Safe Haskell	Safe
Language	Haskell98

Text.XML.PolySoup.Predicate

Description

A generic extracting predicate.

Synopsis

newtype Q a b = Q {
- runQ :: a -> Maybe b
}
true :: Q a a
satisfy :: (a -> Bool) -> Q a a

Documentation

newtype Q a b Source #

A predicate checks if the given element satisfies some properties and extracts its attribute values. You can compose predicates using Functor, Applicative and Alternative operators: *>, <*, <|> etc. Note, that it doesn't really have sense to use function like many or some, since the extracting predicate doesn't consume any input.

Constructors

Q
Fields runQ :: a -> Maybe b

Instances

Functor (Q a) Source #
Instance details Defined in Text.XML.PolySoup.Predicate Methods fmap :: (a0 -> b) -> Q a a0 -> Q a b # (<$) :: a0 -> Q a b -> Q a a0 #
Applicative (Q a) Source #
Instance details Defined in Text.XML.PolySoup.Predicate Methods pure :: a0 -> Q a a0 # (<>) :: Q a (a0 -> b) -> Q a a0 -> Q a b # liftA2 :: (a0 -> b -> c) -> Q a a0 -> Q a b -> Q a c # (>) :: Q a a0 -> Q a b -> Q a b # (<*) :: Q a a0 -> Q a b -> Q a a0 #
Alternative (Q a) Source #
Instance details Defined in Text.XML.PolySoup.Predicate Methods empty :: Q a a0 # (<\|>) :: Q a a0 -> Q a a0 -> Q a a0 # some :: Q a a0 -> Q a [a0] # many :: Q a a0 -> Q a [a0] #

true :: Q a a Source #

Predicate which is always satisfied.

satisfy :: (a -> Bool) -> Q a a Source #

Check if the given predicate is satisfied.