That's true. I think that there is a good number of people out there who have been waiting for exactly this. Hopefully it will be available soon but unfortunately I know of no signs that it is actively being worked on by anyone at the moment.
In terms of performance, I was able to reduce the computational time from 1m57.812s to 0m30.203s (25.6% of the original time) on my 2.8 GHz 16 GB memory machine simply by changing each 'class' to a 'struct'. The difference is that structs are allocated on the stack in Crystal. This is a common performance optimization in Crystal (https://crystal-lang.org/docs/guides/performance.html). For comparison, the Go code, also listed on the site, ran on my machine in 1m22.466s. I think that with the use of structs instead of classes, Crystal does run very similar to C speeds. Otherwise, I really enjoyed this article. The author compares several other languages with the same benchmark (see http://www.eccentricdevelopments.com/programming-language-co...). It would be interesting to see D-lang in a future comparison.
Maybe try Crystal (https://crystal-lang.org/) then. It has many of the benefits of Go and a Ruby-like syntax. It feels even more like a scripting language than Go because of awesome type inference, uses a similar model as Go for concurrency, and even has proper generics ;-)
I've enjoyed Crystal (https://crystal-lang.org/) a lot lately. Others have mentioned Nim, which is quite good. Also, D-lang (http://dlang.org/) doesn't get nearly enough love by people. It's an excellent language too.
I've previously used Go to develop a command-line tool and it worked quite well. I particularly liked the fact that I could cross-compile it so that I had a single static binary that could target various platforms/OSes without the need to compile explicitly on those platforms. I also think that Nim and Crystal could be quite good for this. Crystal, in particular has a remarkable scripting language feel, because of the extensive type inference, despite being natively compiled. It's also faster than Go, which is itself quite fast. Nim is no slouch performance wise either though and has the most pythonic like syntax of the languages I've described here.
I'm so excited about the prospect of Crystal language approaching 1.0 stability even if this is a fair way away. It just seems like a language with a lot of potential. If they added multi-threading and Windows support tomorrow, I think I'd be using it for all of my new projects. These things take time though...
My favorite is Tip #36: Integer numbers less than ten should be written in long-form unless they are measurements with associated units or are within a range (e.g. 2-5). For example, you shouldn’t write, "There were 4 cats that scratched the researchers more than all others." For those of us that are old enough to recall life before we started publicly broadcasting 144-character reports on the nuances of our breakfasts (Forget my diet; I'm having 2 bowls of cornflakes this morning!), these low-integer numerals are particularly grating.