Protocols and generics are definitely complex, but we have seen that they can be used to effectively let the compiler protect us from ourselves. In this chapter, we have covered how protocols are like contracts for types to sign. We have also seen that protocols can be made more flexible using type aliases. Generics allow us to take full advantage of protocols with type aliases and also allow us to create powerful and flexible types that adapt to the contexts in which they are used. Finally, we looked at how we can use protocols and generics in the form of sequences and generators to solve a complex math problem in a very clean and understandable way, as an inspiration to solve other types of problems just as cleanly.

At this point we have covered all of the core features of the Swift language. We are now ready to look a little bit deeper at how data is actually stored while a program is run and how we can best manage the resources used by our programs.