Looking at the wiki summary [1] (very good, BTW), I have a question (I've skipped much of the debate, so please just give a message pointer if I missed something). Why does RandomIO need to use the unsafePerformIO hack if its already in the IO monad? BTW, if the goal is to have a random number generator as a pure (non-IO) function, I *do* think there's a reasonable semantic objection here. I'd also like to request that some reference links are added for some of the proposed solutions: 2b - reference to stToIO 3 - reference to Data.Dynamic, and how a dictionary of types can be used to provide global variables. #g -- [1] http://haskell.org/hawiki/GlobalMutableState ------------ Graham Klyne For email: http://www.ninebynine.org/#Contact