From: Michael Andreen <harv@ruin.nu>
Date: Thu, 2 Mar 2006 19:48:59 +0000 (+0000)
Subject: added  pushAndPop function to push and pop the scope
X-Git-Url: https://ruin.nu/git/?p=proglang.git;a=commitdiff_plain;h=92fd10b102519d03741d61c2679c4cfbe1b486a4

added  pushAndPop function to push and pop the scope
---

diff --git a/Interpret.hs b/Interpret.hs
index 5a792b9..8ac65bf 100644
--- a/Interpret.hs
+++ b/Interpret.hs
@@ -89,6 +89,11 @@ 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 ()
@@ -96,17 +101,14 @@ 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 ()
+	if b then pushAndPop (execute s) >> execute (SWhile e s) else return ()
 execute (SDecl t i e) =do
 	e' <- eval e
 	(m:ms) <- get