| Copyright | Daan Leijen 1999-2001 Bryan O'Sullivan 2007-2015 |
|---|---|
| License | BSD3 |
| Maintainer | bos@serpentine.com |
| Stability | experimental |
| Portability | portable |
| Safe Haskell | Trustworthy |
| Language | Haskell2010 |
Data.Attoparsec.Combinator
Contents
Description
Useful parser combinators, similar to those provided by Parsec.
Synopsis
- try :: Parser i a -> Parser i a
- (<?>) :: Parser i a -> String -> Parser i a
- choice :: Alternative f => [f a] -> f a
- count :: Monad m => Int -> m a -> m [a]
- option :: Alternative f => a -> f a -> f a
- many' :: MonadPlus m => m a -> m [a]
- many1 :: Alternative f => f a -> f [a]
- many1' :: MonadPlus m => m a -> m [a]
- manyTill :: Alternative f => f a -> f b -> f [a]
- manyTill' :: MonadPlus m => m a -> m b -> m [a]
- sepBy :: Alternative f => f a -> f s -> f [a]
- sepBy' :: MonadPlus m => m a -> m s -> m [a]
- sepBy1 :: Alternative f => f a -> f s -> f [a]
- sepBy1' :: MonadPlus m => m a -> m s -> m [a]
- skipMany :: Alternative f => f a -> f ()
- skipMany1 :: Alternative f => f a -> f ()
- eitherP :: Alternative f => f a -> f b -> f ( Either a b)
- feed :: Monoid i => IResult i r -> i -> IResult i r
- satisfyElem :: forall t. Chunk t => ( ChunkElem t -> Bool ) -> Parser t ( ChunkElem t)
- endOfInput :: forall t. Chunk t => Parser t ()
- atEnd :: Chunk t => Parser t Bool
- lookAhead :: Parser i a -> Parser i a
Combinators
try :: Parser i a -> Parser i a Source #
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. attoparsec parsers always backtrack on failure.
Name the parser, in case failure occurs.
choice :: Alternative f => [f a] -> f a Source #
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] Source #
Apply the given action repeatedly, returning every result.
option :: Alternative f => a -> f a -> f a Source #
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] Source #
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] Source #
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] Source #
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] Source #
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] Source #
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] Source #
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] Source #
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] Source #
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] Source #
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 () Source #
Skip zero or more instances of an action.
skipMany1 :: Alternative f => f a -> f () Source #
Skip one or more instances of an action.
eitherP :: Alternative f => f a -> f b -> f ( Either a b) Source #
Combine two alternatives.
feed :: Monoid i => IResult i r -> i -> IResult i r Source #
If a parser has returned a
Partial
result, supply it with more
input.
satisfyElem :: forall t. Chunk t => ( ChunkElem t -> Bool ) -> Parser t ( ChunkElem t) Source #
The parser
satisfyElem p
succeeds for any chunk element for which the
predicate
p
returns
True
. Returns the element that is
actually parsed.
endOfInput :: forall t. Chunk t => Parser t () Source #
Match only if all input has been consumed.