Re: putStr

On Monday 13 October 2003 11:54 am, Jose Morais wrote:

Hi,

I am trying to something like

f1 :: Int -> Int f1 x = f2 x

f2 :: Int -> Int f2 x = 2 * x

but before f2 returns its result I'd like it to print something like "The initial value is " ++ show x.

f1 :: Int -> IO Int f1 x = f2 x f2 :: Int -> IO Int f2 x = do putStrLn $ "The initial value is " ++ show x return (2 * x) The previously mentioned trace method is prefered for debugging because with this, one is now in the IO monad. Shawn