The Emacs Widget Library 1 Introduction 2 User Interface 2.1 Editable Text Fields 2.2 Buttons 2.3 Navigation 3 Programming Example 4 Widgets Basics 5 Setting Up the Buffer 6 Working with Widgets 7 Widgets and the Buffer 8 Widget Gallery 8.1 Basic Types 8.1.1 The ‘item’ Widget 8.1.2 The ‘link’ Widget 8.1.3 The ‘url-link’ Widget 8.1.4 The ‘info-link’ Widget 8.1.5 The ‘function-link’ Widget 8.1.6 The ‘variable-link’ Widget 8.1.7 The ‘face-link’ Widget 8.1.8 The ‘file-link’ Widget 8.1.9 The ‘emacs-library-link’ Widget 8.1.10 The ‘emacs-commentary-link’ Widget 8.1.11 The ‘push-button’ Widget 8.1.12 The ‘editable-field’ Widget 8.1.13 The ‘text’ Widget 8.1.14 The ‘menu-choice’ Widget 8.1.15 The ‘radio-button-choice’ Widget 8.1.16 The ‘choice-item’ Widget 8.1.17 The ‘toggle’ Widget 8.1.18 The ‘radio-button-toggle’ Widget 8.1.19 The ‘checkbox’ Widget 8.1.20 The ‘checklist’ Widget 8.1.21 The ‘editable-list’ Widget 8.1.22 The ‘group’ Widget 8.1.23 The ‘documentation-string’ Widget 8.2 Sexp Types 8.2.1 The Constant Widgets 8.2.2 Generic Sexp Widget 8.2.3 Atomic Sexp Widgets 8.2.4 Composite Sexp Widgets 9 Defining New Widgets 10 Inspecting Widgets 11 Widget Minor Mode 12 Utilities 13 Customization 14 Wishlist Appendix A GNU Free Documentation License Index The Emacs Widget Library ************************ Copyright © 2000–2023 Free Software Foundation, Inc. Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.3 or any later version published by the Free Software Foundation; with no Invariant Sections, with the Front-Cover Texts being “A GNU Manual”, and with the Back-Cover Texts as in (a) below. A copy of the license is included in the section entitled “GNU Free Documentation License”. (a) The FSF’s Back-Cover Text is: “You have the freedom to copy and modify this GNU manual.” 1 Introduction ************** Most graphical user interface toolkits provide a number of standard user interface controls (sometimes known as “widgets” or “gadgets”). Emacs doesn’t really support anything like this, except for an incredibly powerful text “widget”. On the other hand, Emacs does provide the necessary primitives to implement many other widgets within a text buffer. The ‘widget’ package simplifies this task. The basic widgets are: ‘link’ Areas of text with an associated action. Intended for hypertext links embedded in text. ‘push-button’ Like link, but intended for stand-alone buttons. ‘editable-field’ An editable text field. It can be either variable or fixed length. ‘menu-choice’ Allows the user to choose one of multiple options from a menu, where each option is itself a widget. Only the selected option is visible in the buffer. ‘radio-button-choice’ Allows the user to choose one of multiple options by activating radio buttons. The options are implemented as widgets. All options are visible in the buffer, with the selected one marked as chosen. ‘item’ A simple constant widget intended to be used in the ‘menu-choice’ and ‘radio-button-choice’ widgets. ‘choice-item’ A button item only intended for use in choices. When invoked, the user will be asked to select another option from the choice widget. ‘toggle’ A simple ‘on’/‘off’ switch. ‘checkbox’ A checkbox (‘[ ]’/‘[X]’). ‘editable-list’ Create an editable list. The user can insert or delete items in the list. Each list item is itself a widget. Now, of what possible use can support for widgets be in a text editor? I’m glad you asked. The answer is that widgets are useful for implementing forms. A “form” in Emacs is a buffer where the user is supposed to fill out a number of fields, each of which has a specific meaning. The user is not supposed to change or delete any of the text between the fields. Examples of forms in Emacs are the ‘forms’ package (of course), the customize buffers, the mail and news compose modes, and the HTML form support in the ‘w3’ browser. The advantages for a programmer of using the ‘widget’ package to implement forms are: 1. More complex fields than just editable text are supported. 2. You can give the users immediate feedback if they enter invalid data in a text field, and sometimes prevent entering invalid data. 3. You can have fixed sized fields, thus allowing multiple fields to be lined up in columns. 4. It is simple to query or set the value of a field. 5. Editing happens in the buffer, not in the mini-buffer. 6. Packages using the library get a uniform look, making them easier for the user to learn. 7. As support for embedded graphics improve, the widget library will be extended to use the GUI features. This means that your code using the widget library will also use the new graphic features automatically. 2 User Interface **************** A form consists of read only text for documentation and some fields, where each field contains two parts, a tag and a value. The tags are used to identify the fields, so the documentation can refer to the ‘foo field’, meaning the field tagged with ‘Foo’. Here is an example form: Here is some documentation. Name: My Name *Choose*: This option Address: Some Place In some City Some country. See also _other work_ for more information. Numbers: count to three below [INS] [DEL] One [INS] [DEL] Eh, two? [INS] [DEL] Five! [INS] Select multiple: [X] This [ ] That [X] Thus Select one: (*) One ( ) Another One. ( ) A Final One. [Apply Form] [Reset Form] The top level widgets in this example are tagged ‘Name’, ‘Choose’, ‘Address’, ‘_other work_’, ‘Numbers’, ‘Select multiple’, ‘Select one’, ‘[Apply Form]’, and ‘[Reset Form]’. There are basically two things the user can do within a form, namely editing the editable text fields and activating the buttons. 2.1 Editable Text Fields ======================== In the example, the value for the ‘Name’ is most likely displayed in an editable text field, and so are values for each of the members of the ‘Numbers’ list. All the normal Emacs editing operations are available for editing these fields. The only restriction is that each change you make must be contained within a single editable text field. For example, capitalizing all text from the middle of one field to the middle of another field is prohibited. Editable text fields are created by the ‘editable-field’ widget. The ‘:format’ keyword is useful for generating the necessary text; for instance, if you give it a value of ‘"Name: %v "’, the ‘Name: ’ part will provide the necessary separating text before the field and the trailing space will provide the separating text after the field. If you don’t include the ‘:size’ keyword, the field will extend to the end of the line, and the terminating newline will provide separation after. The editing text fields are highlighted with the ‘widget-field-face’ face, making them easy to find. 2.2 Buttons =========== Some portions of the buffer have an associated “action”, which can be “invoked” by a standard key or mouse command. These portions are called “buttons”. The default commands for activating a button are ‘widget-button-press’ and ‘widget-button-click’. The user typically interacts with the buttons with a key, like , or with the mouse buttons. There are several different kind of buttons, all of which are present in the example: _The Option Field Tags_ When you invoke one of these buttons, you will be asked to choose between a number of different options. This is how you edit an option field. Option fields are created by the ‘menu-choice’ widget. In the example, ‘Choose’ is an option field tag. _The ‘[INS]’ and ‘[DEL]’ buttons_ Activating these will insert or delete elements from an editable list. The list is created by the ‘editable-list’ widget. _Embedded Buttons_ The ‘_other work_’ is an example of an embedded button. Embedded buttons are not associated with any fields, but can serve any purpose, such as implementing hypertext references. They are usually created by the ‘link’ widget. _The ‘[ ]’ and ‘[X]’ buttons_ Activating one of these will convert it to the other. This is useful for implementing multiple-choice fields. You can create them with the ‘checkbox’ widget. _The ‘( )’ and ‘(*)’ buttons_ Only one radio button in a ‘radio-button-choice’ widget can be selected at any time. When you invoke one of the unselected radio buttons, it will be selected and the previous selected radio button will become unselected. _The ‘[Apply Form]’ and ‘[Reset Form]’ buttons_ These are explicit buttons made with the ‘push-button’ widget. The main difference from the ‘link’ widget is that the buttons will be displayed as GUI buttons when possible. To make them easier to locate, buttons are emphasized in the buffer with a distinctive face, like ‘widget-button-face’ or ‘widget-mouse-face’. 2.3 Navigation ============== You can use all the normal Emacs commands to move around in a form buffer, plus you will have these additional commands to navigate from widget to widget: ‘widget-forward’ and ‘widget-backward’. 3 Programming Example ********************* Here is the code to implement the user interface example (*note User Interface::). (require 'widget) (eval-when-compile (require 'wid-edit)) (defvar widget-example-repeat) (defun widget-example () "Create the widgets from the Widget manual." (interactive) (switch-to-buffer "*Widget Example*") (kill-all-local-variables) (make-local-variable 'widget-example-repeat) (let ((inhibit-read-only t)) (erase-buffer)) (remove-overlays) (widget-insert "Here is some documentation.\n\n") (widget-create 'editable-field :size 13 :format "Name: %v " ; Text after the field! "My Name") (widget-create 'menu-choice :tag "Choose" :value "This" :help-echo "Choose me, please!" :notify (lambda (widget &rest ignore) (message "%s is a good choice!" (widget-value widget))) '(item :tag "This option" :value "This") '(choice-item "That option") '(editable-field :menu-tag "No option" "Thus option")) (widget-create 'editable-field :format "Address: %v" "Some Place\nIn some City\nSome country.") (widget-insert "\nSee also ") (widget-create 'link :notify (lambda (&rest ignore) (widget-value-set widget-example-repeat '("En" "To" "Tre")) (widget-setup)) "other work") (widget-insert " for more information.\n\nNumbers: count to three below\n") (setq widget-example-repeat (widget-create 'editable-list :entry-format "%i %d %v" :notify (lambda (widget &rest ignore) (let ((old (widget-get widget ':example-length)) (new (length (widget-value widget)))) (unless (eq old new) (widget-put widget ':example-length new) (message "You can count to %d." new)))) :value '("One" "Eh, two?" "Five!") '(editable-field :value "three"))) (widget-insert "\n\nSelect multiple:\n\n") (widget-create 'checkbox t) (widget-insert " This\n") (widget-create 'checkbox nil) (widget-insert " That\n") (widget-create 'checkbox :notify (lambda (&rest ignore) (message "Tickle")) t) (widget-insert " Thus\n\nSelect one:\n\n") (widget-create 'radio-button-choice :value "One" :notify (lambda (widget &rest ignore) (message "You selected %s" (widget-value widget))) '(item "One") '(item "Another One.") '(item "A Final One.")) (widget-insert "\n") (widget-create 'push-button :notify (lambda (&rest ignore) (if (= (length (widget-value widget-example-repeat)) 3) (message "Congratulation!") (error "Three was the count!"))) "Apply Form") (widget-insert " ") (widget-create 'push-button :notify (lambda (&rest ignore) (widget-example)) "Reset Form") (widget-insert "\n") (use-local-map widget-keymap) (widget-setup)) 4 Widgets Basics **************** The Widget Library deals with widgets objects. A widget object has properties whose value may be anything, be it numbers, strings, symbols, functions, etc. Those properties are referred to as keywords and are responsible for the way a widget is represented in a buffer, and control the way a user or a program can interact with it. The library defines several widget types, and gives you a way to define new types as well. In addition, widgets can derive from other types, creating a sort of widget inheritance. In fact, all widgets defined in the Widget Library share a common parent, the “default” widget. In this manual, when we talk about a default behavior, we usually mean the behavior as defined by this ‘default’ widget. *Note Widget Gallery::, for a description of each defined widget. Defining a new type that derives from a previous one is not mandatory to create widgets that work very different from a specified type. When creating a widget, you can override any default property, including functions, that control the widget. That is, you can specialize a widget on creation, without having to define it as a new type of widget. In addition to the function for defining a widget, this library provides functions to create widgets, query and change its properties, respond to user events and destroy them. The following sections describe them. One important property of a widget is its “value”. All widgets may have a value, which is stored in a so-called “internal format”. For the rest of Emacs, the widget presents its value in a so-called “external format”. Both formats can be equal or different, and each widget is responsible for defining how the conversion between each format should happen. The value property is an important property for almost all widgets, and perhaps more important for ‘editable-field’ widgets. This type of widgets allow the user to edit them via the usual editing commands in Emacs. They can also be edited programmatically. *Important:* You _must_ call ‘widget-setup’ after modifying the value of a widget before the user is allowed to edit the widget again. It is enough to call ‘widget-setup’ once if you modify multiple widgets. This is currently only necessary if the widget contains an editing field, but may be necessary for other widgets in the future. If your application needs to associate some information with the widget objects, for example a reference to the item being edited, it can be done with the ‘widget-put’ and ‘widget-get’ functions. The property names, as shown, are keywords, so they must begin with a ‘:’. 