Safe Haskell	None
Language	Haskell2010

Optics.IxLens

Contents

Formation
Introduction
Elimination
Additional introduction forms
Subtyping
van Laarhoven encoding

Description

An IxLens is an indexed version of an Lens. See the "Indexed optics" section of the overview documentation in the Optics module of the main optics package for more details on indexed optics.

Synopsis

type IxLens i s t a b = Optic A_Lens (WithIx i) s t a b
type IxLens' i s a = Optic' A_Lens (WithIx i) s a
ilens :: (s -> (i, a)) -> (s -> b -> t) -> IxLens i s t a b
devoid :: IxLens' i Void a
data A_Lens
type IxLensVL i s t a b = forall f. Functor f => (i -> a -> f b) -> s -> f t
type IxLensVL' i s a = IxLensVL i s s a a
ilensVL :: IxLensVL i s t a b -> IxLens i s t a b
toIxLensVL :: (Is k A_Lens, is `HasSingleIndex` i) => Optic k is s t a b -> IxLensVL i s t a b
withIxLensVL :: (Is k A_Lens, is `HasSingleIndex` i) => Optic k is s t a b -> (IxLensVL i s t a b -> r) -> r

Formation

type IxLens i s t a b = Optic A_Lens (WithIx i) s t a b Source #

Type synonym for a type-modifying indexed lens.

type IxLens' i s a = Optic' A_Lens (WithIx i) s a Source #

Type synonym for a type-preserving indexed lens.

Introduction

ilens :: (s -> (i, a)) -> (s -> b -> t) -> IxLens i s t a b Source #

Build an indexed lens from a getter and a setter.

If you want to build an IxLens from the van Laarhoven representation, use ilensVL.

Elimination

An IxLens is in particular an IxGetter and an IxSetter, therefore you can specialise types to obtain:

iview :: IxLens i s t a b -> s -> (i, a)

iover :: IxLens i s t a b -> (i -> a -> b) -> s -> t
iset  :: IxLens i s t a b -> (i      -> b) -> s -> t

Additional introduction forms

devoid :: IxLens' i Void a Source #

There is an indexed field for every type in the Void.

>>> set (mapped % devoid) 1 []
[]

>>> over (_Just % devoid) abs Nothing
Nothing

Subtyping

data A_Lens Source #

Tag for a lens.

Instances

ReversibleOptic A_Lens Source #
Instance details Defined in Optics.Re Associated Types type ReversedOptic A_Lens = (r :: Type) Source # Methods re :: AcceptsEmptyIndices "re" is => Optic A_Lens is s t a b -> Optic (ReversedOptic A_Lens) is b a t s Source #
Is A_Lens A_Fold Source #
Instance details Defined in Optics.Internal.Optic.Subtyping Methods implies :: proxy A_Lens A_Fold p -> (Constraints A_Lens p -> r) -> Constraints A_Fold p -> r Source #
Is A_Lens An_AffineFold Source #
Instance details Defined in Optics.Internal.Optic.Subtyping Methods implies :: proxy A_Lens An_AffineFold p -> (Constraints A_Lens p -> r) -> Constraints An_AffineFold p -> r Source #
Is A_Lens A_Getter Source #
Instance details Defined in Optics.Internal.Optic.Subtyping Methods implies :: proxy A_Lens A_Getter p -> (Constraints A_Lens p -> r) -> Constraints A_Getter p -> r Source #
Is A_Lens A_Setter Source #
Instance details Defined in Optics.Internal.Optic.Subtyping Methods implies :: proxy A_Lens A_Setter p -> (Constraints A_Lens p -> r) -> Constraints A_Setter p -> r Source #
Is A_Lens A_Traversal Source #
Instance details Defined in Optics.Internal.Optic.Subtyping Methods implies :: proxy A_Lens A_Traversal p -> (Constraints A_Lens p -> r) -> Constraints A_Traversal p -> r Source #
Is A_Lens An_AffineTraversal Source #
Instance details Defined in Optics.Internal.Optic.Subtyping Methods implies :: proxy A_Lens An_AffineTraversal p -> (Constraints A_Lens p -> r) -> Constraints An_AffineTraversal p -> r Source #
Is An_Iso A_Lens Source #
Instance details Defined in Optics.Internal.Optic.Subtyping Methods implies :: proxy An_Iso A_Lens p -> (Constraints An_Iso p -> r) -> Constraints A_Lens p -> r Source #
Arrow arr => ArrowOptic A_Lens arr Source #
Instance details Defined in Optics.Arrow Methods overA :: Optic A_Lens is s t a b -> arr a b -> arr s t Source #
ToReadOnly A_Lens s t a b Source #
Instance details Defined in Optics.ReadOnly Methods getting :: Optic A_Lens is s t a b -> Optic' (Join A_Getter A_Lens) is s a Source #
IxOptic A_Lens s t a b Source #
Instance details Defined in Optics.Indexed.Core Methods noIx :: NonEmptyIndices is => Optic A_Lens is s t a b -> Optic A_Lens NoIx s t a b Source #
type ReversedOptic A_Lens Source #
Instance details Defined in Optics.Re type ReversedOptic A_Lens = A_ReversedLens

van Laarhoven encoding

type IxLensVL i s t a b = forall f. Functor f => (i -> a -> f b) -> s -> f t Source #

Type synonym for a type-modifying van Laarhoven indexed lens.

type IxLensVL' i s a = IxLensVL i s s a a Source #

Type synonym for a type-preserving van Laarhoven indexed lens.

ilensVL :: IxLensVL i s t a b -> IxLens i s t a b Source #

Build an indexed lens from the van Laarhoven representation.

toIxLensVL :: (Is k A_Lens, is `HasSingleIndex` i) => Optic k is s t a b -> IxLensVL i s t a b Source #

Convert an indexed lens to its van Laarhoven representation.

withIxLensVL :: (Is k A_Lens, is `HasSingleIndex` i) => Optic k is s t a b -> (IxLensVL i s t a b -> r) -> r Source #

Work with an indexed lens in the van Laarhoven representation.