Practical Expressive Types for Active Objects

                          Franz Puntigam
    Institut für Computersprachen, Technische Universität Wien
           Argentinierstraße 8, A-1040 Vienna, Austria
             E-mail: franz@complang.tuwien.ac.at

While statically checkable types expressing partial object behavior
are included in many sequential object-oriented languages, there is
no corresponding practical type concept for languages based on active
objects. We propose a type concept for active objects which ensures
that all sent messages are accepted by the receivers, supports the
specification of object behavior modifications, and is statically
checkable.