ask_for_element

# File ext/json/lib/json/editor.rb, line 902
      def ask_for_element(parent = nil, default_type = nil, value_text = @content)
        type_input = value_input = nil

        dialog = Dialog.new(
          "New element into #{parent ? parent.type : 'root'}",
          nil, nil,
          [ Stock::OK, Dialog::RESPONSE_ACCEPT ],
          [ Stock::CANCEL, Dialog::RESPONSE_REJECT ]
        )
        hbox = HBox.new(false, 5)
        hbox.pack_start(Label.new("Type:"), false)
        hbox.pack_start(type_input = ComboBox.new(true))
        default_active = 0
        types = parent ? ALL_TYPES : CONTAINER_TYPES
        types.each_with_index do |t, i|
          type_input.append_text(t)
          if t == default_type
            default_active = i
          end
        end
        type_input.active = default_active
        dialog.vbox.pack_start(hbox, false)
        type_input.signal_connect(:changed) do
          configure_value(value_input, types[type_input.active])
        end

        hbox = HBox.new(false, 5)
        hbox.pack_start(Label.new("Value:"), false)
        hbox.pack_start(value_input = Entry.new)
        value_input.width_chars = 60
        value_input.text = value_text if value_text
        configure_value(value_input, types[type_input.active])

        dialog.vbox.pack_start(hbox, false)

        dialog.signal_connect(:'key-press-event', &DEFAULT_DIALOG_KEY_PRESS_HANDLER)
        dialog.show_all
        self.focus = dialog
        dialog.run do |response| 
          if response == Dialog::RESPONSE_ACCEPT
            type = types[type_input.active]
            @content = case type
            when 'Numeric'
              if (t = value_input.text) == 'Infinity'
                1 / 0.0
              else
                Integer(t) rescue Float(t) rescue 0
              end
            else
              value_input.text
            end.to_s
            return type, @content
          end
        end
        return
      ensure
        dialog.destroy if dialog
      end