On Fri, 09 Dec 2011 23:05:15 +0100, David McBride
data Monster = Orc | Wolf | Dragon deriving (Show, Enum)
randomMonster :: RandomGen g => Rand g Monster randomMonster = do x <- getRandomR (0,2::Int) return $ case x of 0 -> Orc 1 -> Dragon 2 -> Wolf
You have already created an Enum instance of Monster, so why not use it: randomMonster :: RandomGen g => Rand g Monster randomMonster = do x <- getRandomR (0,2::Int) return $ toEnum x Or: randomMonster :: RandomGen g => Rand g Monster randomMonster = toEnum <$> getRandomR (0,2::Int) where <$> is imported from module Data.Functor or Control.Applicative. Regards, Henk-Jan van Tuyl -- http://Van.Tuyl.eu/ http://members.chello.nl/hjgtuyl/tourdemonad.html --