Using associated values effectively

Good programming is about more than just grand, universal concepts of how to write effective code. The best programmers know how to play to the strengths of the tools at hand. We are now going to move from looking at the core tenants of programming design to some of the gritty details of enhancing your code with the power of Swift.

The first thing we will look at is making effective use of the associated value of an enumeration. Associated values are a pretty unique feature of Swift, so they open up some pretty interesting possibilities.

Replacing class hierarchies

We have already seen in Chapter 3, One Piece at a Time – Types, Scopes, and Projects that we can use an enumeration with associated values to represent a measurement like distance in multiple measurement systems:

enum Height {
    case Imperial(feet: Int, Inches: Double)
    case Metric(meters: Double)
    case Other(String)
}

We can generalize this use case as using an enumeration to flatten out...