{-# LANGUAGE CPP #-}
{-# LANGUAGE UndecidableInstances #-}
#if defined(__GLASGOW_HASKELL__) && __GLASGOW_HASKELL__ >= 704
#define USE_DEFAULT_SIGNATURES
#endif
#ifdef USE_DEFAULT_SIGNATURES
{-# LANGUAGE DefaultSignatures, TypeFamilies #-}
#endif
module Text.Parser.LookAhead
(
LookAheadParsing(..)
) where
import Control.Monad (MonadPlus(..))
import Control.Monad.Trans.State.Lazy as Lazy
import Control.Monad.Trans.State.Strict as Strict
import Control.Monad.Trans.Writer.Lazy as Lazy
import Control.Monad.Trans.Writer.Strict as Strict
import Control.Monad.Trans.RWS.Lazy as Lazy
import Control.Monad.Trans.RWS.Strict as Strict
import Control.Monad.Trans.Reader
import Control.Monad.Trans.Identity
#if __GLASGOW_HASKELL__ < 710
import Data.Monoid
#endif
import qualified Text.ParserCombinators.ReadP as ReadP
import Text.Parser.Combinators
#ifdef MIN_VERSION_parsec
import qualified Text.Parsec as Parsec
#endif
#ifdef MIN_VERSION_attoparsec
import qualified Data.Attoparsec.Types as Att
import qualified Data.Attoparsec.Combinator as Att
#endif
#ifdef MIN_VERSION_binary
import qualified Data.Binary.Get as B
#endif
class Parsing m => LookAheadParsing m where
lookAhead :: m a -> m a
instance (LookAheadParsing m, MonadPlus m) => LookAheadParsing (Lazy.StateT s m) where
lookAhead :: StateT s m a -> StateT s m a
lookAhead (Lazy.StateT s -> m (a, s)
m) = (s -> m (a, s)) -> StateT s m a
forall s (m :: * -> *) a. (s -> m (a, s)) -> StateT s m a
Lazy.StateT ((s -> m (a, s)) -> StateT s m a)
-> (s -> m (a, s)) -> StateT s m a
forall a b. (a -> b) -> a -> b
$ m (a, s) -> m (a, s)
forall (m :: * -> *) a. LookAheadParsing m => m a -> m a
lookAhead (m (a, s) -> m (a, s)) -> (s -> m (a, s)) -> s -> m (a, s)
forall b c a. (b -> c) -> (a -> b) -> a -> c
. s -> m (a, s)
m
{-# INLINE lookAhead #-}
instance (LookAheadParsing m, MonadPlus m) => LookAheadParsing (Strict.StateT s m) where
lookAhead :: StateT s m a -> StateT s m a
lookAhead (Strict.StateT s -> m (a, s)
m) = (s -> m (a, s)) -> StateT s m a
forall s (m :: * -> *) a. (s -> m (a, s)) -> StateT s m a
Strict.StateT ((s -> m (a, s)) -> StateT s m a)
-> (s -> m (a, s)) -> StateT s m a
forall a b. (a -> b) -> a -> b
$ m (a, s) -> m (a, s)
forall (m :: * -> *) a. LookAheadParsing m => m a -> m a
lookAhead (m (a, s) -> m (a, s)) -> (s -> m (a, s)) -> s -> m (a, s)
forall b c a. (b -> c) -> (a -> b) -> a -> c
. s -> m (a, s)
m
{-# INLINE lookAhead #-}
instance (LookAheadParsing m, MonadPlus m) => LookAheadParsing (ReaderT e m) where
lookAhead :: ReaderT e m a -> ReaderT e m a
lookAhead (ReaderT e -> m a
m) = (e -> m a) -> ReaderT e m a
forall r (m :: * -> *) a. (r -> m a) -> ReaderT r m a
ReaderT ((e -> m a) -> ReaderT e m a) -> (e -> m a) -> ReaderT e m a
forall a b. (a -> b) -> a -> b
$ m a -> m a
forall (m :: * -> *) a. LookAheadParsing m => m a -> m a
lookAhead (m a -> m a) -> (e -> m a) -> e -> m a
forall b c a. (b -> c) -> (a -> b) -> a -> c
. e -> m a
m
{-# INLINE lookAhead #-}
instance (LookAheadParsing m, MonadPlus m, Monoid w) => LookAheadParsing (Strict.WriterT w m) where
lookAhead :: WriterT w m a -> WriterT w m a
lookAhead (Strict.WriterT m (a, w)
m) = m (a, w) -> WriterT w m a
forall w (m :: * -> *) a. m (a, w) -> WriterT w m a
Strict.WriterT (m (a, w) -> WriterT w m a) -> m (a, w) -> WriterT w m a
forall a b. (a -> b) -> a -> b
$ m (a, w) -> m (a, w)
forall (m :: * -> *) a. LookAheadParsing m => m a -> m a
lookAhead m (a, w)
m
{-# INLINE lookAhead #-}
instance (LookAheadParsing m, MonadPlus m, Monoid w) => LookAheadParsing (Lazy.WriterT w m) where
lookAhead :: WriterT w m a -> WriterT w m a
lookAhead (Lazy.WriterT m (a, w)
m) = m (a, w) -> WriterT w m a
forall w (m :: * -> *) a. m (a, w) -> WriterT w m a
Lazy.WriterT (m (a, w) -> WriterT w m a) -> m (a, w) -> WriterT w m a
forall a b. (a -> b) -> a -> b
$ m (a, w) -> m (a, w)
forall (m :: * -> *) a. LookAheadParsing m => m a -> m a
lookAhead m (a, w)
m
{-# INLINE lookAhead #-}
instance (LookAheadParsing m, MonadPlus m, Monoid w) => LookAheadParsing (Lazy.RWST r w s m) where
lookAhead :: RWST r w s m a -> RWST r w s m a
lookAhead (Lazy.RWST r -> s -> m (a, s, w)
m) = (r -> s -> m (a, s, w)) -> RWST r w s m a
forall r w s (m :: * -> *) a.
