## ReverseIndexType

protocol ReverseIndexType
Inheritance BidirectionalIndexType, Equatable, ForwardIndexType, _Incrementable View Protocol Hierarchy → 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 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

Return 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

Return 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

#### Declared In

ForwardIndexType

Return 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

Return 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

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

Requires: self has a well-defined successor.

#### Declaration

func successor() -> Self

_Incrementable

### Default Implementations

Return 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

#### Declared In

BidirectionalIndexType, ForwardIndexType

Return 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