function to insert all available choices. + +@item :value-get +Returns the value for the chosen widget. + +@item :value-set +A function to set the value to one of its available options. + +@item :value-inline +A function that returns the inline value of the child widget. + +@item :offset +By default, this widget has an offset of 4. + +@item :validate +The widget validates if the current value is valid for one of its +children. + +@item :match +This widget matches any value that matches at least one of +the specified @var{type} arguments. + +@item :match-inline +Like the @code{:match} function, but taking into account inline +values. @end table You can add extra radio button items to a @code{radio-button-choice} @@ -960,22 +2092,8 @@ 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 -@section The @code{item} Widget -@findex item@r{ widget} - -Syntax: - -@example -@var{item} ::= (item [@var{keyword} @var{argument}]... @var{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 -@section The @code{choice-item} Widget +@subsection The @code{choice-item} Widget @findex choice-item@r{ widget} Syntax: @@ -984,14 +2102,26 @@ Syntax: @var{item} ::= (choice-item [@var{keyword} @var{argument}]... @var{value}) @end example +A widget to represent a choice in a @code{menu-choice} widget. Its +super is the @code{item} widget. + 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. +property. + +It overrides the following properties: + +@table @code +@item :action +Activating the button of a @code{choice-item} is equivalent to +activating the parent widget. + +@item :format +By default, it buttonizes the tag (i.e., its value) and adds a newline +character at the end of the widget. +@end table @node toggle -@section The @code{toggle} Widget +@subsection The @code{toggle} Widget @findex toggle@r{ widget} Syntax: @@ -1000,43 +2130,163 @@ Syntax: @var{type} ::= (toggle [@var{keyword} @var{argument}]...) @end example +A widget that can toggle between two states. Its super is the +@code{item} widget. + The widget has two possible states, @samp{on} and @samp{off}, which correspond to a @code{t} or @code{nil} value, respectively. -The following extra properties are recognized: +@noindent +Example: + +@lisp +@group +(widget-insert "Press the button to activate/deactivate the field: ") +(widget-create 'toggle + :notify (lambda (widget &rest _ignored) + (widget-apply widget-example-field + (if (widget-value widget) + :activate + :deactivate)))) +(widget-insert "\n") +@end group +@group +(setq widget-example-field + (widget-create 'editable-field + :deactivate (lambda (widget) + (widget-specify-inactive + widget + (widget-field-start widget) + (widget-get widget :to))))) +(widget-apply widget-example-field :deactivate))) +@end group +@end lisp + + +It either overrides or adds the following properties: @table @code +@item :format +By default, it buttonizes the value and adds a newline at the end of +the widget. + @item :on A string representing the @samp{on} state. By default the string @samp{on}. + @item :off A string representing the @samp{off} state. By default the string @samp{off}. + @vindex on-glyph@r{ keyword} @item :on-glyph Name of a glyph to be used instead of the @samp{:on} text string, on emacsen that supports this. + @vindex off-glyph@r{ keyword} @item :off-glyph Name of a glyph to be used instead of the @samp{:off} text string, on emacsen that supports this. + +@item :value-create +A function for creating the widget's value, according to its +@samp{:on} or @samp{:off} state. + +@item :action +Function to toggle the state of the widget. After toggling, it +notifies itself. + +@item :match +This widget matches anything. +@end table + +@node radio-button-toggle +@subsection The @code{radio-button-toggle} Widget +@findex radio-button-toggle@r{ widget} +Syntax: + +@example +@var{type} ::= (radio-button-toggle [@var{keyword} @var{argument}]...) +@end example + +A toggle to use in the @code{radio} widget. + +It overrides the following properties: + +@table @code +@item :button-prefix +The empty string. + +@item :button-suffix +The empty string. + +@item :on +The string ``(*)'', to represent the @samp{on} state. + +@item :off +The string ``( )'', to represent the @samp{off} state. + +@item :on-glyph +The name of an image to represent the @samp{on} state. + +@item :off-glpyh +The name of an image to represent the @samp{off} state. + +@item :format +By default, it buttonizes its value. + +@item :notify +A function to notify its parent. @end table @node checkbox -@section The @code{checkbox} Widget +@subsection The @code{checkbox} Widget @findex checkbox@r{ widget} -This widget has two possible states, @samp{selected} and -@samp{unselected}, which corresponds to a @code{t} or @code{nil} value. - Syntax: @example @var{type} ::= (checkbox [@var{keyword} @var{argument}]...) @end example +A widget to represent a toggle widget, with a checkbox. Its super is +the @code{toggle} widget. + +This widget has two possible states, @samp{selected} and +@samp{unselected}, which corresponds to a @code{t} or @code{nil} +value, respectively. + +It either overrides or adds the following properties: + +@table @code +@item :button-prefix +The empty string. + +@item :button-suffix +The empty string. + +@item :format +By default, buttonizes the value. + +@item :on +By default, the string ``[X]''. + +@item :off +By default, the string ``[ ]''. + +@item :on-glyph +The name of the image to use when the state is @samp{on}. + +@item :off-glyph +The name of the image to use when the state is @samp{off}. + +@item :action +A function that toggles the checkbox, notifies the parents and in the +@samp{on} state, activates its siblings. +@end table + @node checklist -@section The @code{checklist} Widget +@subsection The @code{checklist} Widget @findex checklist@r{ widget} Syntax: @@ -1045,14 +2295,41 @@ Syntax: @var{type} ::= (checklist [@var{keyword} @var{argument}]... @var{type} ... ) @end example +A widget to represent a multiplice choice. Its super is the +@code{default} widget. + The @var{type} arguments represent each checklist item. The widget's value will be a list containing the values of all checked @var{type} -arguments. The checklist widget will match a list whose elements all -match at least one of the specified @var{type} arguments. +arguments. + +@noindent +Example: + +@lisp +(widget-create 'checklist + :notify (lambda (widget child &optional _event) + (funcall + (widget-value (widget-get-sibling child)) + 'toggle)) + :value (list 'tool-bar-mode 'menu-bar-mode) + '(item :tag "Tool-bar" tool-bar-mode) + '(item :tag "Menu-bar" menu-bar-mode)))) +@end lisp + -The following extra properties are recognized: +It either overrides or adds the following properties: @table @code +@item :convert-widget +As other composite widgets, a function that takes care of converting +each checklist item. + +@item :copy +A function to copy each checklist item. + +@item :format +By default, it inserts its value. + @vindex entry-format@r{ keyword} @item :entry-format This string will be inserted for each entry in the list. @@ -1066,14 +2343,6 @@ Replace with the checkbox. Insert a literal @samp{%}. @end table -@vindex greedy@r{ keyword} -@item :greedy -Usually a checklist will only match if the items are in the exact -sequence given in the specification. By setting @code{:greedy} to -non-@code{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. - @vindex button-args@r{ keyword} @item :button-args A list of keywords to pass to the checkboxes. Useful for setting, @@ -1090,10 +2359,35 @@ The widgets representing each type. @vindex args@r{ keyword} @item :args The list of types. + +@item :value-create +The function that takes care of inserting all values. + +@item :value-get +A function that returns all values of selected items. + +@item :validate +A function that ensures all selected children are valid. + +@item :match +The checklist widget will match a list whose elements all +match at least one of the specified @var{type} arguments. + +@item :match-inline +Like the @code{:match} function, but taking into account the +@code{:inline} property. + +@vindex greedy@r{ keyword} +@item :greedy +Usually a checklist will only match if the items are in the exact +sequence given in the specification. By setting @code{:greedy} to +non-@code{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. @end table @node editable-list -@section The @code{editable-list} Widget +@subsection The @code{editable-list} Widget @findex editable-list@r{ widget} Syntax: @@ -1102,12 +2396,19 @@ Syntax: @var{type} ::= (editable-list [@var{keyword} @var{argument}]... @var{type}) @end example -The value is a list, where each member represents one widget of type -@var{type}. +A widget that can hold a variable list of widgets of the same type, +represented by @var{type}. Its super is the @code{default} widget. -The following extra properties are recognized: +It either overrides or adds the following properties: @table @code +@item :convert-widget +As other composite widgets, a function that takes care of converting +each type in @var{type}. + +@item :copy +A function to copy the types given in @var{type}. + @vindex entry-format@r{ keyword} @item :entry-format This string will be inserted for each entry in the list. @@ -1117,9 +2418,9 @@ The following @samp{%} escapes are available: This will be replaced with the buffer representation of the @var{type} widget. @item %i -Insert the @b{[INS]} button. +Insert the @b{[INS]} button, a widget of type @code{insert-button}. @item %d -Insert the @b{[DEL]} button. +Insert the @b{[DEL]} button, a widget of type @code{delete-button}. @item %% Insert a literal @samp{%}. @end table @@ -1140,6 +2441,18 @@ A list of keyword arguments to pass to the trailing insert button. @item :buttons The widgets representing the insert and delete buttons. +@item :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. + +@item :format-handler +A function that recognize the escape for inserting an insert button. + +@item :offset +By default, this widget has an offset of 12. + @vindex children@r{ keyword} @item :children The widgets representing the elements of the list. @@ -1147,24 +2460,124 @@ The widgets representing the elements of the list. @vindex args@r{ keyword} @item :args List whose @sc{car} is the type of the list elements. + +@item :insert-before +Function to insert a new widget as a child of the @code{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. + +@item :delete-at +Function to delete a child from the widget, and store it into the +@code{:last-deleted} list, so that it can be reinserted when the +@code{:insert-before} function executes. + +@item :value-create +The function that takes care of inserting all values. + +@item :value-get +Function that returns a list with the value of the child widgets. + +@item :validate +This widget validates if all children validate. + +@item :match +To match, the value must be a list and all the list members must match +the specified @var{type}. + +@item :match-inline +Like the @code{:match} function, but taking into account inline +values and widgets. @end table @node group -@section The @code{group} Widget +@subsection The @code{group} Widget @findex group@r{ widget} -This widget simply group other widgets together. - Syntax: @example @var{type} ::= (group [@var{keyword} @var{argument}]... @var{type}...) @end example -The value is a list, with one member for each @var{type}. +A widget to group other widgets. Its super is the @code{default} +widget. + +Its value is a list, with one member for each @var{type}. + +It overrides the following properties: + +@table @code +@item :convert-widget +As other composite widgets, a function that takes care of converting +each widget in @var{type}. + +@item :copy +A function to copy the types given in @var{type}. + +@item :format +By default, displays a newline character and its value. + +@item :value-create +A function to create each of its components. + +@item :value-get +The same function used by the @code{editable-list} widget. + +@item :default-get +A function that returns a list whose members are the default values of +each widget it groups. + +@item :validate +This widget validates if all of its children validate. + +@item :match +This widget matches a value that matches each of its components. + +@item :match-inline +As @code{:match}, but taking into account widgets and values that are +inline. +@end table + +@node documentation-string +@subsection The @code{documentation-string} Widget +@findex documentation-string@r{ widget} +Syntax: + +@example +@var{type} ::= (documentation-string [@var{keyword} @var{argument}]... @var{value}) +@end example + +A widget to represent a documentation string. Its super is the +@code{item} widget. + +It either overrides or adds the following properties: + +@table @code +@item :format +By default, insert its value. + +@item :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 +@code{visibility} widget. + +@item :action +Function to toggle showing the documentation upon an event. + +@item :visibility-widget +A symbol, the type of the widget to use for the visibility widget. + +This is, by default, the symbol @code{visibility}. +@end table @node Sexp Types -@chapter Sexp Types +@section Sexp Types @cindex sexp types A number of widgets for editing @dfn{s-expressions} (Lisp types), sexp @@ -1179,7 +2592,7 @@ categories described in this section. @end menu @node constants -@section The Constant Widgets +@subsection The Constant Widgets @cindex constant widgets The @code{const} widget can contain any Lisp expression, but the user is @@ -1192,19 +2605,26 @@ The syntax for the @code{const} widget is: @var{type} ::= (const [@var{keyword} @var{argument}]... [ @var{value} ]) @end example -The @var{value}, if present, is used to initialize the @code{:value} -property and can be any s-expression. +Its super is the @code{item} widget. 