Advanced Pattern Matching


released Fri, 15 Feb 2019
Swift Version 5.0


There're many ways to unwrap optionals, and pattern matching is one of them. You've probably used that quite frequently by now, nevertheless, here's a short example:

var result: String? = secretMethod()
switch result {
case nil:
    print("is nothing")
case let a?:
    print("\(a) is a value")

As you can see, result could be a string, but it could also be nil. It's an Optional. By switching on result, we can figure out whether it is .none or whether it is an actual value. Even more, if it is a value, we can also bind this value to variable right away. In this case a. What's beautiful here, is the clearly visible distinction between the two states, that the variable result can be in.