5 Setting Up the Buffer *********************** To show the widgets in a buffer, you have to create them. Widget creation is actually a two-step process: conversion and creation per se. With simple projects, usually the conversion step isn’t really important, and you only care about widget creation, so feel free to skip the conversion description until you really need to know it. Widget conversion is the process that involves taking a widget specification and transforming it into a “widget” object, suitable to be created, queried and manipulated with other widget functions. Widget creation is the process that takes a widget object and actually inserts it in the buffer. The simplest function to create a widget is ‘widget-create’, which gets a widget specification and returns a widget object. -- Function: widget-create type [ keyword argument ]... args Create and return a widget of type TYPE, converting it. TYPE is a symbol that specifies a widget type. KEYWORD may be one of the properties supported by the widget type, and ARGUMENT specify the value for that property. These keyword arguments can be used to overwrite the keyword arguments that are part of TYPE by default, as well as to provide other properties not present in TYPE by default. ARGS holds additional information for the creation of TYPE and each widget type is responsible for handling that information in a specific way. The syntax for the TYPE argument is described in *note Widget Gallery::, and in more detail in every widget where it’s relevant. There are other functions for creating widgets, useful when you work with composite widgets. That is, widgets that are part of other widgets. -- Function: widget-create-child-and-convert parent type &rest args Create a widget of type TYPE as a child of PARENT. Before creating it, converts TYPE using the keyword arguments provided in ARGS. Adds the ‘:indent’ property, unless it is already present, and sets it to the sum of the values of: ‘:indent’ and ‘:offset’ from PARENT and ‘:extra-offset’ from TYPE. Returns a widget object, with the property ‘:parent’ set to PARENT. -- Function: widget-create-child parent type Create a widget of type TYPE as a child of PARENT. This function is like ‘widget-create-child-and-convert’ but it doesn’t convert TYPE, so it expects an already converted widget. -- Function: widget-create-child-value parent type value Create a widget of type TYPE as a child of PARENT with value VALUE. This function is like ‘widget-create-child’, but it lets you specify a value for the widget. Converts VALUE to the internal format, as specified by TYPE, and stores it into the ‘:value’ property of TYPE. That means, VALUE should be in the external format, as specified by TYPE. All these creating functions described here use the function stored in the ‘:create’ property. So, to modify the creation logic for a widget, you can provide a different ‘:create’ function. When you’re done creating widgets and you’re ready for the user to interact with the buffer, use the function ‘widget-setup’. -- Function: widget-setup Setup the current buffer, so that editable widgets can be edited. This should be called after creating all the widgets and before allowing the user to edit them. As mentioned, all these functions return a widget object. That widget object can be queried and manipulated with widget functions that take widgets as arguments, until deleting it with the widgets functions available to delete widgets. Even if you don’t save the returned widget object, you still can interact programmatically with the widget. *Note Working with Widgets::. -- Function: widget-delete widget Delete the widget WIDGET and remove it from the buffer. -- Function: widget-children-value-delete widget Delete all children and buttons in widget WIDGET. This function does not delete WIDGET itself, only the widgets stored in the ‘:children’ and ‘:buttons’ properties. It also sets those properties to ‘nil’. As with the creation mechanism, the function stored in ‘:delete’ controls the deletion mechanism for a widget. Additionally, the library provides a way to make a copy of a widget. -- Function: widget-copy widget Makes a copy of widget WIDGET and returns it. It uses the function stored in the ‘:copy’ property of WIDGET and returns the widget that that function returns. As discussed, there is a conversion step when creating a widget. To do the conversion without actually creating the widget, you can use the ‘widget-convert’ function. -- Function: widget-convert type &rest args Convert TYPE to a widget object, using keyword arguments ARGS. Returns a widget object, suitable for creation. It calls the function stored in the ‘:convert-widget’ property, after putting into the ‘:args’ property the arguments that the widget in question needs. If TYPE has a ‘:value’ property, either originally or after doing the conversion, this function converts the value stored in ‘:value’ to the internal format, and stores it into ‘:value’. Apart from only creating widgets in the buffer, It’s useful to have plain text. For inserting text, the recommended way is with the ‘widget-insert’ function. -- Function: widget-insert &rest args Insert ARGS, either strings or characters, at point. Uses ‘insert’ to perform the insertion, passing ARGS as argument. *Note (elisp)Insertion::, for more information about ARGS. The resulting text will be read-only. 6 Working with Widgets ********************** This section covers the more important functions needed to query and manipulate widgets in a generic way. Widgets may have additional functions for interacting with them, those are described in the description for each widget. *Note Widget Gallery::. -- Function: widgetp widget Non-‘nil’ if WIDGET is a widget. -- Function: widget-type widget Return the type of widget WIDGET, a symbol. This function is useful to find out which kind of widget WIDGET represents, i.e., the name of the widget type when the widget was created. -- Function: widget-member widget property Non-‘nil’ if widget WIDGET has a value (even ‘nil’) for property PROPERTY. -- Function: widget-get widget property For widget WIDGET, return the value of the property PROPERTY. PROPERTY should be a keyword, and the value is what was last set by ‘widget-put’ for PROPERTY. -- Function: widget-put widget property value For widget WIDGET, set the property PROPERTY to VALUE. PROPERTY should be a keyword, while VALUE can be anything. -- Function: widget-at &optional pos Return the widget at position POS, or at point if POS is ‘nil’. -- Function: widget-field-at pos Return the widget field at position POS, or ‘nil’ if there is none. -- Function: widget-apply widget property &rest args Apply the function stored in PROPERTY to WIDGET, passing ARGS as additional arguments to the function. Returns the result of that function call. -- Function: widget-value widget Return the current value contained in WIDGET. Note that the value returned by this function might differ from what’s stored in the ‘:value’ property of WIDGET. This is because this function extracts the current value of WIDGET from the buffer, taking editions into account. The value returned is in the external format, after getting it with the ‘:value-get’ function. It is an error to call this function on an uninitialized widget. -- Function: widget-value-set widget value Set the value contained in WIDGET to VALUE. Converts VALUE to the internal format, and then sets it by applying the ‘:value-set’ function. It is an error to call this function with an invalid VALUE, that is, a value that WIDGET cannot represent. -- Function: widget-default-get widget Return the default external value of widget WIDGET. The default value is the one stored in ‘:value’ or the result of applying the ‘:default-get’ function to the arguments of WIDGET, as stored in ‘:args’. A value of ‘nil’ is ignored by default, so in order for a widget to respect ‘nil’ as a value, it has to override the ‘:default-get’ function. -- Function: widget-type-default-get widget Convert the ‘:type’ attribute in WIDGET and return its default value. -- Function: widget-child-value-get widget Return the value of the first member of ‘:children’ in WIDGET. -- Function: widget-child-value-inline widget Return the inline value of the first member of ‘:children’ in WIDGET. The inline value is whatever the function stored in ‘:value-inline’ returns. -- Function: widget-type-value-create widget Create a child widget for WIDGET, of type stored in ‘:type’. Creates the child widget taking the value from the ‘:value’ property and stores the newly created widget in the ‘:children’ property of WIDGET. The value stored in ‘:type’ should be an unconverted widget type. -- Function: widget-value-convert-widget widget Initializes the ‘:value’ property of WIDGET from ‘:args’. Sets ‘:args’ to ‘nil’ and returns the modified widget WIDGET. -- Function: widget-value-value-get widget Return the value stored in ‘:value’ for widget WIDGET. This is different to getting the current value for WIDGET with ‘widget-value’, since that function extracts the value from the buffer. -- Function: widget-apply-action widget &optional event Apply the function stored in ‘:action’ to WIDGET, in response to EVENT. It is an error to call this function with an inactive widget. -- Function: widget-parent-action widget &optional event Tell ‘:parent’ of WIDGET to handle EVENT. Optional EVENT is the event that triggered the action. -- Function: widget-child-validate widget Check that the first member of ‘:children’ in WIDGET is valid. To be valid means that the widget value passes the checks that the function stored in ‘:validate’ makes. -- Function: widget-children-validate widget Check that all ‘:children’ in WIDGET are valid. Returns ‘nil’ on success, or the first child that isn’t valid. -- Function: widget-type-match widget value Return non-‘nil’ if VALUE matches the value for the ‘:type’ widget. As with the other type functions, the widget stored in ‘:type’ should be an unconverted widget. -- Function: widget-types-copy widget Copy the ‘:args’ value in WIDGET and store them in ‘:args’. Makes the copies by calling ‘widget-copy’ on each element present in ‘:args’. Returns the modified widget WIDGET. -- Function: widget-types-convert-widget widget Convert the ‘:args’ value in WIDGET and store them in ‘args’. Returns the modified widget WIDGET. 7 Widgets and the Buffer ************************ This chapter describes commands that are specific to buffers that contain widgets. -- Const: widget-keymap Keymap containing useful bindings for buffers containing widgets. Binds and ‘C-’ to ‘widget-forward’ and ‘widget-backward’, respectively. It also binds to ‘widget-button-press’ and ‘down-mouse-1’ and ‘down-mouse-2’ to ‘widget-button-click’. There’s also a keymap for events that the widget library doesn’t need to handle. -- Variable: widget-global-map Keymap used by ‘widget-button-press’ and ‘widget-button-click’ when not on a button. By default this is ‘global-map’. In addition to these two keymaps, each widget might define a keymap of its own, active when events happen at that widget. The following navigation commands are available: ‘’ -- Command: widget-forward &optional count Move point COUNT buttons or editing fields forward. ‘M-’ ‘S-’ -- Command: widget-backward &optional count Move point COUNT buttons or editing fields backward. When editing an ‘editable-field’ widget, the following commands are available: ‘’ -- Command: widget-end-of-line Move point to the end of field or end of line, whichever is first. ‘C-k’ -- Command: widget-kill-line Kill to end of field or end of line, whichever is first. ‘M-TAB’ -- Command: widget-complete Complete the content of the editable field at point. ‘C-m’ -- Command: widget-field-activate Invoke the editable field at point. The following two are commands that can execute widget actions. ‘’ -- Command: widget-button-press POS &optional EVENT Invoke the button at POS, defaulting to point. Invocation means to run the function stored in the ‘:action’ property. If point is not located on a button, invoke the binding in ‘widget-global-map’ (by default the global map). ‘mouse-2’ -- Command: widget-button-click EVENT Invoke the button at the location of the mouse pointer. If the mouse pointer is located in an editable text field, invoke the binding in ‘widget-global-map’ (by default the global map). In case the mouse-click is on a widget, calls the function stored in the ‘:mouse-down-action’ property. 8 Widget Gallery **************** All widgets can be created from a type specification. The general syntax of a type specification is: NAME ::= (NAME [KEYWORD ARGUMENT]... ARGS) | NAME Where NAME is a widget name, as defined with ‘define-widget’, KEYWORD is the name of a property and ARGUMENT is the value for that property, and ARGS are interpreted in a widget specific way. *Note Defining New Widgets::. The most basic widget in the Widget Library is the “default” widget. It provides the basic behavior for all other widgets, and all its properties are present by default in derived widgets. You’re seldom (if ever) going to effectively create a default widget, but here we describe its properties and behavior, so that we can describe other widgets only by mentioning the properties and behavior those other widgets specialize. -- Widget: default Widget used as a base for other widgets. It provides most of the functionality that is referred to as “by default” in this text. If you want to define a new widget from scratch, use the ‘default’ widget as its base. The following keyword arguments apply to all widgets: ‘:create’ Function to create a widget from scratch. The function takes one argument, a widget type, and creates a widget of that type, inserts it in the buffer, and returns a widget object. By default, it inserts the widget at point, using the format provided in the ‘:format’ property. ‘:delete’ Function to delete a widget. The function should take one argument, a widget, and should remove all traces of the widget from the buffer. The default value is: -- Function: widget-default-delete widget Remove WIDGET from the buffer. Delete all ‘:children’ and ‘:buttons’ in WIDGET. In most cases you should not change this value, but instead use ‘:value-delete’ to make any additional cleanup. ‘:value’ The initial value for widgets of this type. Typically, a widget represents its value in two formats: external and internal. The external format is the value as the rest of Emacs sees it, and the internal format is a representation that the widget defines and uses in a widget specific way. Both formats might be the same for certain widgets and might differ for others, and there is no guarantee about which format the value stored in the ‘:value’ property has. However, when creating a widget or defining a new one (*note Defining New Widgets::), the ‘:value’ should be in the external format. ‘:value-to-internal’ Function to convert the value to the internal format. The function takes two arguments, a widget and an external value, and returns the internal value. The function