;;; wid-edit.el --- Functions for creating and using widgets -*-byte-compile-dynamic: t;-*-
;;
-;; Copyright (C) 1996,97,1999,2000,01,02,2003 Free Software Foundation, Inc.
+;; Copyright (C) 1996,97,1999,2000,01,02,2003, 2004 Free Software Foundation, Inc.
;;
;; Author: Per Abrahamsen <abraham@dina.kvl.dk>
;; Maintainer: FSF
found (widget-apply child :validate)))
found))
+(defun widget-child-value-get (widget)
+ "Get the value of the first member of :children in WIDGET."
+ (widget-value (car (widget-get widget :children))))
+
+(defun widget-child-value-inline (widget)
+ "Get the inline value of the first member of :children in WIDGET."
+ (widget-apply (car (widget-get widget :children)) :value-inline))
+
+(defun widget-child-validate (widget)
+ "The result of validating the first member of :children in WIDGET."
+ (widget-apply (car (widget-get widget :children)) :validate))
+
+(defun widget-type-value-create (widget)
+ "Convert and instantiate the value of the :type attribute of WIDGET.
+Store the newly created widget in the :children attribute.
+
+The value of the :type attribute should be an unconverted widget type."
+ (let ((value (widget-get widget :value))
+ (type (widget-get widget :type)))
+ (widget-put widget :children
+ (list (widget-create-child-value widget
+ (widget-convert type)
+ value)))))
+
+(defun widget-type-default-get (widget)
+ "Get default value from the :type attribute of WIDGET.
+
+The value of the :type attribute should be an unconverted widget type."
+ (widget-default-get (widget-convert (widget-get widget :type))))
+
+(defun widget-type-match (widget value)
+ "Non-nil if the :type value of WIDGET matches VALUE.
+
+The value of the :type attribute should be an unconverted widget type."
+ (widget-apply (widget-convert (widget-get widget :type)) :match value))
+
(defun widget-types-copy (widget)
"Copy :args as widget types in WIDGET."
(widget-put widget :args (mapcar 'widget-copy (widget-get widget :args)))
:copy 'identity
:value-set 'widget-default-value-set
:value-inline 'widget-default-value-inline
+ :value-delete 'ignore
:default-get 'widget-default-default-get
:menu-tag-get 'widget-default-menu-tag-get
:validate #'ignore
(inhibit-modification-hooks t)
(inhibit-read-only t))
(widget-apply widget :value-delete)
+ (widget-children-value-delete widget)
(when inactive-overlay
(delete-overlay inactive-overlay))
(when button-overlay
:tag "choice"
:void '(item :format "invalid (%t)\n")
:value-create 'widget-choice-value-create
- :value-delete 'widget-children-value-delete
- :value-get 'widget-choice-value-get
- :value-inline 'widget-choice-value-inline
+ :value-get 'widget-child-value-get
+ :value-inline 'widget-child-value-inline
:default-get 'widget-choice-default-get
:mouse-down-action 'widget-choice-mouse-down-action
:action 'widget-choice-action
widget void :value value)))
(widget-put widget :choice void))))))
-(defun widget-choice-value-get (widget)
- ;; Get value of the child widget.
- (widget-value (car (widget-get widget :children))))
-
-(defun widget-choice-value-inline (widget)
- ;; Get value of the child widget.
- (widget-apply (car (widget-get widget :children)) :value-inline))
-
(defun widget-choice-default-get (widget)
;; Get default for the first choice.
(widget-default-get (car (widget-get widget :args))))
:entry-format "%b %v"
:greedy nil
:value-create 'widget-checklist-value-create
- :value-delete 'widget-children-value-delete
:value-get 'widget-checklist-value-get
:validate 'widget-checklist-validate
:match 'widget-checklist-match
:format "%v"
:entry-format "%b %v"
:value-create 'widget-radio-value-create
- :value-delete 'widget-children-value-delete
:value-get 'widget-radio-value-get
:value-inline 'widget-radio-value-inline
:value-set 'widget-radio-value-set
:format-handler 'widget-editable-list-format-handler
:entry-format "%i %d %v"
:value-create 'widget-editable-list-value-create
- :value-delete 'widget-children-value-delete
:value-get 'widget-editable-list-value-get
:validate 'widget-children-validate
:match 'widget-editable-list-match
:copy 'widget-types-copy
:format "%v"
:value-create 'widget-group-value-create
- :value-delete 'widget-children-value-delete
:value-get 'widget-editable-list-value-get
:default-get 'widget-group-default-get
:validate 'widget-children-validate
"A documentation string."
:format "%v"
:action 'widget-documentation-string-action
- :value-delete 'widget-children-value-delete
:value-create 'widget-documentation-string-value-create)
(defun widget-documentation-string-value-create (widget)
(widget-group-match widget
(widget-apply widget :value-to-internal value))))
\f
+;;; The `lazy' Widget.
+;;
+;; Recursive datatypes.
+
+(define-widget 'lazy 'default
+ "Base widget for recursive datastructures.
+
+The `lazy' widget will, when instantiated, contain a single inferior
+widget, of the widget type specified by the :type parameter. The
+value of the `lazy' widget is the same as the value of the inferior
+widget. When deriving a new widget from the 'lazy' widget, the :type
+parameter is allowed to refer to the widget currently being defined,
+thus allowing recursive datastructures to be described.
+
+The :type parameter takes the same arguments as the defcustom
+parameter with the same name.
+
+Most composite widgets, i.e. widgets containing other widgets, does
+not allow recursion. That is, when you define a new widget type, none
+of the inferior widgets may be of the same type you are currently
+defining.
+
+In Lisp, however, it is custom to define datastructures in terms of
+themselves. A list, for example, is defined as either nil, or a cons
+cell whose cdr itself is a list. The obvious way to translate this
+into a widget type would be
+
+ (define-widget 'my-list 'choice
+ \"A list of sexps.\"
+ :tag \"Sexp list\"
+ :args '((const nil) (cons :value (nil) sexp my-list)))
+
+Here we attempt to define my-list as a choice of either the constant
+nil, or a cons-cell containing a sexp and my-lisp. This will not work
+because the `choice' widget does not allow recursion.
+
+Using the `lazy' widget you can overcome this problem, as in this
+example:
+
+ (define-widget 'sexp-list 'lazy
+ \"A list of sexps.\"
+ :tag \"Sexp list\"
+ :type '(choice (const nil) (cons :value (nil) sexp sexp-list)))"
+ :format "%{%t%}: %v"
+ ;; We don't convert :type because we want to allow recursive
+ ;; datastructures. This is slow, so we should not create speed
+ ;; critical widgets by deriving from this.
+ :convert-widget 'widget-value-convert-widget
+ :value-create 'widget-type-value-create
+ :value-get 'widget-child-value-get
+ :value-inline 'widget-child-value-inline
+ :default-get 'widget-type-default-get
+ :match 'widget-type-match
+ :validate 'widget-child-validate)
+
+\f
;;; The `plist' Widget.
;;
;; Property lists.
(help-echo (and widget (widget-get widget :help-echo))))
(if (functionp help-echo)
(setq help-echo (funcall help-echo widget)))
- (if (stringp help-echo)
- (message "%s" help-echo))))
+ (if help-echo (message "%s" (eval help-echo)))))
;;; The End:
(provide 'wid-edit)
+;;; arch-tag: a076e75e-18a1-4b46-8be5-3f317bcbc707
;;; wid-edit.el ends here
HCoop / bpt / emacs.git / blobdiff