Quick and dirty skelleton

Main.hs

module Main (main) where

import           Control.Monad (unless)
import           Prelude       hiding (Left, Right)
import           System.IO     (BufferMode (NoBuffering), hSetBuffering, isEOF,
                                stdout)

type Stone = Int

data Direction = Up
               | Right
               | Down
               | Left

-- Main, was sonst?
main :: IO ()
main = do
  hSetBuffering stdout NoBuffering -- stdout nicht Buffern!
  processInput respond             -- Springe in Hauptschleife und rufe dort
                                   -- immer `respond` auf.

-- Hauptschleife, liest die Eingabezeile und kümmert sich um die Ausgabe
processInput :: (String -> Char) -> IO ()
processInput f = do
  finished <- isEOF
  unless finished $ do
    getLine >>= putChar . f
    processInput f

-------------------------------------------------------------------------------
-------------------------------------------------------------------------------


respond :: String -> Char
respond = dirToKey . makeMove . parseBoard

dirToKey :: Direction -> Char
dirToKey Up    = 'n'
dirToKey Down  = 's'
dirToKey Left  = 'w'
dirToKey Right = 'e'

parseBoard :: String -> [[Stone]]
parseBoard input = read (modifiedInput) :: [[Stone]]
  where
    modifiedInput = '[': (tail . init) input ++ "]"

-------------------------------------------------------------------------------
-------------------------------------------------------------------------------

makeMove :: [[Stone]] -> Direction
makeMove d = Up