Safe Haskell	None
Language	Haskell2010

Optics.Re

Description

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.

Reversed Optics

Synopsis

class ReversibleOptic k where
- type ReversedOptic k = r | r -> k
- re :: "re" `AcceptsEmptyIndices` is => Optic k is s t a b -> Optic (ReversedOptic k) is b a t s

Documentation

class ReversibleOptic k where Source #

Class for optics that can be reversed.

Associated Types

type ReversedOptic k = r | r -> k Source #

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 Source #

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

Instances

Instances details

ReversibleOptic A_Review Source #
Instance details Defined in Optics.Re Associated Types type ReversedOptic A_Review = (r :: Type) Source # Methods re :: forall (is :: IxList) s t a b. AcceptsEmptyIndices "re" is => Optic A_Review is s t a b -> Optic (ReversedOptic A_Review) is b a t s Source #
ReversibleOptic A_ReversedLens Source #
Instance details Defined in Optics.Re Associated Types type ReversedOptic A_ReversedLens = (r :: Type) Source # Methods re :: forall (is :: IxList) s t a b. AcceptsEmptyIndices "re" is => Optic A_ReversedLens is s t a b -> Optic (ReversedOptic A_ReversedLens) is b a t s Source #
ReversibleOptic A_Getter Source #
Instance details Defined in Optics.Re Associated Types type ReversedOptic A_Getter = (r :: Type) Source # Methods re :: forall (is :: IxList) s t a b. AcceptsEmptyIndices "re" is => Optic A_Getter is s t a b -> Optic (ReversedOptic A_Getter) is b a t s Source #
ReversibleOptic A_ReversedPrism Source #
Instance details Defined in Optics.Re Associated Types type ReversedOptic A_ReversedPrism = (r :: Type) Source # Methods re :: forall (is :: IxList) s t a b. AcceptsEmptyIndices "re" is => Optic A_ReversedPrism is s t a b -> Optic (ReversedOptic A_ReversedPrism) is b a t s Source #
ReversibleOptic A_Prism Source #
Instance details Defined in Optics.Re Associated Types type ReversedOptic A_Prism = (r :: Type) Source # Methods re :: forall (is :: IxList) s t a b. AcceptsEmptyIndices "re" is => Optic A_Prism is s t a b -> Optic (ReversedOptic A_Prism) is b a t s Source #
ReversibleOptic A_Lens Source #
Instance details Defined in Optics.Re Associated Types type ReversedOptic A_Lens = (r :: Type) Source # Methods re :: forall (is :: IxList) s t a b. AcceptsEmptyIndices "re" is => Optic A_Lens is s t a b -> Optic (ReversedOptic A_Lens) is b a t s Source #
ReversibleOptic An_Iso Source #
Instance details Defined in Optics.Re Associated Types type ReversedOptic An_Iso = (r :: Type) Source # Methods re :: forall (is :: IxList) s t a b. AcceptsEmptyIndices "re" is => Optic An_Iso is s t a b -> Optic (ReversedOptic An_Iso) is b a t s Source #