mirror of
https://github.com/mrkkrp/megaparsec.git
synced 2024-11-24 12:04:23 +03:00
move core data type over to CPS
This commit is contained in:
Antoine Latter
parent
200492f57c
commit
a98a3ccbca
@ -46,8 +46,8 @@ sysUnExpectError msg pos = Error (newErrorMessage (SysUnExpect msg) pos)
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unexpected :: (Stream s m t) => String -> ParsecT s u m a
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unexpected msg
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= ParsecT $ \s -> return $ Empty $ return $
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Error (newErrorMessage (UnExpect msg) (statePos s))
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= ParsecT $ \s _ _ _ eerr ->
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eerr $ newErrorMessage (UnExpect msg) (statePos s)
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-- | ParserT monad transformer and Parser type
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@ -56,8 +56,37 @@ unexpected msg
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-- If this is undesirable, simply used a data type like @data Box a = Box a@ and
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-- the state type @Box YourStateType@ to add a level of indirection.
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data ParsecT s u m a
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= ParsecT { runParsecT :: State s u -> m (Consumed (m (Reply s u a))) }
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newtype ParsecT s u m a
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= ParsecT {unParser :: forall b .
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State s u
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-> (a -> State s u -> ParseError -> m b) -- consumed ok
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-> (ParseError -> m b) -- consumed err
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-> (a -> State s u -> ParseError -> m b) -- empty ok
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-> (ParseError -> m b) -- empty err
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-> m b
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}
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runParsecT :: Monad m => ParsecT s u m a -> State s u -> m (Consumed (m (Reply s u a)))
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runParsecT p s = unParser p s cok cerr eok eerr
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where cok a s' err = return . Consumed . return $ Ok a s' err
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cerr err = return . Consumed . return $ Error err
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eok a s' err = return . Empty . return $ Ok a s' err
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eerr err = return . Empty . return $ Error err
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mkPT :: Monad m => (State s u -> m (Consumed (m (Reply s u a)))) -> ParsecT s u m a
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mkPT k = ParsecT $ \s cok cerr eok eerr -> do
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cons <- k s
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case cons of
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Consumed mrep -> do
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rep <- mrep
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case rep of
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Ok x s' err -> cok x s' err
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Error err -> cerr err
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Empty mrep -> do
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rep <- mrep
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case rep of
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Ok x s' err -> eok x s' err
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Error err -> eerr err
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type Parsec s u = ParsecT s u Identity
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@ -81,22 +110,23 @@ instance Functor (Reply s u) where
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fmap f (Ok x s e) = Ok (f x) s e
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fmap _ (Error e) = Error e -- XXX
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instance (Monad m) => Functor (ParsecT s u m) where
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instance Functor (ParsecT s u m) where
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fmap f p = parsecMap f p
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parsecMap :: (Monad m) => (a -> b) -> ParsecT s u m a -> ParsecT s u m b
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parsecMap :: (a -> b) -> ParsecT s u m a -> ParsecT s u m b
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parsecMap f p
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= ParsecT $ \s -> liftM (fmap (liftM (fmap f))) (runParsecT p s)
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= ParsecT $ \s cok cerr eok eerr ->
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unParser p s (cok . f) cerr (eok . f) eerr
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instance (Monad m) => Applicative.Applicative (ParsecT s u m) where
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instance Applicative.Applicative (ParsecT s u m) where
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pure = return
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(<*>) = ap -- TODO: Can this be optimized?
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instance (Monad m) => Applicative.Alternative (ParsecT s u m) where
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instance Applicative.Alternative (ParsecT s u m) where
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empty = mzero
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(<|>) = mplus
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instance (Monad m) => Monad (ParsecT s u m) where
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instance Monad (ParsecT s u m) where
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return x = parserReturn x
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p >>= f = parserBind p f
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fail msg = parserFail msg
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@ -106,7 +136,7 @@ instance (MonadIO m) => MonadIO (ParsecT s u m) where
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instance (MonadReader r m) => MonadReader r (ParsecT s u m) where
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ask = lift ask
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local f p = ParsecT $ \s -> local f (runParsecT p s)
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local f p = mkPT $ \s -> local f (runParsecT p s)
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-- I'm presuming the user might want a separate, non-backtracking
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-- state aside from the Parsec user state.
