Contents

isTriviallyIdentical(to:)

Returns a boolean value indicating whether this array is identical to other.

Declaration

func isTriviallyIdentical(to other: ContiguousArray<Element>) -> Bool

Discussion

Two array values are identical if there is no way to distinguish between them.

For any values a, b, and c:

  • a.isTriviallyIdentical(to: a) is always true. (Reflexivity)

  • a.isTriviallyIdentical(to: b) implies b.isTriviallyIdentical(to: a). (Symmetry)

  • If a.isTriviallyIdentical(to: b) and b.isTriviallyIdentical(to: c) are both true, then a.isTriviallyIdentical(to: c) is also true. (Transitivity)

  • If a and b are Equatable, then a.isTriviallyIdentical(b) implies a == b

    • a == b does not imply a.isTriviallyIdentical(b)

Values produced by copying the same value, with no intervening mutations, will compare identical:

let d = c
print(c.isTriviallyIdentical(to: d))
// Prints true

Comparing arrays this way includes comparing (normally) hidden implementation details such as the memory location of any underlying array storage object. Therefore, identical arrays are guaranteed to compare equal with ==, but not all equal arrays are considered identical.