Towards Model-Based Design with PNtalk

The classic approach to the system design consists of two key parts -- the formal (or informal) specification allowing to check the validity and correctness of the designed system, and subsequently the system implementation. The implementations are usually done using traditional programming and tend to diverge from the specifications. To avoid this, there are the possible ways allowing to get the implementation directly from the specification. Since the specification is usually based on models, these approaches are often called model-based. This paper presents our approach to model-based design using PNtalk. PNtalk is an experimental language and system that combines Petri nets and Smalltalk. It is based on a formalism called Object Oriented Petri Nets and its objective is modeling, simulation, and prototyping. The model-based design approach using PNtalk preserves OOPN-based models during all design stages including final implementation. To get the implementation, we use the PNtalk feature allowing to use models not only for the system specification, but also like the system prototype.