import Data.Map as Map
import Data.Maybe

data Coordinates = Coordinates Int Int deriving Eq

instance Ord Coordinates where
    compare (Coordinates a b) (Coordinates c d)
        |(b == d) = a `compare` c
        |otherwise = b `compare` d

data Color = White | Black

instance Show Color where
   show White = "o"
   show Black = "x"

data Board = Board (Map Coordinates Color)

toString (Board map) =
    putStr(iterate([Coordinates x y | y <- [1..19], x <- [1..19]]))
        where
            iterate [element] = (mapToCharacter element) ++ (newLine element)
            iterate (element:listOfCoordinates) = (mapToCharacter element) ++ (newLine element) ++ iterate(listOfCoordinates)
            mapToCharacter coordinates
                | (member coordinates map) = show(fromJust (Map.lookup coordinates map))
                | otherwise = " "
            newLine (Coordinates x y)
                | (x == 19) = "\n"
                | otherwise = ""