rover.hs

import Data.List

dirs = "NESW"

shifts 0 = (0, 1)
shifts 1 = (1, 0)
shifts 2 = (0, -1)
shifts 3 = (-1, 0)

instrn (x, y, a) 'R' = (x, y, mod (a + 1) 4)
instrn (x, y, a) 'L' = (x, y, mod (a - 1 + 4) 4)
instrn (x, y, a) 'M' = (x+fst (shifts a), y+snd (shifts a), a)

showpos (x, y, a) = show x ++ " " ++ show y ++ " " ++ [dirs !! a]
finddir dirchar = 
    case elemIndex dirchar dirs of
      Nothing -> error "invalid direction"
      Just position -> position
readpos line = (x, y, a)
        where a = finddir $ head $ drop 1 line3
              [(y,line3)] = reads line2 :: [(Integer, String)]          
              [(x,line2)] = reads line :: [(Integer, String)]

robo = do
  posn <- getLine
  instrns <- getLine
  putStrLn (showpos (foldl instrn (readpos posn) instrns))
  robo

main = do
  skip <- getLine               -- Skip reading the grid size
  robo