typechecking of functions added, not function calls yet though

diff --git a/Typecheck.hs b/Typecheck.hs
index 29008bd2213c250a487f7c303287e3f245c445b7..18146506a227857ce792198ba9e8575491c7f553 100644 (file)
--- a/Typecheck.hs
+++ b/Typecheck.hs
@@ -1,15 +1,15 @@
-module Typecheck where -- (typeCheckExp, typeCheckStm, typeCheckVar, State) where 
+module Typecheck (typeCheckExp, typeCheckStm, typeCheckVar, typeCheckFunction, addFunction, State(..)) where 
 
 
 import Abssyntax
 import Control.Monad.State hiding (State)
-import Data.Map as Map
+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}
+data State = State {variables::Types,functions::(Map Ident Function),function::Ident}
 
 
 inList :: Eq a => a -> [a] -> Bool
@@ -87,6 +87,12 @@ 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 State m) => Ident -> Type -> m ()
 addVariable i t = do
@@ -94,3 +100,18 @@ addVariable i t = do
        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

diff --git a/Typechecker.hs b/Typechecker.hs
index 8828fbeab974b228fead9839c44491f20d6114a7..71810e698b7854109d0f728951f504b25ab45cda 100644 (file)
--- a/Typechecker.hs
+++ b/Typechecker.hs
@@ -45,7 +45,7 @@ run v p s = let ts = myLLexer s in case p ts of
        Ok (Program s) -> let (fun,st) = splitFunStm (s) in do
                putStrLn "\nParse Successful!"
                showTree v (Program s)
-               runStateT (mapM typeCheckStm st) State{variables=[empty], functions=[empty], function=(Ident "")}
+               runStateT (do mapM addFunction fun; mapM typeCheckFunction fun; mapM typeCheckStm st) State{variables=[empty], functions=(empty), function=(Ident "")}
                print "The program is type-correct!!"
                return ()
 

diff --git a/examples/func b/examples/func
index fcebceb5f0c5fb97663d8986ef41603a29cc0ef7..4abaa7e66fb44ad6d8231cec37e14bf75c3d594f 100644 (file)
--- a/examples/func
+++ b/examples/func
@@ -8,5 +8,5 @@ int fac(int n){
        n++;
        int sum = 1;
        while (n-- > 1) sum = sum * n;
-       return n;
+       return sum;
 }