Enumerations as data structures

Although we have already seen in Chapter 2, Basic Swift, that enum in Swift goes a lot further than merely representing integers with more memorable symbols; we have only just scratched the surface. The enum in Swift is so powerful that its use encroaches far into terrain that once belonged exclusively to heavyweight data structures such as classes.

Note

For that reason, enum plays a huge part in Swift; give yourself some time to play around with them, and start to uncover the many ways in which they can offer a lightweight and clear option for structuring your data.

In this section, we'll look at three areas that are particularly powerful, one of which we might not expect to associate with an enum:

• enum methods
• Associated types
• Recursive enum definitions

Adding methods to enums

The first feature of a Swift enum that makes them so much more than just names of integer values (or any other type) is the ability to add methods to them.

Let us create an enum of traffic...