John Goerzen wrote:
Which leaves me with an odd curiosity -- I still can't figure out how state monads are anything but syntactic sugar (and lead more to spaghetti code at that <g>)
Perhaps because state monads = syntactic sugar. The state monad is just a nice(er) way of passing around some global state (Junk). Without state monads f :: Junk -> a -> (Junk, b) With state monads, f :: a -> State Junk b .... Though if some function doesn't need to 'modify' your Junk, you find yourself having to re-factor things like, decend :: Junk -> Exp -> Exp decend state (Node a t1 t2) = Node a (decend state t1) (decend state t2) into decend :: Exp -> State Junk Exp decend (Node a t1 t2) = do t1' <- decend t1 t2' <- decend t2 return $ Node a t1' t2' .. which IMHO is not as pretty. Ben.