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3 Programming Example

Here is the code to implement the user interface example (see 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))