[vvanders]

Yeah, the Kotlin inter-op is really well done. Having IntelliJ just work is always discounted more than I think people should.

I do wish Kotlin had more pattern matching semantics but that's just me being picky, it's a really nice language.

[logicchains]

>Having IntelliJ just work is always discounted more than I think people should.

To be fair, Kotlin has the advantage of being created by the company that makes IntelliJ, so it's got a big head start IDE-wise.

[aembleton]

Yes, and that is really important when it comes to language use. The more people who use the language, the more it can develop and the more libraries that can be built for it.

The other advantage of Kotlin is that it builds on top of the existing Java code base. Java has had decades to build up an ecosystem of frameworks and libraries. Kotlin builds on these with excellent interop.

[mike_hearn]

I like Kotlin too but in fairness this is a Ceylon thread ;)

From what I can see, Ceylon has a blend of strengths that should make it appeal to a certain segment of the market. On one hand, it's a fresh start and has a lot of the cleanness and terseness that I like from Kotlin. On the other, Gavin is clearly very much into type systems and type theory, and Ceylon has a more complex/powerful type system than Kotlin does.

I'll admit that I'm not totally sure whether the additional complexity is worth it, but I'm very open to being persuaded.

So it seems to me like Ceylon should appeal to people who currently like Scala or Haskell and push the type systems to the limit, but really want something without historical baggage like XML literals and other oddities. And I'm sure there are plenty of programmers like that.

The real question will be interop costs. Kotlin doesn't have any and that's the main reason people can consider it in existing projects, or introduction inside large corporations. Ceylon takes a more Scala-like approach where it has its own standard library, its own collections, etc.

[on_and_off]

not having interop costs also makes Kotlin much more realistically useable for Android apps, which could really help bootstrap its adoption.

Android could use a better language than Java 7 (or even 8) and Kotlin seems to be the only one that can easily replace it.

[gavinking]

Well the thing is that Ceylon offers fantastically smooth interop with both Java and JavaScript. That's one of it's main selling features for most people.

[mike_hearn]

Right, but by "interop" I didn't just mean the ability to call into Java code and vice-versa, although I admit that's the traditional definition. Scala can do that too.

What I meant is, Kotlin raised the bar in the interop department to new heights: it uses the same collection types, so there's no conversion between Java and some other SDK, but still manages to enhance them via compiler magic and extensions. It has an auto-converter tool so nobody has to waste time rewriting code that already works in order to use the new features. It can use annotation processors, etc.

Of course it also pays a fairly steep price to get that.

[justthistime_]

> but still manages to enhance them via compiler magic and extensions

The thing is that Scala tried to do that for years, and after years of battling subtle, leaky abstractions, they picked a different design.

It feels like Kotlin designers are completely unaware of what other languages tried and keep repeating all the mistakes ...

[UnFroMage]

Ceylon also has excellent Java/JVM (and JavaScript) interop. You should try it :)

[UnFroMage]

Ceylon has an IntelliJ plugin in the works that builds on the solid foundation of the Eclipse plugin, so it's picking up features really fast. It should be out in a few months.