Filmed at https://2017.dotswift.io on January 27th in Paris. More talks on http://thedotpost.com In this talk, Karoly describes several ways to implement the same simple ordered set protocol in Swift, demonstrating how the language supports a number of surprisingly different approaches to programming. At every step, we trade extra complexity for improved runtime performance, ending on an implementation that is ludicrously fast but also quite difficult to handle.