is called on the present ‘:value’ when the widget is created, and on any value set later with ‘widget-value-set’. ‘:value-to-external’ Function to convert the value to the external format. The function takes two arguments, a widget and an internal value, and returns the value in the external format. ‘:value-create’ Function to expand the ‘%v’ escape in the format string. It will be called with the widget as its argument and should insert a representation of the widget’s value in the buffer. ‘:value-delete’ A function that should remove the representation of the widget’s value from the buffer. It will be called with the widget as its argument. It doesn’t have to remove the text, but it should release markers and delete nested widgets if these are not listed in ‘:children’ or ‘:buttons’. By default, it’s a no-op. ‘:value-get’ Function to extract the value of a widget, as it is displayed in the buffer. ‘:value-set’ Function that takes a widget and a value as arguments, and recreates it. The value must already be in the internal format for widget. By default, it deletes the widget with the ‘:delete’ function and creates it again with the ‘:create’ function. ‘:value-inline’ Function that takes a widget and returns its value, inlined. Inlined means that if the widget is not inline (i.e., its ‘:inline’ property is ‘nil’), the return value is wrapped in a list. ‘:default-get’ Function that takes a widget and returns its default value. By default, it just returns the value stored in ‘:value’. ‘:format’ This string will be inserted in the buffer when you create a widget. The following ‘%’ escapes are available: ‘%[’ ‘%]’ The text inside will be marked as a button. By default, the text will be shown in ‘widget-button-face’, and surrounded by brackets. ‘%{’ ‘%}’ The text inside will be displayed with the face specified by ‘:sample-face’. ‘%v’ This will be replaced with the buffer representation of the widget’s value. What this is depends on the widget type. ‘%d’ Insert the string specified by ‘:doc’ here. ‘%h’ Like ‘%d’, with the following modifications: If the documentation string is more than one line, it will add a button which will toggle between showing only the first line, and showing the full text. Furthermore, if there is no ‘:doc’ property in the widget, it will instead examine the ‘:documentation-property’ property. If it is a lambda expression, it will be called with the widget’s value as an argument, and the result will be used as the documentation text. ‘%t’ Insert the string specified by ‘:tag’ here, or the ‘princ’ representation of the value if there is no tag. ‘%%’ Insert a literal ‘%’. ‘:button-face’ Face used to highlight text inside %[ %] in the format. ‘:button-prefix’ ‘:button-suffix’ Strings used as prefix and suffix for widgets that are buttons. By default, the values are ‘widget-button-prefix’ and ‘widget-button-suffix’. Text around %[ %] in the format. These can be _nil_ No text is inserted. _a string_ The string is inserted literally. _a symbol_ The value of the symbol is expanded according to this table. ‘:doc’ The string inserted by the ‘%d’ escape in the format string. ‘:tag’ The string inserted by the ‘%t’ escape in the format string. ‘:tag-glyph’ Name of image to use instead of the string specified by ‘:tag’ on Emacsen that supports it. ‘:help-echo’ Specifies how to display a message whenever you move to the widget with either ‘widget-forward’ or ‘widget-backward’ or move the mouse over it (using the standard ‘help-echo’ mechanism). The value is either a string to display, or a function of one argument, the widget. If a function, it should return a string to display, or a form that evaluates to such a string. ‘:follow-link’ Specifies how to interpret a click on the widget. *Note Defining Clickable Text: (elisp)Clickable Text. ‘:indent’ An integer indicating the absolute number of spaces to indent children of this widget. Its value might be ‘nil’ too, which corresponds to a value of 0. The default ‘:create’ functions and the functions that create the value per se use this property as a rudimentary layout mechanism for the widgets. ‘:offset’ An integer indicating how many extra spaces to add to the widget’s grandchildren compared to this widget. ‘:extra-offset’ An integer indicating how many extra spaces to add to the widget’s children compared to this widget. ‘:menu-tag’ Tag used in the menu when the widget is used as an option in a ‘menu-choice’ widget. ‘:menu-tag-get’ Function that takes a widget and returns the tag when the widget is used as an option in a ‘menu-choice’ widget. By default, the tag used will be either the ‘:menu-tag’ or ‘:tag’ property if present, or the ‘princ’ representation of the ‘:value’ property if not. ‘:match’ Should be a function called with two arguments, the widget and an external value, and should return non-‘nil’ if the widget can represent the specified value. ‘:validate’ A function which takes a widget as an argument, and returns ‘nil’ if the widget’s current value is valid for the widget. Otherwise, it should return the widget containing the invalid data, and set that widget’s ‘:error’ property to a string explaining the error. By default, it always returns ‘nil’. ‘:tab-order’ Specify the order in which widgets are traversed with ‘widget-forward’ or ‘widget-backward’. This is only partially implemented. a. Widgets with tabbing order ‘-1’ are ignored. b. (Unimplemented) When on a widget with tabbing order N, go to the next widget in the buffer with tabbing order N+1 or ‘nil’, whichever comes first. c. When on a widget with no tabbing order specified, go to the next widget in the buffer with a positive tabbing order, or ‘nil’ ‘:parent’ The parent of a nested widget (e.g., a ‘menu-choice’ item or an element of a ‘editable-list’ widget). ‘:sibling-args’ This keyword is only used for members of a ‘radio-button-choice’ or ‘checklist’. The value should be a list of extra keyword arguments, which will be used when creating the ‘radio-button’ or ‘checkbox’ associated with this item. ‘:completions-function’ Function that takes a widget and returns completion data for that widget, like ‘completion-at-point-functions’ would. *Note (elisp)Completion::. It’s used by ‘editable-field’ widgets to provide completions. By default, it looks into the property ‘:completions’, which should be a completion table. If ‘:completions’ is ‘nil’, then it calls the function stored either in the ‘:complete’ or ‘:complete-function’ property. ‘:format-handler’ Function to handle unknown ‘%’ escapes in the format string. It takes a widget and the character that follows the ‘%’ as arguments. You can set this to allow your widget to handle non-standard escapes in your own specialized widgets. You should end up calling ‘widget-default-format-handler’ to handle unknown escape sequences, which will handle the ‘%h’ and any future escape sequences, as well as give an error for unknown escapes. ‘:button-face-get’ Function to return the face used to fontify a widget button. Takes a widget and returns an appropriate face for the widget. By default, it either returns the face stored in the ‘:button-face’ property, or calls the ‘:button-face-get’ function from the parent of the widget, if it has one. ‘:mouse-face-get’ Function to return the face used to fontify a widget when the mouse pointer hovers over it. Takes a widget and returns an appropriate face. By default, it either returns the face stored in the ‘:mouse-face’ property, or calls the ‘:button-face-get’ function from the parent of the widget, if it has one. ‘:copy’ Function to deep copy a widget type. It takes a shallow copy of the widget type as an argument (made by ‘copy-sequence’), and returns a deep copy. The purpose of this is to avoid having different instances of combined widgets share nested attributes. Its value by default is ‘identity’. ‘:active’ Function that takes a widget and returns ‘t’ if it is active. A widget might be effectively always active, if its ‘:always-active’ property is ‘t’. Widgets can be in two states: active, which means they are modifiable by the user, or inactive, which means they cannot be modified by the user. You can query or set the state with the following code: ;; Examine if WIDGET is active or not. (if (widget-apply WIDGET :active) (message "Widget is active.") (message "Widget is inactive.") ;; Make WIDGET inactive. (widget-apply WIDGET :deactivate) ;; Make WIDGET active. (widget-apply WIDGET :activate) A widget is inactive if it, or any of its ancestors (found by following the ‘:parent’ link), have been deactivated. To make sure a widget is really active, you must therefore activate both it and all its ancestors. (while widget (widget-apply widget :activate) (setq widget (widget-get widget :parent))) You can check if a widget has been made inactive by examining the value of the ‘:inactive’ keyword. If this is non-‘nil’, the widget itself has been deactivated. This is different from using the ‘:active’ keyword, in that the latter tells you if the widget *or* any of its ancestors have been deactivated. Do not attempt to set the ‘:inactive’ keyword directly. Use the ‘:activate’ ‘:deactivate’ functions instead. ‘:activate’ Function that takes a widget and makes it active for user modifications. ‘:deactivate’ Function that takes a widget and makes it inactive for user modifications. ‘:action’ Function that takes a widget and optionally an event, and handles a user initiated event. By default, uses the ‘:notify’ function to notify the widget’s parent about the event. ‘:mouse-down-action’ Function that takes a widget and optionally an event, and handles a mouse click on the widget. By default, it does nothing. ‘:notify’ A function called each time the widget or a nested widget is changed. The function is called with two or three arguments. The first argument is the widget itself, the second argument is the widget that was changed, and the third argument is the event leading to the change, if any. By default, it passes the notification to the widget’s parent. ‘:prompt-value’ Function to prompt for a value in the minibuffer. The function should take four arguments, a widget, a prompt (a string), a value and a boolean, and should return a value for the widget, entered by the user. The prompt is the prompt to use. The value is the default value to use, unless the fourtha argument is non-‘nil’, in which case there is no default value. The function should read the value using the method most natural for this widget, and does not have to check that it matches. 8.1 Basic Types =============== 8.1.1 The ‘item’ Widget ----------------------- Syntax: TYPE ::= (item [KEYWORD ARGUMENT]... VALUE) A useful widget that holds a constant value, and can be included in other widgets. Its super is the ‘default’ widget. As can be seen in the syntax, the ‘item’ widget is one of the widget that handles the ARGS argument to ‘widget-create’ in a specific way. If present, VALUE is used to initialize the ‘:value’ property. When created, it inserts the value as a string in the buffer. By default, it has the following properties: ‘:convert-widget’ The function that allows it to handle VALUE. ‘:value-create’ Prints the representation of ‘:value’ in the buffer. ‘:value-get’ Returns the value stored in ‘:value’. ‘:match’ A value matches the ‘item’ widget if it’s ‘equal’ to its ‘:value’. ‘:match-inline’ Inline values match the ‘item’ widget if ‘:value’ is a sublist of values. ‘:action’ The ‘item’ widget notifies itself of an event. ‘:format’ By default, the ‘item’ widget inserts its tag in the buffer. 8.1.2 The ‘link’ Widget ----------------------- Syntax: TYPE ::= (link [KEYWORD ARGUMENT]... [ VALUE ]) A widget to represent an embedded link. Its super is the ‘item’ widget. The VALUE, if present, is used to initialize the ‘:value’ property. The value should be a string, which will be inserted in the buffer. By default, it has the following properties: ‘:button-prefix’ The value of ‘widget-link-prefix’. ‘:button-suffix’ The value of ‘widget-link-suffix’. ‘:keymap’ A custom keymap for the link widget, so that it can respond to mouse clicks. ‘:follow-link’ This property allows the link to respect the value of ‘mouse-1-click-follows-link’. *Note (elisp)Clickable Text::. ‘:format’ Buttonizes the link, to make it clickable. If you override this property, you should make sure to provide the ‘%[’ and ‘%]’ escape sequences, so that the link is clickable. By default the link will be shown in brackets. 8.1.3 The ‘url-link’ Widget --------------------------- Syntax: TYPE ::= (url-link [KEYWORD ARGUMENT]... URL) A widget to represent a link to a web page. Its super is the ‘link’ widget. It overrides the ‘:action’ property to open up the URL specified. 8.1.4 The ‘info-link’ Widget ---------------------------- Syntax: TYPE ::= (info-link [KEYWORD ARGUMENT]... ADDRESS) A widget to represent a link to an info file. Its super is the ‘link’ widget. It overrides the ‘:action’ property, to a function to start the built-in Info reader on ADDRESS, when invoked. 8.1.5 The ‘function-link’ Widget -------------------------------- Syntax: TYPE ::= (function-link [KEYWORD ARGUMENT]... FUNCTION) A widget to represent a link to an Emacs function. Its super is the ‘link’ widget. It overrides the ‘:action’ property, to a function to describe FUNCTION. 8.1.6 The ‘variable-link’ Widget -------------------------------- Syntax: TYPE ::= (variable-link [KEYWORD ARGUMENT]... VAR) A widget to represent a link to an Emacs variable. Its super is the ‘link’ widget. It overrides the ‘:action’ property, to a function to describe VAR. 8.1.7 The ‘face-link’ Widget ---------------------------- Syntax: TYPE ::= (face-link [KEYWORD ARGUMENT]... FACE) A widget to represent a link to an Emacs face. Its super is the ‘link’ widget. It overrides the ‘:action’ property, to a function to describe FACE. 8.1.8 The ‘file-link’ Widget ---------------------------- Syntax: TYPE ::= (file-link [KEYWORD ARGUMENT]... FILE) A widget to represent a link to a file. Its super is the ‘link’ widget. It overrides the ‘:action’ property, to a function to find the file FILE. 8.1.9 The ‘emacs-library-link’ Widget ------------------------------------- Syntax: TYPE ::= (emacs-library-link [KEYWORD ARGUMENT]... FILE) A widget to represent a link to an Emacs Lisp file. Its super is the ‘link’ widget. It overrides the ‘:action’ property, to a function to find the file FILE. 8.1.10 The ‘emacs-commentary-link’ Widget ----------------------------------------- Syntax: TYPE ::= (emacs-commentary-link [KEYWORD ARGUMENT]... FILE) A widget to represent a link to the Comment section of an Emacs Lisp file. Its super is the ‘link’ widget. It overrides the ‘:action’ property, to a function to find the file FILE and put point in the Comment section. 