Using Protocols and Protocol Extensions

While watching the presentations from WWDC 2015 about protocol extensions and protocol-oriented programming (POP), I will admit that I was very skeptical. I have worked with object-oriented programming (OOP) for so long that I was unsure whether this new programming paradigm would solve all of the problems that Apple was claiming it would. Since I am not one who lets my skepticism get in the way of trying something new, I set up a new project that mirrored the one I was currently working on, but wrote the code using Apple's recommendations for POP. I also used protocol extensions extensively in the code. I can honestly say that I was amazed by how much cleaner the new project was compared to the original one. I believe that protocol extensions are going to be one of those defining features that set one programming language apart from...