X-Git-Url: https://ruin.nu/git/?a=blobdiff_plain;f=Typecheck.hs;h=6f65d6e2f538d18d554787225c4aa138918a586f;hb=2c2f90fca1005f6dedc69ee7f3d7c5072e5c123b;hp=35ed382d11e00e572eb4094153101ba54a34453e;hpb=e9be0603d9dbd1caa6a0032cad0e39815cb8f38d;p=proglang.git

diff --git a/Typecheck.hs b/Typecheck.hs
index 35ed382..6f65d6e 100644
--- a/Typecheck.hs
+++ b/Typecheck.hs
@@ -1,44 +1,58 @@
-module Typecheck where 
+module Typecheck (typeCheckExp, typeCheckStm, typeCheckVar) where 
+
 
 import Abssyntax
 import Control.Monad.State
 import Data.Map as Map
 import Prelude hiding (lookup)
 
+type Types = [Map Ident Type]
 
-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
-	b <- typeCheckExp e
-	if a == b then return a else fail "FEL!"
+	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 
 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 "FEL!"
+	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
-
+typeCheckExp (ENeg e) = do
+	TInt <- typeCheckExp e
+	return TInt
+typeCheckExp (ENot e) = do
+	TBool <- typeCheckExp e
+	return TBool
 
 typeCheckVar :: (MonadState Types m) => Ident -> m Type 
 typeCheckVar i = do
-	e <- get
-	lookup i e
+	ms <- get
+	findVariable i ms
+
+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
@@ -46,7 +60,9 @@ typeCheckStm (SExp e) = do
 	typeCheckExp e
 	return NoType
 typeCheckStm (SBlock ss) = do 
+	modify (empty:)
 	mapM typeCheckStm ss
+	modify tail
 	return NoType
 typeCheckStm (SIf e s s') = do
 	TBool <- typeCheckExp e
@@ -59,12 +75,13 @@ typeCheckStm (SWhile e s) = do
 	return NoType
 typeCheckStm (SDecl t i e) = do
 	t2 <- typeCheckExp e
-	if t == t2 then do
-		m <- get
-		put (insert i t m)
+	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 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
-