Write main engine algorithm

GOL/Engine.hs

@@ -11,3 +11,20 @@ import GOL.Space
 
 type GOL f = EnvT Rule (Store f)
 
+getNeighbors :: forall s f a. Space s f => GOL f a -> [a]
+getNeighbors = experiment $ neighbors @s @f
+
+nextState :: Space s f => GOL f Bool -> Bool
+nextState = do
+  selfState <- extract
+  neighborStates <- getNeighbors
+  let count = sum . fmap (bool 0 1) $ neighborStates
+  
+  Rule survive birth <- ask
+  return $ if selfState
+            then survive count
+            else birth count
+
+
+tick :: Space s f => GOL f Bool -> GOL f Bool
+tick = extend nextState