Text.XML.PolySoup.Parser

The module defines a generic parser which can be used, in particular, to parse XML forests. The main characteristic of the parser is that it can be used in a sequential (sub-trees are processed in order) and a selective (subtrees are process regardless of their position) way.

Core

newtype P a b

An XML forest parser.

Constructors

P

Fields

• runP :: [a] -> Maybe (b, [a])

Instances

Monad (P a)

Methods

(>>=) :: P a a -> (a -> P a b) -> P a b

(>>) :: P a a -> P a b -> P a b

return :: a -> P a a

fail :: String -> P a a

Functor (P a)

Methods

fmap :: (a -> b) -> P a a -> P a b

(<$) :: a -> P a b -> P a a

Applicative (P a)

Methods

pure :: a -> P a a

(<*>) :: P a (a -> b) -> P a a -> P a b

(*>) :: P a a -> P a b -> P a b

(<*) :: P a a -> P a b -> P a a

Alternative (P a)

Methods

empty :: P a a

(<|>) :: P a a -> P a a -> P a a

some :: P a a -> P a [a]

many :: P a a -> P a [a]

evalP :: P a b -> [a] -> Maybe b

Evaluate parser on the given XML forest.

Parsing

Selective

first :: Q a b -> P a b

Find the first tree satisfying the given predicate.

every :: Q a b -> P a [b]

Select every tree satisfying the given predicate.

every' :: Q a b -> P a [b]

A lazy version of every which "forgets" non-matching subtrees along the way.

Sequential

pop :: Q a b -> P a b

Check, if the first tree satisfies the given predicate.

Peek

peek :: Q a b -> P a b

Like pop, but doesn't consume the tree.

spy :: Q a b -> P a b

Like first, but doesn't consume the tree.

Utilities

many_ :: Alternative f => f a -> f ()

Many combinator which ignores parsing results.