In this chapter, we have had to shift the way we think about code. At the very least, this is a great exercise so we don't get set in our programming ways. We have covered the philosophy behind functional programming and how it differs from object-oriented programming. We have looked into the specifics of closures and how they enable functional programming techniques in Swift. Lastly, we explored some of the specific functional methods that Swift has built in.

The sign of a truly great programmer is not someone who knows a lot about one tool, but one who knows which tool to use when. We get there by learning and practicing using lots of different tools and techniques without ever becoming too attached to a specific one.

Once you are comfortable with the concepts of closures and functional programming, you are ready to move on to our next topic, generics. Generics is our first opportunity to make the strongly typed nature of Swift really work for us.