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. + +It overrides the @code{:prompt-value} function, to avoid prompting and +just return the widget's value. @end deffn There are two variations of the @code{const} widget, namely @code{variable-item} and @code{function-item}. These should contain a -symbol with a variable or function binding. The major difference from -the @code{const} widget is that they will allow the user to see the -variable or function documentation for the symbol. +symbol with a variable or function binding, respectively. The major +difference from the @code{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 @samp{%h} format escape, and adding +an appropriate @code{:documentation-property} function for each widget. @deffn Widget variable-item An immutable symbol that is bound as a variable. @@ -1215,7 +2635,7 @@ An immutable symbol that is bound as a function. @end deffn @node generic -@section Generic Sexp Widget +@subsection Generic Sexp Widget @cindex generic sexp widget The @code{sexp} widget can contain any Lisp expression, and allows the @@ -1228,23 +2648,42 @@ The syntax for the @code{sexp} widget is: @end example @deffn 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 @code{sexp} widget takes the same keyword arguments as the @code{editable-field} widget. @xref{editable-field}. + +Its default value is @code{nil}. +@end deffn + +@deffn Widget restricted-sexp +A widget to edit Lisp expressions restricted to certain values or +types. Its super is the @code{sexp} widget. + +It works just like the sexp widget, but it overrides the @code{:match} +function to match for certain values. To use this widget, either you +must define a @code{:match} function or give a +@code{:match-alternatives} property. The @code{: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-@code{nil} on success. + +As an example, the @code{integer} widget overrides +@code{:match-alternatives} to @code{(integerp)}. @end deffn @node atoms -@section Atomic Sexp Widgets +@subsection Atomic Sexp Widgets @cindex atomic sexp widget 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. +widgets described in this section. -The syntax for all the atoms are: +The syntax for all the atoms is: @example @var{type} ::= (@var{construct} [@var{keyword} @var{argument}]... [ @var{value} ]) @@ -1252,68 +2691,151 @@ The syntax for all the atoms are: 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. -That is, the string widget can only be initialized with a string. +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 @code{editable-field} widget. @xref{editable-field}. @deffn 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 @code{:complete} +property. @end deffn @deffn 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 @code{:match} and the @code{:validate} properties to +check that the value is a valid regexp. @end deffn @deffn 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. @end deffn @deffn Widget file -Allows you to edit a file name in an editable field. +A widget for editing file names. Keywords: @table @code +@item :completions +Offers file name completion to the user. + +@item :prompt-value +A function to read a file name from the minibuffer. + @vindex must-match@r{ keyword} @item :must-match -If this is set to non-@code{nil}, only existing file names will be -allowed in the minibuffer. +If this is set to non-@code{nil}, only existing file names are allowed +when prompting for a value in the minibuffer. + +@item :match +The widget matches if the value is a string, and the file whose name +is that string is an existing file, or if @code{:must-match} is +@code{nil}. + +@item :validate +The widget is valid if its value matches. + @end table @end deffn @deffn Widget directory -Allows you to edit a directory name in an editable field. -Similar to the @code{file} widget. +A widget for editing directory names. + +Its super is the @code{file} widget, and it overrides the +@code{:completions} property, to offer completions only for +directories. @end deffn @deffn 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 @code{nil}. @end deffn @deffn 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 @code{restricted-sexp} widget. @end deffn @deffn Widget variable -Allows you to edit a variable name, with completion. +A widget for editing variable names, offering completion. Its super +is the @code{symbol} widget. @end deffn @deffn 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 +@code{restricted-sexp} widget. + +It has a default @code{:value} of 0. +@end deffn + +@deffn Widget natnum +A widget for editing non-negative integers. Its super is the +@code{restricted-sexp} widget. + +It has a default @code{:value} of 0. +@end deffn + +@deffn Widget float +A widget for editing a floating point number. Its super is the +@code{restricted-sexp} widget. + +It has a default @code{:value} of 0.0. @end deffn @deffn 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 @code{restricted-sexp} widget. + +It has a default @code{:value} of 0.0. @end deffn @deffn Widget boolean -Allows you to edit a boolean. In Lisp this means a variable which is -either @code{nil} meaning false, or non-@code{nil} meaning true. +A widget for editing a boolean value. Its super is the @code{toggle} +widget. + +Its value may be @code{nil}, meaning false, or non-@code{nil}, meaning +true. +@end deffn + +@deffn Widget color +A widget to edit a color name. + +In addition, shows a sample that shows the selected color, if any. @end deffn +@deffn Widget other +A widget useful as the last item in a @code{choice} widget, since it +matches any value. + +Its super is the @code{sexp} widget, and its @code{:value} is +@code{other}, by default. +@end deffn + +@deffn Widget coding-system +A widget that can represent a coding system name, offering +completions. @xref{Coding Systems,,,elisp, the Emacs Lisp Reference +Manual}. Its super is the @code{symbol} widget. + +It has a default value of @code{undecided}. +@end deffn + +@deffn Widget key +A widget to represent a key sequence. + +It uses a special keymap as the @code{:keymap}. +@end deffn @node composite -@section Composite Sexp Widgets +@subsection Composite Sexp Widgets @cindex composite sexp widgets The syntax for the composite widget construct is: @@ -1327,6 +2849,9 @@ where each @var{component} must be a widget type. Each component widget will be displayed in the buffer, and will be editable by the user. @deffn Widget cons +A widget to edit cons-cell values. Its super is the @code{group} +widget. + The value of a @code{cons} widget must be a cons-cell whose @sc{car} and @sc{cdr} have two specified types. It uses this syntax: @@ -1336,8 +2861,10 @@ and @sc{cdr} have two specified types. It uses this syntax: @end deffn @deffn Widget choice -The value matched by a @code{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 @code{menu-choice} widget. + +The widget's syntax is as follows: @example @var{type} ::= (choice [@var{keyword} @var{argument}]... @var{type} ... ) @@ -1345,9 +2872,19 @@ set of types. The widget's syntax is as follows: The value of a @code{choice} widget can be anything that matches any of the @var{types}. + +This widget only displays the widget that corresponds to the current +choice. +@end deffn + +@deffn Widget radio +A widget to hold a value of one of a fixed set of options. Its super is +the @code{radio-button-choice} widget. @end deffn @deffn Widget list +A widget to edit a list value. Its super is the @code{group} widget. + The value of a @code{list} widget must be a list whose element types match the specified component types: @@ -1355,15 +2892,18 @@ match the specified component types: @var{type} ::= (list [@var{keyword} @var{argument}]... @var{component-type}...) @end example -Thus, @code{(list string number)} matches lists of two elements, -the first being a string and the second being a number. +Thus, for example, @code{(list string number)} matches lists of two +elements, the first being a string and the second being a number. @end deffn @deffn Widget vector +A widget to edit a vector value. Its super is the @code{group} +widget. + The @code{vector} widget is like the @code{list} widget but matches -vectors instead of lists. Thus, @code{(vector string number)} matches -vectors of two elements, the first being a string and the second being -a number. +vectors instead of lists. Thus, for example, @code{(vector string +number)} matches vectors of two elements, the first being a string and +the second being a number. @end deffn The above suffice for specifying fixed size lists and vectors. To get @@ -1393,8 +2933,12 @@ trying to explain it here, I'll just suggest you meditate over it for a while. @deffn 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. +A widget to hold a list of members from a fixed set. Its super is the +@code{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: @example @@ -1407,111 +2951,55 @@ Use @code{const} to specify each permitted element, like this: @deffn Widget repeat Specifies a list of any number of elements that fit a certain type. +Its super is the @code{editable-list} widget. @example @var{type} ::= (repeat [@var{keyword} @var{argument}]... @var{type}) @end example @end deffn -@node Widget Properties -@chapter Properties -@cindex properties of widgets -@cindex widget 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-@code{nil} if @var{widget} has a value (even @code{nil}) for -property @var{property}. -@end defun - -@defun widget-apply widget property &rest args -Apply the value of @var{property} to @var{widget}, passing @var{args} -as additional arguments to the function. Return the result of that -function call. -@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. +@deffn Widget plist +A widget to edit property lists. Its super is the @code{list} widget. -@defun widget-type widget -Return the name of @var{widget}, a symbol. -@end defun +It recognizes the following properties: -@cindex active widget -@cindex inactive widget -@cindex activate a widget -@cindex deactivate a 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: +@table @code +@item :options +A given set of recommended key-value values