[Haskell-cafe] Monad transformer, liftIO

Michael Roth mroth at nessie.de
Fri Apr 3 12:49:36 EDT 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?


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