Summary

In this chapter, we saw that protocols are treated as full-fledged types by Swift. We also saw how polymorphism can be implemented in Swift with protocols. We concluded this chapter with an in-depth look at protocol extensions and saw how we would use them in Swift. Protocols and protocol extensions are the backbone of Apple's new POP paradigm. This new model for programming has the potential to change the way we write and think about code. While we did not specifically cover POP in this chapter, getting to grips with the topics in this chapter gives us the solid understanding of protocols and protocol extensions needed to learn about this new programming model. In the next chapter, we will look at how to use protocols and protocol extensions when we are designing our application.