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@ -115,56 +145,61 @@ instance (MonadState s m) => MonadState s (ParsecT s' u m) where
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put = lift . put
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instance (MonadCont m) => MonadCont (ParsecT s u m) where
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callCC f = ParsecT $ \s ->
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callCC f = mkPT $ \s ->
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callCC $ \c ->
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runParsecT (f (\a -> ParsecT $ \s' -> c (pack s' a))) s
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runParsecT (f (\a -> mkPT $ \s' -> c (pack s' a))) s
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where pack s a= Empty $ return (Ok a s (unknownError s))
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instance (MonadError e m) => MonadError e (ParsecT s u m) where
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throwError = lift . throwError
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p `catchError` h = ParsecT $ \s ->
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p `catchError` h = mkPT $ \s ->
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runParsecT p s `catchError` \e ->
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runParsecT (h e) s
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parserReturn :: (Monad m) => a -> ParsecT s u m a
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parserReturn :: a -> ParsecT s u m a
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parserReturn x
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= ParsecT $ \s -> return $ Empty $ return (Ok x s (unknownError s))
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= ParsecT $ \s _ _ eok _ ->
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eok x s (unknownError s)
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parserBind :: (Monad m)
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=> ParsecT s u m a -> (a -> ParsecT s u m b) -> ParsecT s u m b
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parserBind :: ParsecT s u m a -> (a -> ParsecT s u m b) -> ParsecT s u m b
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{-# INLINE parserBind #-}
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parserBind m k
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= ParsecT $ \s cok cerr eok eerr ->
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let
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-- consumed-okay case for m
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mcok x s err =
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let
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-- if (k x) consumes, those go straigt up
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pcok = cok
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pcerr = cerr
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parserBind p f
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= ParsecT $ \s -> do -- TODO: This was \s@(State _ u _) ???
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res1 <- runParsecT p s
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case res1 of
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-- if (k x) doesn't consume input, but is okay,
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-- we still return in the consumed continuation
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peok = cok
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Empty mReply1
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-> do reply1 <- mReply1
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case reply1 of
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Ok x s' err1 -> do
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res2 <- runParsecT (f x) s'
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case res2 of
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Empty mReply2
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-> do reply2 <- mReply2
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return $ Empty $
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return $ mergeErrorReply err1 reply2
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other
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-> do return $ other
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Error err1 -> return $ Empty $ return $ Error err1
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-- if (k x) doesn't consume input, but errors,
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-- we return the error in the 'consumed-error'
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-- continuation
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peerr err' = cerr (mergeError err err')
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in unParser (k x) s pcok pcerr peok peerr
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Consumed mReply1
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-> do reply1 <- mReply1
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return $ Consumed $ -- `early' returning
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case reply1 of
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Ok x s' err1 -> do
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res2 <- runParsecT (f x) s'
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case res2 of
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Empty mReply2
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-> do reply2 <- mReply2
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return $ mergeErrorReply err1 reply2
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Consumed reply2 -> reply2
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Error err1 -> return $ Error err1
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-- empty-ok case for m
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meok x s err =
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let
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-- in these cases, (k x) can return as empty
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pcok = cok
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peok = eok
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pcerr = cerr
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peerr err' = eerr (mergeError err err')
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in unParser (k x) s pcok pcerr peok peerr
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-- consumed-error case for m
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mcerr = cerr
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-- empty-error case for m
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meerr = eerr
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in unParser m s mcok mcerr meok meerr
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mergeErrorReply :: ParseError -> Reply s u a -> Reply s u a
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@ -173,12 +208,12 @@ mergeErrorReply err1 reply -- XXX where to put it?
