Now the player can't walk on solid cells

src/Dungeon.hs

@@ -1,13 +1,14 @@
 module Dungeon where
 
 import Data.Matrix hiding ((<|>))
+import Linear.V2
 import Data.Tuple
 import Data.Maybe
 import Control.Applicative ((<|>))
 
 data Cell = Solid
-  | Empty
-  deriving (Eq)
+          | Empty
+          deriving (Eq)
 
 instance Show Cell where
   show cell = [fromJust (lookup cell cellChars <|> Just '?')]
@@ -30,3 +31,6 @@ makeDungeonFromFile f = do
 
 dungeonToLists :: Dungeon -> [[Cell]]
 dungeonToLists (Dungeon m) = toLists m
+
+getCell :: V2 Int -> Dungeon -> Cell
+getCell (V2 x y) (Dungeon m) = fromMaybe Solid (safeGet (y+1) (x+1) m)

src/Game.hs

@@ -20,9 +20,13 @@ makeLenses ''Game
 newGame :: IO Game
 newGame = do
   dun <- makeDungeonFromFile "maps/test.map"
-  return $ Game dun (Player $ V2 0 0)
+  return $ Game dun (Player $ V2 1 1)
 
 runAction :: Action -> Game -> Maybe Game
-runAction (Move vec) game = Just $ game & player . pos +~ vec
+runAction (Move vec) game =
+  if ableToMove then Just $ game & player . pos .~ newPos
+                else Just game
+  where ableToMove = getCell newPos (game ^. dungeon) == Empty
+        newPos = (game ^. player . pos) + vec
 runAction None g = Just g
 runAction ExitGame _ = Nothing