Classes and subclasses in actor-oriented design

Actor-oriented languages provide a component composition methodology that emphasizes concurrency. The interfaces to actors are parameters and ports (vs. members and methods in object-oriented languages). Actors interact with one another through their ports via a messaging schema that can follow any of several concurrent semantics (vs. procedure calls, with prevail in OO languages). Domain-specific actor-oriented languages and frameworks are common (e.g. Simulink, LabVIEW, and many others). However, they lack many of the modularity and abstraction mechanisms that programmers have become accustomed to in 00 languages, such as classes, inheritance, interfaces, and polymorphism. This extended abstract shows the form that such mechanisms might take in AO languages. A prototype of these mechanisms realized in Ptolemy II is described.