Swift Programming: The Big Nerd Ranch Guide, 3rd Edition

Comparable

Now that your Point type conforms to the Equatable protocol, you may be interested in more nuanced forms of comparison. For example, perhaps you want to know if one point is less than another point. As with equality, types must define for themselves what it means for one instance to be “less than” another. You define this functionality by conforming to the Comparable protocol.

Start by reviewing the documentation for Comparable. You have not typed it anywhere yet, so you cannot Option-click its name. Instead, open Xcode’s Help menu and select Developer Documentation.

Search the documentation for “Comparable” and select the result for the Comparable protocol in the Swift standard library. Under “Conforming to the Comparable Protocol,” ...