Question

here’s a snip from my code:

io f = interact (unlines . f . lines)

io (sortBy compare (read :: String -> Int))

so I read the lines, get the numeric value, and sort by them. Care to guide me in the right path?

Answer 1

You need to use comparing from the Data.Ord module instead of compare:

import Data.Ord
import Data.List

io f = interact (unlines . f . lines)
main = io (sortBy (comparing (read :: String -> Int)))