Hands-On Design Patterns with Swift

Throwing and catching errors

Swift has an error handling mechanism that is based on throwing and catching errors, very similar to JavaScript or Java. In Swift, Error is simply a protocol. Any of your custom types conforming to the Error protocol can be used, and can also be thrown. This provides us with the ability to be as expressive as possible with the underlying types that we'll be using.

Unlike in Java, for example, it is not possible to specialize error catching, but you can always leverage pattern matching to determine the kind of error that's been thrown. You may want to define functions that throw, in order to indicate that an abnormal operation has run, and therefore, the execution of the program should properly handle these abnormal ...