ParseLib.Parallel.Core

The type of parsers

data Parser s r

The parser is a CPS version of Parser'

Instances

Monad (Parser s)

Defined in ParseLib.Parallel.Core

Methods

(>>=) :: Parser s a -> (a -> Parser s b) -> Parser s b

(>>) :: Parser s a -> Parser s b -> Parser s b

return :: a -> Parser s a

fail :: String -> Parser s a

Functor (Parser s)

Defined in ParseLib.Parallel.Core

Methods

fmap :: (a -> b) -> Parser s a -> Parser s b

(<$) :: a -> Parser s b -> Parser s a

Applicative (Parser s)

Defined in ParseLib.Parallel.Core

Methods

pure :: a -> Parser s a

(<*>) :: Parser s (a -> b) -> Parser s a -> Parser s b

liftA2 :: (a -> b -> c) -> Parser s a -> Parser s b -> Parser s c

(*>) :: Parser s a -> Parser s b -> Parser s b

(<*) :: Parser s a -> Parser s b -> Parser s a

Alternative (Parser s)

Defined in ParseLib.Parallel.Core

Methods

empty :: Parser s a

(<|>) :: Parser s a -> Parser s a -> Parser s a

some :: Parser s a -> Parser s [a]

many :: Parser s a -> Parser s [a]

MonadPlus (Parser s)

Defined in ParseLib.Parallel.Core

Methods

mzero :: Parser s a

mplus :: Parser s a -> Parser s a -> Parser s a

Elementary parsers

anySymbol :: Parser s s

Parses any single symbol.

satisfy :: (s -> Bool) -> Parser s s

Takes a predicate and returns a parser that parses a single symbol satisfying that predicate.

empty :: Alternative f => f a

The identity of <|>

failp :: Parser s a

Same as empty; provided for compatibility with the lecture notes.

succeed :: a -> Parser s a

Parser that always succeeds, i.e., for epsilon.

pure :: Applicative f => a -> f a

Lift a value.

Parser combinators

(<|>) :: Alternative f => f a -> f a -> f a infixl 3

An associative binary operation

(<<|>) :: Parser s a -> Parser s a -> Parser s a infixl 3

Biased choice. Not implemented by the parallel parser combinators. Just maps to parallel choice.

(<*>) :: Applicative f => f (a -> b) -> f a -> f b infixl 4

Sequential application.

A few functors support an implementation of <*> that is more efficient than the default one.

(<$>) :: Functor f => (a -> b) -> f a -> f b infixl 4

An infix synonym for fmap.

The name of this operator is an allusion to $. Note the similarities between their types:

 ($)  ::              (a -> b) ->   a ->   b
(<$>) :: Functor f => (a -> b) -> f a -> f b

Whereas $ is function application, <$> is function application lifted over a Functor.

Examples

Convert from a Maybe Int to a Maybe String using show:

>>> show <$> Nothing
Nothing
>>> show <$> Just 3
Just "3"

Convert from an Either Int Int to an Either Int String using show:

>>> show <$> Left 17
Left 17
>>> show <$> Right 17
Right "17"

Double each element of a list:

>>> (*2) <$> [1,2,3]
[2,4,6]

Apply even to the second element of a pair:

>>> even <$> (2,2)
(2,True)

(>>=) :: Monad m => m a -> (a -> m b) -> m b infixl 1

Sequentially compose two actions, passing any value produced by the first as an argument to the second.

Lookahead

look :: Parser s [s]

Returns the rest of the input without consuming anything.

Running parsers

parse :: Parser s a -> [s] -> [(a, [s])]

Runs a parser to a given string.