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Ok x state err2 -> Ok x state (mergeError err1 err2)
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Error err2 -> Error (mergeError err1 err2)
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parserFail :: (Monad m) => String -> ParsecT s u m a
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parserFail :: String -> ParsecT s u m a
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parserFail msg
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= ParsecT $ \s -> return $ Empty $ return $
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Error (newErrorMessage (Message msg) (statePos s))
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= ParsecT $ \s _ _ _ eerr ->
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eerr $ newErrorMessage (Message msg) (statePos s)
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instance (Monad m) => MonadPlus (ParsecT s u m) where
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instance MonadPlus (ParsecT s u m) where
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mzero = parserZero
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mplus p1 p2 = parserPlus p1 p2
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@ -186,34 +221,27 @@ instance (Monad m) => MonadPlus (ParsecT s u m) where
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-- equal to the 'mzero' member of the 'MonadPlus' class and to the 'Control.Applicative.empty' member
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-- of the 'Control.Applicative.Applicative' class.
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parserZero :: (Monad m) => ParsecT s u m a
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parserZero :: ParsecT s u m a
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parserZero
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= ParsecT $ \s -> return $ Empty $ return $ Error (unknownError s)
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= ParsecT $ \s _ _ _ eerr ->
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eerr $ unknownError s
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parserPlus :: (Monad m)
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=> ParsecT s u m a -> ParsecT s u m a -> ParsecT s u m a
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parserPlus (ParsecT p1) (ParsecT p2)
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= ParsecT $ \s -> do
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c1 <- p1 s
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case c1 of
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Empty mReply1
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-> do r1 <- mReply1
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case r1 of
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Error err -> do
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c2 <- p2 s
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case c2 of
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Empty mReply2
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-> do reply2 <- mReply2
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return $ Empty $ return (mergeErrorReply err reply2)
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consumed
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-> return $ consumed
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other -> return $ Empty $ return $ other
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other -> return $ other
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parserPlus :: ParsecT s u m a -> ParsecT s u m a -> ParsecT s u m a
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{-# INLINE parserPlus #-}
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parserPlus m n
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= ParsecT $ \s cok cerr eok eerr ->
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let
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meerr err =
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let
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neok y s' err' = eok y s' (mergeError err err')
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neerr err' = eerr $ mergeError err err'
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in unParser n s cok cerr neok neerr
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in unParser m s cok cerr eok meerr
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instance MonadTrans (ParsecT s u) where
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lift amb = ParsecT $ \s -> do
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a <- amb
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return $ Empty $ return $ Ok a s (unknownError s)
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lift amb = ParsecT $ \s _ _ eok _ -> do
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a <- amb
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eok a s $ unknownError s
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infix 0 <?>
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infixr 1 <|>
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@ -230,8 +258,7 @@ infixr 1 <|>
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-- combinator, the message would be like '...: expecting \"let\" or
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-- letter', which is less friendly.
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(<?>) :: (Monad m)
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=> (ParsecT s u m a) -> String -> (ParsecT s u m a)
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(<?>) :: (ParsecT s u m a) -> String -> (ParsecT s u m a)
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p <?> msg = label p msg
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-- | This combinator implements choice. The parser @p \<|> q@ first
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@ -246,34 +273,29 @@ p <?> msg = label p msg
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-- implementation of the parser combinators and the generation of good
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-- error messages.
