Given a list of numbers, I want to modify
each of those numbers by adding a
random offset. However, each such modified number shall stay within
certain
bounds, given by the integers minValue and maxValue. After that, I want
to
continue computation with the resulting list of type [Int].
Personally, I'd do something like this, isolate the IO code outside the
algorithm to keep the algorithm pure:
modify' :: Int -> Int -> Int
modify' offset a = normalize (a + offset)
generateInfiniteListOfRandomNumbers :: IO [Int]
-- implementation left as an exercise
main = do
randomNumbers <- generateInfiniteListOfRandomNumbers
print $ zipWith modify' randomNumbers [0, 200, 400, 600, 800, 1000]
I may be wrong, but generateInfiniteListOfRandomNumbers won't
terminate and I think it has to before the next IO action occurs.
(Laziness is great, but I don't think you can really do lazy IO like
that.)
Instead of map :: (a -> b) -> [a] -> [b], I think
you are looking for mapM :: Monad m => (a -> m b) -> [a]
-> m [b].
Hope this helps,
Thomas