A System Class is a pre-defined class which is part of APLX. They are mostly used for user-interface programming. Examples are the Form, Timer, ChooseColor and Chart classes. (In previous versions of APLX, these classes were accessed through ŚWI. Although you can continue to use ŚWI, you may find the new class-based syntax more readable and more consistent.)
To create an instance of a top-level System class (such as a Form or a pre-defined dialog), you provide the name of the class as the right argument to ŚNEW, and use 'Ś' as the left argument to indicate that this is a System class:
DLG„'Ś' ŚNEW 'ChooseColor' DLG.ŚNL 3 Close Create Delete New Open Send Set Show Trigger
You can then use dot notation to access the properties and methods of the object:
DLG.color„234 23 56 DLG.Show 1
See the separate manual on System Classes and User-Interface Programming for more details.