X-Git-Url: https://ruin.nu/git/?a=blobdiff_plain;f=Interpret.hs;h=8cf3c1b2657270d016c8f28256b993adbd566c96;hb=d606bc7eda59e30fbb75555b4d4c5da91b7327b9;hp=9e4dcff34541b1f180b73b3c12dc15cbcfb3e642;hpb=4f21d932178a490040cf5e054f3ba9d006579368;p=proglang.git

diff --git a/Interpret.hs b/Interpret.hs
index 9e4dcff..8cf3c1b 100644
--- a/Interpret.hs
+++ b/Interpret.hs
@@ -9,7 +9,8 @@ data Value = VInt Integer | VBool Bool deriving Eq
 
 instance Show Value where
 	show (VInt n) = show n
-	show (VBool b) = show b
+	show (VBool True) = "1"
+	show (VBool False) = "0"
 
 type Variables = [Map Ident Value]
 
@@ -22,8 +23,7 @@ eval :: Exp -> StateT Variables IO Value
 eval (EBool b) = return (VBool b)
 eval (EInt n) = return (VInt n)
 eval (EVar i) = getVariableValue i
-eval (EAss i e) = setVariableValue i e 
-eval EDefault = error "EDefault called from an illegal place"
+eval (EAss i e) = setVariableValue i e
 eval (BiOpExp e o e') = do
 	v <- eval e
 	v'<- eval e'
@@ -44,24 +44,24 @@ eval EReadI = do
 	return $ VInt $ read s
 eval EReadB = do
 	s <- lift $ getWord
-	return $ VBool $ read s
+	return $ VBool $ if (read s == 0) then False else True
 
 getWord :: IO String
 getWord =  do
 	c <- getChar
-	if inList c ['\n','\r',' ', '\t']
+	if inList c [' ', '\n', '\t', '\r']
 		then return ""
 		else do
 			l <- getWord
-			return (c:l) 
+			return (c:l)
 
 -- op :: Op -> (a -> a -> Value)
 opE Eq = \e e' -> VBool $ e == e'
 opE NEq = \e e' -> VBool $ not (e == e')
 op Plus = \e e' -> VInt $ e + e'
-op Minus = \e e' -> VInt $ e - e' 
-op Times = \e e' -> VInt $ e * e' 
-op Div = \e e' -> VInt $ e `div` e' 
+op Minus = \e e' -> VInt $ e - e'
+op Times = \e e' -> VInt $ e * e'
+op Div = \e e' -> VInt $ e `div` e'
 op Lt = \e e' -> VBool $ e < e'
 op ELt = \e e' -> VBool $ e <= e'
 op Gt = \e e' -> VBool $ e > e'
@@ -78,11 +78,6 @@ findVariable i (m:ms) = if member i m then lookup i m else findVariable i ms
 
 --setVariableValue :: (MonadState Variables m) => Ident -> Exp -> m Value 
 --setVariableValue :: (MonadState Variables m) => Ident -> Exp -> m Value 
-addVariable :: Ident -> Exp -> StateT Variables IO ()
-addVariable i e = do
-	e' <- eval e
-	(m:ms) <- get
-	put $ (insert i e' m):ms
 
 setVariableValue :: Ident -> Exp -> StateT Variables IO Value
 setVariableValue i e = do
@@ -95,6 +90,11 @@ updateVariable :: Ident -> Value -> Variables -> Variables
 updateVariable _ _ [] = []
 updateVariable i v (m:ms) = if member i m then insert i v m:ms else m:updateVariable i v ms
 
+pushAndPop :: (MonadState Variables m) => m a -> m ()
+pushAndPop s = do
+	modify (empty:)
+	s
+	modify tail
 
 -- execute :: (MonadState Variables m) => Stm -> m ()
 execute :: Stm -> StateT Variables IO ()
@@ -102,20 +102,18 @@ execute (SNoop) = return ()
 execute (SExp e) = eval e >> return ()
 execute (SIf b s s') = do
 	(VBool b') <- eval b
-	if b' then execute s else execute s'
+	pushAndPop $ if b' then execute s else execute s'
 execute (SPrint e) = do
 	e' <- eval e
 	lift $ print e'
-execute (SBlock ss) = do
-	modify (empty:)
-	mapM execute ss
-	modify tail
+execute (SBlock ss) = pushAndPop $ mapM execute ss
 execute (SWhile e s) = do
 	(VBool b) <- eval e
-	if b then execute s >> execute (SWhile e s) else return ()
-execute (SDecl t i EDefault) = do
-	case t of
-		TInt -> addVariable i (EInt 0)
-		TBool -> addVariable i (EBool False)
-	return ()
-execute (SDecl t i e) = addVariable i e >> return ()
+	if b then pushAndPop (execute s) >> execute (SWhile e s) else return ()
+execute (SDeclD t i) = execute $ SDecl t i $ case t of
+	TInt -> EInt 0
+	TBool -> EBool False
+execute (SDecl t i e) =do
+	v <- eval e
+	(m:ms) <- get
+	put $ (insert i v m):ms