An object oriented extension to APL

This paper describes an object oriented extension of APL, which is currently being implemented in a new APL system. This extension is integrated in a rather conservative way to APL. However, all the paradigms of object oriented languages (message passing, instance variables, methods, classes and inheritance) are made available to the user, without losing any of the successful features of APL. The paper first explains what are the interests of object oriented programming, and what is expected from this introduction in the language. It then discusses syntactic and semantic choices, and shows how the selected solutions fit the philosophy of APL. An example of this new style of programming in APL is proposed, then the internals of the implementation are presented, showing that this new possibility is made available at the cost of a minimal system overhead. Finally, the paper discusses about the results obtained so far.