[Haskell-cafe] Monad transformer, liftIO

3 Apr 2009

      Hello list,

maybe I'm just stupid, I'm trying to do something like this:

	import Control.Monad
	import Control.Monad.Trans
	import Control.Monad.List

	foobar = do
	        a <- [1,2,3]
        	b <- [4,5,6]
	        liftIO $ putStrLn $ (show a) ++ " " ++ (show b)
        	return (a+b)

	main = do
		sums <- foobar
		print sums

But this apparently doesn't work... I'm total clueless how
to achieve the correct solution. Maybe my mental image
on the monad transformer thing is totally wrong?

Michael

[Haskell-cafe] Monad transformer, liftIO

Michael Roth