JNP3 Sokoban coordinates and direction handling

SokobanCoord.hs

data Coord = C Integer Integer
data Direction = R | U | L | D
data World = W Coord Direction Maze

handleEvent :: Event -> World -> World
handleEvent (KeyPress key) (W pos direction maze) = W pos'' dir'' maze where
      maybeDir = keyToDir key
      (pos', dir'')
        | Just  dir' <- maybeDir = (moveCoordDir dir' pos, dir')
        | otherwise = (pos, direction)
      pos'' = if isCoordValidForPlayer pos' maze then pos' else pos
handleEvent _ world = world

type CoordVec = (Integer, Integer)
-- dirToVec d = (round (negate $ sin a), round(cos a)) where a = directionToAngle d
dirToVec :: Direction -> CoordVec
dirToVec R = (1,0)
dirToVec U = (0,1)
dirToVec L = (-1,0)
dirToVec D = (0,-1)

maybeDirToVec :: Maybe Direction -> CoordVec
maybeDirToVec = maybe (0,0) dirToVec 

moveCoordVec :: CoordVec -> Coord -> Coord
moveCoordVec (dx, dy) (C x y) = C (x+dx) (y+dy)

moveCoordDir :: Direction -> Coord -> Coord
moveCoordDir = moveCoordVec . dirToVec

keyToDir :: Text -> Maybe Direction
keyToDir "Left"  = Just L
keyToDir "Up"    = Just U
keyToDir "Right" = Just R
keyToDir "Down"  = Just D
keyToDir _       = Nothing