This paper examines how object-oriented extensions to the Petri Net formalism can address a number of issues in the modelling of network protocols. The object-oriented extensions lead to the formalism of Object Petri Nets, with a textual language form referred to as LOOPN++. The paper considers practical examples for which clean, well-structured models can be created because of the support for modularity, inheritance, polymorphism, genericity, and mobile objects.

We propose adding safe, efficient garbage collection to C++, eliminating the possibility of storage-management bugs and making the design of complex, object-oriented systems much easier. This can be accomplished with almost no change to the language itself and only small changes to existing implementations, while retaining compatibility with existing class libraries. Our proposal is the first to take a holistic, system-level approach, integrating four technologies. The language interface specifies how programmers access garbage collection through the language. An optional safe subset of the language automatically enforces the safe-use rules of garbage collection and precludes storage bugs. A variety of collection algorithms are compatible with the language interface, but some are easier to implement and more compatible with existing C++ and C implementations. Finally, codegenerator safety ensures that compilers generate correct code for use with collectors. John R. Ellis and David L. D...

Abstract:Object-oriented languages dominate procedural languages in certain software-engineering categories but not in others. Further progress may involve adapting and reintroducing principles that are already well understood and widely exploited in procedural languages..