[Haskell-cafe] Re: Composing monads

[Maurí­cio]

 >> Hi,
 >>
 >> If I have two computations a->IO b and
 >> b->IO c, can I join them to get an a->IO
 >> c computation? I imagine something like a
 >> liftM dot operator.

 >     This is called Kleisli composition, by the way; it's
 >     defined as (>=>) in Control.Monad.
 >     jcc

 > Even if you didn't know about (>=>)(...):>
 >
 > (>=>) :: (Monad m) => (a -> m b) -> (b -> m c) -> (a -> m c)
 > (>=>) f g a = f a >>= g
 > (...)

I always learn a lot in this list. Here is my >*>
operator, that helps the code I was actually
trying to write. Feel free to send it to
obfuscated monad composition context.

Thanks for the tips,
Maurício

-----------
module Main (Main.main) where
import Control.Monad
import System.IO

(>*>) :: Monad m => m () -> (a -> m ()) -> (a -> m ())
(>*>) f f' = \a -> do{
   f;
   f' a;
}

main :: IO ()
main = mapM_ ((putStrLn "") >*> putStrLn) $
           map show [1,2,3]