Data.Record.Label.Core

Documentation

data Point f i o

Constructors

Point

Fields

_get :: f -> o

_set :: i -> f -> f

Instances

Functor (Point f i)

Applicative (Point f i)

_mod :: Point f i o -> (o -> i) -> f -> f

newtype f :-> a

Constructors

Lens

Fields

unLens :: Point f a a

Instances

Category :->

Iso (:-> i)

lens :: (f -> a) -> (a -> f -> f) -> f :-> a

Create a lens out of a getter and setter.

getL :: (f :-> a) -> f -> a

Get the getter function from a lens.

setL :: (f :-> a) -> a -> f -> f

Get the setter function from a lens.

modL :: (f :-> a) -> (a -> a) -> f -> f

Get the modifier function from a lens.

fmapL :: Applicative f => (a :-> b) -> f a :-> f b

class Iso f where

This isomorphism type class is like a Functor but works in two directions.

Methods

(%) :: (a :<->: b) -> f a -> f b

Instances

Iso (:<->: i)

Iso (:-> i)

data a :<->: b

The bijections datatype, a function that works in two directions.

Constructors

:<->:

Fields

fw :: a -> b

bw :: b -> a

Instances

Category :<->:

Constructor for bijections.

Iso (:<->: i)

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

dimap :: (o' -> o) -> (i -> i') -> Point f i' o' -> Point f i o

for :: (i -> o) -> (f :-> o) -> Point f i o

Combine a partial destructor with a lens into something easily used in the applicative instance for the hidden Point datatype. Internally uses the covariant in getter, contravariant in setter bi-functioral-map function. (Please refer to the example because this function is just not explainable on its own.)