As I understand it, as a user of Swift, I can't define a non-frozen enum in Swift?
Presumably there's a reason for that? It would seem beneficial if we could as we could then avoid breaking changes in library APIs when adding new cases to the enum.
Currently a user of my library gets frozen enums which I may intend to add new values to in the future. They have to write exhaustive switch statements, which might take the form a listing our each possible case, with no default case, so adding a new value will break compilation.
In ObjC, or Apple's code, enums can be defined as non-frozen to avoid this issue.