8.1.11 The ‘push-button’ Widget ------------------------------- Syntax: TYPE ::= (push-button [KEYWORD ARGUMENT]... [ VALUE ]) A widget that acts as a pushable button. Its super is the ‘item’ widget. The VALUE, if present, is used to initialize the ‘:value’ property. The value should be a string, which will be inserted in the buffer. By default, it has the following properties: ‘:button-prefix’ The empty string. ‘:button-suffix’ The empty string. ‘:value-create’ Inserts a representation of the “on” and “off” states for the push button. The representation might be an image, stored in the ‘:tag-glyph’ property, or text. If it is text, it might be the value of the ‘:tag’ property, or the ‘:value’ of the widget, surrounded with ‘widget-push-button-prefix’ and ‘widget-push-button-suffix’. *Note Customization::. ‘:format’ Buttonizes the widget, to make it clickable. 8.1.12 The ‘editable-field’ Widget ---------------------------------- Syntax: TYPE ::= (editable-field [KEYWORD ARGUMENT]... [ VALUE ]) A widget that can be edited by the user. Its super is the ‘default’ widget. The VALUE, if present, is used to initialize the ‘:value’ property. The value should be a string, which will be inserted in the field. If not present, ‘:value’ is the empty string. *Warning:* In an ‘editable-field’ widget, the editable field must not be adjacent to another widget—that won’t work. You must put some text in between. Either make this text part of the ‘editable-field’ widget itself, or insert it with ‘widget-insert’. This widget either overrides or adds the following properties: ‘:convert-widget’ Just like the ‘item’ widget, this function allows it to initialize ‘:value’ from VALUE. ‘:keymap’ Keymap used in the editable field. The default value is ‘widget-field-keymap’, which allows the user to use all the normal editing commands, even if the buffer’s major mode suppresses some of them. Pressing invokes the function specified by ‘:action’. ‘:format’ By default, it specifies to insert only the widget’s value. *Warning:* In an ‘editable-field’ widget, the ‘%v’ escape must be preceded by some other text in the ‘:format’ string (if specified). ‘:size’ The width of the editable field. By default the field will reach to the end of the line. ‘:value-face’ Face used for highlighting the editable field. Default is ‘widget-field-face’, *note User Interface::. ‘:secret’ Character used to display the value. You can set this to, e.g., ‘?*’ if the field contains a password or other secret information. By default, this is ‘nil’, and the value is not secret. ‘:valid-regexp’ By default the ‘:validate’ function will match the content of the field with the value of this attribute. The default value is ‘""’ which matches everything. ‘:validate’ Returns ‘nil’ if the current value of the widget matches the ‘:valid-regexp’ value. ‘:prompt-internal’ A function to read a value for widget, used by the ‘:prompt-value’ function. ‘:prompt-history’ A variable that holds the history of field minibuffer edits. ‘:prompt-value’ A function that uses the ‘:prompt-internal’ function and the ‘:prompt-history’ value to prompt for a string, and retun the user response in the external format. ‘:action’ When invoked, moves point to the next field. ‘:value-create’ Function that takes care of creating the widget, respecting its ‘:size’ and ‘:value’. ‘:value-set’ Function to use to modify programatically the current value of the widget. ‘:value-delete’ Function that removes the widget so it cannot be edited anymore. ‘:value-get’ Function to return the current text in the widget. It takes an optional argument, NO-TRUNCATE. If NO-TRUNCATE is nil, truncates trailing spaces. ‘:match’ Function that makes the widget match any string value. 8.1.13 The ‘text’ Widget ------------------------ Syntax: TYPE ::= (text [KEYWORD ARGUMENT]... [ VALUE ]) A widget just like the ‘editable-field’ widget, but intended for multiline text fields. Its super is the ‘editable-field’ widget. It overrides the following properties: ‘:format’ By default, prints a tag and the value. ‘:keymap’ The default is ‘widget-text-keymap’, which does not rebind the key. 8.1.14 The ‘menu-choice’ Widget ------------------------------- Syntax: TYPE ::= (menu-choice [KEYWORD ARGUMENT]... TYPE ... ) A widget to represent a menu of options. Its super is the ‘default’ widget. The TYPE argument represents each possible choice. The widget’s value will be that of the chosen TYPE argument. It either overrides or adds the following properties: ‘:convert-widget’ A function that takes care of converting each possible choice. ‘:copy’ A function to copy each possible choice. ‘:format’ By default, buttonize the tag and show the value. ‘:void’ Widget type used as a fallback when the value does not match any of the specified TYPE arguments. By default this is an ‘item’ widget. ‘:case-fold’ If ‘nil’ don’t ignore case when prompting for a choice through the minibuffer. By default, its value is ‘t’. ‘:children’ A list whose CAR is the widget representing the currently chosen type in the buffer. ‘:choice’ The current chosen type. ‘:args’ The list of types. ‘:value-create’ The function that inserts the current value for the widget. It inserts the first choice that matches, as with the ‘:match’ function, the value of the widget. ‘:value-get’ Returns the value of the first child for the widget (see the description for ‘:children’ above). ‘:value-inline’ Returns the inline value of the first child for the widget. ‘:default-get’ The default value for this widget is the default value for the first choice, in case ‘:value’ is missing. This means that if you want a specific default value for the ‘menu-choice’ widget, you should either pass a ‘:value’ property when creating it, or arrange the choices so that the first one can hold your desired default value. ‘:mouse-down-action’ A function that takes care of showing a menu, if possible and desired. ‘:action’ A function that takes care of getting a new choice for the widget. Depending on the number of choices available, it may show a menu or just toggle the choices, or even do nothing at all. After getting the choice, it recreates the widget and notifies it. ‘:validate’ Returns ‘nil’ if the widget’s value is a valid choice. ‘:match’ This widget will match any value matching at least one of the specified TYPE arguments. ‘:match-inline’ A function that returns non-‘nil’ if the values match the widget, taking into account the ‘:inline’ property. 8.1.15 The ‘radio-button-choice’ Widget --------------------------------------- Syntax: TYPE ::= (radio-button-choice [KEYWORD ARGUMENT]... TYPE ... ) A widget to represent a choice from multiple options. Its super is the ‘default’ widget. The component TYPES specify the choices, with one radio button for each. The widget’s value will be that of the chosen TYPE argument. It overrides the following properties: ‘:convert-widget’ As other composite widgets, a function that takes care of converting each available choice. ‘:copy’ A function to copy each available choice. ‘:action’ A function that checks if any radio button was pressed and activates the pressed one, possibly deactivating an old one. Then, it notifies itself. ‘:entry-format’ This string will be inserted for each entry in the list. The following ‘%’ escapes are available: ‘%v’ Replace with the buffer representation of the TYPE widget. ‘%b’ Replace with the radio button. ‘%%’ Insert a literal ‘%’. ‘:format’ By default, it inserts its value. ‘:button-args’ A list of keywords to pass to the radio buttons. Useful for setting, e.g., the ‘:help-echo’ for each button. ‘:buttons’ The widgets representing the radio buttons. ‘:children’ The widgets representing each type. ‘:choice’ The current chosen type. ‘:args’ The list of types. ‘:value-create’ A function to insert all available choices. ‘:value-get’ Returns the value for the chosen widget. ‘:value-set’ A function to set the value to one of its available options. ‘:value-inline’ A function that returns the inline value of the child widget. ‘:offset’ By default, this widget has an offset of 4. ‘:validate’ The widget validates if the current value is valid for one of its children. ‘:match’ This widget matches any value that matches at least one of the specified TYPE arguments. ‘:match-inline’ Like the ‘:match’ function, but taking into account inline values. You can add extra radio button items to a ‘radio-button-choice’ widget after it has been created with the function ‘widget-radio-add-item’. -- Function: widget-radio-add-item widget type Add to ‘radio-button-choice’ widget WIDGET a new radio button item of type TYPE. Please note that such items added after the ‘radio-button-choice’ widget has been created will *not* be properly destructed when you call ‘widget-delete’. 8.1.16 The ‘choice-item’ Widget ------------------------------- Syntax: ITEM ::= (choice-item [KEYWORD ARGUMENT]... VALUE) A widget to represent a choice in a ‘menu-choice’ widget. Its super is the ‘item’ widget. The VALUE, if present, is used to initialize the ‘:value’ property. It overrides the following properties: ‘:action’ Activating the button of a ‘choice-item’ is equivalent to activating the parent widget. ‘:format’ By default, it buttonizes the tag (i.e., its value) and adds a newline character at the end of the widget. 8.1.17 The ‘toggle’ Widget -------------------------- Syntax: TYPE ::= (toggle [KEYWORD ARGUMENT]...) A widget that can toggle between two states. Its super is the ‘item’ widget. The widget has two possible states, ‘on’ and ‘off’, which correspond to a ‘t’ or ‘nil’ value, respectively. It either overrides or adds the following properties: ‘:format’ By default, it buttonizes the value and adds a newline at the end of the widget. ‘:on’ A string representing the ‘on’ state. By default the string ‘on’. ‘:off’ A string representing the ‘off’ state. By default the string ‘off’. ‘:on-glyph’ Name of a glyph to be used instead of the ‘:on’ text string, on emacsen that supports this. ‘:off-glyph’ Name of a glyph to be used instead of the ‘:off’ text string, on emacsen that supports this. ‘:value-create’ A function for creating the widget’s value, according to its ‘:on’ or ‘:off’ state. ‘:action’ Function to toggle the state of the widget. After toggling, it notifies itself. ‘:match’ This widget matches anything. 8.1.18 The ‘radio-button-toggle’ Widget --------------------------------------- Syntax: TYPE ::= (radio-button-toggle [KEYWORD ARGUMENT]...) A toggle to use in the ‘radio’ widget. It overrides the following properties: ‘:button-prefix’ The empty string. ‘:button-suffix’ The empty string. ‘:on’ The string “(*)”, to represent the ‘on’ state. ‘:off’ The string “( )”, to represent the ‘off’ state. ‘:on-glyph’ The name of an image to represent the ‘on’ state. ‘:off-glpyh’ The name of an image to represent the ‘off’ state. ‘:format’ By default, it buttonizes its value. ‘:notify’ A function to notify its parent. 8.1.19 The ‘checkbox’ Widget ---------------------------- Syntax: TYPE ::= (checkbox [KEYWORD ARGUMENT]...) A widget to represent a toggle widget, with a checkbox. Its super is the ‘toggle’ widget. This widget has two possible states, ‘selected’ and ‘unselected’, which corresponds to a ‘t’ or ‘nil’ value, respectively. It either overrides or adds the following properties: ‘:button-prefix’ The empty string. ‘:button-suffix’ The empty string. ‘:format’ By default, buttonizes the value. ‘:on’ By default, the string “[X]”. ‘:off’ By default, the string “[ ]”. ‘:on-glyph’ The name of the image to use when the state is ‘on’. ‘:off-glyph’ The name of the image to use when the state is ‘off’. ‘:action’ A function that toggles the checkbox, notifies the parents and in the ‘on’ state, activates its siblings. 8.1.20 The ‘checklist’ Widget ----------------------------- Syntax: TYPE ::= (checklist [KEYWORD ARGUMENT]... TYPE ... ) A widget to represent a multiplice choice. Its super is the ‘default’ widget. The TYPE arguments represent each checklist item. The widget’s value will be a list containing the values of all checked TYPE arguments. It either overrides or adds the following properties: ‘:convert-widget’ As other composite widgets, a function that takes care of converting each checklist item. ‘:copy’ A function to copy each checklist item. ‘:format’ By default, it inserts its value. ‘:entry-format’ This string will be inserted for each entry in the list. The following ‘%’ escapes are available: ‘%v’ Replaced with the buffer representation of the TYPE widget. ‘%b’ Replace with the checkbox. ‘%%’ Insert a literal ‘%’. ‘:button-args’ A list of keywords to pass to the checkboxes. Useful for setting, e.g., the ‘:help-echo’ for each checkbox. ‘:buttons’ The widgets representing the checkboxes. ‘:children’ The widgets representing each type. ‘:args’ The list of types. ‘:value-create’ The function that takes care of inserting all values. ‘:value-get’ A function that returns all values of selected items. ‘:validate’ A function that ensures all selected children are valid. ‘:match’ The checklist widget will match a list whose elements all match at least one of the specified TYPE arguments. ‘:match-inline’ Like the ‘:match’ function, but taking into account the ‘:inline’ property. ‘:greedy’ Usually a checklist will only match if the items are in the exact sequence given in the specification. By setting ‘:greedy’ to non-‘nil’, it will allow the items to come in any sequence. However, if you extract the value they will be in the sequence given in the checklist, i.e., the original sequence is forgotten. 