Copyright	© 2015–present Megaparsec contributors © 2007 Paolo Martini © 1999–2001 Daan Leijen
License	FreeBSD
Maintainer	Mark Karpov <markkarpov92@gmail.com>
Stability	experimental
Portability	portable
Safe Haskell	Safe
Language	Haskell2010

Text.Megaparsec.Internal

Contents

Data types
Helper functions

Description

Internal definitions. Versioning rules do not apply here. Please do not rely on these unless you really know what you're doing.

Since: 6.5.0

Synopsis

newtype Hints t = Hints (Set (ErrorItem t))
data Reply e s a = Reply (State s e) Consumption (Result s e a)
data Consumption
- = Consumed
- | NotConsumed
data Result s e a
- = OK (Hints (Token s)) a
- | Error (ParseError s e)
newtype ParsecT e s m a = ParsecT {
- unParser :: forall b. State s e -> (a -> State s e -> Hints (Token s) -> m b) -> (ParseError s e -> State s e -> m b) -> (a -> State s e -> Hints (Token s) -> m b) -> (ParseError s e -> State s e -> m b) -> m b
}
toHints :: Stream s => Int -> ParseError s e -> Hints (Token s)
withHints :: Stream s => Hints (Token s) -> (ParseError s e -> State s e -> m b) -> ParseError s e -> State s e -> m b
accHints :: Stream s => Hints (Token s) -> (a -> State s e -> Hints (Token s) -> m b) -> a -> State s e -> Hints (Token s) -> m b
refreshHints :: Hints t -> Maybe (ErrorItem t) -> Hints t
runParsecT :: Monad m => ParsecT e s m a -> State s e -> m (Reply e s a)
withParsecT :: forall e e' s m a. (Monad m, Ord e') => (e -> e') -> ParsecT e s m a -> ParsecT e' s m a

Data types

newtype Hints t Source #

Hints represent a collection of ErrorItems to be included into ParseError (when it's a TrivialError) as “expected” message items when a parser fails without consuming input right after successful parser that produced the hints.

For example, without hints you could get:

>>> parseTest (many (char 'r') <* eof) "ra"
1:2:
unexpected 'a'
expecting end of input

We're getting better error messages with the help of hints:

>>> parseTest (many (char 'r') <* eof) "ra"
1:2:
unexpected 'a'
expecting 'r' or end of input

Constructors

Hints (Set (ErrorItem t))

Instances

Instances details

Ord t => Monoid (Hints t) Source #
Instance details Defined in Text.Megaparsec.Internal Methods mempty :: Hints t # mappend :: Hints t -> Hints t -> Hints t # mconcat :: [Hints t] -> Hints t #
Ord t => Semigroup (Hints t) Source #
Instance details Defined in Text.Megaparsec.Internal Methods (<>) :: Hints t -> Hints t -> Hints t # sconcat :: NonEmpty (Hints t) -> Hints t # stimes :: Integral b => b -> Hints t -> Hints t #

data Reply e s a Source #

All information available after parsing. This includes consumption of input, success (with the returned value) or failure (with the parse error), and parser state at the end of parsing. Reply can also be used to resume parsing.

