Prism

 
public typealias Prism<S, A> = PPrism<S, S, A, A>

  • Focuses on a specific index of this prism.

    Declaration

    Swift

    func at(_ i: A.AtIndex) -> AffineTraversal<S, A.AtFoci>

    Parameters

    i

    Index to focus.

    Return Value

    An optional from this structure to the focused index.

  • Provides a traversal over all elements of the focus of this prism.

    Declaration

    Swift

    var every: Traversal<S, A.EachFoci> { get }

  • Provides an AffineTraversal focused on an index of the focus of this prism.

    Declaration

    Swift

    func index(_ i: A.IndexType) -> AffineTraversal<S, A.IndexFoci>

    Parameters

    i

    Index to focus.

    Return Value

    An AffineTraversal focused on an index of the focus of this prism.

  • Provides an AffineTraversal focused on an index of the focus of this prism.

    Declaration

    Swift

    subscript(i: A.IndexType) -> AffineTraversal<S, A.IndexFoci> { get }

    Parameters

    i

    Index to focus.

    Return Value

    An AffineTraversal focused on an index of the focus of this prism.

  • Provides an identity Prism.

    Declaration

    Swift

    static var identity: Prism<S, S> { get }

  • Creates a prism based on functions to extract and embed a value into a sum type.

    Declaration

    Swift

    convenience init(extract: @escaping (S) -> A?, embed: @escaping (A) -> S)

    Parameters

    extract

    Function to extract a value from the source.
    embed

    Function to embed a value into the source.

  • Extract a value from the source.

    Declaration

    Swift

    var extract: (S) -> A? { get }

  • Embed a value into the source

    This is equivalent to reverseGet

    Declaration

    Swift

    var embed: (A) -> S { get }

  • Provides a prism that checks equality with a value.

    Declaration

    Swift

    static func only(_ a: A) -> Prism<A, ()>

    Parameters

    a

    Value to check equality with.

    Return Value

    A Prism that only matches with the provided value.