minor change

[proglang.git] / Typecheck.hs

diff --git a/Typecheck.hs b/Typecheck.hs
index a78f8f02c6a51d5d6d643d01ee8a4232f4223dab..a8c10e55f5dc570e99e79fd9b30b9ad085664d11 100644 (file)
--- a/Typecheck.hs
+++ b/Typecheck.hs
@@ -1,30 +1,36 @@
-module Typecheck (typeCheckExp, typeCheckStm, typeCheckVar) where 
+module Typecheck (typeCheck, typeCheckExp, typeCheckStm, typeCheckVar, typeCheckFunction, addFunction, emptyState, 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])
 
-inList :: Eq a => a -> [a] -> Bool
-inList _ [] = False
-inList a (x:xs) = if a == x then True else inList a xs
+data State = State {variables::Types,functions::(Map Ident Function),function::Ident}
+
+emptyState = State{variables=[empty], functions=(empty), function=(Ident "")}
 
 assert :: Monad m => Bool -> String -> m ()
 assert True _ = return ()
 assert False s = fail s
 
-typeCheckExp :: (MonadState Types m) => Exp -> m Type
+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
@@ -46,44 +52,85 @@ 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
 
-typeCheckVar :: (MonadState Types m) => Ident -> m Type 
+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
-       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
 
-typeCheckStm :: (MonadState Types m) => Stm -> m ()
+pushAndPop :: (MonadState State m) => m a -> m ()
+pushAndPop s = do
+       modify (\s -> s { variables = empty:variables s})
+       s
+       modify (\s -> s { variables = tail $ variables s})
+
+typeCheckStm :: (MonadState State m) => Stm -> m ()
 typeCheckStm SNoop = return ()
 typeCheckStm (SExp e) = do 
        typeCheckExp e
        return ()
-typeCheckStm (SBlock ss) = do 
-       modify (empty:)
-       mapM typeCheckStm ss
-       modify tail
+typeCheckStm (SBlock ss) = pushAndPop $ mapM typeCheckStm ss
 typeCheckStm (SIf e s s') = do
        TBool <- typeCheckExp e
-       modify (empty:)
-       typeCheckStm s
-       modify (\s -> empty:tail s)
-       typeCheckStm s'
-       modify tail
+       pushAndPop $ typeCheckStm s
+       pushAndPop $ typeCheckStm s'
 typeCheckStm (SWhile e s) = do
        TBool <- typeCheckExp e
-       modify (empty:)
-       typeCheckStm s
-       modify tail
+       pushAndPop $ typeCheckStm s
+typeCheckStm (SDeclD t i) = addVariable i t
 typeCheckStm (SDecl t i e) = do
        t2 <- typeCheckExp e
        assert (t == t2) $ "Illegal to assign an expression of type "++show t2++" to variable "++show i++" of type "++show t
-       (m:ms) <- get
-       case insertLookupWithKey (\k a1 a2 -> a1) i t m of
-               (Nothing,m') -> put (m':ms)
-               _ -> fail $ "Duplicate variable declaration: "++show i
+       addVariable i t
 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
+       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
+       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