Stephen Tetley wrote: > > To work with monads in Haskell its not ignoble simple to decide what > effect or combination of effects you want and use the relevant monad > (for a single effect) or build a transformer (for multiple effects).
... or use the "free term algebra" approach outlined in http://apfelmus.nfshost.com/articles/operational-monad.html when the semantics of the effects are a bit tricky to fit into existing transformers. My package "operational" http://projects.haskell.org/operational/ contains a bunch of examples. Regards, Heinrich Apfelmus -- http://apfelmus.nfshost.com _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe