## System Classes

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.

Topic: APLX Help : Help on APL language : APL Fundamentals : System Classes

[ Previous | Next | Contents | Index ]