Re: [Haskell-cafe] Simple network client

Peter Verswyvelen wrote:

main = do cs <- getLine putStrLn ("Hello "++cs)

looks so much like

main = do cs <- readFile "foo" writeFile "foo" cs

but in the first one cs is strict, while the second it is lazy... But that's not obvious.

Now I'm confused (which happens quite a lot, I'm afraid!) Prelude> readFile undefined *** Exception: Prelude.undefined Prelude> readFile undefined >>= \cs -> putStrLn "Hello" *** Exception: Prelude.undefined It seems that readFile is strict in its argument. As for getLine, it has no argument to be strict in. What am I missing? Dan