for the @code{plist} +widget. Each option shows up as a checklist item. -@lisp -;; Examine if @var{widget} is active or not. -(if (widget-apply @var{widget} :active) - (message "Widget is active.") - (message "Widget is inactive.") +@item :key-type +The widget type to use for the plist keys. By default, it uses the +@code{symbol} widget. -;; Make @var{widget} inactive. -(widget-apply @var{widget} :deactivate) +@item :value-type +The widget type to use for the plist values. By default, it uses the +@code{sexp} widget. +@end table +@end deffn -;; Make @var{widget} active. -(widget-apply @var{widget} :activate) -@end lisp +@deffn Widget alist +A widget to edit association lists. Its super is the @code{list} +widget. -A widget is inactive if it, 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 it and -all its ancestors. +It recognizes the same properties that the @code{plist} widget, with +the difference that the @code{:key-type} uses by default a @code{sexp} +widget. +@end deffn -@lisp -(while widget - (widget-apply widget :activate) - (setq widget (widget-get widget :parent))) -@end lisp +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 @code{lazy} +widget. -You can check if a widget has been made inactive by examining the value -of the @code{:inactive} keyword. If this is non-@code{nil}, the widget itself -has been deactivated. This is different from using the @code{:active} -keyword, in that the latter tells 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{:deactivate} keywords instead. +@deffn Widget lazy +A base widget for recursive data structures. Its super is the +@code{default} widget. +When instantiated, it contains a single inferior widget of the widget +type specified in the @code{:type} property. Its value is the same as +the value of this inferior widget. +@end deffn @node Defining New Widgets @chapter Defining New Widgets @@ -1520,19 +3008,27 @@ its ancestors have been deactivated. Do not attempt to set the 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 new default values for the keyword -arguments. +component widgets and new default values for the keyword arguments. @defun define-widget name class doc &rest args -Define a new widget type named @var{name} from @code{class}. +Define a new widget type named @var{name} that derives from @var{class}. -@var{name} and class should both be symbols, @code{class} should be one -of the existing widget types. +@var{name} and @var{class} should both be symbols, and @var{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: +@var{args} should be key-value pairs, overriding keyword values of +@var{class}, or adding new recognized keywords for @var{name}. + +Usually, you'll want to derive from an existing widget type, like the +@code{editable-field} widget, or the @code{default} widget, but it's +also possible to derive from nothing, by passing a value of @code{nil} +as @var{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: @itemize @bullet @item @@ -1555,170 +3051,120 @@ in the @code{widget-type} property of @var{name}, which is what If you only 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: +When defining new widgets, the @code{:convert-widget} property might +be useful: + @table @code @vindex convert-widget@r{ keyword} @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 widget's parent types, most derived first. - -The following predefined functions can be used here: - -@defun widget-types-convert-widget widget -Convert @code{:args} as widget types in @var{widget}. -@end defun - -@defun widget-value-convert-widget widget -Initialize @code{:value} from @code{:args} in @var{widget}. -@end defun - -@vindex copy@r{ keyword} -@item :copy -Function to deep copy a widget type. It takes a shallow copy of the -widget type as an argument (made by @code{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: - -@defun widget-types-copy widget -Copy @code{:args} as widget types in @var{widget}. -@end defun +type. -@vindex value-to-internal@r{ keyword} -@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}. - -@vindex value-to-external@r{ keyword} -@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 -external value. - -@vindex create@r{ keyword} -@item :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. - -@vindex delete@r{ keyword} -@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. - -The default value is: +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. -@defun widget-default-delete widget -Remove @var{widget} from the buffer. -Delete all @code{:children} and @code{:buttons} in @var{widget}. -@end defun - -In most cases you should not change this value, but instead use -@code{:value-delete} to make any additional cleanup. - -@vindex value-create@r{ keyword} -@item :value-create -Function to expand the @samp{%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 @code{:children} or @code{:buttons} -to make sure they are automatically deleted. - -@vindex value-delete@r{ keyword} -@item :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 @code{:children} or @code{:buttons}. - -@vindex value-get@r{ keyword} -@item :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: - -@defun widget-value-value-get widget -Return the @code{:value} property of @var{widget}. -@end defun - -@vindex format-handler@r{ keyword} -@item :format-handler -Function to handle unknown @samp{%} escapes in the format string. It -will be called with the widget and the character that follows the -@samp{%} as arguments. You can set this to allow your widget to handle -non-standard escapes. - -@findex widget-default-format-handler -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. - -@vindex action@r{ keyword} -@item :action -Function to handle user initiated events. By default, @code{:notify} -the parent. - -The following predefined function can be used here: - -@defun widget-parent-action widget &optional event -Tell @code{:parent} of @var{widget} to handle the @code{:action}. -Optional @var{event} is the event that triggered the action. -@end defun - -@vindex prompt-value@r{ keyword} -@item :prompt-value -Function to prompt for a value in the minibuffer. The function should -take four arguments, @var{widget}, @var{prompt}, @var{value}, and -@var{unbound} and should return a value for widget entered by the user. -@var{prompt} is the prompt to use. @var{value} is the default value to -use, unless @var{unbound} is non-@code{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. +The predefined functions @code{widget-types-convert-widget} and +@code{widget-value-convert-widget} can be used here. @end table -If you want to define a new widget from scratch, use the @code{default} -widget as its base. - -@deffn Widget default -Widget used as a base for other widgets. +@noindent +Example: -It provides most of the functionality that is referred to as ``by -default'' in this text. -@end deffn +@lisp +@group +(defvar widget-ranged-integer-map + (let ((map (copy-keymap widget-keymap))) + (define-key map [up] #'widget-ranged-integer-increase) + (define-key map [down] #'widget-ranged-integer-decrease) + map)) +@end group + +@group +(define-widget 'ranged-integer 'integer + "A ranged integer widget." + :min-value most-negative-fixnum + :max-value most-positive-fixnum + :keymap widget-ranged-integer-map) +@end group + +@group +(defun widget-ranged-integer-change (widget how) + "Change the value of the ranged-integer WIDGET, according to HOW." + (let* ((value (widget-value widget)) + (newval (cond + ((eq how 'up) + (if (< (1+ value) (widget-get widget :max-value)) + (1+ value) + (widget-get widget :max-value))) + ((eq how 'down) + (if (> (1- value) (widget-get widget :min-value)) + (1- value) + (widget-get widget :min-value))) + (t (error "HOW has a bad value")))) + (inhibit-read-only t)) + (widget-value-set widget newval))) +@end group + +@group +(defun widget-ranged-integer-increase (widget) + "Increase the value of the ranged-integer WIDGET." + (interactive (list (widget-at))) + (widget-ranged-integer-change widget 'up)) +@end group + +@group +(defun widget-ranged-integer-decrease (widget) + "Decrease the value of the ranged-integer WIDGET." + (interactive (list (widget-at))) + (widget-ranged-integer-change widget 'down)) +@end group +@end lisp -@node Widget Browser -@chapter Widget Browser +@node Inspecting Widgets +@chapter Inspecting Widgets @cindex 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 @samp{:parent}, which avoids printing cyclic structures. +There is a separate package to browse widgets, in +@samp{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 +@samp{:parent}, which avoids printing cyclic structures. @deffn Command widget-browse @var{widget} Create a widget browser for @var{widget}. + When called interactively, prompt for @var{widget}. @end deffn @deffn Command widget-browse-other-window @var{widget} Create a widget browser for @var{widget} and show it in another window. + When called interactively, prompt for @var{widget}. @end deffn @deffn Command widget-browse-at @var{pos} Create a widget browser for the widget at @var{pos}. + When called interactively, use the position of point. @end deffn +In addition, there's a function to describe the widget at point. + +@deffn Command widget-describe &optional widget-or-pos +Describe the widget at point. + +When called from Lisp, @var{widget-or-pos} might be the widget to +describe or a buffer position where a widget is present. If +@var{widget-or-pos} is @code{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 @code{:action} and @code{:mouse-down-action} +functions, and provides links to describe it in more detail using the +@code{widget-browse} commands described above. +@end deffn + @node Widget Minor Mode @chapter Widget Minor Mode @cindex widget minor mode @@ -1740,14 +3186,24 @@ Keymap used in @code{widget-minor-mode}. @chapter Utilities @cindex utility functions for widgets +Here we describe some utility functions that don't really have a place +earlier in this manual. + @defun widget-prompt-value widget prompt [ value unbound ] Prompt for a value matching @var{widget}, using @var{prompt}. The current value is assumed to be @var{value}, unless @var{unbound} is non-@code{nil}. + +Converts @var{widget} before prompting, and for prompting it uses the +@code{: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 @code{:match} function. + +If the answer matches the widget, returns the answer. @end defun @defun widget-get-sibling widget -Get the item which @var{widget} is assumed to toggle. +Get the item which @var{widget} should toggle. This is only meaningful for radio buttons or checkboxes in a list. @end defun @@ -1773,6 +3229,142 @@ the form (@var{name} . @var{value}) (i.e., the simplified format), then the return value is the @var{value} of the chosen element. @end defun +@defun widget-image-find image +Create a graphical button from @var{image}, an image or a file name +sans extension. + +If @var{image} is a file name, the file should be in +@code{widget-image-directory}, or in a place where @code{find-image} +will find it. +@end defun + +@defun widget-image-insert widget tag image +As part of @var{widget}, insert the text @var{tag} or, if supported, +the image @var{image}. + +@var{image} should be as described in @code{widget-image-find}. +@end defun + +@defun widget-echo-help pos +Display help-echo text for the widget at @var{pos}. + +Uses the value of @code{:help-echo}. If it is a function, it calls it +to get a string. Otherwise, it @code{eval}s it. +@end defun + +@node Customization +@chapter Customization +This chapter is about the customization options for the Widget +library, for the end user. + +@deffn Face widget-field-face +Face used for other editing fields. +@end deffn + +@deffn Face widget-button-face +Face used for buttons. +@end deffn + +@defopt widget-mouse-face +Face used for highlighting a button when the mouse pointer moves +across it. + +The default value is @code{highlight}. +@end defopt + +@defopt 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 @file{.xpm} (if supported) or @file{.xbm} extension. +@end defopt + +@defopt widget-image-enable +If non-@code{nil}, allow images to appear on displays where they are supported. +@end defopt + +@defopt widget-image-conversion +An alist to convert symbols from image formats to file name suffixes. + +Each element is a cons cell (@var{format} . @var{suffix}), where +@var{format} is a symbol that represents an image format and +@var{suffix} is its correspondent suffix. +@end defopt + +@defopt widget-button-prefix +String to prefix buttons. +@end defopt + +@defopt widget-button-suffix +String to suffix buttons. +@end defopt + +@defopt widget-push-button-prefix +String to prefix push buttons. +@end defopt + +@defopt widget-push-button-suffix +String to suffix push buttons. +@end defopt + +@defopt widget-link-prefix +String to prefix links. +@end defopt + +@defopt widget-link-suffix +String to suffix links. +@end defopt + +@defopt widget-choice-toggle +If non-@code{nil}, toggle when there are just two options. + +By default, its value is @code{nil}. +@end defopt + +@defopt widget-documentation-links +If non-@code{nil}, add hyperlinks to documentation strings. +@end defopt + +@defopt widget-documentation-link-regexp +A regexp that matches potential links in documentation strings. The +link itself should match to the first group. +@end defopt + +@defopt 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-@code{nil} if there should be a link for that string. + +By default, the value is @code{intern-soft}. +@end defopt + +@defopt widget-documentation-link-type +A symbol that represents a widget type to use for links in +documentation strings. + +By default, the value is @code{documentation-link}. +@end defopt + +@defopt 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. +@end defopt + +@defopt 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. +@end defopt + +@defopt widget-menu-minibuffer-flag +Whether to use the minibuffer to ask for a choice. + +If @code{nil}, the default, read a single character. +@end defopt + @node Widget Wishlist @chapter Wishlist @cindex todo @@ -1809,15 +3401,6 @@ Find a way to disable mouse highlight for inactive widgets. Find a way to make glyphs look inactive. @item -Add @code{property-list} widget. - -@item -Add @code{association-list} widget. - -@item -Add @code{key-binding} widget. - -@item Add @code{widget} widget for editing widget specifications. @item |