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(<|>) :: (Monad m)
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=> (ParsecT s u m a) -> (ParsecT s u m a) -> (ParsecT s u m a)
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(<|>) :: (ParsecT s u m a) -> (ParsecT s u m a) -> (ParsecT s u m a)
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p1 <|> p2 = mplus p1 p2
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label :: (Monad m) => ParsecT s u m a -> String -> ParsecT s u m a
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label :: ParsecT s u m a -> String -> ParsecT s u m a
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label p msg
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= labels p [msg]
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labels :: (Monad m) => ParsecT s u m a -> [String] -> ParsecT s u m a
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labels p msgs
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= ParsecT $ \s -> do
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r <- runParsecT p s
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case r of
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Empty mReply -> do
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reply <- mReply
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return $ Empty $ case reply of
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Error err
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-> return $ Error (setExpectErrors err msgs)
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Ok x s' err
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| errorIsUnknown err -> return $ reply
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| otherwise -> return (Ok x s' (setExpectErrors err msgs))
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other -> return $ other
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where
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setExpectErrors err [] = setErrorMessage (Expect "") err
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setExpectErrors err [msg] = setErrorMessage (Expect msg) err
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setExpectErrors err (msg:msgs)
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= foldr (\msg' err' -> addErrorMessage (Expect msg') err')
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(setErrorMessage (Expect msg) err) msgs
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labels :: ParsecT s u m a -> [String] -> ParsecT s u m a
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labels p msgs =
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ParsecT $ \s cok cerr eok eerr ->
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let eok' x s' error = eok x s' $ if errorIsUnknown error
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then error
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else setExpectErrors error msgs
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eerr' err = eerr $ setExpectErrors err msgs
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in unParser p s cok cerr eok' eerr'
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where
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setExpectErrors err [] = setErrorMessage (Expect "") err
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setExpectErrors err [msg] = setErrorMessage (Expect msg) err
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setExpectErrors err (msg:msgs)
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= foldr (\msg' err' -> addErrorMessage (Expect msg') err')
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(setErrorMessage (Expect msg) err) msgs
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-- TODO: There should be a stronger statement that can be made about this
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@ -293,32 +315,37 @@ tokens :: (Stream s m t, Eq t)
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-> (SourcePos -> [t] -> SourcePos)
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-> [t] -- List of tokens to parse
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-> ParsecT s u m [t]
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{-# INLINE tokens #-}
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tokens _ _ []
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= ParsecT $ \s -> return $ Empty $ return $ Ok [] s (unknownError s)
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= ParsecT $ \s _ _ eok _ ->
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eok [] s $ unknownError s
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tokens showTokens nextposs tts@(tok:toks)
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= ParsecT $ \(State input pos u) ->
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= ParsecT $ \(State input pos u) cok cerr eok eerr ->
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let
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errEof = return $ Error (setErrorMessage (Expect (showTokens tts))
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(newErrorMessage (SysUnExpect "") pos))
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errExpect x = return $ Error (setErrorMessage (Expect (showTokens tts))
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(newErrorMessage (SysUnExpect (showTokens [x])) pos))
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walk [] rs = return (ok rs)
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errEof = (setErrorMessage (Expect (showTokens tts))
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(newErrorMessage (SysUnExpect "") pos))
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errExpect x = (setErrorMessage (Expect (showTokens tts))
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(newErrorMessage (SysUnExpect (showTokens [x])) pos))
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walk [] rs = ok rs
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walk (t:ts) rs = do
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sr <- uncons rs
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case sr of
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Nothing -> errEof
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Nothing -> cerr $ errEof
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Just (x,xs) | t == x -> walk ts xs
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| otherwise -> errExpect x
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| otherwise -> cerr $ errExpect x
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ok rs = let pos' = nextposs pos tts
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s' = State rs pos' u
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in Ok tts s' (newErrorUnknown pos')
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in cok tts s' (newErrorUnknown pos')
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in do
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sr <- uncons input
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return $ case sr of
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Nothing -> Empty $ errEof
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case sr of
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Nothing -> eerr $ errEof
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Just (x,xs)
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| tok == x -> Consumed $ walk toks xs
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| otherwise -> Empty $ errExpect x
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| tok == x -> walk toks xs
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| otherwise -> eerr $ errExpect x
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-- | The parser @try p@ behaves like parser @p@, except that it
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-- pretends that it hasn't consumed any input when an error occurs.
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@ -351,17 +378,11 @@ tokens showTokens nextposs tts@(tok:toks)
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-- > letExpr = do{ try (string "let"); ... }
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-- > identifier = many1 letter
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try :: (Stream s m t) => ParsecT s u m a -> ParsecT s u m a
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try (ParsecT p)
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= ParsecT $ \s@(State _ pos _) -> do
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res <- p s
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case res of
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Consumed rep -> do r <- rep
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case r of
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Error err -> return $ Empty $ return $ Error
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(setErrorPos pos err)
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ok -> return $ Consumed $ return $ ok
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empty -> return $ empty
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try :: ParsecT s u m a -> ParsecT s u m a
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try p =
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ParsecT $ \s@(State _ pos _) cok _ eok eerr ->
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let pcerr parseError = eerr $ setErrorPos pos parseError
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in unParser p s cok pcerr eok eerr
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-- | The parser @token showTok posFromTok testTok@ accepts a token @t@
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-- with result @x@ when the function @testTok t@ returns @'Just' x@. The
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@ -413,6 +434,7 @@ tokenPrim :: (Stream s m t)
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-> (SourcePos -> t -> s -> SourcePos) -- ^ Next position calculating function.