8.1.21 The ‘editable-list’ Widget --------------------------------- Syntax: TYPE ::= (editable-list [KEYWORD ARGUMENT]... TYPE) A widget that can hold a variable list of widgets of the same type, represented by TYPE. Its super is the ‘default’ widget. It either overrides or adds the following properties: ‘:convert-widget’ As other composite widgets, a function that takes care of converting each type in TYPE. ‘:copy’ A function to copy the types given in TYPE. ‘:entry-format’ This string will be inserted for each entry in the list. The following ‘%’ escapes are available: ‘%v’ This will be replaced with the buffer representation of the TYPE widget. ‘%i’ Insert the [INS] button, a widget of type ‘insert-button’. ‘%d’ Insert the [DEL] button, a widget of type ‘delete-button’. ‘%%’ Insert a literal ‘%’. ‘:insert-button-args’ A list of keyword arguments to pass to the insert buttons. ‘:delete-button-args’ A list of keyword arguments to pass to the delete buttons. ‘:append-button-args’ A list of keyword arguments to pass to the trailing insert button. ‘:buttons’ The widgets representing the insert and delete buttons. ‘:format’ By default, insert its value and at the and adds an insert button. This is useful so that new elements can be added to the list upon user request. ‘:format-handler’ A function that recognize the escape for inserting an insert button. ‘:offset’ By default, this widget has an offset of 12. ‘:children’ The widgets representing the elements of the list. ‘:args’ List whose CAR is the type of the list elements. ‘:insert-before’ Function to insert a new widget as a child of the ‘editable-list’ widget. This function inserts a recently deleted child, if there is one. That is useful, so that the user can move elements in a list easily. If there is not a recently deleted child, it inserts a child with its default value. ‘:delete-at’ Function to delete a child from the widget, and store it into the ‘:last-deleted’ list, so that it can be reinserted when the ‘:insert-before’ function executes. ‘:value-create’ The function that takes care of inserting all values. ‘:value-get’ Function that returns a list with the value of the child widgets. ‘:validate’ This widget validates if all children validate. ‘:match’ To match, the value must be a list and all the list members must match the specified TYPE. ‘:match-inline’ Like the ‘:match’ function, but taking into account inline values and widgets. 8.1.22 The ‘group’ Widget ------------------------- Syntax: TYPE ::= (group [KEYWORD ARGUMENT]... TYPE...) A widget to group other widgets. Its super is the ‘default’ widget. Its value is a list, with one member for each TYPE. It overrides the following properties: ‘:convert-widget’ As other composite widgets, a function that takes care of converting each widget in TYPE. ‘:copy’ A function to copy the types given in TYPE. ‘:format’ By default, displays a newline character and its value. ‘:value-create’ A function to create each of its components. ‘:value-get’ The same function used by the ‘editable-list’ widget. ‘:default-get’ A function that returns a list whose members are the default values of each widget it groups. ‘:validate’ This widget validates if all of its children validate. ‘:match’ This widget matches a value that matches each of its components. ‘:match-inline’ As ‘:match’, but taking into account widgets and values that are inline. 8.1.23 The ‘documentation-string’ Widget ---------------------------------------- Syntax: TYPE ::= (documentation-string [KEYWORD ARGUMENT]... VALUE) A widget to represent a documentation string. Its super is the ‘item’ widget. It either overrides or adds the following properties: ‘:format’ By default, insert its value. ‘:value-create’ Function to insert a documentation string, possibly hiding part of the documentation if its large. To show or hide the rest of the documentation, uses a ‘visibility’ widget. ‘:action’ Function to toggle showing the documentation upon an event. ‘:visibility-widget’ A symbol, the type of the widget to use for the visibility widget. This is, by default, the symbol ‘visibility’. 8.2 Sexp Types ============== A number of widgets for editing “s-expressions” (Lisp types), sexp for short, are also available. These basically fall in several categories described in this section. 8.2.1 The Constant Widgets -------------------------- The ‘const’ widget can contain any Lisp expression, but the user is prohibited from editing it, which is mainly useful as a component of one of the composite widgets. The syntax for the ‘const’ widget is: TYPE ::= (const [KEYWORD ARGUMENT]... [ VALUE ]) Its super is the ‘item’ widget. The VALUE, if present, is used to initialize the ‘:value’ property and can be any s-expression. -- Widget: const This will display any valid s-expression in an immutable part of the buffer. It overrides the ‘:prompt-value’ function, to avoid prompting and just return the widget’s value. There are two variations of the ‘const’ widget, namely ‘variable-item’ and ‘function-item’. These should contain a symbol with a variable or function binding, respectively. The major difference from the ‘const’ widget is that they will allow the user to see the variable or function documentation for the symbol. This is accomplished via using the ‘%h’ format escape, and adding an appropiate ‘:documentation-property’ function for each widget. -- Widget: variable-item An immutable symbol that is bound as a variable. -- Widget: function-item An immutable symbol that is bound as a function. 8.2.2 Generic Sexp Widget ------------------------- The ‘sexp’ widget can contain any Lisp expression, and allows the user to edit it inline in the buffer. The syntax for the ‘sexp’ widget is: TYPE ::= (sexp [KEYWORD ARGUMENT]... [ VALUE ]) -- Widget: sexp This widget represents an editable field that’s useful to edit any valid s-expression. The ‘sexp’ widget takes the same keyword arguments as the ‘editable-field’ widget. *Note editable-field::. Its default value is ‘nil’. -- Widget: restricted-sexp A widget to edit Lisp expressions restricted to certain values or types. Its super is the ‘sexp’ widget. It works just like the sexp widget, but it overrides the ‘:match’ function to match for certain values. To use this widget, either you must define a ‘:match’ function or give a ‘:match-alternatives’ property. The ‘:match-alternatives’ property holds a list of predicate functions to call when checking if a given value matches the widget. Each predicate function will be called with one argument, the value to be matched, and should return non-‘nil’ on success. As an example, the ‘integer’ widget overrides ‘:match-alternatives’ to ‘(integerp)’. 8.2.3 Atomic Sexp Widgets ------------------------- The atoms are s-expressions that do not consist of other s-expressions. For example, a string, a file name, or a symbol are atoms, while a list is a composite type. You can edit the value of an atom with the widgets described in this section. The syntax for all the atoms is: TYPE ::= (CONSTRUCT [KEYWORD ARGUMENT]... [ VALUE ]) The VALUE, if present, is used to initialize the ‘:value’ property and must be an expression of the same type as the widget. That is, for example, the string widget can only be initialized with a string. All the atom widgets take the same keyword arguments as the ‘editable-field’ widget. *Note editable-field::. -- Widget: string An editable field widget that can represent any Lisp string. It offers completion via the ispell library and the ‘:complete’ property. -- Widget: regexp An editable field widget that can represent a regular expression. Overrides the ‘:match’ and the ‘:validate’ properties to check that the value is a valid regexp. -- Widget: character An editable field widget that can represent a character. The character widget represents some characters (like the newline character) in a special manner, to make it easier for the user to see what’s the content of the character field. -- Widget: file A widget for editing file names. Keywords: ‘:completions’ Offers file name completion to the user. ‘:prompt-value’ A function to read a file name from the minibuffer. ‘:must-match’ If this is set to non-‘nil’, only existing file names are allowed when prompting for a value in the minibuffer. ‘:match’ The widget matches if the value is a string, and the file whose name is that string is an existing file, or if ‘:must-match’ is ‘nil’. ‘:validate’ The widget is valid if its value matches. -- Widget: directory A widget for editing directory names. Its super is the ‘file’ widget, and it overrides the ‘:completions’ property, to offer completions only for directories. -- Widget: symbol A widget for editing a Lisp symbol. Its value by default is ‘nil’. -- Widget: function A widget for editing a lambda expression, or a function name, offering completion. Its super is the ‘restricted-sexp’ widget. -- Widget: variable A widget for editing variable names, offering completion. Its super is the ‘symbol’ widget. -- Widget: integer A widget for editing integers in an editable field. Its super is the ‘restricted-sexp’ widget. It has a default ‘:value’ of 0. -- Widget: natnum A widget for editing non-negative integers. Its super is the ‘restricted-sexp’ widget. It has a default ‘:value’ of 0. -- Widget: float A widget for editing a floating point number. Its super is the ‘restricted-sexp’ widget. It has a default ‘:value’ of 0.0. -- Widget: number A widget for editing a number, either floating point or integer. Its super is the ‘restricted-sexp’ widget. It has a default ‘:value’ of 0.0. -- Widget: boolean A widget for editing a boolean value. Its super is the ‘toggle’ widget. Its value may be ‘nil’, meaning false, or non-‘nil’, meaning true. -- Widget: color A widget to edit a color name. In addition, shows a sample that shows the selected color, if any. -- Widget: other A widget useful as the last item in a ‘choice’ widget, since it matches any value. Its super is the ‘sexp’ widget, and its ‘:value’ is ‘other’, by default. -- Widget: coding-system A widget that can represent a coding system name, offering completions. *Note (elisp)Coding Systems::. Its super is the ‘symbol’ widget. It has a default value of ‘undecided’. -- Widget: key A widget to represent a key sequence. It uses a special keymap as the ‘:keymap’. 8.2.4 Composite Sexp Widgets ---------------------------- The syntax for the composite widget construct is: TYPE ::= (CONSTRUCT [KEYWORD ARGUMENT]... COMPONENT...) where each COMPONENT must be a widget type. Each component widget will be displayed in the buffer, and will be editable by the user. -- Widget: cons A widget to edit cons-cell values. Its super is the ‘group’ widget. The value of a ‘cons’ widget must be a cons-cell whose CAR and CDR have two specified types. It uses this syntax: TYPE ::= (cons [KEYWORD ARGUMENT]... CAR-TYPE CDR-TYPE) -- Widget: choice A widget to hold a value of one of a fixed set of types. Its super is the ‘menu-choice’ widget. The widget’s syntax is as follows: TYPE ::= (choice [KEYWORD ARGUMENT]... TYPE ... ) The value of a ‘choice’ widget can be anything that matches any of the TYPES. This widget only displays the widget that corresponds to the current choice. -- Widget: radio A widget to hold a value of one of a fixed set of options. Its super is the ‘radio-button-choice’ widget. -- Widget: list A widget to edit a list value. Its super is the ‘group’ widget. The value of a ‘list’ widget must be a list whose element types match the specified component types: TYPE ::= (list [KEYWORD ARGUMENT]... COMPONENT-TYPE...) Thus, for example, ‘(list string number)’ matches lists of two elements, the first being a string and the second being a number. -- Widget: vector A widget to edit a vector value. Its super is the ‘group’ widget. The ‘vector’ widget is like the ‘list’ widget but matches vectors instead of lists. Thus, for example, ‘(vector string number)’ matches vectors of two elements, the first being a string and the second being a number. The above suffice for specifying fixed size lists and vectors. To get variable length lists and vectors, you can use a ‘choice’, ‘set’, or ‘repeat’ widget together with the ‘:inline’ keyword. If any component of a composite widget has the ‘:inline’ keyword set, its value must be a list which will then be spliced into the composite. For example, to specify a list whose first element must be a file name, and whose remaining elements should either be the symbol ‘t’ or two strings (file names), you can use the following widget specification: (list file (choice (const t) (list :inline t :value ("foo" "bar") string string))) The value of a widget of this type will either have the form ‘(file t)’ or ‘(file STRING STRING)’. This concept of ‘:inline’ may be hard to understand. It was certainly hard to implement, so instead of confusing you more by trying to explain it here, I’ll just suggest you meditate over it for a while. -- Widget: set A widget to hold a list of members from a fixed set. Its super is the ‘checklist’ widget. Its value is a list where the elements all belong to a given set. The order of elements of the list is not significant. Here’s the syntax: TYPE ::= (set [KEYWORD ARGUMENT]... PERMITTED-ELEMENT ... ) Use ‘const’ to specify each permitted element, like this: ‘(set (const a) (const b))’. -- Widget: repeat Specifies a list of any number of elements that fit a certain type. Its super is the ‘editable-list’ widget. TYPE ::= (repeat [KEYWORD ARGUMENT]... TYPE) -- Widget: plist A widget to edit property lists. Its super is the ‘list’ widget. It recognizes the following properties: ‘:options’ A given set of recommended key-value values for the ‘plist’ widget. Each option shows up as a checklist item. ‘:key-type’ The widget type to use for the plist keys. By default, it uses the ‘symbol’ widget. ‘:value-type’ The widget type to use for the plist values. By default, it uses the ‘sexp’ widget. -- Widget: alist A widget to edit association lists. Its super is the ‘list’ widget. It recognizes the same properties that the ‘plist’ widget, with the difference that the ‘:key-type’ uses by default a ‘sexp’ widget. Most composite widgets do not allow for recursion. That is, none of the contained widgets may be of the same type that is currently being defined. To allow for this kind of widgets, there’s the ‘lazy’ widget. -- Widget: lazy A base widget for recursive data structures. Its super is the ‘default’ widget. When instantiated, it contains a single inferior widget of the widget type specified in the ‘:type’ property. Its value is the same as the value of this inferior widget. 