minor stuff

[proglang.git] / Typecheck.hs

diff --git a/Typecheck.hs b/Typecheck.hs
index cdba298976ad2aefcecaf7e71a52b74ebb6415f0..1b0baa00ed5d48dc760f029f9759e8bb821eed9c 100644 (file)
--- a/Typecheck.hs
+++ b/Typecheck.hs
@@ -1,4 +1,4 @@
-module Typecheck (typeCheckExp, typeCheckStm, typeCheckVar) where 
+module Typecheck (typeCheck,typeCheckExp, typeCheckStm, typeCheckVar) where 
 
 
 import Abssyntax
@@ -16,6 +16,9 @@ assert :: Monad m => Bool -> String -> m ()
 assert True _ = return ()
 assert False s = fail s
 
+typeCheck :: [Stm] -> IO ()
+typeCheck s = runStateT (mapM typeCheckStm s) [empty] >> return ()
+
 typeCheckExp :: (MonadState Types m) => Exp -> m Type
 typeCheckExp (BiOpExp e o e') = do
        t1 <- typeCheckExp e
@@ -75,13 +78,18 @@ typeCheckStm (SIf e s s') = do
 typeCheckStm (SWhile e s) = do
        TBool <- typeCheckExp e
        pushAndPop $ typeCheckStm s
+typeCheckStm (SDeclD t i) = addVariable i t
 typeCheckStm (SDecl t i e) = do
        t2 <- typeCheckExp e
        assert (t == t2) $ "Illegal to assign an expression of type "++show t2++" to variable "++show i++" of type "++show t
+       addVariable i t
+typeCheckStm (SPrint e) = do
+       typeCheckExp e
+       return ()
+
+addVariable :: (MonadState Types m) => Ident -> Type -> m ()
+addVariable i t = do
        (m:ms) <- get
        case insertLookupWithKey (\k a1 a2 -> a1) i t m of
                (Nothing,m') -> put (m':ms)
                _ -> fail $ "Duplicate variable declaration: "++show i
-typeCheckStm (SPrint e) = do
-       typeCheckExp e
-       return ()