ptk is a tool that performs a syntax and semantic analysis on Message Sequence Charts and generates test scripts from them in a number of different languages including SDL, TTCN, and C. Message Sequence Charts are typically used in the telecommmunications  industry for specifying system requirements. The generated test scripts are used to verify applications that implement the requirements.

The implementation models MSCs with the process algebra CSP, and uses a tactical term rewriting engine to generate test scripts.  Functional languages were found to be ideal for implementing tactical term rewriters.