Utility

A wrapper around the metatype of any type.

This wrapper allows a metatype (T.Type, String.self, etc.) to conform to Equatable and Hashable. Therefore, a metatype can be used as a key in a dictionary.

A type-safe identifier.

An Identifier is merely a wrapper around an Int, but with the added type-safety of the generic type parameter Subject.

let truck: Identifier<Truck> = 0
let friend: Identifier<Friend> = 0

The Subject is not used within the type, but it exists to ensure that things like this don’t compile:

truck == friend
// Binary operator '==' cannot be applied to operands of type 'Identifier<Truck>' and
// 'Identifier<Friend>'

Unifying interface for Range and ClosedRange types.

Interface for enum values whose values can be inverted.