Hopefully, we'll have Scala support with Java 9, when Quasar is expected to work will all JVM languages automatically. We might also add support beforehand, but the problem is that supporting Scala is a large effort, due to its complicated compilation, which isn't justified by the number of Scala developers, compounded by the fact that developers who like monads -- and developers who choose Scala often like monads -- will find the excellent Akka framework very satisfactory. Clojure and Kotlin have far fewer users, but supporting them is easy, as their compilation is fairly straightforward.

We are, however, more than happy to accept contributions towards supporting Scala.