On Sun, 2008-08-03 at 14:52 +0000, Roly Perera wrote: > > I'm obviously missing something basic here but I don't seem to be able to > > use > > the >=> operator which is apparently defined in the Prelude and also in > > Control.Monad. > > Sorry, I wasn't very clear in my original posting. What I meant to say is > that > the compiler seems to be unable to find a definition of >=>. I get the > message: > > Not in scope: `>=>' > > My understanding is that I shouldn't need to import this at all by default, > and > that importing Control.Monad should also pick it up.
It's not in the Prelude but it is in Control.Monad in base version 3 and later. You're probably using an older GHC which has base version 2.x. You can define it locally: -- | Left-to-right Kleisli composition of monads. (>=>) :: Monad m => (a -> m b) -> (b -> m c) -> (a -> m c) f >=> g = \x -> f x >>= g Duncan _______________________________________________ Haskell-Cafe mailing list [email protected] http://www.haskell.org/mailman/listinfo/haskell-cafe
