-module Interpret (interpret, eval, execute, Value(VInt, VBool)) where
+module Interpret (interpret, eval, execute,addFunction, emptyState, Value(..), State(..)) where
import Abssyntax
-import Control.Monad.State
+import Control.Monad.State hiding (State)
+import Control.Monad.Error
+import Control.Concurrent.MVar
import Data.Map as Map
import Prelude hiding (lookup)
+emptyState = State{variables=[empty], functions=(empty)}
+
data Value = VInt Integer | VBool Bool deriving Eq
instance Show Value where
show (VBool False) = "0"
type Variables = [Map Ident Value]
+type Function = ([Decl],[Stm])
+
+data State = State {variables::Variables,functions::(Map Ident Function),ret::(MVar Value)}
-interpret :: [Stm] -> IO ()
-interpret s = runStateT (mapM execute s) [empty] >> return ()
+interpret :: [Func] -> [Stm] -> IO ()
+interpret fun st = do
+ mv <- newEmptyMVar
+ runStateT (do mapM Interpret.addFunction fun; mapM execute st) emptyState{ret=mv}
+ return ()
--eval :: (MonadState Variables m) => Exp -> m Value
-eval :: Exp -> StateT Variables IO Value
+eval :: Exp -> StateT State IO Value
eval (EBool b) = return (VBool b)
eval (EInt n) = return (VInt n)
eval (EVar i) = getVariableValue i
eval EReadB = do
s <- lift $ getWord
return $ VBool $ if (read s == 0) then False else True
+eval (EFunc i as) = do
+ vs <- mapM eval as
+ state <- get
+ (ds,ss) <- lookup i $ functions state
+ let m = foldr (\((Decl t i),v) m -> insert i v m) empty $ zip ds vs
+ in modify (\s -> s{variables=[m]})
+ mapM_ execute ss `catchError` (\_ -> return ())
+ v <- lift $ takeMVar $ ret state
+ put state
+ return v
getWord :: IO String
getWord = do
op Gt = \e e' -> VBool $ e > e'
op EGt = \e e' -> VBool $ e >= e'
-getVariableValue :: (MonadState Variables m) => Ident -> m Value
+getVariableValue :: (MonadState State m) => Ident -> m Value
getVariableValue i = do
- ms <- get
- findVariable i ms
+ s <- get
+ findVariable i $ variables s
-findVariable :: (MonadState Variables m) => Ident -> Variables -> m Value
+findVariable :: (MonadState State m) => Ident -> Variables -> m Value
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
--setVariableValue :: (MonadState Variables m) => Ident -> Exp -> m Value
--setVariableValue :: (MonadState Variables m) => Ident -> Exp -> m Value
-setVariableValue :: Ident -> Exp -> StateT Variables IO Value
+setVariableValue :: Ident -> Exp -> StateT State IO Value
setVariableValue i e = do
v <- eval e
- ms <- get
- put $ updateVariable i v ms
+ state <- get
+ modify (\s -> s{variables= updateVariable i v $ variables state} )
return v
updateVariable :: Ident -> Value -> Variables -> Variables
updateVariable _ _ [] = []
updateVariable i v (m:ms) = if member i m then insert i v m:ms else m:updateVariable i v ms
-pushAndPop :: (MonadState Variables 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})
-- execute :: (MonadState Variables m) => Stm -> m ()
-execute :: Stm -> StateT Variables IO ()
+execute :: Stm -> StateT State IO ()
execute (SNoop) = return ()
execute (SExp e) = eval e >> return ()
execute (SIf b s s') = do
TBool -> EBool False
execute (SDecl t i e) =do
v <- eval e
- (m:ms) <- get
- put $ (insert i v m):ms
+ state <- get
+ let (m:ms) = variables state in modify (\s -> s{variables=insert i v m:ms })
+execute (SReturn e) = do
+ v <- eval e
+ s <- get
+ lift $ putMVar (ret s) v
+ throwError $ userError "Returning.."
+
+addFunction :: (MonadState State m) => Func -> m ()
+addFunction (Func _ i d ss) = modify (\s -> s{functions=insert i (d,ss) (functions s) })