import Control.Monad
import Control.Monad.State
import Control.Monad.Identity
+import Control.Monad.Trans
import StdMisc
from StdFunc import id, const
import StdString
from parse import :: ParserOutput, :: Error
:: Gamma :== 'Map'.Map String Type
-:: Env a = Env (State Gamma (Either SemError a))
+:: Env a :== StateT Gamma (Either SemError) a
-instance Functor Env where
- fmap f m = liftM f m
+//we need to redefine this even though it is in Control.Monad.State
+instance MonadTrans (StateT Gamma) where
+ liftT m = StateT \s-> m >>= \a-> return (a, s)
-instance Applicative Env where
- (<*>) f g = ap f g
- pure a = Env $ pure $ Right a
-
-instance Alternative Env where
- empty = Env $ pure $ Left (Error "Undefined error")
- (<|>) f g = f >>= \ef -> g >>= \eg -> Env $ pure $ (ef <|> eg) //case ef of
- //Left e = eg
- //Right r = Right r
-
-instance Monad Env where
- bind e f = e >>= \ee -> Env $ pure $ case ee of
- (Left e) = Left e
- (Right r) = f r
-
-get = state $ \s -> (s,s)
+get = gets id
instance toString SemError where
toString (ParseError p e) = concat [
"SemError: Cannot unify types. Expected: ",
toString t1, ". Given: ", toString t2]
-sem :: AST -> SemOutput
-sem x = undef
-/*
putIdent :: String Type -> Env Void
putIdent i t = gets ('Map'.get i) >>= \mt -> case mt of
- Nothing = pure <$> modify ('Map'.put i t)
- Just t2 = unify t t2 >>= \r -> case r of
- Left e = pure $ Left e
- Right t3 = pure <$> modify ('Map'.put i t3)
+ Nothing = modify ('Map'.put i t)
+ Just t2 = unify t t2 >>= \t3-> modify ('Map'.put i t3)
sem :: AST -> SemOutput
-sem (AST vd fd)
-# (eithervds, gamma) = runState (mapM semVarDecl vd) 'Map'.newMap
-# (eitherfds, gamma) = runState (mapM semFunDecl fd) gamma
-= case splitEithers eithervds of
- (Left errs) = Left $ errs ++ [x\\(Left x)<-eitherfds]
- (Right vds) = case splitEithers eitherfds of
- (Left errs) = Left errs
- (Right fds) = Right $ AST vds fds
+sem (AST vd fd) = case evalStateT m 'Map'.newMap of
+ Left e = Left [e]
+ Right (vds, fds) = Right (AST vds fds)
+where
+ m :: Env (([VarDecl], [FunDecl]))
+ m = (mapM semVarDecl vd) >>= \vds ->
+ mapM semFunDecl fd >>= \fds ->
+ pure (vds, fds)
splitEithers :: [Either a b] -> Either [a] [b]
splitEithers [] = Right []
splitEithers xs = Left $ [x\\(Left x)<-xs]
semFunDecl :: FunDecl -> Env FunDecl
-semFunDecl f = pure $ Right f
+semFunDecl f = pure f
semVarDecl :: VarDecl -> Env VarDecl
-semVarDecl vd=:(VarDecl pos type ident ex) = unify type ex
- >>= \et->case et of
- Left err = pure $ Left err
- Right t = putIdent ident t >>| pure (Right $ VarDecl pos t ident ex)
+semVarDecl (VarDecl pos type ident ex) = unify type ex
+ >>= \t-> putIdent ident t >>| (pure $ VarDecl pos t ident ex)
typeExpr :: Expr -> Env Type
-typeExpr (IntExpr _ _) = pure $ Right IntType
-typeExpr (CharExpr _ _) = pure $ Right CharType
-typeExpr (BoolExpr _ _) = pure $ Right BoolType
+typeExpr (IntExpr _ _) = pure IntType
+typeExpr (CharExpr _ _) = pure CharType
+typeExpr (BoolExpr _ _) = pure BoolType
typeExpr (Op1Expr p UnNegation expr) = unify BoolType expr
typeExpr (Op1Expr p UnMinus expr) = unify IntType expr
typeExpr (TupleExpr p (e1, e2)) = typeExpr e1
- >>= \ete1->typeExpr e2 >>= \ete2->pure (
- ete1 >>= \te1->ete2 >>= \te2->Right $ TupleType (te1, te2))
+ >>= \t1-> typeExpr e2 >>= \t2-> pure $ TupleType (t1, t2)
//Int
typeExpr (Op2Expr p e1 BiPlus e2) = unify IntType e1 >>| unify IntType e2
typeExpr (Op2Expr p e1 BiMinus e2) = unify IntType e1 >>| unify IntType e2
class unify a :: Type a -> Env Type
instance unify Expr where
- unify (_ ->> _) e = pure $ Left $ ParseError (extrPos e)
+ unify (_ ->> _) e = liftT $ Left $ ParseError (extrPos e)
"Expression cannot be a higher order function. Yet..."
- unify VoidType e = pure $ Left $ ParseError (extrPos e)
+ unify VoidType e = liftT $ Left $ ParseError (extrPos e)
"Expression cannot be a Void type."
- unify (IdType _) e = pure $ Left $ ParseError (extrPos e)
+ unify (IdType _) e = liftT $ Left $ ParseError (extrPos e)
"Expression cannot be an polymorf type."
unify VarType e = typeExpr e
- unify t e = typeExpr e
- >>= \eithertype->case eithertype of
- Left e = pure $ Left e
- Right tex = unify t tex >>= \eitherun->case eitherun of
- Left err = pure $ Left $ decErr e err
- Right t = pure $ Right t
+ //we have to cheat to decorate the error, can be done nicer?
+ unify t e = StateT $ \s0 -> let res = runStateT m s0 in case res of
+ Left err = Left $ decErr e err
+ Right t = Right t //note, t :: (Type, Gamma)
+ where m = typeExpr e >>= \tex-> unify t tex
instance unify Type where
- unify IntType IntType = pure $ Right IntType
- unify BoolType BoolType = pure $ Right BoolType
- unify CharType CharType = pure $ Right CharType
- unify t1 t2 = pure $ Left $ UnifyError zero t1 t2
+ unify IntType IntType = pure IntType
+ unify BoolType BoolType = pure BoolType
+ unify CharType CharType = pure CharType
+ unify t1 t2 = liftT $ Left $ UnifyError zero t1 t2
instance zero Pos where
zero = {line=0,col=0}
decErr e (ParseError _ s) = ParseError (extrPos e) s
decErr e err = err
+dc2 :: Expr (Either SemError a) -> Either SemError a
+dc2 e (Right t) = Right t
+dc2 e (Left err) = Left err
+
extrPos :: Expr -> Pos
extrPos (VarExpr p _) = p
extrPos (Op2Expr p _ _ _) = p
extrPos (BoolExpr p _) = p
extrPos (FunExpr p _) = p
extrPos (EmptyListExpr p) = p
-extrPos (TupleExpr p _) = p
-*/
\ No newline at end of file
+extrPos (TupleExpr p _) = p
\ No newline at end of file
repositories / cc1516.git / blobdiff