Instances

Instances details

(Ord e, Stream s) => MonadParsec e s (ParsecT e s m) Source #
Instance details Defined in Text.Megaparsec.Internal Methods parseError :: ParseError s e -> ParsecT e s m a Source # label :: String -> ParsecT e s m a -> ParsecT e s m a Source # hidden :: ParsecT e s m a -> ParsecT e s m a Source # try :: ParsecT e s m a -> ParsecT e s m a Source # lookAhead :: ParsecT e s m a -> ParsecT e s m a Source # notFollowedBy :: ParsecT e s m a -> ParsecT e s m () Source # withRecovery :: (ParseError s e -> ParsecT e s m a) -> ParsecT e s m a -> ParsecT e s m a Source # observing :: ParsecT e s m a -> ParsecT e s m (Either (ParseError s e) a) Source # eof :: ParsecT e s m () Source # token :: (Token s -> Maybe a) -> Set (ErrorItem (Token s)) -> ParsecT e s m a Source # tokens :: (Tokens s -> Tokens s -> Bool) -> Tokens s -> ParsecT e s m (Tokens s) Source # takeWhileP :: Maybe String -> (Token s -> Bool) -> ParsecT e s m (Tokens s) Source # takeWhile1P :: Maybe String -> (Token s -> Bool) -> ParsecT e s m (Tokens s) Source # takeP :: Maybe String -> Int -> ParsecT e s m (Tokens s) Source # getParserState :: ParsecT e s m (State s e) Source # updateParserState :: (State s e -> State s e) -> ParsecT e s m () Source # mkParsec :: (State s e -> Reply e s a) -> ParsecT e s m a Source #
(VisualStream s, ShowErrorComponent e) => MonadParsecDbg e s (ParsecT e s m) Source #
Instance details Defined in Text.Megaparsec.Debug Methods dbg :: Show a => String -> ParsecT e s m a -> ParsecT e s m a Source #
(Stream s, MonadError e' m) => MonadError e' (ParsecT e s m) Source #
Instance details Defined in Text.Megaparsec.Internal Methods throwError :: e' -> ParsecT e s m a # catchError :: ParsecT e s m a -> (e' -> ParsecT e s m a) -> ParsecT e s m a #
(Stream s, MonadReader r m) => MonadReader r (ParsecT e s m) Source #
Instance details Defined in Text.Megaparsec.Internal Methods ask :: ParsecT e s m r # local :: (r -> r) -> ParsecT e s m a -> ParsecT e s m a # reader :: (r -> a) -> ParsecT e s m a #
(Stream s, MonadState st m) => MonadState st (ParsecT e s m) Source #
Instance details Defined in Text.Megaparsec.Internal Methods get :: ParsecT e s m st # put :: st -> ParsecT e s m () # state :: (st -> (a, st)) -> ParsecT e s m a #
Stream s => MonadTrans (ParsecT e s) Source #
Instance details Defined in Text.Megaparsec.Internal Methods lift :: Monad m => m a -> ParsecT e s m a #
Stream s => MonadFail (ParsecT e s m) Source #
Instance details Defined in Text.Megaparsec.Internal Methods fail :: String -> ParsecT e s m a #
(Stream s, MonadFix m) => MonadFix (ParsecT e s m) Source #	Since: 6.0.0
Instance details Defined in Text.Megaparsec.Internal Methods mfix :: (a -> ParsecT e s m a) -> ParsecT e s m a #
(Stream s, MonadIO m) => MonadIO (ParsecT e s m) Source #
Instance details Defined in Text.Megaparsec.Internal Methods liftIO :: IO a -> ParsecT e s m a #
(Ord e, Stream s) => Alternative (ParsecT e s m) Source #	`empty` is a parser that fails without consuming input.
Instance details Defined in Text.Megaparsec.Internal Methods empty :: ParsecT e s m a # (<\|>) :: ParsecT e s m a -> ParsecT e s m a -> ParsecT e s m a # some :: ParsecT e s m a -> ParsecT e s m [a] # many :: ParsecT e s m a -> ParsecT e s m [a] #
Stream s => Applicative (ParsecT e s m) Source #	`pure` returns a parser that succeeds without consuming input.
Instance details Defined in Text.Megaparsec.Internal Methods pure :: a -> ParsecT e s m a # (<>) :: ParsecT e s m (a -> b) -> ParsecT e s m a -> ParsecT e s m b # liftA2 :: (a -> b -> c) -> ParsecT e s m a -> ParsecT e s m b -> ParsecT e s m c # (>) :: ParsecT e s m a -> ParsecT e s m b -> ParsecT e s m b # (<*) :: ParsecT e s m a -> ParsecT e s m b -> ParsecT e s m a #
Functor (ParsecT e s m) Source #
Instance details Defined in Text.Megaparsec.Internal Methods fmap :: (a -> b) -> ParsecT e s m a -> ParsecT e s m b # (<$) :: a -> ParsecT e s m b -> ParsecT e s m a #
Stream s => Monad (ParsecT e s m) Source #	`return` returns a parser that succeeds without consuming input.
Instance details Defined in Text.Megaparsec.Internal Methods (>>=) :: ParsecT e s m a -> (a -> ParsecT e s m b) -> ParsecT e s m b # (>>) :: ParsecT e s m a -> ParsecT e s m b -> ParsecT e s m b # return :: a -> ParsecT e s m a #
(Ord e, Stream s) => MonadPlus (ParsecT e s m) Source #	`mzero` is a parser that fails without consuming input. Note: strictly speaking, this instance is unlawful. The right identity law does not hold, e.g. in general this is not true: v >> mzero = mero However the following holds: try v >> mzero = mzero
Instance details Defined in Text.Megaparsec.Internal Methods mzero :: ParsecT e s m a # mplus :: ParsecT e s m a -> ParsecT e s m a -> ParsecT e s m a #
(Stream s, MonadCont m) => MonadCont (ParsecT e s m) Source #
Instance details Defined in Text.Megaparsec.Internal Methods callCC :: ((a -> ParsecT e s m b) -> ParsecT e s m a) -> ParsecT e s m a #
(a ~ Tokens s, IsString a, Eq a, Stream s, Ord e) => IsString (ParsecT e s m a) Source #	Since: 6.3.0
Instance details Defined in Text.Megaparsec.Internal Methods fromString :: String -> ParsecT e s m a #
(Stream s, Monoid a) => Monoid (ParsecT e s m a) Source #	Since: 5.3.0
Instance details Defined in Text.Megaparsec.Internal Methods mempty :: ParsecT e s m a # mappend :: ParsecT e s m a -> ParsecT e s m a -> ParsecT e s m a # mconcat :: [ParsecT e s m a] -> ParsecT e s m a #
(Stream s, Semigroup a) => Semigroup (ParsecT e s m a) Source #	Since: 5.3.0
Instance details Defined in Text.Megaparsec.Internal Methods (<>) :: ParsecT e s m a -> ParsecT e s m a -> ParsecT e s m a # sconcat :: NonEmpty (ParsecT e s m a) -> ParsecT e s m a # stimes :: Integral b => b -> ParsecT e s m a -> ParsecT e s m a #