9 Defining New Widgets ********************** You can define specialized widgets with ‘define-widget’. It allows you to create a shorthand for more complex widgets, including specifying component widgets and new default values for the keyword arguments. -- Function: define-widget name class doc &rest args Define a new widget type named NAME that derives from CLASS. NAME and CLASS should both be symbols, and CLASS should be one of the existing widget types. The third argument DOC is a documentation string for the widget. ARGS should be key-value pairs, overriding keyword values of CLASS, or adding new recognized keywords for NAME. Usually, you’ll want to derive from an existing widget type, like the ‘editable-field’ widget, or the ‘default’ widget, but it’s also possible to derive from nothing, by passing a value of ‘nil’ as CLASS. Note that if you do this, you’re entirely responsible for defining a whole new default behavior for your widgets. After using this function, the following two calls will create identical widgets: • (widget-create NAME) • (apply widget-create CLASS ARGS) Using ‘define-widget’ just stores the definition of the widget type in the ‘widget-type’ property of NAME, which is what ‘widget-create’ uses. If you only want to specify defaults for keywords with no complex conversions, you can use ‘identity’ as your conversion function. When defining new widgets, the ‘:convert-widget’ property might be useful: ‘:convert-widget’ Function to convert a widget type before creating a widget of that type. It takes a widget type as an argument, and returns the converted widget type. When a widget is created, this function is called for the widget type and all the widget’s parent types, most derived first. The predefined functions ‘widget-types-convert-widget’ and ‘widget-value-convert-widget’ can be used here. 10 Inspecting Widgets ********************* There is a separate package to browse widgets, in ‘wid-browse.el’. This is intended to help programmers who want to examine the content of a widget. The browser shows the value of each keyword, but uses links for certain keywords such as ‘:parent’, which avoids printing cyclic structures. -- Command: widget-browse WIDGET Create a widget browser for WIDGET. When called interactively, prompt for WIDGET. -- Command: widget-browse-other-window WIDGET Create a widget browser for WIDGET and show it in another window. When called interactively, prompt for WIDGET. -- Command: widget-browse-at POS Create a widget browser for the widget at POS. When called interactively, use the position of point. In addition, there’s a function to describe the widget at point. -- Command: widget-describe &optional widget-or-pos Describe the widget at point. When called from Lisp, WIDGET-OR-POS might be the widget to describe or a buffer position where a widget is present. If WIDGET-OR-POS is ‘nil’, the widget to describe is the widget at point. This command sets up a help buffer for providing information about the widget, mainly its ‘:action’ and ‘:mouse-down-action’ functions, and provides links to describe it in more detail using the ‘widget-browse’ commands described above. 11 Widget Minor Mode ******************** There is a minor mode for manipulating widgets in major modes that don’t provide any support for widgets themselves. This is mostly intended to be useful for programmers doing experiments. -- Command: widget-minor-mode Toggle minor mode for traversing widgets. With arg, turn widget mode on if and only if arg is positive. -- Variable: widget-minor-mode-keymap Keymap used in ‘widget-minor-mode’. 12 Utilities ************ Here we describe some utility functions that don’t really have a place earlier in this manual. -- Function: widget-prompt-value widget prompt [ value unbound ] Prompt for a value matching WIDGET, using PROMPT. The current value is assumed to be VALUE, unless UNBOUND is non-‘nil’. Converts WIDGET before prompting, and for prompting it uses the ‘:prompt-value’ function. This function returns the user “answer”, and it’s an error if that answer doesn’t match the widget, as with the ‘:match’ function. If the answer matches the widget, returns the answer. -- Function: widget-get-sibling widget Get the item which WIDGET should toggle. This is only meaningful for radio buttons or checkboxes in a list. -- Function: widget-choose title items &optional event Prompt the user to choose an item from a list of options. TITLE is the name of the list of options. ITEMS should be a menu, with its items in the simple format or in the extended format. *Note Defining Menus: (elisp)Defining Menus. Independently of the format, you don’t have to provide a title for the menu, just pass the desired title in TITLE. The optional EVENT is an input event. If EVENT is a mouse event and the number of elements in ITEMS is less than the user option ‘widget-menu-max-size’, then ‘widget-choose’ uses a popup menu to prompt the user. Otherwise, ‘widget-choose’ uses the minibuffer. When ITEMS is a keymap menu, the returned value is the symbol in the key vector, as in the argument of ‘define-key’ (*note (elisp)Changing Key Bindings::). When ITEMS is a list whose selectable items are of the form (NAME . VALUE) (i.e., the simplified format), then the return value is the VALUE of the chosen element. -- Function: widget-image-find image Create a graphical button from IMAGE, an image or a file name sans extension. If IMAGE is a file name, the file should be in ‘widget-image-directory’, or in a place where ‘find-image’ will find it. -- Function: widget-image-insert widget tag image As part of WIDGET, insert the text TAG or, if supported, the image IMAGE. IMAGE should be as described in ‘widget-image-find’. -- Function: widget-echo-help pos Display help-echo text for the widget at POS. Uses the value of ‘:help-echo’. If it is a function, it calls it to get a string. Otherwise, it ‘eval’s it. 13 Customization **************** This chapter is about the customization options for the Widget library, for the end user. -- Face: widget-field-face Face used for other editing fields. -- Face: widget-button-face Face used for buttons. -- User Option: widget-mouse-face Face used for highlighting a button when the mouse pointer moves across it. The default value is ‘highlight’. -- User Option: widget-image-directory Directory where Widget should look for images. Widget will look here for a file with the same name as specified for the image, with either a ‘.xpm’ (if supported) or ‘.xbm’ extension. -- User Option: widget-image-enable If non-‘nil’, allow images to appear on displays where they are supported. -- User Option: widget-image-conversion An alist to convert symbols from image formats to file name suffixes. Each element is a cons cell (FORMAT . SUFFIX), where FORMAT is a symbol that represents an image format and SUFFIX is its correspondent suffix. -- User Option: widget-button-prefix String to prefix buttons. -- User Option: widget-button-suffix String to suffix buttons. -- User Option: widget-push-button-prefix String to prefix push buttons. -- User Option: widget-push-button-suffix String to suffix push buttons. -- User Option: widget-link-prefix String to prefix links. -- User Option: widget-link-suffix String to suffix links. -- User Option: widget-choice-toggle If non-‘nil’, toggle when there are just two options. By default, its value is ‘nil’. -- User Option: widget-documentation-links If non-‘nil’, add hyperlinks to documentation strings. -- User Option: widget-documentation-link-regexp A regexp that matches potential links in documentation strings. The link itself should match to the first group. -- User Option: widget-documentation-link-p A predicate function to test if a string is useful as a link. The function is called with one argument, a string, and should return non-‘nil’ if there should be a link for that string. By default, the value is ‘intern-soft’. -- User Option: widget-documentation-link-type A symbol that represents a widget type to use for links in documentation strings. By default, the value is ‘documentation-link’. -- User Option: widget-menu-max-size Maximum size for a popup menu. By default, its value is 40. If a function ask you to choose from a menu that is larger than this value, it will use the minibuffer. -- User Option: widget-menu-max-shortcuts Largest number of items for which it works to choose one with a character. For a larger number, use the minibuffer. -- User Option: widget-menu-minibuffer-flag Whether to use the minibuffer to ask for a choice. If ‘nil’, the default, read a single character. 14 Wishlist *********** • It should be possible to add or remove items from a list with ‘C-k’ and ‘C-o’ (suggested by RMS). • The ‘[INS]’ and ‘[DEL]’ buttons should be replaced by a single dash (‘-’). The dash should be a button that, when invoked, asks whether you want to add or delete an item (RMS wanted to git rid of the ugly buttons, the dash is my idea). • The ‘menu-choice’ tag should be prettier, something like the abbreviated menus in Open Look. • Finish ‘:tab-order’. • Make indentation work with glyphs and proportional fonts. • Add commands to show overview of object and class hierarchies to the browser. • Find a way to disable mouse highlight for inactive widgets. • Find a way to make glyphs look inactive. • Add ‘widget’ widget for editing widget specifications. • Find clean way to implement variable length list. See ‘TeX-printer-list’ for an explanation. • ‘C-h’ in ‘widget-prompt-value’ should give type specific help. • Add a ‘mailto’ widget. Appendix A GNU Free Documentation License ***************************************** Version 1.3, 3 November 2008 Copyright © 2000, 2001, 2002, 2007, 2008 Free Software Foundation, Inc. Everyone is permitted to copy and distribute verbatim copies of this license document, but changing it is not allowed. 0. PREAMBLE The purpose of this License is to make a manual, textbook, or other functional and useful document “free” in the sense of freedom: to assure everyone the effective freedom to copy and redistribute it, with or without modifying it, either commercially or noncommercially. Secondarily, this License preserves for the author and publisher a way to get credit for their work, while not being considered responsible for modifications made by others. This License is a kind of “copyleft”, which means that derivative works of the document must themselves be free in the same sense. It complements the GNU General Public License, which is a copyleft license designed for free software. We have designed this License in order to use it for manuals for free software, because free software needs free documentation: a free program should come with manuals providing the same freedoms that the software does. But this License is not limited to software manuals; it can be used for any textual work, regardless of subject matter or whether it is published as a printed book. We recommend this License principally for works whose purpose is instruction or reference. 1. APPLICABILITY AND DEFINITIONS This License applies to any manual or other work, in any medium, that contains a notice placed by the copyright holder saying it can be distributed under the terms of this License. Such a notice grants a world-wide, royalty-free license, unlimited in duration, to use that work under the conditions stated herein. The “Document”, below, refers to any such manual or work. Any member of the public is a licensee, and is addressed as “you”. You accept the license if you copy, modify or distribute the work in a way requiring permission under copyright law. A “Modified Version” of the Document means any work containing the Document or a portion of it, either copied verbatim, or with modifications and/or translated into another language. A “Secondary Section” is a named appendix or a front-matter section of the Document that deals exclusively with the relationship of the publishers or authors of the Document to the Document’s overall subject (or to related matters) and contains nothing that could fall directly within that overall subject. (Thus, if the Document is in part a textbook of mathematics, a Secondary Section may not explain any mathematics.) The relationship could be a matter of historical connection with the subject or with related matters, or of legal, commercial, philosophical, ethical or political position regarding them. The “Invariant Sections” are certain Secondary Sections whose titles are designated, as being those of Invariant Sections, in the notice that says that the Document is released under this License. If a section does not fit the above definition of Secondary then it is not allowed to be designated as Invariant. The Document may contain zero Invariant Sections. If the Document does not identify any Invariant Sections then there are none. The “Cover Texts” are certain short passages of text that are listed, as Front-Cover Texts or Back-Cover Texts, in the notice that says that the Document is released under this License. A Front-Cover Text may be at most 5 words, and a Back-Cover Text may be at most 25 words. A “Transparent” copy of the Document means a machine-readable copy, represented in a format whose specification is available to the general public, that is suitable for revising the document straightforwardly with generic text editors or (for images composed of pixels) generic paint programs or (for drawings) some widely available drawing editor, and that is suitable for input to text formatters or for automatic translation to a variety of formats suitable for input to text formatters. A copy made in an otherwise Transparent file format whose markup, or absence of markup, has been arranged to thwart or discourage subsequent modification by readers is not Transparent. An image format is not Transparent if used for any substantial amount of text. A copy that is not “Transparent” is called “Opaque”. Examples of suitable formats for Transparent copies include plain ASCII without markup, Texinfo input format, LaTeX input format, SGML or XML using a publicly available DTD, and standard-conforming simple HTML, PostScript or PDF designed for human modification. Examples of transparent image formats include PNG, XCF and JPG. Opaque formats include proprietary formats that can be read and edited only by proprietary word processors, SGML or XML for which the DTD and/or processing tools are not generally available, and the machine-generated HTML, PostScript or PDF produced by some word processors for output purposes only. The “Title Page” means, for a printed book, the title page itself, plus such following pages as are needed to hold, legibly, the material this License requires to appear in the title page. For works in formats which do not have any title page as such, “Title Page” means the text near the most prominent appearance of the work’s title, preceding the beginning of the body of the text. The “publisher” means any person or entity that distributes copies of the Document to the public. A section “Entitled XYZ” means a named subunit of the Document whose title either is precisely XYZ or contains XYZ in parentheses following text that translates XYZ in another language. (Here XYZ stands for a specific section name mentioned below, such as “Acknowledgements”, “Dedications”, “Endorsements”, or “History”.) To “Preserve the Title” of such a section when you modify the Document means that it remains a section “Entitled XYZ” according to this definition. The Document may include Warranty Disclaimers next to the notice which states that this License applies to the Document. These Warranty Disclaimers are considered to be included by reference in this License, but only as regards disclaiming warranties: any other implication that these Warranty Disclaimers may have is void and has no effect on the meaning of this License. 