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-> (t -> Maybe a) -- ^ Matching function for the token to parse.
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-> ParsecT s u m a
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{-# INLINE tokenPrim #-}
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tokenPrim showToken nextpos test = tokenPrimEx showToken nextpos Nothing test
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tokenPrimEx :: (Stream s m t)
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@ -421,37 +443,35 @@ tokenPrimEx :: (Stream s m t)
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-> Maybe (SourcePos -> t -> s -> u -> u)
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-> (t -> Maybe a)
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-> ParsecT s u m a
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tokenPrimEx showToken nextpos mbNextState test
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= case mbNextState of
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Nothing
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-> ParsecT $ \(State input pos user) -> do
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r <- uncons input
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case r of
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Nothing -> return $ Empty $ return (sysUnExpectError "" pos)
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Just (c,cs)
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-> case test c of
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Just x -> let newpos = nextpos pos c cs
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newstate = State cs newpos user
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in seq newpos $ seq newstate $
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return $ Consumed $ return $
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(Ok x newstate (newErrorUnknown newpos))
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Nothing -> return $ Empty $ return $
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(sysUnExpectError (showToken c) pos)
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Just nextState
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-> ParsecT $ \(State input pos user) -> do
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r <- uncons input
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case r of
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Nothing -> return $ Empty $ return (sysUnExpectError "" pos)
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Just (c,cs)
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-> case test c of
|
||||
Just x -> let newpos = nextpos pos c cs
|
||||
newuser = nextState pos c cs user
|
||||
newstate = State cs newpos newuser
|
||||
in seq newpos $ seq newstate $
|
||||
return $ Consumed $ return $
|
||||
(Ok x newstate (newErrorUnknown newpos))
|
||||
Nothing -> return $ Empty $ return $
|
||||
(sysUnExpectError (showToken c) pos)
|
||||
{-# INLINE tokenPrimEx #-}
|
||||
tokenPrimEx showToken nextpos Nothing test
|
||||
= ParsecT $ \(State input pos user) cok cerr eok eerr -> do
|
||||
r <- uncons input
|
||||
case r of
|
||||
Nothing -> eerr $ unexpectError "" pos
|
||||
Just (c,cs)
|
||||
-> case test c of
|
||||
Just x -> let newpos = nextpos pos c cs
|
||||
newstate = State cs newpos user
|
||||
in seq newpos $ seq newstate $
|
||||
cok x newstate (newErrorUnknown newpos)
|
||||
Nothing -> eerr $ unexpectError (showToken c) pos
|
||||
tokenPrimEx showToken nextpos (Just nextState) test
|
||||
= ParsecT $ \(State input pos user) cok cerr eok eerr -> do
|
||||
r <- uncons input
|
||||
case r of
|
||||
Nothing -> eerr $ unexpectError "" pos
|
||||
Just (c,cs)
|
||||
-> case test c of
|
||||
Just x -> let newpos = nextpos pos c cs
|
||||
newUser = nextState pos c cs user
|
||||
newstate = State cs newpos newUser
|
||||
in seq newpos $ seq newstate $
|
||||
cok x newstate $ newErrorUnknown newpos
|
||||
Nothing -> eerr $ unexpectError (showToken c) pos
|
||||
|
||||
unexpectError msg pos = newErrorMessage (SysUnExpect msg) pos
|
||||
|
||||
|
||||
-- | @many p@ applies the parser @p@ /zero/ or more times. Returns a
|
||||
-- list of the returned values of @p@.
