typechecking of functions added, not function calls yet though

[proglang.git] / Typecheck.hs

diff --git a/Typecheck.hs b/Typecheck.hs
index 70aad706a88cfc5b38a1863744ccce563772e490..18146506a227857ce792198ba9e8575491c7f553 100644 (file)
--- a/Typecheck.hs
+++ b/Typecheck.hs
@@ -1,12 +1,16 @@
-module Typecheck (typeCheckExp, typeCheckStm, typeCheckVar) where 
+module Typecheck (typeCheckExp, typeCheckStm, typeCheckVar, typeCheckFunction, addFunction, State(..)) where 
 
 
 import Abssyntax
-import Control.Monad.State
-import Data.Map as Map
+import Control.Monad.State hiding (State)
+import Data.Map as Map hiding (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
@@ -83,10 +87,31 @@ typeCheckStm (SDecl t i e) = do
 typeCheckStm (SPrint e) = do
        typeCheckExp e
        return ()
+typeCheckStm (SReturn e) = do
+       t <- typeCheckExp e
+       state <- get
+       (t2,_) <- lookup (function state) $ functions state
+       assert (t == t2) $ "Illegal to return "++show t++" in function "++show (function state)++" which returns "++show t2
+
 
-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
+
+typeCheckFunction :: (MonadState State m) => Func -> m ()
+typeCheckFunction (Func t i d s) = do
+       state <- get
+       modify (\s -> s{variables=[empty], function=i})
+       mapM (\(Decl t i) -> addVariable i t) d
+       mapM typeCheckStm s
+       put state
+
+addFunction :: (MonadState State m) => Func -> m ()
+addFunction (Func t i d _) = do
+       s <- get
+       let m = functions s in case insertLookupWithKey (\k a1 a2 -> a1) i (t, map (\(Decl t i) -> t) d) m of
+               (Nothing,m') -> modify (\s -> s{ functions = m'})
                _ -> fail $ "Duplicate variable declaration: "++show i