2. VERBATIM COPYING You may copy and distribute the Document in any medium, either commercially or noncommercially, provided that this License, the copyright notices, and the license notice saying this License applies to the Document are reproduced in all copies, and that you add no other conditions whatsoever to those of this License. You may not use technical measures to obstruct or control the reading or further copying of the copies you make or distribute. However, you may accept compensation in exchange for copies. If you distribute a large enough number of copies you must also follow the conditions in section 3. You may also lend copies, under the same conditions stated above, and you may publicly display copies. 3. COPYING IN QUANTITY If you publish printed copies (or copies in media that commonly have printed covers) of the Document, numbering more than 100, and the Document’s license notice requires Cover Texts, you must enclose the copies in covers that carry, clearly and legibly, all these Cover Texts: Front-Cover Texts on the front cover, and Back-Cover Texts on the back cover. Both covers must also clearly and legibly identify you as the publisher of these copies. The front cover must present the full title with all words of the title equally prominent and visible. You may add other material on the covers in addition. Copying with changes limited to the covers, as long as they preserve the title of the Document and satisfy these conditions, can be treated as verbatim copying in other respects. If the required texts for either cover are too voluminous to fit legibly, you should put the first ones listed (as many as fit reasonably) on the actual cover, and continue the rest onto adjacent pages. If you publish or distribute Opaque copies of the Document numbering more than 100, you must either include a machine-readable Transparent copy along with each Opaque copy, or state in or with each Opaque copy a computer-network location from which the general network-using public has access to download using public-standard network protocols a complete Transparent copy of the Document, free of added material. If you use the latter option, you must take reasonably prudent steps, when you begin distribution of Opaque copies in quantity, to ensure that this Transparent copy will remain thus accessible at the stated location until at least one year after the last time you distribute an Opaque copy (directly or through your agents or retailers) of that edition to the public. It is requested, but not required, that you contact the authors of the Document well before redistributing any large number of copies, to give them a chance to provide you with an updated version of the Document. 4. MODIFICATIONS You may copy and distribute a Modified Version of the Document under the conditions of sections 2 and 3 above, provided that you release the Modified Version under precisely this License, with the Modified Version filling the role of the Document, thus licensing distribution and modification of the Modified Version to whoever possesses a copy of it. In addition, you must do these things in the Modified Version: A. Use in the Title Page (and on the covers, if any) a title distinct from that of the Document, and from those of previous versions (which should, if there were any, be listed in the History section of the Document). You may use the same title as a previous version if the original publisher of that version gives permission. B. List on the Title Page, as authors, one or more persons or entities responsible for authorship of the modifications in the Modified Version, together with at least five of the principal authors of the Document (all of its principal authors, if it has fewer than five), unless they release you from this requirement. C. State on the Title page the name of the publisher of the Modified Version, as the publisher. D. Preserve all the copyright notices of the Document. E. Add an appropriate copyright notice for your modifications adjacent to the other copyright notices. F. Include, immediately after the copyright notices, a license notice giving the public permission to use the Modified Version under the terms of this License, in the form shown in the Addendum below. G. Preserve in that license notice the full lists of Invariant Sections and required Cover Texts given in the Document’s license notice. H. Include an unaltered copy of this License. I. Preserve the section Entitled “History”, Preserve its Title, and add to it an item stating at least the title, year, new authors, and publisher of the Modified Version as given on the Title Page. If there is no section Entitled “History” in the Document, create one stating the title, year, authors, and publisher of the Document as given on its Title Page, then add an item describing the Modified Version as stated in the previous sentence. J. Preserve the network location, if any, given in the Document for public access to a Transparent copy of the Document, and likewise the network locations given in the Document for previous versions it was based on. These may be placed in the “History” section. You may omit a network location for a work that was published at least four years before the Document itself, or if the original publisher of the version it refers to gives permission. K. For any section Entitled “Acknowledgements” or “Dedications”, Preserve the Title of the section, and preserve in the section all the substance and tone of each of the contributor acknowledgements and/or dedications given therein. L. Preserve all the Invariant Sections of the Document, unaltered in their text and in their titles. Section numbers or the equivalent are not considered part of the section titles. M. Delete any section Entitled “Endorsements”. Such a section may not be included in the Modified Version. N. Do not retitle any existing section to be Entitled “Endorsements” or to conflict in title with any Invariant Section. O. Preserve any Warranty Disclaimers. If the Modified Version includes new front-matter sections or appendices that qualify as Secondary Sections and contain no material copied from the Document, you may at your option designate some or all of these sections as invariant. To do this, add their titles to the list of Invariant Sections in the Modified Version’s license notice. These titles must be distinct from any other section titles. You may add a section Entitled “Endorsements”, provided it contains nothing but endorsements of your Modified Version by various parties—for example, statements of peer review or that the text has been approved by an organization as the authoritative definition of a standard. You may add a passage of up to five words as a Front-Cover Text, and a passage of up to 25 words as a Back-Cover Text, to the end of the list of Cover Texts in the Modified Version. Only one passage of Front-Cover Text and one of Back-Cover Text may be added by (or through arrangements made by) any one entity. If the Document already includes a cover text for the same cover, previously added by you or by arrangement made by the same entity you are acting on behalf of, you may not add another; but you may replace the old one, on explicit permission from the previous publisher that added the old one. The author(s) and publisher(s) of the Document do not by this License give permission to use their names for publicity for or to assert or imply endorsement of any Modified Version. 5. COMBINING DOCUMENTS You may combine the Document with other documents released under this License, under the terms defined in section 4 above for modified versions, provided that you include in the combination all of the Invariant Sections of all of the original documents, unmodified, and list them all as Invariant Sections of your combined work in its license notice, and that you preserve all their Warranty Disclaimers. The combined work need only contain one copy of this License, and multiple identical Invariant Sections may be replaced with a single copy. If there are multiple Invariant Sections with the same name but different contents, make the title of each such section unique by adding at the end of it, in parentheses, the name of the original author or publisher of that section if known, or else a unique number. Make the same adjustment to the section titles in the list of Invariant Sections in the license notice of the combined work. In the combination, you must combine any sections Entitled “History” in the various original documents, forming one section Entitled “History”; likewise combine any sections Entitled “Acknowledgements”, and any sections Entitled “Dedications”. You must delete all sections Entitled “Endorsements.” 6. COLLECTIONS OF DOCUMENTS You may make a collection consisting of the Document and other documents released under this License, and replace the individual copies of this License in the various documents with a single copy that is included in the collection, provided that you follow the rules of this License for verbatim copying of each of the documents in all other respects. You may extract a single document from such a collection, and distribute it individually under this License, provided you insert a copy of this License into the extracted document, and follow this License in all other respects regarding verbatim copying of that document. 7. AGGREGATION WITH INDEPENDENT WORKS A compilation of the Document or its derivatives with other separate and independent documents or works, in or on a volume of a storage or distribution medium, is called an “aggregate” if the copyright resulting from the compilation is not used to limit the legal rights of the compilation’s users beyond what the individual works permit. When the Document is included in an aggregate, this License does not apply to the other works in the aggregate which are not themselves derivative works of the Document. If the Cover Text requirement of section 3 is applicable to these copies of the Document, then if the Document is less than one half of the entire aggregate, the Document’s Cover Texts may be placed on covers that bracket the Document within the aggregate, or the electronic equivalent of covers if the Document is in electronic form. Otherwise they must appear on printed covers that bracket the whole aggregate. 8. TRANSLATION Translation is considered a kind of modification, so you may distribute translations of the Document under the terms of section 4. Replacing Invariant Sections with translations requires special permission from their copyright holders, but you may include translations of some or all Invariant Sections in addition to the original versions of these Invariant Sections. You may include a translation of this License, and all the license notices in the Document, and any Warranty Disclaimers, provided that you also include the original English version of this License and the original versions of those notices and disclaimers. In case of a disagreement between the translation and the original version of this License or a notice or disclaimer, the original version will prevail. If a section in the Document is Entitled “Acknowledgements”, “Dedications”, or “History”, the requirement (section 4) to Preserve its Title (section 1) will typically require changing the actual title. 9. TERMINATION You may not copy, modify, sublicense, or distribute the Document except as expressly provided under this License. Any attempt otherwise to copy, modify, sublicense, or distribute it is void, and will automatically terminate your rights under this License. However, if you cease all violation of this License, then your license from a particular copyright holder is reinstated (a) provisionally, unless and until the copyright holder explicitly and finally terminates your license, and (b) permanently, if the copyright holder fails to notify you of the violation by some reasonable means prior to 60 days after the cessation. Moreover, your license from a particular copyright holder is reinstated permanently if the copyright holder notifies you of the violation by some reasonable means, this is the first time you have received notice of violation of this License (for any work) from that copyright holder, and you cure the violation prior to 30 days after your receipt of the notice. Termination of your rights under this section does not terminate the licenses of parties who have received copies or rights from you under this License. If your rights have been terminated and not permanently reinstated, receipt of a copy of some or all of the same material does not give you any rights to use it. 10. FUTURE REVISIONS OF THIS LICENSE The Free Software Foundation may publish new, revised versions of the GNU Free Documentation License from time to time. Such new versions will be similar in spirit to the present version, but may differ in detail to address new problems or concerns. See . Each version of the License is given a distinguishing version number. If the Document specifies that a particular numbered version of this License “or any later version” applies to it, you have the option of following the terms and conditions either of that specified version or of any later version that has been published (not as a draft) by the Free Software Foundation. If the Document does not specify a version number of this License, you may choose any version ever published (not as a draft) by the Free Software Foundation. If the Document specifies that a proxy can decide which future versions of this License can be used, that proxy’s public statement of acceptance of a version permanently authorizes you to choose that version for the Document. 