Helper functions

toHints Source #

Arguments

:: Stream s
=> Int	Current offset in input stream
-> ParseError s e	Parse error to convert
-> Hints (Token s)

Convert a ParseError record into Hints.

withHints Source #

Arguments

:: Stream s
=> Hints (Token s)	Hints to use
-> (ParseError s e -> State s e -> m b)	Continuation to influence
-> ParseError s e	First argument of resulting continuation
-> State s e	Second argument of resulting continuation
-> m b

withHints hs c makes “error” continuation c use given hints hs.

Note that if resulting continuation gets ParseError that has custom data in it, hints are ignored.

accHints Source #

Arguments

:: Stream s
=> Hints (Token s)	`Hints` to add
-> (a -> State s e -> Hints (Token s) -> m b)	An “OK” continuation to alter
-> a -> State s e -> Hints (Token s) -> m b	Altered “OK” continuation

accHints hs c results in “OK” continuation that will add given hints hs to third argument of original continuation c.

refreshHints :: Hints t -> Maybe (ErrorItem t) -> Hints t Source #

Replace the hints with the given ErrorItem (or delete it if Nothing is given). This is used in the label primitive.

runParsecT Source #

Arguments

:: Monad m
=> ParsecT e s m a	Parser to run
-> State s e	Initial state
-> m (Reply e s a)

Low-level unpacking of the ParsecT type.

withParsecT Source #

Arguments

:: forall e e' s m a. (Monad m, Ord e')
=> (e -> e')
-> ParsecT e s m a	Inner parser
-> ParsecT e' s m a	Outer parser

Transform any custom errors thrown by the parser using the given function. Similar in function and purpose to withExceptT.

Note that the inner parser will start with an empty collection of “delayed” ParseErrors. Any delayed ParseErrors produced in the inner parser will be lifted by applying the provided function and added to the collection of delayed parse errors of the outer parser.

Since: 7.0.0

Consumed	Some part of input stream was consumed
NotConsumed	No input was consumed

OK (Hints (Token s)) a	Parser succeeded (includes hints)
Error (ParseError s e)	Parser failed

ParsecT
Fields unParser :: forall b. State s e -> (a -> State s e -> Hints (Token s) -> m b) -> (ParseError s e -> State s e -> m b) -> (a -> State s e -> Hints (Token s) -> m b) -> (ParseError s e -> State s e -> m b) -> m b