ReverseIndexType

protocol ReverseIndexType

An index that traverses the same positions as an underlying index, with inverted traversal direction.

Inheritance BidirectionalIndexType, Equatable, ForwardIndexType, _Incrementable View Protocol Hierarchy →
Associated Types
Base : BidirectionalIndexType
Distance : _SignedIntegerType = Self.Base.Distance

A type that can represent the number of steps between pairs of ReverseIndex values where one value is reachable from the other.
Import import Swift

Initializers

init(_:) Required

Declaration

init(_ base: Self.Base)

Instance Variables

var base: Self.Base Required

The successor position in the underlying (un-reversed) collection.

If self is advance(c.reverse.startIndex, n), then: - self.base is advance(c.endIndex, -n). - if n != c.count, then c.reverse[self] is equivalent to [self.base.predecessor()].

Declaration

var base: Self.Base { get }

Instance Methods

func ==(_:rhs:) Required

Returns true if lhs is equal to rhs.

Equality implies substitutability. When x == y, x and y are interchangeable in any code that only depends on their values.

Class instance identity as distinguished by triple-equals === is notably not part of an instance's value. Exposing other non-value aspects of Equatable types is discouraged, and any that are exposed should be explicitly pointed out in documentation.

Equality is an equivalence relation

  • x == x is true
  • x == y implies y == x
  • x == y and y == z implies x == z

Inequality is the inverse of equality, i.e. !(x == y) iff x != y.

Declaration

func ==(lhs: Self, rhs: Self) -> Bool

Declared In

Equatable
func advancedBy(_:)

Returns the result of advancing self by n positions.

Returns: - If n > 0, the result of applying successor to self n times. - If n < 0, the result of applying predecessor to self -n times. - Otherwise, self.

Requires: n >= 0 if only conforming to ForwardIndexType Complexity: - O(1) if conforming to RandomAccessIndexType - O(abs(n)) otherwise

Declaration

func advancedBy(n: Self.Distance) -> Self

Declared In

ForwardIndexType
func advancedBy(_:limit:)

Returns the result of advancing self by n positions, or until it equals limit.

Returns: - If n > 0, the result of applying successor to self n times but not past limit. - If n < 0, the result of applying predecessor to self -n times but not past limit. - Otherwise, self.

Requires: n >= 0 if only conforming to ForwardIndexType.

Complexity: - O(1) if conforming to RandomAccessIndexType - O(abs(n)) otherwise

Declaration

func advancedBy(n: Self.Distance, limit: Self) -> Self

Declared In

ForwardIndexType
func distanceTo(_:)

Measure the distance between self and end.

Requires: - start and end are part of the same sequence when conforming to RandomAccessSequenceType. - end is reachable from self by incrementation otherwise.

Complexity: - O(1) if conforming to RandomAccessIndexType - O(n) otherwise, where n is the function's result.

Declaration

func distanceTo(end: Self) -> Self.Distance

Declared In

ForwardIndexType
func predecessor() Required

Returns the previous consecutive value in a discrete sequence.

If self has a well-defined successor, self.successor().predecessor() == self. If self has a well-defined predecessor, self.predecessor().successor() == self.

Requires: self has a well-defined predecessor.

Declaration

func predecessor() -> Self

Declared In

BidirectionalIndexType
func successor() Required

Returns the next consecutive value in a discrete sequence of Self values.

Requires: self has a well-defined successor.

Declaration

func successor() -> Self

Declared In

_Incrementable

Default Implementations

func advancedBy(_:)

Returns the result of advancing self by n positions.

Returns: - If n > 0, the result of applying successor to self n times. - If n < 0, the result of applying predecessor to self -n times. - Otherwise, self.

Requires: n >= 0 if only conforming to ForwardIndexType Complexity: - O(1) if conforming to RandomAccessIndexType - O(abs(n)) otherwise

Declaration

func advancedBy(n: Self.Distance) -> Self

Declared In

BidirectionalIndexType, ForwardIndexType
func advancedBy(_:limit:)

Returns the result of advancing self by n positions, or until it equals limit.

Returns: - If n > 0, the result of applying successor to self n times but not past limit. - If n < 0, the result of applying predecessor to self -n times but not past limit. - Otherwise, self.

Requires: n >= 0 if only conforming to ForwardIndexType.

Complexity: - O(1) if conforming to RandomAccessIndexType - O(abs(n)) otherwise

Declaration

func advancedBy(n: Self.Distance, limit: Self) -> Self

Declared In

BidirectionalIndexType, ForwardIndexType
func distanceTo(_:)

Measure the distance between self and end.

Requires: - start and end are part of the same sequence when conforming to RandomAccessSequenceType. - end is reachable from self by incrementation otherwise.

Complexity: - O(1) if conforming to RandomAccessIndexType - O(n) otherwise, where n is the function's result.

Declaration

func distanceTo(end: Self) -> Self.Distance

Declared In

BidirectionalIndexType, ForwardIndexType