{-# LANGUAGE FlexibleInstances #-}
{-# LANGUAGE IncoherentInstances #-}
-- | Main entry point to the application.
module Main where
import Data.Monoid
import Control.Monad

type Knight = (Int,Int)

move::Knight->[Knight]
move (x,y) = do
    (x',y') <- [(x+1,y+2),(x+2,y+1),(x+1,y-2),(x+2,y-1),(x-1,y+2),(x-2,y+1),(x-1,y-2),(x-2,y-1)]
    guard $ (x' `elem` [1..8]) && (y' `elem` [1..8])
    return (x',y')

instance (Monad m) => Monoid (a-> m a) where
    mempty = return
    mappend  =  (>=>)

-- | The main entry point.
main :: IO ()
main = do
    print $ (mconcat [move | _ <- [1..1]]) (1,1)