Copyright	(C) 2026 - Eitan Chatav
License	BSD-style (see the file LICENSE)
Maintainer	Eitan Chatav <eitan.chatav@gmail.com>
Stability	provisional
Portability	non-portable
Safe Haskell	Safe-Inferred
Language	Haskell2010

Control.Lens.Bifocal

Contents

Bifocal
Combinators
Binocular
Prismoid
Filtroid

Description

Synopsis

type Bifocal s t a b = forall p f. (Alternator p, Filtrator p, Alternative f, Filterable f) => p a (f b) -> p s (f t)
type ABifocal s t a b = Binocular a b a (Maybe b) -> Binocular a b s (Maybe t)
bifocal :: Binocular a b s t -> Bifocal s t a b
mapBifocal :: (Alternator p, Filtrator p) => ABifocal s t a b -> p a b -> p s t
cloneBifocal :: ABifocal s t a b -> Bifocal s t a b
withBifocal :: (Alternative f, Filterable f) => ABifocal s t a b -> ((s -> Maybe a) -> f b) -> f t
newtype Binocular a b s t = Binocular {
- unBinocular :: forall f. (Alternative f, Filterable f) => ((s -> Maybe a) -> f b) -> f t
}
runBinocular :: (Alternator p, Filtrator p) => Binocular a b s t -> p a b -> p s t
type Prismoid s t a b = forall p f. (Alternator p, Alternative f) => p a (f b) -> p s (f t)
somed :: Prismoid [a] [b] a b
lefted :: Prismoid (Either a c) (Either b d) a b
righted :: Prismoid (Either c a) (Either d b) a b
chained1 :: (forall x. x -> Either x x) -> APartialIso a b (a, a) (b, b) -> Prismoid a b a b
chained :: (forall x. x -> Either x x) -> APartialIso a b (a, a) (b, b) -> APrism a b () () -> Prismoid a b a b
type Filtroid s t a b = forall p f. (Filtrator p, Filterable f) => p a (f b) -> p s (f t)
unlefted :: Filtroid a b (Either a c) (Either b d)
unrighted :: Filtroid a b (Either c a) (Either d b)

Bifocal

type Bifocal s t a b = forall p f. (Alternator p, Filtrator p, Alternative f, Filterable f) => p a (f b) -> p s (f t) Source #

Bifocals are bidirectional parser optics.

Every one of the following is a Bifocal.

Bifocals are isomorphic to Binoculars.

type ABifocal s t a b = Binocular a b a (Maybe b) -> Binocular a b s (Maybe t) Source #

If you see ABifocal in a signature for a function, the function is expecting a Bifocal.

Combinators

bifocal :: Binocular a b s t -> Bifocal s t a b Source #

Build a Bifocal from a concrete Binocular.

mapBifocal :: (Alternator p, Filtrator p) => ABifocal s t a b -> p a b -> p s t Source #

Action of ABifocal on partial Distributors.

cloneBifocal :: ABifocal s t a b -> Bifocal s t a b Source #

Clone ABifocal so that you can reuse the same monomorphically typed Bifocal for different purposes.

withBifocal :: (Alternative f, Filterable f) => ABifocal s t a b -> ((s -> Maybe a) -> f b) -> f t Source #

Run ABifocal over an Alternative & Filterable.

Binocular

newtype Binocular a b s t Source #

Binocular provides an efficient concrete representation of Bifocals.

Constructors

Binocular
Fields unBinocular :: forall f. (Alternative f, Filterable f) => ((s -> Maybe a) -> f b) -> f t

