So, now Swift 4 is here and things are changing. One of the big improvements of Swift 4 is the incorporation of serialisation for classes, structs and enums. In contrast to the previous versions which rely on the old NSObject/NSCoding mechanisms the new Codable protocol is not restricted to classes only. And even better, if you do not have special needs the compiler will synthesise the needed functions for you as we will see later.
Just for completeness I’d like to show in this post how to make structs serializable in the same manner as enums (see this post). Again, we transform the struct to a dictionary of NSCoding compliant types and give it to an NSCoder (e.g. NSKeyedArchiver) for coding. The other way round we get the decoded dictionary and initialize the desired struct with it. Sounds simple, doesn’t it. Let’s start.
Welcome to this new posts in my series about enums with associated values. In the previous posts we looked at the equatability of enums with associated values. Another problem arises when we want to store enums (maybe as part of the model) on a file or want to send it over a network, let’s say: want to serialize the enum. Although the primitive types as Int and String conform to the NSCoding protocol as well as collections of those types (e.g. Arrays and Dictionaries) enums and structs don’t. And since they are not classes we can also not implement the NSCoding protocol for them. For simple enums we can use its raw values for coding, but that’s not possible for enums with associated values.