| Copyright | © 2017–present Mark Karpov |
|---|---|
| License | BSD 3 clause |
| Maintainer | Mark Karpov <markkarpov92@gmail.com> |
| Stability | experimental |
| Portability | portable |
| Safe Haskell | Safe-Inferred |
| Language | Haskell2010 |
Control.Monad.Combinators
Description
The module provides more efficient versions of the combinators from
Control.Applicative.Combinators defined in terms of Monad and
MonadPlus instead of Applicative and
Alternative . When there is no difference in
performance we just re-export the combinators from
Control.Applicative.Combinators.
Since: 0.4.0
Synopsis
- (<|>) :: Alternative f => f a -> f a -> f a
- optional :: Alternative f => f a -> f (Maybe a)
- empty :: Alternative f => f a
- between :: Applicative m => m open -> m close -> m a -> m a
- choice :: (Foldable f, Alternative m) => f (m a) -> m a
- count :: Monad m => Int -> m a -> m [a]
- count' :: MonadPlus m => Int -> Int -> m a -> m [a]
- eitherP :: Alternative m => m a -> m b -> m (Either a b)
- endBy :: MonadPlus m => m a -> m sep -> m [a]
- endBy1 :: MonadPlus m => m a -> m sep -> m [a]
- many :: MonadPlus m => m a -> m [a]
- manyTill :: MonadPlus m => m a -> m end -> m [a]
- manyTill_ :: MonadPlus m => m a -> m end -> m ([a], end)
- some :: MonadPlus m => m a -> m [a]
- someTill :: MonadPlus m => m a -> m end -> m [a]
- someTill_ :: MonadPlus m => m a -> m end -> m ([a], end)
- option :: Alternative m => a -> m a -> m a
- sepBy :: MonadPlus m => m a -> m sep -> m [a]
- sepBy1 :: MonadPlus m => m a -> m sep -> m [a]
- sepEndBy :: MonadPlus m => m a -> m sep -> m [a]
- sepEndBy1 :: MonadPlus m => m a -> m sep -> m [a]
- skipMany :: MonadPlus m => m a -> m ()
- skipSome :: MonadPlus m => m a -> m ()
- skipCount :: Monad m => Int -> m a -> m ()
- skipManyTill :: MonadPlus m => m a -> m end -> m end
- skipSomeTill :: MonadPlus m => m a -> m end -> m end
Re-exports from Control.Applicative
(<|>) :: Alternative f => f a -> f a -> f a infixl 3 #
An associative binary operation
This combinator implements choice. The parser p first applies
<|> qp. If it succeeds, the value of p is returned. If p fails, parser
q is tried.
optional :: Alternative f => f a -> f (Maybe a) #
One or none.
optional pp. It will parse p or
Nothing . It only fails if p fails after consuming input. On success
result of p is returned inside of Just , on failure Nothing is
returned.
See also: option .
empty :: Alternative f => f a #
The identity of <|>
This parser fails unconditionally without providing any information about the cause of the failure.
Original combinators
between :: Applicative m => m open -> m close -> m a -> m a Source #
between open close popen, followed by p and close.
Returns the value returned by p.
braces = between (symbol "{") (symbol "}")choice :: (Foldable f, Alternative m) => f (m a) -> m a Source #
choice psps in order,
until one of them succeeds. Returns the value of the succeeding parser.
choice = asum
eitherP :: Alternative m => m a -> m b -> m (Either a b) Source #
Combine two alternatives.
eitherP a b = (Left <$> a) <|> (Right <$> b)
endBy :: MonadPlus m => m a -> m sep -> m [a] Source #
endBy p sepp, separated and
ended by sep. Returns a list of values returned by p.
cStatements = cStatement `endBy` semicolon
endBy1 :: MonadPlus m => m a -> m sep -> m [a] Source #
endBy1 p sepp, separated and
ended by sep. Returns a list of values returned by p.
many :: MonadPlus m => m a -> m [a] Source #
many pp zero or more times and returns a
list of the values returned by p.
identifier = (:) <$> letter <*> many (alphaNumChar <|> char '_')
manyTill :: MonadPlus m => m a -> m end -> m [a] Source #
manyTill p endp zero or more times until parser
end succeeds. Returns the list of values returned by p. Note that
end result is consumed and lost. Use manyTill_ if you wish to keep
it.
See also: skipMany , skipManyTill .
manyTill_ :: MonadPlus m => m a -> m end -> m ([a], end) Source #
manyTill_ p endp zero or more times until
parser end succeeds. Returns the list of values returned by p and the
end result. Use manyTill if you have no need in the result of the
end.
See also: skipMany , skipManyTill .
Since: 1.2.0
some :: MonadPlus m => m a -> m [a] Source #
some pp one or more times and returns a
list of the values returned by p.
word = some letter
someTill :: MonadPlus m => m a -> m end -> m [a] Source #
someTill p endmanyTill p endp
should succeed at least once. Note that end result is consumed and
lost. Use someTill_ if you wish to keep it.
someTill p end = liftM2 (:) p (manyTill p end)
See also: skipSome , skipSomeTill .
someTill_ :: MonadPlus m => m a -> m end -> m ([a], end) Source #
someTill_ p endmanyTill_ p endp
should succeed at least once. Use someTill if you have no need in the
result of the end.
See also: skipSome , skipSomeTill .
Since: 1.2.0
option :: Alternative m => a -> m a -> m a Source #
sepBy :: MonadPlus m => m a -> m sep -> m [a] Source #
sepBy p sepp, separated by
sep. Returns a list of values returned by p.
commaSep p = p `sepBy` comma
sepBy1 :: MonadPlus m => m a -> m sep -> m [a] Source #
sepBy1 p sepp, separated by
sep. Returns a list of values returned by p.
sepEndBy :: MonadPlus m => m a -> m sep -> m [a] Source #
sepEndBy p sepp, separated
and optionally ended by sep. Returns a list of values returned by p.
sepEndBy1 :: MonadPlus m => m a -> m sep -> m [a] Source #
sepEndBy1 p sepp, separated
and optionally ended by sep. Returns a list of values returned by p.
skipMany :: MonadPlus m => m a -> m () Source #
skipMany pp zero or more times, skipping
its result.
See also: manyTill , skipManyTill .
skipSome :: MonadPlus m => m a -> m () Source #
skipSome pp one or more times, skipping its
result.
See also: someTill , skipSomeTill .
skipManyTill :: MonadPlus m => m a -> m end -> m end Source #
skipManyTill p endp zero or more times
skipping results until parser end succeeds. Result parsed by end is
then returned.
skipSomeTill :: MonadPlus m => m a -> m end -> m end Source #
skipSomeTill p endp one or more times
skipping results until parser end succeeds. Result parsed by end is
then returned.