Modular PNML revisited: Some ideas for strict typing

The Petri Net Markup Language (PNML) is cur- rently standardised by ISO/IEC JTC1/SC7 WG 19 as Part 2 of ISO/IEC 15909. But, there is not yet a mechanism for structuring large Petri nets and for constructing Petri nets from modules. To this end, modular PNML has been proposed some time ago. But, modular PNML has some problems. These problems along with ideas for their solution will be discussed in this paper. As a first step toward standardising a module concept for PNML in Part 3 of ISO/IEC 15909, this paper proposes a refined concept of modular PNML, which is independent of a particular kind of Petri net, but still has a strict type system. This paper focuses on the ideas and concepts; the technical details still need to be worked out. To this end, this paper also raises some issues and questions that need to be discussed before standardising modular PNML.