[microtonal]

Haskell is a much better choice than Scala, as long as JVM isn't required.

Haskell is much cleaner than Scala. But I think most people will get stuck reasoning about laziness (which is necessary to avoid space leaks). Another problem is that many modules require extensive use of the type system and advanced concepts to use (monads, arrows, lenses, existential typing, etc.).

I think that on the JVM Kotlin is a good candidate for eventually fixing most of Java's immediate shortcomings. Scala is there for people who'd like to go all-functional (regardless' its complexity). One of the nice things is that you get at least some amount of interoperability, e.g. one can perfectly write Play applications in Java and still get many of the benefits of Play.

[mercurial]

> Haskell is much cleaner than Scala. But I think most people will get stuck reasoning about laziness (which is necessary to avoid space leaks). Another problem is that many modules require extensive use of the type system and advanced concepts to use (monads, arrows, lenses, existential typing, etc.).

Not to mention that many modules require various GHC extensions.

I'm not so sure about Kotlin. From what I can see, it's pretty straightforward, with no risk or ambition of achieving the anxiety-inducing Scala method signatures. On the other hand, it seems to be seriously lacking in the marketing department, which can often be enough to push forward a language even when a better option is available.