optimize store with const 0

Eval.hs

@@ -51,7 +51,10 @@ instance Monad Turn where
 	return x = Turn $ \game -> return (game, Right x)
 	fail s = Turn $ \game -> return (game, Left s)
 
-liftIO :: IO x -> Turn x
+class Monad m => MonadIO m where
+	liftIO :: IO x -> m x
+
+instance MonadIO Turn where
 	liftIO f = Turn $ \game -> f >>= \x -> return (game, Right x)
 
 apply :: Int -> Turn ()

Lambda.hs

@@ -1,3 +1,4 @@
+{-# OPTIONS -XTypeSynonymInstances #-}
 
 module Lambda where
 
@@ -81,7 +82,9 @@ copyTo src dst = if (src == dst) then [] else storeInt dst src ++ [MoveLeft Card
 store :: Int -> Term -> [Move]
 store pos (Const n) = storeInt pos n
 store pos (Apply (Prim c) t) = store pos t ++ [MoveLeft c pos]
+store pos (Apply (Const 0) t) = store pos t ++ [MoveLeft Card_Zero pos]
 store pos (Apply t (Prim c)) = store pos t ++ [MoveRight pos c]
+store pos (Apply t (Const 0)) = store pos t ++ [MoveRight pos Card_Zero]
 store pos (Prim c) = [MoveLeft Card_Zero pos, MoveRight pos c]
 store pos (Seq a b) = store pos (Apply (Apply (Apply (Prim Card_S) a) b) (Prim Card_Zero))
 store pos (Apply a b) = if (pos == 0) then store 1 (Apply a b) ++ copyTo 1 0 else store pos a ++ store (pos+1) b ++ copyTo (pos+1) 0 ++ [MoveLeft Card_K pos, MoveLeft Card_S pos, MoveRight pos Card_Get, MoveRight pos Card_Zero]