Optics.Re

Some optics can be reversed with re. This is mainly useful to invert Isos:

>>> let _Identity = iso runIdentity Identity
>>> view (_1 % re _Identity) ('x', "yz")
Identity 'x'

Yet we can use a Lens as a Review too:

>>> review (re _1) ('x', "yz")
'x'

In the following diagram, red arrows illustrate how re transforms optics. The ReversedLens and ReversedPrism optic kinds are backwards versions of Lens and Prism respectively, and are present so that re . re does not change the optic kind.

Documentation

class ReversibleOptic k where

Class for optics that can be reversed.

Associated Types

type ReversedOptic k = r | r -> k

Injective type family that maps an optic kind to the optic kind produced by reversing it.

ReversedOptic An_Iso            = An_Iso
ReversedOptic A_Prism           = A_ReversedPrism
ReversedOptic A_ReversedPrism   = A_Prism
ReversedOptic A_Lens            = A_ReversedLens
ReversedOptic A_ReversedLens    = A_Lens
ReversedOptic A_Getter          = A_Review
ReversedOptic A_Review          = A_Getter

Methods

re :: "re" `AcceptsEmptyIndices` is => Optic k is s t a b -> Optic (ReversedOptic k) is b a t s

Reverses optics, turning around Iso into Iso, Prism into ReversedPrism (and back), Lens into ReversedLens (and back) and Getter into Review (and back).

Instances

ReversibleOptic A_Review

Defined in Optics.Re

Associated Types

type ReversedOptic A_Review = (r :: Type)

Methods

re :: AcceptsEmptyIndices "re" is => Optic A_Review is s t a b -> Optic (ReversedOptic A_Review) is b a t s

ReversibleOptic A_ReversedLens

Defined in Optics.Re

Associated Types

type ReversedOptic A_ReversedLens = (r :: Type)

Methods

re :: AcceptsEmptyIndices "re" is => Optic A_ReversedLens is s t a b -> Optic (ReversedOptic A_ReversedLens) is b a t s

ReversibleOptic A_Getter

Defined in Optics.Re

Associated Types

type ReversedOptic A_Getter = (r :: Type)

Methods

re :: AcceptsEmptyIndices "re" is => Optic A_Getter is s t a b -> Optic (ReversedOptic A_Getter) is b a t s

ReversibleOptic A_ReversedPrism

Defined in Optics.Re

Associated Types

type ReversedOptic A_ReversedPrism = (r :: Type)

Methods

re :: AcceptsEmptyIndices "re" is => Optic A_ReversedPrism is s t a b -> Optic (ReversedOptic A_ReversedPrism) is b a t s

ReversibleOptic A_Prism

Defined in Optics.Re

Associated Types

type ReversedOptic A_Prism = (r :: Type)

Methods

re :: AcceptsEmptyIndices "re" is => Optic A_Prism is s t a b -> Optic (ReversedOptic A_Prism) is b a t s

ReversibleOptic A_Lens

Defined in Optics.Re

Associated Types

type ReversedOptic A_Lens = (r :: Type)

Methods

re :: AcceptsEmptyIndices "re" is => Optic A_Lens is s t a b -> Optic (ReversedOptic A_Lens) is b a t s

ReversibleOptic An_Iso

Defined in Optics.Re

Associated Types

type ReversedOptic An_Iso = (r :: Type)

Methods

re :: AcceptsEmptyIndices "re" is => Optic An_Iso is s t a b -> Optic (ReversedOptic An_Iso) is b a t s