Yes, the enhanced enums we shipped in 2.17 are like Java enums.

We are also working on support for pattern matching and algebraic datatype-style programming: https://github.com/dart-lang/language/blob/master/working/05...

I say "style" here because object-oriented languages like Dart can already mostly model sum types using subclasses. What you need to get the rest of the way there is basically just:

1. Sealed types so that the compiler can check for exhaustiveness when you match over all of the subclasses.

2. A nice pattern matching syntax to let you discriminate between the subclasses and destructure them.

3. Ideally, a nice lightweight syntax for defining a sum type family as a superclass and set of subclasses, though this is relatively less critical.

We're hard at work on this, but pattern matching in general is a pretty large feature and retrofitting it into a language whose syntax wasn't initially designed around it is a challenge.

I'm very excited about macros too. That's another large, difficult feature, but one that I hope will provide a lot of power to users and make the entire ecosystem more valuable over time.