I'm curious to see how Clojure fares against the current crop of folks becoming intrigued by statically-typed languages like Haskell, F#, etc.
The key of Clojure is that it's pragmatic, as opposed to dogmatic. It's a language designed to solve real-world problems in production environments (hence the focus on concurrency, for example).
Also, being a lisp, it's a "programmable programming language", and once you realize the power that that gives you, it's hard not to fall in love with it.
It would be nice to see example(s) of clojure solving real world concurrency problems.
I am looking for 'pure concurrency' in a app like videos games exctracting last ounce of processing power from a multicore machine. This what the original comment stated was the core competence of Clojure.
That's not actually what the parent comment stated though. It says that Clojure is designed to solve real-world problems in production environments.
In many cases this doesn't mean squeezing out the last ounce of processing power, but being able to reason about concurrent code safely. You pay an overhead of using immutability in order to facilitate higher correctness.
When your system grows it becomes important to be able to reason about parts of it in isolation. This is particularly important when you're running in a multithreaded environment.
That's what people generally mean when they say that Clojure has focus on concurrency. Since the data is immutable you can make assumptions about what the code is doing that you wouldn't be able to make otherwise.
On the other hand, Clojure is at least a functional language. You get the benefits of immutability, no side effects, higher order functions, etc, in a neat and understandable package. And it runs in the JVM and thus has access to the bazillion or so libraries written in Java, thus getting around the interop problems that other modern languages (and some older ones) have.
On the other hand, Typed Clojure does not offer nearly the cohesive experience one gets from Haskell, nor do the types guide optimizations etc. Type checking is really a lint step rather than a build step. And almost all existing Clojure code is still dynamically typed, so you can't usually infer how to use a lib based on its type signatures (since it doesn't have them), which I love being able to do in hs.
Back to tooling, usually you're into a mess of apis because you are forced to use or choose a type, which then enters a whole world of semantics architects love arguing about. For Clojure, a lot of functionality can be clear and concisely done in maps and lists and the handful of functions which operate on them.
I feel fairly productive.