Optics.IxAffineTraversal

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

Formation

type IxAffineTraversal i s t a b = Optic An_AffineTraversal (WithIx i) s t a b

Type synonym for a type-modifying indexed affine traversal.

type IxAffineTraversal' i s a = Optic' An_AffineTraversal (WithIx i) s a

Type synonym for a type-preserving indexed affine traversal.

Introduction

iatraversal :: (s -> Either t (i, a)) -> (s -> b -> t) -> IxAffineTraversal i s t a b

Build an indexed affine traversal from a matcher and an updater.

If you want to build an IxAffineTraversal from the van Laarhoven representation, use iatraversalVL.

Elimination

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

ipreview :: IxAffineTraversal i s t a b -> s -> Maybe (i, a)

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

Combinators

unsafeFilteredBy :: Is k An_AffineFold => Optic' k is a i -> IxAffineTraversal' i a a

Obtain a potentially empty IxAffineTraversal by taking the element from another AffineFold and using it as an index.

• - Note: This is not a legal IxTraversal, unless you are very careful not to invalidate the predicate on the target (see unsafeFiltered for more details).

Since: 0.3

Additional introduction forms

ignored :: IxAffineTraversal i s s a b

This is the trivial empty IxAffineTraversal, i.e. the optic that targets no substructures.

This is the identity element when a Fold, AffineFold, IxFold or IxAffineFold is viewed as a monoid.

>>> 6 & ignored %~ absurd
6

Subtyping

data An_AffineTraversal :: OpticKind

Tag for an affine traversal.

Instances

Is An_AffineTraversal A_Fold

Defined in Optics.Internal.Optic.Subtyping

Methods

implies :: (Constraints An_AffineTraversal p -> r) -> Constraints A_Fold p -> r

Is An_AffineTraversal An_AffineFold

Defined in Optics.Internal.Optic.Subtyping

Methods

implies :: (Constraints An_AffineTraversal p -> r) -> Constraints An_AffineFold p -> r

Is An_AffineTraversal A_Setter

Defined in Optics.Internal.Optic.Subtyping

Methods

implies :: (Constraints An_AffineTraversal p -> r) -> Constraints A_Setter p -> r

Is An_AffineTraversal A_Traversal

Defined in Optics.Internal.Optic.Subtyping

Methods

implies :: (Constraints An_AffineTraversal p -> r) -> Constraints A_Traversal p -> r

Is A_Prism An_AffineTraversal

Defined in Optics.Internal.Optic.Subtyping

Methods

implies :: (Constraints A_Prism p -> r) -> Constraints An_AffineTraversal p -> r

Is A_Lens An_AffineTraversal

Defined in Optics.Internal.Optic.Subtyping

Methods

implies :: (Constraints A_Lens p -> r) -> Constraints An_AffineTraversal p -> r

Is An_Iso An_AffineTraversal

Defined in Optics.Internal.Optic.Subtyping

Methods

implies :: (Constraints An_Iso p -> r) -> Constraints An_AffineTraversal p -> r

ArrowChoice arr => ArrowOptic An_AffineTraversal arr

Defined in Optics.Arrow

Methods

overA :: Optic An_AffineTraversal is s t a b -> arr a b -> arr s t

ToReadOnly An_AffineTraversal s t a b

Defined in Optics.ReadOnly

Methods

getting :: Optic An_AffineTraversal is s t a b -> Optic' (Join A_Getter An_AffineTraversal) is s a

IxOptic An_AffineTraversal s t a b

Defined in Optics.Indexed.Core

Methods

noIx :: NonEmptyIndices is => Optic An_AffineTraversal is s t a b -> Optic An_AffineTraversal NoIx s t a b

van Laarhoven encoding

type IxAffineTraversalVL i s t a b = forall f. Functor f => (forall r. r -> f r) -> (i -> a -> f b) -> s -> f t

Type synonym for a type-modifying van Laarhoven indexed affine traversal.

Note: this isn't exactly van Laarhoven representation as there is no Pointed class (which would be a superclass of Applicative that contains pure but not <*>). You can interpret the first argument as a dictionary of Pointed that supplies the point function (i.e. the implementation of pure).

type IxAffineTraversalVL' i s a = IxAffineTraversalVL i s s a a

Type synonym for a type-preserving van Laarhoven indexed affine traversal.

iatraversalVL :: IxAffineTraversalVL i s t a b -> IxAffineTraversal i s t a b

Build an indexed affine traversal from the van Laarhoven representation.

iatraverseOf :: (Is k An_AffineTraversal, Functor f, is `HasSingleIndex` i) => Optic k is s t a b -> (forall r. r -> f r) -> (i -> a -> f b) -> s -> f t

Traverse over the target of an IxAffineTraversal and compute a Functor-based answer.

Since: 0.3