Copyright	Daan Leijen 1999-2001 Bryan O'Sullivan 2009-2010 Mario Blažević <blamario@yahoo.com> 2014
License	BSD3
Maintainer	Mario Blažević
Stability	experimental
Portability	portable
Safe Haskell	Safe
Language	Haskell2010

Data.Picoparsec.Combinator

Contents

Combinators

Description

Useful parser combinators, similar to those provided by Parsec.

Synopsis

Combinators

try :: Parser i a -> Parser i a #

Attempt a parse, and if it fails, rewind the input so that no input appears to have been consumed.

This combinator is provided for compatibility with Parsec. Picoparsec parsers always backtrack on failure.

(<?>) infix 0 #

Arguments

:: Parser i a
-> String	the name to use if parsing fails
-> Parser i a

Name the parser, in case failure occurs.

choice :: Alternative f => [f a] -> f a #

choice ps tries to apply the actions in the list ps in order, until one of them succeeds. Returns the value of the succeeding action.

count :: Monad m => Int -> m a -> m [a] #

Apply the given action repeatedly, returning every result.

option :: Alternative f => a -> f a -> f a #

option x p tries to apply action p. If p fails without consuming input, it returns the value x, otherwise the value returned by p.

priority  = option 0 (digitToInt <$> digit)

many' :: MonadPlus m => m a -> m [a] #

many' p applies the action p zero or more times. Returns a list of the returned values of p. The value returned by p is forced to WHNF.

 word  = many' letter

many1 :: Alternative f => f a -> f [a] #

many1 p applies the action p one or more times. Returns a list of the returned values of p.

 word  = many1 letter

many1' :: MonadPlus m => m a -> m [a] #

many1' p applies the action p one or more times. Returns a list of the returned values of p. The value returned by p is forced to WHNF.

 word  = many1' letter

manyTill :: Alternative f => f a -> f b -> f [a] #

manyTill p end applies action p zero or more times until action end succeeds, and returns the list of values returned by p. This can be used to scan comments:

 simpleComment   = string "<!--" *> manyTill anyChar (string "-->")

(Note the overlapping parsers anyChar and string "-->". While this will work, it is not very efficient, as it will cause a lot of backtracking.)

manyTill' :: MonadPlus m => m a -> m b -> m [a] #

manyTill' p end applies action p zero or more times until action end succeeds, and returns the list of values returned by p. This can be used to scan comments:

 simpleComment   = string "<!--" *> manyTill' anyChar (string "-->")

(Note the overlapping parsers anyChar and string "-->". While this will work, it is not very efficient, as it will cause a lot of backtracking.)

The value returned by p is forced to WHNF.

sepBy :: Alternative f => f a -> f s -> f [a] #

sepBy p sep applies zero or more occurrences of p, separated by sep. Returns a list of the values returned by p.

commaSep p  = p `sepBy` (char ',')

sepBy' :: MonadPlus m => m a -> m s -> m [a] #

sepBy' p sep applies zero or more occurrences of p, separated by sep. Returns a list of the values returned by p. The value returned by p is forced to WHNF.

commaSep p  = p `sepBy'` (char ',')

sepBy1 :: Alternative f => f a -> f s -> f [a] #

sepBy1 p sep applies one or more occurrences of p, separated by sep. Returns a list of the values returned by p.

commaSep p  = p `sepBy1` (char ',')

sepBy1' :: MonadPlus m => m a -> m s -> m [a] #

sepBy1' p sep applies one or more occurrences of p, separated by sep. Returns a list of the values returned by p. The value returned by p is forced to WHNF.

commaSep p  = p `sepBy1'` (char ',')

skipMany :: Alternative f => f a -> f () #

Skip zero or more instances of an action.

skipMany1 :: Alternative f => f a -> f () #

Skip one or more instances of an action.

eitherP :: Alternative f => f a -> f b -> f (Either a b) #

Combine two alternatives.

feed :: Monoid i => IResult i r -> i -> IResult i r #

If a parser has returned a Partial result, supply it with more input.

endOfInput :: MonoidNull t => Parser t () #

Match only if all input has been consumed.

atEnd :: MonoidNull t => Parser t Bool #

Return an indication of whether the end of input has been reached.

lookAhead :: Monoid i => Parser i a -> Parser i a #

Apply a parser without consuming any input.

notFollowedBy :: (Monoid i, Show a) => Parser i a -> Parser i () #

Apply a parser without consuming any input, and succeed if and only if the parser fails.