X-Git-Url: https://ruin.nu/git/?p=proglang.git;a=blobdiff_plain;f=Interpret.hs;h=62cc7fd9d5f839978692359779b16ecc9c465e92;hp=f1c820682806950a7912115488eb40be0f5fa4fc;hb=HEAD;hpb=2316d61f350f8b39c9a3f76b91d1d14796d5183b

diff --git a/Interpret.hs b/Interpret.hs
index f1c8206..62cc7fd 100644
--- a/Interpret.hs
+++ b/Interpret.hs
@@ -1,83 +1,153 @@
-module 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), ret=(VInt 0)}
+
 data Value = VInt Integer | VBool Bool deriving Eq
 
 instance Show Value where
 	show (VInt n) = show n
-	show (VBool b) = show b
+	show (VBool True) = "1"
+	show (VBool False) = "0"
 
 type Variables = [Map Ident Value]
+type Function = ([Decl],[Stm])
+
+data State = State {variables::Variables,functions::(Map Ident Function),ret::Value}
 
-inList :: Eq a => a -> [a] -> Bool
-inList _ [] = False
-inList a (x:xs) = if a == x then True else inList a xs
+type EvalM m = ErrorT String m
 
---eval :: (MonadState Variables m) => Exp -> m Value
-eval :: Exp -> StateT Variables IO Value
+interpret :: [Func] -> [Stm] -> IO ()
+interpret fun st = do
+	runStateT (runErrorT  (do mapM addFunction fun; mapM_ execute st)) emptyState
+	return ()
+
+eval :: (MonadState State m, MonadIO m) => Exp -> EvalM m Value
 eval (EBool b) = return (VBool b)
 eval (EInt n) = return (VInt n)
 eval (EVar i) = getVariableValue i
-eval (EAss i e) = setVariableValue i e 
-eval EDefault = return (VInt 0) --FIXME!!!
+eval (EAss i e) = do 
+	v <- eval e
+	setVariableValue i v
 eval (BiOpExp e o e') = do
 	v <- eval e
 	v'<- eval e'
-	if inList o [Eq,NEq] then return $ opE o v v'
-		else let (VInt n1) = v in let (VInt n2) = v' in return $ op o n1 n2
-typeCheckExp (EPost i op) = do
+	if elem o [Eq,NEq] then return $ opE o v v'
+		else let (VInt n1) = v in let (VInt n2) = v' in return $! op o n1 n2
+eval (EPost i o) = do
 	(VInt n) <- getVariableValue i
-	setVariableValue i $ EInt $ n+1
+	setVariableValue i $ op o n 1
 	return $ VInt n
+eval (ENeg e) = do
+	(VInt n) <- eval e
+	return $ VInt $ -n
+eval (ENot e) = do
+	(VBool b) <- eval e
+	return $ VBool $ not b
+eval EReadI = do
+	s <- liftIO $ getNumber
+	return $ VInt $ read s
+eval EReadB = do
+	s <- liftIO $ getNumber
+	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 >> (fail $ "Function "++show i++" didn't return anything."))
+		`catchError` (\_ ->return ()) --Only errors thrown in ErrorT can be caught here, runtime errors pass through, so no need to check the error
+	v <- liftM ret get
+	put state
+	return v
+
+--Stricter evaluation of the input
+getNumber :: IO String
+getNumber = do
+	c <- getChar
+	if elem c $ '-':['0'..'9']
+		then do
+			l <- getNumber2
+			return (c:l)
+		else fail "Non integer input."
+
+getNumber2 :: IO String
+getNumber2 =  do
+	c <- getChar
+	if elem c ['0'..'9']
+		then do
+			l <- getNumber2
+			return (c:l)
+		else return ""
 
 -- op :: Op -> (a -> a -> Value)
-opE Eq = \e e' -> VBool $ e == e'
-opE NEq = \e e' -> VBool $ not (e == e')
-op Plus = \e e' -> VInt $ e + e'
-op Minus = \e e' -> VInt $ e - e' 
-op Times = \e e' -> VInt $ e * e' 
-op Div = \e e' -> VInt $ e `div` e' 
-
-getVariableValue :: (MonadState Variables m) => Ident -> m Value 
-getVariableValue i = do
-	ms <- get 
-	findVariable i ms
+opE Eq e e' = VBool $ e == e'
+opE NEq e e' = VBool $ not (e == e')
+op Plus e e' =VInt $ e + e'
+op Minus e e' = VInt $ e - e'
+op Times e e' = VInt $ e * e'
+op Div _ 0 = error "Division by zero"
+op Div e e' = VInt $ e `div` e'
+op Lt e e' = VBool $ e < e'
+op ELt e e' = VBool $ e <= e'
+op Gt e e' = VBool $ e > e'
+op EGt e e' = VBool $ e >= e'
 
---setVariableValue :: (MonadState Variables m) => Ident -> Exp -> m Value 
-setVariableValue :: Ident -> Exp -> StateT Variables IO Value
-setVariableValue i e = do
-	e' <- eval e
-	(m:ms) <- get
-	put $ (insert i e' m):ms
-	return e'
+getVariableValue :: (MonadState State m) => Ident -> m Value 
+getVariableValue i = do
+	s <- get 
+	findVariable i $ variables s
 
-findVariable :: (MonadState  Variables m) => Ident -> Variables -> m Value
+findVariable :: (Monad 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
 
--- execute :: (MonadState Variables m) => Stm -> m ()
-execute :: Stm -> StateT Variables IO ()
+setVariableValue :: (MonadState State m) => Ident -> Value -> EvalM m Value
+setVariableValue i v = do
+	modify (\s -> s{variables= updateVariable i v $ variables s} )
+	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 State m) => m a -> m ()
+pushAndPop s = do
+	modify (\s -> s { variables = empty:variables s})
+	s
+	modify (\s -> s { variables = tail $ variables s})
+
+execute :: (MonadState State m, MonadIO m) => Stm -> EvalM m ()
+execute (SNoop) = return ()
+execute (SExp e) = eval e >> return ()
 execute (SIf b s s') = do
 	(VBool b') <- eval b
-	if b' then execute s else execute s'
+	pushAndPop $ if b' then execute s else execute s'
 execute (SPrint e) = do
 	e' <- eval e
-	lift $ print e'
-execute (SNoop) = return ()
-execute (SBlock ss) = do
-	modify (empty:)
-	mapM execute ss
-	modify tail
+	liftIO $ print e'
+execute (SBlock ss) = pushAndPop $ mapM execute ss
 execute (SWhile e s) = do
 	(VBool b) <- eval e
-	if b then execute (SWhile e s) else return ()
-execute (SDecl t i EDefault) = do
-	case t of
-		TInt -> setVariableValue i (EInt 0)
-		TBool -> setVariableValue i (EBool False)
-	return ()
-execute (SDecl t i e) = setVariableValue i e >> return ()
+	if b then pushAndPop (execute s) >> execute (SWhile e s) else return ()
+execute (SDeclD t i) = execute $ SDecl t i $ case t of
+	TInt -> EInt 0
+	TBool -> EBool False
+execute (SDecl t i e) =do
+	v <- eval e
+	(m:ms) <- liftM variables get
+	modify (\s -> s{variables=insert i v m:ms })
+execute (SReturn e) = do
+	v <- eval e
+	modify (\s -> s{ret=v})
+	throwError "Returning.."
+
+addFunction :: (MonadState State m) => Func -> m ()
+addFunction (Func _ i d ss) = modify (\s -> s{functions=insert i (d,ss) (functions s) })