typechecker compiles and is compatible with old programs while using the new state...

[proglang.git] / Typecheck.hs

diff --git a/Typecheck.hs b/Typecheck.hs
index 70aad706a88cfc5b38a1863744ccce563772e490..29008bd2213c250a487f7c303287e3f245c445b7 100644 (file)
--- a/Typecheck.hs
+++ b/Typecheck.hs
@@ -1,12 +1,16 @@
-module Typecheck (typeCheckExp, typeCheckStm, typeCheckVar) where 
+module Typecheck where -- (typeCheckExp, typeCheckStm, typeCheckVar, State) where 
 
 
 import Abssyntax
-import Control.Monad.State
+import Control.Monad.State hiding (State)
 import Data.Map as Map
 import Prelude hiding (lookup)
 
 type Types = [Map Ident Type]
+type Function = (Type, [Type])
+
+data State = State {variables::Types,functions::[Map Ident Function],function::Ident}
+
 
 inList :: Eq a => a -> [a] -> Bool
 inList _ [] = False
@@ -16,7 +20,7 @@ assert :: Monad m => Bool -> String -> m ()
 assert True _ = return ()
 assert False s = fail s
 
-typeCheckExp :: (MonadState Types m) => Exp -> m Type
+typeCheckExp :: (MonadState State m) => Exp -> m Type
 typeCheckExp (BiOpExp e o e') = do
        t1 <- typeCheckExp e
        t2 <- typeCheckExp e'
@@ -47,22 +51,22 @@ typeCheckExp (ENot e) = do
        TBool <- typeCheckExp e
        return TBool
 
-typeCheckVar :: (MonadState Types m) => Ident -> m Type 
+typeCheckVar :: (MonadState State m) => Ident -> m Type 
 typeCheckVar i = do
-       ms <- get
-       findVariable i ms
+       s <- get
+       findVariable i $ variables s
 
-findVariable :: (MonadState Types m) => Ident -> Types -> m Type
+findVariable :: (MonadState State 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
 
-pushAndPop :: (MonadState Types m) => m a -> m ()
+pushAndPop :: (MonadState State m) => m a -> m ()
 pushAndPop s = do
-       modify (empty:)
+       modify (\s -> s { variables = empty:variables s})
        s
-       modify tail
+       modify (\s -> s { variables = tail $ variables s})
 
-typeCheckStm :: (MonadState Types m) => Stm -> m ()
+typeCheckStm :: (MonadState State m) => Stm -> m ()
 typeCheckStm SNoop = return ()
 typeCheckStm (SExp e) = do 
        typeCheckExp e
@@ -84,9 +88,9 @@ typeCheckStm (SPrint e) = do
        typeCheckExp e
        return ()
 
-addVariable :: (MonadState Types m) => Ident -> Type -> m ()
+addVariable :: (MonadState State m) => Ident -> Type -> m ()
 addVariable i t = do
-       (m:ms) <- get
-       case insertLookupWithKey (\k a1 a2 -> a1) i t m of
-               (Nothing,m') -> put (m':ms)
+       s <- get
+       let (m:ms) = variables s in case insertLookupWithKey (\k a1 a2 -> a1) i t m of
+               (Nothing,m') -> modify (\s -> s{ variables = m':ms})
                _ -> fail $ "Duplicate variable declaration: "++show i