Implementation of the Equatable protocol in Swift on a custom object.

EquatableProtocol.swift

public class MyCustomObject: Equatable {}

// MARK: Equatable

/**
 Evaluate equality as an identity check on an ObjectIdentifier constructed with an instance of our type. This is a public function in the global scope.
*/
public func ==(lhs: MyCustomObject, rhs: MyCustomObject) -> Bool {
    return ObjectIdentifier(lhs) == ObjectIdentifier(rhs)
}

MyCustomObject() == MyCustomObject() // false