|
||||
@ -461,7 +481,7 @@ tokenPrimEx showToken nextpos mbNextState test
|
||||
-- > ; return (c:cs)
|
||||
-- > }
|
||||
|
||||
many :: (Stream s m t) => ParsecT s u m a -> ParsecT s u m [a]
|
||||
many :: ParsecT s u m a -> ParsecT s u m [a]
|
||||
many p
|
||||
= do xs <- manyAccum (:) p
|
||||
return (reverse xs)
|
||||
@ -471,44 +491,25 @@ many p
|
||||
--
|
||||
-- > spaces = skipMany space
|
||||
|
||||
skipMany :: (Stream s m t) => ParsecT s u m a -> ParsecT s u m ()
|
||||
skipMany :: ParsecT s u m a -> ParsecT s u m ()
|
||||
skipMany p
|
||||
= do manyAccum (\_ _ -> []) p
|
||||
return ()
|
||||
|
||||
manyAccum :: (Stream s m t)
|
||||
=> (a -> [a] -> [a])
|
||||
manyAccum :: (a -> [a] -> [a])
|
||||
-> ParsecT s u m a
|
||||
-> ParsecT s u m [a]
|
||||
manyAccum accum p
|
||||
= ParsecT $ \s ->
|
||||
let walk xs state mr
|
||||
= do r <- mr
|
||||
case r of
|
||||
Empty mReply
|
||||
-> do reply <- mReply
|
||||
case reply of
|
||||
Error err -> return $ Ok xs state err
|
||||
_ -> error "Text.Parsec.Prim.many: combinator 'many' is applied to a parser that accepts an empty string."
|
||||
Consumed mReply
|
||||
-> do reply <- mReply
|
||||
case reply of
|
||||
Error err
|
||||
-> return $ Error err
|
||||
Ok x s' _err
|
||||
-> let ys = accum x xs
|
||||
in seq ys (walk ys s' (runParsecT p s'))
|
||||
in do r <- runParsecT p s
|
||||
case r of
|
||||
Empty mReply
|
||||
-> do reply <- mReply
|
||||
case reply of
|
||||
Ok _ _ _
|
||||
-> error "Text.ParserCombinators.Parsec.Prim.many: combinator 'many' is applied to a parser that accepts an empty string."
|
||||
Error err
|
||||
-> return $ Empty $ return (Ok [] s err)
|
||||
consumed
|
||||
-> return $ Consumed $ walk [] s (return consumed)
|
||||
manyAccum acc p =
|
||||
ParsecT $ \s cok cerr _eok eerr ->
|
||||
let walk xs x s' err =
|
||||
unParser p s'
|
||||
(seq xs $ walk $ acc x xs) -- consumed-ok
|
||||
cerr -- consumed-err
|
||||
manyErr -- empty-ok
|
||||
(\e -> cok xs s' e) -- empty-err
|
||||
in unParser p s (walk []) cerr manyErr (\e -> cok [] s e)
|
||||
|
||||
manyErr = error "Text.ParserCombinators.Parsec.Prim.many: combinator 'many' is applied to a parser that accepts an empty string."
|
||||
|
||||
|
||||
-- < Running a parser: monadic (runPT) and pure (runP)
|
||||
@ -627,11 +628,11 @@ setParserState st = updateParserState (const st)
|
||||
|
||||
-- | @updateParserState f@ applies function @f@ to the parser state.
|
||||
|
||||
updateParserState :: (Monad m)
|
||||
=> (State s u -> State s u) -> ParsecT s u m (State s u)
|
||||
updateParserState f
|
||||
= ParsecT $ \s -> let s' = f s
|
||||
in return $ Empty $ return (Ok s' s' (unknownError s'))
|
||||
updateParserState :: (State s u -> State s u) -> ParsecT s u m (State s u)
|
||||
updateParserState f =
|
||||
ParsecT $ \s _ _ eok _ ->
|
||||
let s' = f s
|
||||
in eok s' s' $ unknownError s'
|
||||
|
||||
-- < User state combinators
|
||||
|
||||
|
||||
@ -25,6 +25,7 @@ import Text.Parsec.Prim
|
||||
instance (Monad m) => Stream [tok] m tok where
|
||||
uncons [] = return $ Nothing
|
||||
uncons (t:ts) = return $ Just (t,ts)
|
||||
{-# INLINE uncons #-}
|
||||
|
||||
type Parser = Parsec String ()
|
||||
type GenParser tok st = Parsec [tok] st
|
||||
|
||||
Loading…
Reference in New Issue
Block a user