Haskell-Coloured Petri Nets

Colored Petri Nets (CPNs) are a high-level form of Petri Nets, in which transition inscriptions in some programming language operate on individual tokens, i.e., tokens attributed with values of the inscription language. Petri Nets have been known to combine wen with functional inscription languages, but complex or even proprietary implementations have so far been obstacles to more widespread use. We show that such functional CPNs can have straightforward embeddings into their functional inscription languages. As a concrete example, we introduce the variant of Haskell-Colored Petri Nets (HCPNs) and show that they have a simple mapping to Haskell. HCPNs are thus readily available for system modeling, possibly in preparation of system implementation in Haskell, following a process of stepwise refinement in which all intermediate specifications are executable Haskell programs. Similar mappings can be used to introduce functional Petri Nets as graphical specification languages on top of other functional languages.