(r -> s -> m (a, s, w)) -> RWST r w s m a
Lazy.RWST ((r -> s -> m (a, s, w)) -> RWST r w s m a)
-> (r -> s -> m (a, s, w)) -> RWST r w s m a
forall a b. (a -> b) -> a -> b
$ \r
r s
s -> m (a, s, w) -> m (a, s, w)
forall (m :: * -> *) a. LookAheadParsing m => m a -> m a
lookAhead (r -> s -> m (a, s, w)
m r
r s
s)
{-# INLINE lookAhead #-}
instance (LookAheadParsing m, MonadPlus m, Monoid w) => LookAheadParsing (Strict.RWST r w s m) where
lookAhead :: RWST r w s m a -> RWST r w s m a
lookAhead (Strict.RWST r -> s -> m (a, s, w)
m) = (r -> s -> m (a, s, w)) -> RWST r w s m a
forall r w s (m :: * -> *) a.
(r -> s -> m (a, s, w)) -> RWST r w s m a
Strict.RWST ((r -> s -> m (a, s, w)) -> RWST r w s m a)
-> (r -> s -> m (a, s, w)) -> RWST r w s m a
forall a b. (a -> b) -> a -> b
$ \r
r s
s -> m (a, s, w) -> m (a, s, w)
forall (m :: * -> *) a. LookAheadParsing m => m a -> m a
lookAhead (r -> s -> m (a, s, w)
m r
r s
s)
{-# INLINE lookAhead #-}
instance (LookAheadParsing m, Monad m) => LookAheadParsing (IdentityT m) where
lookAhead :: IdentityT m a -> IdentityT m a
lookAhead = m a -> IdentityT m a
forall k (f :: k -> *) (a :: k). f a -> IdentityT f a
IdentityT (m a -> IdentityT m a)
-> (IdentityT m a -> m a) -> IdentityT m a -> IdentityT m a
forall b c a. (b -> c) -> (a -> b) -> a -> c
. m a -> m a
forall (m :: * -> *) a. LookAheadParsing m => m a -> m a
lookAhead (m a -> m a) -> (IdentityT m a -> m a) -> IdentityT m a -> m a
forall b c a. (b -> c) -> (a -> b) -> a -> c
. IdentityT m a -> m a
forall k (f :: k -> *) (a :: k). IdentityT f a -> f a
runIdentityT
{-# INLINE lookAhead #-}
#ifdef MIN_VERSION_parsec
instance (Parsec.Stream s m t, Show t) => LookAheadParsing (Parsec.ParsecT s u m) where
lookAhead :: ParsecT s u m a -> ParsecT s u m a
lookAhead = ParsecT s u m a -> ParsecT s u m a
forall s (m :: * -> *) t u a.
Stream s m t =>
ParsecT s u m a -> ParsecT s u m a
Parsec.lookAhead
#endif
#ifdef MIN_VERSION_attoparsec
instance Att.Chunk i => LookAheadParsing (Att.Parser i) where
lookAhead :: Parser i a -> Parser i a
lookAhead = Parser i a -> Parser i a
forall i a. Parser i a -> Parser i a
Att.lookAhead
#endif
#ifdef MIN_VERSION_binary
instance LookAheadParsing B.Get where
lookAhead :: Get a -> Get a
lookAhead = Get a -> Get a
forall a. Get a -> Get a
B.lookAhead
#endif
instance LookAheadParsing ReadP.ReadP where
lookAhead :: ReadP a -> ReadP a
lookAhead ReadP a
p = ReadP String
ReadP.look ReadP String -> (String -> ReadP a) -> ReadP a
forall (m :: * -> *) a b. Monad m => m a -> (a -> m b) -> m b
>>= \String
s ->
[ReadP a] -> ReadP a
forall a. [ReadP a] -> ReadP a
ReadP.choice ([ReadP a] -> ReadP a) -> [ReadP a] -> ReadP a
forall a b. (a -> b) -> a -> b
$ ((a, String) -> ReadP a) -> [(a, String)] -> [ReadP a]
forall a b. (a -> b) -> [a] -> [b]
map (a -> ReadP a
forall (m :: * -> *) a. Monad m => a -> m a
return (a -> ReadP a) -> ((a, String) -> a) -> (a, String) -> ReadP a
forall b c a. (b -> c) -> (a -> b) -> a -> c
. (a, String) -> a
forall a b. (a, b) -> a
fst) ([(a, String)] -> [ReadP a]) -> [(a, String)] -> [ReadP a]
forall a b. (a -> b) -> a -> b
$ ReadP a -> ReadS a
forall a. ReadP a -> ReadS a
ReadP.readP_to_S ReadP a
p String
s