835: Mainline

Now, if you move one of the sliders with the mouse, or type a new value in the input field, followed by a carriage return, the following occurs:

• The controller associated with the widget through which you provide new information obtains the value holder from its model instance variable using the model getter. Then, the controller writes a new value into the value holder's value instance variable using the value: setter.
• The value: setter causes the value holder to send the changed: message to itself.
• The changed: method sends update: messages to all dependent parts, which, in the example, amount to the two sliders views and the input field view.
• All three views respond to the update: message by extracting the new value from the value holder, held by their model instance variables, and then updating their displayed information.

Thus, both sliders and the input field all display the same value. If you move a slider, the other slider and the input field follow the change.