Instances

Instances details

Alternator (Binocular a b) Source #
Instance details Defined in Control.Lens.Bifocal Methods alternate :: Either (Binocular a b a0 b0) (Binocular a b c d) -> Binocular a b (Either a0 c) (Either b0 d) Source # someP :: Binocular a b a0 b0 -> Binocular a b [a0] [b0] Source #
Distributor (Binocular a b) Source #
Instance details Defined in Control.Lens.Bifocal Methods zeroP :: Binocular a b Void Void Source # (>+<) :: Binocular a b a0 b0 -> Binocular a b c d -> Binocular a b (Either a0 c) (Either b0 d) Source # optionalP :: Binocular a b a0 b0 -> Binocular a b (Maybe a0) (Maybe b0) Source # manyP :: Binocular a b a0 b0 -> Binocular a b [a0] [b0] Source #
Filtrator (Binocular a b) Source #
Instance details Defined in Control.Lens.Bifocal Methods filtrate :: Binocular a b (Either a0 c) (Either b0 d) -> (Binocular a b a0 b0, Binocular a b c d) Source #
Choice (Binocular a b) Source #
Instance details Defined in Control.Lens.Bifocal Methods left' :: Binocular a b a0 b0 -> Binocular a b (Either a0 c) (Either b0 c) # right' :: Binocular a b a0 b0 -> Binocular a b (Either c a0) (Either c b0) #
Cochoice (Binocular a b) Source #
Instance details Defined in Control.Lens.Bifocal Methods unleft :: Binocular a b (Either a0 d) (Either b0 d) -> Binocular a b a0 b0 # unright :: Binocular a b (Either d a0) (Either d b0) -> Binocular a b a0 b0 #
Profunctor (Binocular a b) Source #
Instance details Defined in Control.Lens.Bifocal Methods dimap :: (a0 -> b0) -> (c -> d) -> Binocular a b b0 c -> Binocular a b a0 d # lmap :: (a0 -> b0) -> Binocular a b b0 c -> Binocular a b a0 c # rmap :: (b0 -> c) -> Binocular a b a0 b0 -> Binocular a b a0 c # (#.) :: forall a0 b0 c q. Coercible c b0 => q b0 c -> Binocular a b a0 b0 -> Binocular a b a0 c # (.#) :: forall a0 b0 c q. Coercible b0 a0 => Binocular a b b0 c -> q a0 b0 -> Binocular a b a0 c #
Alternative (Binocular a b s) Source #
Instance details Defined in Control.Lens.Bifocal Methods empty :: Binocular a b s a0 # (<\|>) :: Binocular a b s a0 -> Binocular a b s a0 -> Binocular a b s a0 # some :: Binocular a b s a0 -> Binocular a b s [a0] # many :: Binocular a b s a0 -> Binocular a b s [a0] #
Applicative (Binocular a b s) Source #
Instance details Defined in Control.Lens.Bifocal Methods pure :: a0 -> Binocular a b s a0 # (<>) :: Binocular a b s (a0 -> b0) -> Binocular a b s a0 -> Binocular a b s b0 # liftA2 :: (a0 -> b0 -> c) -> Binocular a b s a0 -> Binocular a b s b0 -> Binocular a b s c # (>) :: Binocular a b s a0 -> Binocular a b s b0 -> Binocular a b s b0 # (<*) :: Binocular a b s a0 -> Binocular a b s b0 -> Binocular a b s a0 #
Functor (Binocular a b s) Source #
Instance details Defined in Control.Lens.Bifocal Methods fmap :: (a0 -> b0) -> Binocular a b s a0 -> Binocular a b s b0 # (<$) :: a0 -> Binocular a b s b0 -> Binocular a b s a0 #
Filterable (Binocular a b s) Source #
Instance details Defined in Control.Lens.Bifocal Methods mapMaybe :: (a0 -> Maybe b0) -> Binocular a b s a0 -> Binocular a b s b0 # catMaybes :: Binocular a b s (Maybe a0) -> Binocular a b s a0 # filter :: (a0 -> Bool) -> Binocular a b s a0 -> Binocular a b s a0 # drain :: Binocular a b s a0 -> Binocular a b s b0 #

runBinocular :: (Alternator p, Filtrator p) => Binocular a b s t -> p a b -> p s t Source #

Run a Binocular on a partial Distributor.

Prismoid

type Prismoid s t a b = forall p f. (Alternator p, Alternative f) => p a (f b) -> p s (f t) Source #

Prismoids generalize Bifocals, combining Prisms and Diopters.

somed :: Prismoid [a] [b] a b Source #

One or more.

lefted :: Prismoid (Either a c) (Either b d) a b Source #

lefted is like _Left, except with heterogeneous Right parameters.

righted :: Prismoid (Either c a) (Either d b) a b Source #

righted is like _Right, except with heterogeneous Left parameters.

chained1 :: (forall x. x -> Either x x) -> APartialIso a b (a, a) (b, b) -> Prismoid a b a b Source #

Associate a binary constructor pattern to sequence one or more times.

chained :: (forall x. x -> Either x x) -> APartialIso a b (a, a) (b, b) -> APrism a b () () -> Prismoid a b a b Source #

Associate a binary constructor pattern to sequence one or more times, or use a nilary constructor pattern to sequence zero times.

Filtroid

type Filtroid s t a b = forall p f. (Filtrator p, Filterable f) => p a (f b) -> p s (f t) Source #

An optic for Filtrators, Filtroids generalize Bifocals.

unlefted :: Filtroid a b (Either a c) (Either b d) Source #

Dual to lefted.

unrighted :: Filtroid a b (Either c a) (Either d b) Source #

Dual to righted.