haskell version of code from http://blog.8thlight.com/uncle-bob/2013/01/07/FPBE3-Do-the-rules-change.html

gistfile1.hs

makeUpTo n = mlu n []
  where
    mlu n pre []     = [pre]
    mlu n []  (w:ws) = mlu n w ws
    mlu n pre (w:ws) | length pre + 1 + length w <= n = mlu n (pre ++ ' ' : w) ws
                     | otherwise                      = pre : mlu n [] (w:ws)

t2 n i = putStrLn 
       $ unlines 
       $ makeUpTo n
       $ [ frag | w <- words i, frag <- splitIntoSize n w ]


-- basically a library function, and useful for other kinds of list 
splitIntoSize :: Int -> [a] -> [[a]]
splitIntoSize n = map (take n) . takeWhile (not . null) . iterate (drop n)