Initial

1 files changed, 61 insertions, 0 deletions

diff --git a/TypeRules.hs b/TypeRules.hs
new file mode 100644
index 0000000..a3e7678
--- /dev/null
+++ b/TypeRules.hs
@@ -0,0 +1,61 @@
+module TypeRules where
+
+import AST
+
+
+canCoerce :: Type -> Type -> Bool
+canCoerce t1 t2 | t1 == t2 = True
+canCoerce (TArr t1 (Just _)) (TArr t2 Nothing) | t1 == t2 = True
+canCoerce _ _ = False
+
+canCast :: Type -> Type -> Bool
+canCast t1 t2 | canCoerce t1 t2 = True
+canCast t1 t2 | isIntegralType t1 && isIntegralType t2 = True
+canCast _ _ = False
+
+isBasicType :: Type -> Bool
+isBasicType = isIntegralType
+
+isIntegralType :: Type -> Bool
+isIntegralType TInt = True
+isIntegralType TChar = True
+isIntegralType _ = False
+
+isSimpleArithBO :: BinaryOp -> Bool
+isSimpleArithBO = flip elem [BOAdd, BOSub, BOMul, BODiv, BOMod]
+
+isBoolBO :: BinaryOp -> Bool
+isBoolBO = flip elem [BOAnd, BOOr]
+
+isCompareBO :: BinaryOp -> Bool
+isCompareBO = flip elem [BOEq, BONeq, BOGt, BOLt, BOGeq, BOLeq]
+
+retTypeBO :: BinaryOp -> Type -> Type -> Maybe Type
+retTypeBO bo TInt TInt | isSimpleArithBO bo = Just TInt
+retTypeBO bo TChar TChar | isSimpleArithBO bo = Just TChar
+retTypeBO bo TInt TInt | isBoolBO bo = Just TInt
+retTypeBO bo TInt TInt | isCompareBO bo = Just TInt
+retTypeBO bo TChar TChar | isCompareBO bo = Just TInt
+retTypeBO _ _ _ = Nothing
+-- retTypeBO bo t1 t2 = error $ "retTypeBO " ++ show bo ++ " " ++ show t1 ++ " " ++ show t2
+
+retTypeUO :: UnaryOp -> Type -> Maybe Type
+retTypeUO UONot TInt = Just TInt
+retTypeUO UONeg TInt = Just TInt
+retTypeUO UONeg TChar = Just TChar
+retTypeUO _ _ = Nothing
+
+class TypeOf a where
+    typeof :: a -> Maybe Type
+
+instance TypeOf Expression where
+    typeof (EBin _ _ _ mt) = mt
+    typeof (EUn _ _ mt) = mt
+    typeof (ELit _ mt) = mt
+    typeof (ESubscript _ _ mt) = mt
+    typeof (ECast t _) = Just t
+    typeof (ENew t _) = Just $ TArr t Nothing
+
+instance TypeOf AsExpression where
+    typeof (AEVar _ mt) = mt
+    typeof (AESubscript _ _ mt) = mt