Extending defined classes
One benefit of VA Smalltalk is that you can extend predefined classes. When you extend a defined class, you change its behavior by adding one or more methods to it.
The requirements for visibility and group privileges that apply for defined classes apply to extended classes. Extending a class involves the following:
•You must specify a containing application for the class extension.
•You must be a group member of this application.
•The class extension can exist in only one application in your image. However, several different class extensions can exist in one application.
When you extend a class, you become the owner of the extension.
You probably will not be the owner of the defined class that you are extending. Nor is it likely that you will be a group member of the application that contains the defined class. One benefit of being able to extend a defined class is that you can modify the behavior of the defined class even when you do not own the defined class and are not a member of its containing application.
Last modified date: 05/19/2020