protocol _ForwardIndexType

This protocol is an implementation detail of ForwardIndexType; do not use it directly.

Its requirements are inherited by ForwardIndexType and thus must be satisfied by types conforming to that protocol.

Inheritance Equatable, _Incrementable View Protocol Hierarchy →
Associated Types
Distance : _SignedIntegerType = Int

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

Reachability is defined by the ability to produce one value from the other via zero or more applications of successor.

_DisabledRangeIndex = _DisabledRangeIndex_
Import import Swift

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


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

Declared In

func successor() Required

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

Requires: self has a well-defined successor.


func successor() -> Self

Declared In