introduced pushAndPop in the typechecker too

[proglang.git] / Typecheck.hs

diff --git a/Typecheck.hs b/Typecheck.hs
index 770c079e4bf73259e4a77d36cabc4aaccb310c1e..cdba298976ad2aefcecaf7e71a52b74ebb6415f0 100644 (file)
--- a/Typecheck.hs
+++ b/Typecheck.hs
@@ -1,5 +1,6 @@
 module Typecheck (typeCheckExp, typeCheckStm, typeCheckVar) where 
 
+
 import Abssyntax
 import Control.Monad.State
 import Data.Map as Map
@@ -11,29 +12,31 @@ inList :: Eq a => a -> [a] -> Bool
 inList _ [] = False
 inList a (x:xs) = if a == x then True else inList a xs
 
+assert :: Monad m => Bool -> String -> m ()
+assert True _ = return ()
+assert False s = fail s
+
 typeCheckExp :: (MonadState Types m) => Exp -> m Type
 typeCheckExp (BiOpExp e o e') = do
        t1 <- typeCheckExp e
        t2 <- typeCheckExp e'
-       if not(t1 == t2) then fail "The parameters for the binary operator aren't equal" 
-               else if inList o [Eq,NEq] then return TBool
-                       else if not(t1 == TInt) then fail "The parameters need to be of type int" 
-                               else if inList o [Plus,Minus,Times,Div]
-                                       then return TInt
-                                       else return TBool
+       assert (t1 == t2) "The parameters for the binary operator aren't equal"
+       if inList o [Eq,NEq] then return TBool
+               else do 
+                       assert (t1 == TInt) "The parameters need to be of type int" 
+                       if inList o [Plus,Minus,Times,Div]
+                               then return TInt
+                               else return TBool
 typeCheckExp (EVar i) = typeCheckVar i
 typeCheckExp (EAss i e) = do
        t <- typeCheckVar i
        t2 <- typeCheckExp e
-       if t == t2 then return t else fail $ "Illegal to assign an expression of type "++show t2++" to variable "++show i++" of type "++show t 
+       assert (t == t2) $ "Illegal to assign an expression of type "++show t2++" to variable "++show i++" of type "++show t 
+       return t
 typeCheckExp (EInt i) = return TInt
 typeCheckExp (EBool b) = return TBool
 typeCheckExp EReadI = return TInt
 typeCheckExp EReadB = return TBool
-typeCheckExp (ExpT t e) = do
-       t2 <- typeCheckExp e
-       if t == t2 then return t else fail "Something went wrong ExpT is created with the wrong type"
-typeCheckExp EDefault = return NoType
 typeCheckExp (EPost i op) = do
        TInt <- typeCheckVar i
        return TInt
@@ -53,34 +56,32 @@ findVariable :: (MonadState Types m) => Ident -> Types -> m Type
 findVariable i [] = fail $ "Variable "++show i++" not found in any scope."
 findVariable i (m:ms) = if member i m then lookup i m else findVariable i ms
 
-typeCheckStm :: (MonadState Types m) => Stm -> m Type 
-typeCheckStm SNoop = return NoType
-typeCheckStm (SExp e) = do 
-       typeCheckExp e
-       return NoType
-typeCheckStm (SBlock ss) = do 
+pushAndPop :: (MonadState Types m) => m a -> m ()
+pushAndPop s = do
        modify (empty:)
-       mapM typeCheckStm ss
+       s
        modify tail
-       return NoType
+
+typeCheckStm :: (MonadState Types m) => Stm -> m ()
+typeCheckStm SNoop = return ()
+typeCheckStm (SExp e) = do 
+       typeCheckExp e
+       return ()
+typeCheckStm (SBlock ss) = pushAndPop $ mapM typeCheckStm ss
 typeCheckStm (SIf e s s') = do
        TBool <- typeCheckExp e
-       NoType <- typeCheckStm s
-       NoType <- typeCheckStm s
-       return NoType
+       pushAndPop $ typeCheckStm s
+       pushAndPop $ typeCheckStm s'
 typeCheckStm (SWhile e s) = do
        TBool <- typeCheckExp e
-       NoType <- typeCheckStm s
-       return NoType
+       pushAndPop $ typeCheckStm s
 typeCheckStm (SDecl t i e) = do
        t2 <- typeCheckExp e
-       if t == t2 || t2 == NoType then 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
-               return NoType
-               else fail $ "Illegal to assign an expression of type "++show t2++" to variable "++show i++" of type "++show t
+       assert (t == t2) $ "Illegal to assign an expression of type "++show t2++" to variable "++show i++" of type "++show t
+       (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 NoType
+       return ()