In Haskell, you can represent a state machine and its current state using an iteratee: http://www.yesodweb.com/blog/2010/09/enumerators-tutorial-part-1 http://

In Haskell, you can represent a state machine and its current state using an iteratee: http://www.yesodweb.com/blog/2010/09/enumerators-tutorial-part-1 http://www.yesodweb.com/blog/2010/09/enumerators-tutorial-pa... An iteratee is essentially just a function that takes an input symbol and returns either a final state value or another iteratee.