11. RELICENSING “Massive Multiauthor Collaboration Site” (or “MMC Site”) means any World Wide Web server that publishes copyrightable works and also provides prominent facilities for anybody to edit those works. A public wiki that anybody can edit is an example of such a server. A “Massive Multiauthor Collaboration” (or “MMC”) contained in the site means any set of copyrightable works thus published on the MMC site. “CC-BY-SA” means the Creative Commons Attribution-Share Alike 3.0 license published by Creative Commons Corporation, a not-for-profit corporation with a principal place of business in San Francisco, California, as well as future copyleft versions of that license published by that same organization. “Incorporate” means to publish or republish a Document, in whole or in part, as part of another Document. An MMC is “eligible for relicensing” if it is licensed under this License, and if all works that were first published under this License somewhere other than this MMC, and subsequently incorporated in whole or in part into the MMC, (1) had no cover texts or invariant sections, and (2) were thus incorporated prior to November 1, 2008. The operator of an MMC Site may republish an MMC contained in the site under CC-BY-SA on the same site at any time before August 1, 2009, provided the MMC is eligible for relicensing. ADDENDUM: How to use this License for your documents ==================================================== To use this License in a document you have written, include a copy of the License in the document and put the following copyright and license notices just after the title page: Copyright (C) YEAR YOUR NAME. Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.3 or any later version published by the Free Software Foundation; with no Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts. A copy of the license is included in the section entitled ``GNU Free Documentation License''. If you have Invariant Sections, Front-Cover Texts and Back-Cover Texts, replace the “with...Texts.” line with this: with the Invariant Sections being LIST THEIR TITLES, with the Front-Cover Texts being LIST, and with the Back-Cover Texts being LIST. If you have Invariant Sections without Cover Texts, or some other combination of the three, merge those two alternatives to suit the situation. If your document contains nontrivial examples of program code, we recommend releasing these examples in parallel under your choice of free software license, such as the GNU General Public License, to permit their use in free software. Index ***** This is an alphabetical listing of all concepts, functions, commands, variables, and widgets described in this manual. * Menu: * action keyword: Widget Gallery. (line 1124) * activate a widget: Widget Gallery. (line 1083) * activate keyword: Widget Gallery. (line 1116) * active keyword: Widget Gallery. (line 1077) * active widget: Widget Gallery. (line 1083) * alist: composite. (line 2387) * append-button-args keyword: editable-list. (line 1932) * args keyword: menu-choice. (line 1538) * args keyword <1>: radio-button-choice. (line 1639) * args keyword <2>: checklist. (line 1867) * args keyword <3>: editable-list. (line 1954) * atomic sexp widget: atoms. (line 2142) * basic widgets: Introduction. (line 75) * boolean: atoms. (line 2242) * button widgets: User Interface. (line 202) * button-args keyword: radio-button-choice. (line 1626) * button-args keyword <1>: checklist. (line 1857) * button-face keyword: Widget Gallery. (line 915) * button-face-get keyword: Widget Gallery. (line 1050) * button-prefix keyword: Widget Gallery. (line 918) * button-suffix keyword: Widget Gallery. (line 918) * buttons keyword: radio-button-choice. (line 1630) * buttons keyword <1>: checklist. (line 1861) * buttons keyword <2>: editable-list. (line 1935) * case-fold keyword: menu-choice. (line 1525) * character: atoms. (line 2170) * checkbox widget: checkbox. (line 1785) * checklist widget: checklist. (line 1825) * children keyword: menu-choice. (line 1531) * children keyword <1>: radio-button-choice. (line 1633) * children keyword <2>: checklist. (line 1864) * children keyword <3>: editable-list. (line 1951) * choice: composite. (line 2291) * choice keyword: menu-choice. (line 1535) * choice keyword <1>: radio-button-choice. (line 1636) * choice-item widget: choice-item. (line 1683) * coding-system: atoms. (line 2260) * color: atoms. (line 2248) * completions-function keyword: Widget Gallery. (line 1028) * composite sexp widgets: composite. (line 2275) * cons: composite. (line 2282) * const: constants. (line 2082) * constant widgets: constants. (line 2071) * convert-widget keyword: Defining New Widgets. (line 2447) * copy keyword: Widget Gallery. (line 1067) * create keyword: Widget Gallery. (line 782) * deactivate a widget: Widget Gallery. (line 1083) * deactivate keyword: Widget Gallery. (line 1120) * default: Widget Gallery. (line 773) * default-get keyword: Widget Gallery. (line 869) * define-widget: Defining New Widgets. (line 2413) * defining new widgets: Defining New Widgets. (line 2409) * delete keyword: Widget Gallery. (line 792) * delete-button-args keyword: editable-list. (line 1929) * directory: atoms. (line 2199) * doc keyword: Widget Gallery. (line 937) * documentation-string widget: documentation-string. (line 2034) * editable-field widget: editable-field. (line 1378) * editable-list widget: editable-list. (line 1897) * emacs-commentary-link widget: emacs-commentary-link. (line 1332) * emacs-library-link widget: emacs-library-link. (line 1319) * embedded buttons: User Interface. (line 219) * entry-format keyword: radio-button-choice. (line 1613) * entry-format keyword <1>: checklist. (line 1847) * entry-format keyword <2>: editable-list. (line 1913) * example of using widgets: Programming Example. (line 253) * external format: Widget Gallery. (line 807) * extra-offset keyword: Widget Gallery. (line 973) * face-link widget: face-link. (line 1294) * file: atoms. (line 2177) * file-link widget: file-link. (line 1306) * float: atoms. (line 2230) * follow-link keyword: Widget Gallery. (line 956) * format keyword: Widget Gallery. (line 874) * format-handler keyword: Widget Gallery. (line 1039) * function: atoms. (line 2210) * function-item: constants. (line 2101) * function-link widget: function-link. (line 1269) * generic sexp widget: generic. (line 2107) * greedy keyword: checklist. (line 1887) * group widget: group. (line 1991) * help-echo keyword: Widget Gallery. (line 947) * inactive widget: Widget Gallery. (line 1083) * indent keyword: Widget Gallery. (line 960) * info-link widget: info-link. (line 1256) * insert-button-args keyword: editable-list. (line 1926) * integer: atoms. (line 2218) * internal format: Widget Gallery. (line 807) * item widget: item. (line 1168) * key: atoms. (line 2267) * keymap keyword: editable-field. (line 1400) * keyword arguments: Widget Gallery. (line 780) * lazy: composite. (line 2398) * link widget: link. (line 1207) * list: composite. (line 2309) * match keyword: Widget Gallery. (line 989) * menu-choice widget: menu-choice. (line 1498) * menu-tag keyword: Widget Gallery. (line 977) * menu-tag-get keyword: Widget Gallery. (line 981) * mouse-2 (on button widgets): Widgets and the Buffer. (line 740) * mouse-down-action keyword: Widget Gallery. (line 1131) * mouse-face-get keyword: Widget Gallery. (line 1058) * must-match keyword: atoms. (line 2187) * natnum: atoms. (line 2224) * new widgets: Defining New Widgets. (line 2409) * notify keyword: Widget Gallery. (line 1137) * number: atoms. (line 2236) * off-glyph keyword: toggle. (line 1732) * offset keyword: Widget Gallery. (line 969) * on-glyph keyword: toggle. (line 1728) * option field tag: User Interface. (line 212) * other: atoms. (line 2253) * parent keyword: Widget Gallery. (line 1018) * plist: composite. (line 2370) * prompt-value keyword: Widget Gallery. (line 1148) * push-button widget: push-button. (line 1345) * radio: composite. (line 2305) * radio-button-choice widget: radio-button-choice. (line 1589) * radio-button-toggle widget: radio-button-toggle. (line 1750) * regexp: atoms. (line 2164) * repeat: composite. (line 2364) * restricted-sexp: generic. (line 2123) * secret keyword: editable-field. (line 1424) * set: composite. (line 2350) * sexp: generic. (line 2114) * sexp types: Sexp Types. (line 2064) * sibling-args keyword: Widget Gallery. (line 1022) * size keyword: editable-field. (line 1414) * string: atoms. (line 2158) * symbol: atoms. (line 2205) * tab-order keyword: Widget Gallery. (line 1004) * tag keyword: Widget Gallery. (line 940) * tag-glyph keyword: Widget Gallery. (line 943) * text widget: text. (line 1479) * todo: Widget Wishlist. (line 2673) * toggle widget: toggle. (line 1705) * url-link widget: url-link. (line 1244) * utility functions for widgets: Utilities. (line 2515) * valid-regexp keyword: editable-field. (line 1431) * validate keyword: Widget Gallery. (line 994) * value keyword: Widget Gallery. (line 807) * value-create keyword: Widget Gallery. (line 835) * value-delete keyword: Widget Gallery. (line 841) * value-face keyword: editable-field. (line 1419) * value-get keyword: Widget Gallery. (line 851) * value-inline keyword: Widget Gallery. (line 863) * value-set keyword: Widget Gallery. (line 855) * value-to-external keyword: Widget Gallery. (line 829) * value-to-internal keyword: Widget Gallery. (line 821) * variable: atoms. (line 2214) * variable-item: constants. (line 2098) * variable-link widget: variable-link. (line 1282) * vector: composite. (line 2320) * void keyword: menu-choice. (line 1519) * widget browser: Inspecting Widgets. (line 2462) * widget buttons: User Interface. (line 202) * widget creation, widget conversion: Setting Up the Buffer. (line 399) * widget inheritance: Widgets Basics. (line 355) * widget library, why use it: Introduction. (line 116) * widget minor mode: Widget Minor Mode. (line 2501) * widget object: Widgets Basics. (line 349) * widget properties: Widgets Basics. (line 391) * widget syntax: Widget Gallery. (line 754) * widget value: Widgets Basics. (line 374) * widget-apply: Working with Widgets. (line 564) * widget-apply-action: Working with Widgets. (line 636) * widget-at: Working with Widgets. (line 558) * widget-backward: Widgets and the Buffer. (line 706) * widget-browse: Inspecting Widgets. (line 2468) * widget-browse-at: Inspecting Widgets. (line 2478) * widget-browse-other-window: Inspecting Widgets. (line 2473) * widget-button-click: Widgets and the Buffer. (line 741) * widget-button-click <1>: Widgets and the Buffer. (line 741) * widget-button-face: Customization. (line 2582) * widget-button-prefix: Customization. (line 2610) * widget-button-press: Widgets and the Buffer. (line 731) * widget-button-press <1>: Widgets and the Buffer. (line 731) * widget-button-suffix: Customization. (line 2613) * widget-child-validate: Working with Widgets. (line 647) * widget-child-value-get: Working with Widgets. (line 605) * widget-child-value-inline: Working with Widgets. (line 608) * widget-children-validate: Working with Widgets. (line 653) * widget-children-value-delete: Setting Up the Buffer. (line 482) * widget-choice-toggle: Customization. (line 2628) * widget-choose: Utilities. (line 2533) * widget-complete: Widgets and the Buffer. (line 722) * widget-convert: Setting Up the Buffer. (line 504) * widget-copy: Setting Up the Buffer. (line 494) * widget-create: Setting Up the Buffer. (line 414) * widget-create-child: Setting Up the Buffer. (line 443) * widget-create-child-and-convert: Setting Up the Buffer. (line 433) * widget-create-child-value: Setting Up the Buffer. (line 449) * widget-default-delete: Widget Gallery. (line 800) * widget-default-format-handler: Widget Gallery. (line 1046) * widget-default-get: Working with Widgets. (line 592) * widget-delete: Setting Up the Buffer. (line 479) * widget-describe: Inspecting Widgets. (line 2485) * widget-documentation-link-p: Customization. (line 2640) * widget-documentation-link-regexp: Customization. (line 2636) * widget-documentation-link-type: Customization. (line 2647) * widget-documentation-links: Customization. (line 2633) * widget-echo-help: Utilities. (line 2567) * widget-end-of-line: Widgets and the Buffer. (line 713) * widget-field-activate: Widgets and the Buffer. (line 726) * widget-field-at: Working with Widgets. (line 561) * widget-field-face: Customization. (line 2579) * widget-field-keymap: editable-field. (line 1400) * widget-forward: Widgets and the Buffer. (line 702) * widget-get: Working with Widgets. (line 548) * widget-get-sibling: Utilities. (line 2529) * widget-global-map: Widgets and the Buffer. (line 692) * widget-image-conversion: Customization. (line 2602) * widget-image-directory: Customization. (line 2591) * widget-image-enable: Customization. (line 2598) * widget-image-find: Utilities. (line 2553) * widget-image-insert: Utilities. (line 2561) * widget-insert: Setting Up the Buffer. (line 518) * widget-keymap: Widgets and the Buffer. (line 681) * widget-kill-line: Widgets and the Buffer. (line 718) * widget-link-prefix: Customization. (line 2622) * widget-link-suffix: Customization. (line 2625) * widget-member: Working with Widgets. (line 544) * widget-menu-max-shortcuts: Customization. (line 2659) * widget-menu-max-size: Customization. (line 2653) * widget-menu-minibuffer-flag: Customization. (line 2665) * widget-minor-mode: Widget Minor Mode. (line 2505) * widget-minor-mode-keymap: Widget Minor Mode. (line 2509) * widget-mouse-face: Customization. (line 2585) * widget-parent-action: Working with Widgets. (line 642) * widget-prompt-value: Utilities. (line 2518) * widget-push-button-prefix: Customization. (line 2616) * widget-push-button-suffix: Customization. (line 2619) * widget-put: Working with Widgets. (line 554) * widget-radio-add-item: radio-button-choice. (line 1672) * widget-setup: Setting Up the Buffer. (line 466) * widget-text-keymap: text. (line 1491) * widget-type: Working with Widgets. (line 537) * widget-type-default-get: Working with Widgets. (line 601) * widget-type-match: Working with Widgets. (line 658) * widget-type-value-create: Working with Widgets. (line 615) * widget-types-convert-widget: Working with Widgets. (line 670) * widget-types-copy: Working with Widgets. (line 664) * widget-value: Working with Widgets. (line 570) * widget-value-convert-widget: Working with Widgets. (line 624) * widget-value-set: Working with Widgets. (line 583) * widget-value-value-get: Working with Widgets. (line 629) * widgetp: Working with Widgets. (line 534) * widgets, basic types: Introduction. (line 75) * widgets, programming example: Programming Example. (line 253)