X-Git-Url: https://ruin.nu/git/?a=blobdiff_plain;f=Typecheck.hs;h=2414203d7d81441d89080f3c3dc8d5486f140600;hb=d2416679eff983d31ea9b2de4bdd0124c50bd20d;hp=35ed382d11e00e572eb4094153101ba54a34453e;hpb=e9be0603d9dbd1caa6a0032cad0e39815cb8f38d;p=proglang.git

diff --git a/Typecheck.hs b/Typecheck.hs
index 35ed382..2414203 100644
--- a/Typecheck.hs
+++ b/Typecheck.hs
@@ -1,4 +1,4 @@
-module Typecheck where 
+module Typecheck (typeCheckExp, typeCheckStm, typeCheckVar) where 
 
 import Abssyntax
 import Control.Monad.State
@@ -8,15 +8,20 @@ import Prelude hiding (lookup)
 
 type Types = Map Ident Type
 
+inList :: Eq a => a -> [a] -> Bool
+inList _ [] = False
+inList a (x:xs) = if a == x then True else inList a xs
+
 typeCheckExp :: (MonadState Types m) => Exp -> m Type
-typeCheckExp (BExp e o e') = do
-	TInt <- typeCheckExp e
-	TInt <- typeCheckExp e'
-	return TBool
-typeCheckExp (OpExp e o e') = do
-	TInt <- typeCheckExp e
-	TInt <- typeCheckExp e'
-	return TInt
+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
 typeCheckExp (EVar i) = typeCheckVar i
 typeCheckExp (EAss i e) = do
 	a <- typeCheckVar i
@@ -33,6 +38,9 @@ typeCheckExp EDefault = return NoType
 typeCheckExp (EPost i op) = do
 	TInt <- typeCheckVar i
 	return TInt
+typeCheckExp (ENeg e) = do
+	TInt <- typeCheckExp e
+	return TInt
 
 
 typeCheckVar :: (MonadState Types m) => Ident -> m Type 
@@ -59,11 +67,13 @@ typeCheckStm (SWhile e s) = do
 	return NoType
 typeCheckStm (SDecl t i e) = do
 	t2 <- typeCheckExp e
-	if t == t2 then do
+	if t == t2 || t2 == NoType then do
 		m <- get
-		put (insert i t m)
+		case insertLookupWithKey (\k a1 a2 -> a1) i t m of 
+			(Nothing,m') -> put m'
+			_ -> 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 t2
+		else fail $ "Illegal to assign an expression of type "++show t2++" to variable "++show i++" of type "++show t
 typeCheckStm (SPrint e) = do
 	typeCheckExp e
 	return NoType