So that's not safe, and thus it should be in the IO monad.
How can i handle a lazy list with IO monad. For example, function co (x:xs) Šc ==1 = 1:co (xs) Šc == 2 = 0:co (xs) where c = unsafePerformIO(f (x:xs)) will be written without unsafePerformIO: co' (x:xs) = do c1 <- co' xs c<- f (x:xs) if (c==1) then return 1:c1 else return 0:c1 AFAICS, co' does not do lazy evaluation, so wont print any element of the list. Can lazy evaluation be integrated with IO monad ? Cheers TuanAnh _________________________________________________________________ Want to block unwanted pop-ups? Download the free MSN Toolbar now! http://toolbar.msn.co.uk/