Data.IParser

Description

Let's assume we have a parser like the following

int :: Parser (ReaderT String Maybe) (Writer [Int]) Int Int
int = parser (ReaderT readMaybe) (x -> x <$ tell [show x])

Then you can use the parser for parsing:

> runReaderT (decode int) "3"
Just 3

Or for encoding:

> execWriter (encode int 3)
["3"]

Or combine both of them

> runReaderT (decode int) $ head $ execWriter $ encode int 3
Just 3

Synopsis

data IParser r w c a = IParser {
- decoder :: r a
- encoder :: Star w c a
}
parser :: r a -> (c -> w a) -> IParser r w c a
decode :: IParser r w c a -> r a
encode :: IParser r w c a -> c -> w a
(.=) :: (Functor r, Functor w) => (c -> c') -> IParser r w c' a -> IParser r w c a

Documentation

data IParser r w c a Source #

The core bidirectional parser type

See the module for usage example

Constructors

IParser
Fields decoder :: r a Return a value "a" in context "r". encoder :: Star w c a Generate a value "a" from the initial object "c" in the context "w"

Instances

(Functor r, Functor w) => Profunctor (IParser r w) Source #
Instance details Defined in Data.IParser Methods dimap :: (a -> b) -> (c -> d) -> IParser r w b c -> IParser r w a d # lmap :: (a -> b) -> IParser r w b c -> IParser r w a c # rmap :: (b -> c) -> IParser r w a b -> IParser r w a c # (#.) :: Coercible c b => q b c -> IParser r w a b -> IParser r w a c # (.#) :: Coercible b a => IParser r w b c -> q a b -> IParser r w a c #
(Functor w, Functor r) => Functor (IParser r w c) Source #
Instance details Defined in Data.IParser Methods fmap :: (a -> b) -> IParser r w c a -> IParser r w c b # (<$) :: a -> IParser r w c b -> IParser r w c a #
(Applicative w, Applicative r) => Applicative (IParser r w c) Source #
Instance details Defined in Data.IParser Methods pure :: a -> IParser r w c a # (<>) :: IParser r w c (a -> b) -> IParser r w c a -> IParser r w c b # liftA2 :: (a -> b -> c0) -> IParser r w c a -> IParser r w c b -> IParser r w c c0 # (>) :: IParser r w c a -> IParser r w c b -> IParser r w c b # (<*) :: IParser r w c a -> IParser r w c b -> IParser r w c a #

Arguments

Smart constructor for the parser

decode :: IParser r w c a -> r a Source #

Extract the decoder from the parser

encode :: IParser r w c a -> c -> w a Source #

Extract the encoder from the parser

(.=) :: (Functor r, Functor w) => (c -> c') -> IParser r w c' a -> IParser r w c a Source #

Record accessor helper

Due to the nature of the parser, the encoder gets the full record type, when it should only focus on a specific part.

data Person = Person { name :: String, age :: Int }

person :: IParser r w Person Person
person =
 Person $ name .= string
        * age .= int