PEW
PEW is a persistent execution engine for π-calculus workflows generated by the WorkflowFM process composition tools, written in Scala. It is part of our WorkflowFM framework for formal workflow modelling and management.
It is available under the Apache 2.0 License on GitHub: https://github.com/workflowfm/pew
Website and documentation is available here: http://docs.workflowfm.com/pew/