minor change

[proglang.git] / Typecheck.hs

diff --git a/Typecheck.hs b/Typecheck.hs
index 29008bd2213c250a487f7c303287e3f245c445b7..a8c10e55f5dc570e99e79fd9b30b9ad085664d11 100644 (file)
--- a/Typecheck.hs
+++ b/Typecheck.hs
@@ -1,34 +1,36 @@
-module Typecheck where -- (typeCheckExp, typeCheckStm, typeCheckVar, State) where 
+module Typecheck (typeCheck, typeCheckExp, typeCheckStm, typeCheckVar, typeCheckFunction, addFunction, emptyState, 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
-inList _ [] = False
-inList a (x:xs) = if a == x then True else inList a xs
+emptyState = State{variables=[empty], functions=(empty), function=(Ident "")}
 
 assert :: Monad m => Bool -> String -> m ()
 assert True _ = return ()
 assert False s = fail s
 
+typeCheck :: [Func] -> [Stm] -> IO ()
+typeCheck fun st = do
+       runStateT (do mapM addFunction fun; mapM typeCheckFunction fun; mapM typeCheckStm st) emptyState
+       return ()
+
 typeCheckExp :: (MonadState State m) => Exp -> m Type
 typeCheckExp (BiOpExp e o e') = do
        t1 <- typeCheckExp e
        t2 <- typeCheckExp e'
        assert (t1 == t2) "The parameters for the binary operator aren't equal"
-       if inList o [Eq,NEq] then return TBool
+       if elem o [Eq,NEq] then return TBool
                else do 
                        assert (t1 == TInt) "The parameters need to be of type int" 
-                       if inList o [Plus,Minus,Times,Div]
+                       if elem o [Plus,Minus,Times,Div]
                                then return TInt
                                else return TBool
 typeCheckExp (EVar i) = typeCheckVar i
@@ -50,6 +52,20 @@ typeCheckExp (ENeg e) = do
 typeCheckExp (ENot e) = do
        TBool <- typeCheckExp e
        return TBool
+typeCheckExp (EFunc i as) = do
+       state <- get
+       (t,ts) <- lookup i $ functions state
+       checkParams as ts
+       return t
+
+checkParams :: (MonadState State m) => [Exp] -> [Type] -> m ()
+checkParams [] [] = return ()
+checkParams [] _ = fail "Too for arguments when calling function" 
+checkParams _ [] = fail "Too many arguments when calling function" 
+checkParams (e:es) (t:ts) = do
+       t2 <- typeCheckExp e
+       assert (t == t2) "Arugments does not match"
+       checkParams es ts
 
 typeCheckVar :: (MonadState State m) => Ident -> m Type 
 typeCheckVar i = do
@@ -87,6 +103,12 @@ 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 +116,21 @@ 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
+       case last s of
+               (SReturn _) -> return ()
+               _ -> fail $ "Function "++show i++" doesn't end with return statement"
+       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