[Klathmon]

I've actually played with OCaml a bit, and Haskell a bit less. The problem is that I don't know what "problems to solve" with them, and there is no way I'm going to use something like that at work, so I kind of run out of steam before I really get into it.

I might shoot for Scala next time. We don't use Java anywhere at my current job, but I might play around with it in a personal project for a while.

I really like the functional style, and I can see how strong typing works REALLY well with it, but I've already found that it's pretty hard to bring other devs up to speed on it. And that really limits where I use it.

[lmm]

I tried to write a bit about my use cases at http://m50d.github.io/2014/05/16/signs-your-java-program.htm... and http://m50d.github.io/2015/04/21/effects.html (apologies for formatting issues). Basically I find the really useful problem that advanced type systems solve is keeping track of cross-cutting concerns (e.g. database transactions, audit logging - the kind of thing you'd be tempted to use AOP for) in a consistent way.

[loganmhb]

If you like Javascript and you want to try a language with a good static type system, you might like Elm (http://elm-lang.org/). As a bonus, it has fantastic documentation and examples of small in-browser projets -- a clock, Pong, and so on.