Linefy

Linefy.hs

-- An implementation of http://blog.8thlight.com/uncle-bob/2012/04/20/Why-Is-Estimating-So-Hard.html
type Size = Int
type Word = String
type Line = String
linefy :: Size -> [Word] -> [Line]
linefy s ws = go [] ws
   where go []     (w:ws) | length w > s = []
                          | otherwise    = go [w] ws
         go (l:ls) (w:ws) | length w > s                = []
                          | length w + 1 + length l > s = go (w:l:ls)             ws
                          | otherwise                   = go ((l ++ " " ++ w):ls) ws
         go ls     []     = reverse ls

Uncompiled and untested :)

Took me 5 minutes to write it:

• 1 minute for specification (i.e. type signatures)
• 4 minutes for implementation.

I estimated 10 minutes, considering testing, so it seems to be in the right ballpark.