SAS/SCL and SAS/AF --- SAS Class & UI

• Using SCL to create a class and to define: attributes,methods,events and event handlers 
• Using the CLASS block provides the advantages of error detection at compile time and improved performance during run time. 
• You can also overload method definitions, which means that multiple methods can have the same name, but have different numbers and types of parameters.
• 1991, SAS/AF --- Software applications of any sort do not exist in isolation; they are built with a specific need in mind.
• Screen Control Language (SCL,renamed SAS Component Language for Version 7)

For more details:

http://www2.sas.com/proceedings/sugi24/Begtutor/p69-24.pdf

http://support.sas.com/documentation/onlinedoc/91pdf/sasdoc_913/af_gsframes_9346.pdf

To create a class from an SCL entry that contains a CLASS block, you must compile and save the SCL entry as a CLASS entry. To do this, either issue the SAVECLASS command or select File  Save Class from the SCL Source Editor. This is equivalent to using the Class Editor to interactively create a CLASS entry. However, the Class Editor provides a graphical view of the class, whereas the CLASS statement in SCL provides a language view of the class.

Do not declare the _SELF_, _FRAME_, _CFRAME_, _METHOD_, or _EVENT_ system variables inside a CLASS or USECLASS block. SCL automatically sets these values when it is running methods that are defined in CLASS or USECLASS blocks. Redefining any of these system variables can introduce unexpected behavior.

In methods that are defined in a CLASS statement block, all references to the methods and the attributes of the class can bypass two-level references to _SELF_.attribute and _SELF_.method(...). Because these methods are defined within the class, the SCL compiler can detect whether an undefined variable is a local variable or a class attribute.

You can also use the _super method in method code inside a CLASS statement block without having to specify either an object identifier or the method whose super method you are calling. You can use the _super method to call any method. For example, to invoke the super ADD method, you would use