Multi-set rewrite rules with guards and a parallel execution scheme. Thus, we can easily built more high-level concurrency abstractions such as CHRs, join-patterns etc. Installation via cabal: runhaskell Setup.hs configure --ghc --user --prefix=$HOME runhaskell Setup.hs build runhaskell Setup.hs install Check out the examples (extra-source-files) for how to use the library extension. I'll add more information later.