Crystal & Julia 1.0. Crystal because it's a blazing fast, compiled and statically typed version of Ruby (or 80% anyway), and it's web server is awesome. Now it just needs full concurrency.

Julia because it offers a nice, performant alternative to Python & R in data science, while avoiding Java & C++. It has some really nice features like multiple dispatch and the ability to run R, Python, Fortran and C code inside of it, so you can use libraries like Numpy in Julia.

Yes, can't wait for Crystal 1.0 release, awesome language.

From crystal-lang.org, Crystal is a compiled language

I never understood the phrase compiled language.

A compiled language uses a compiler to create a executable binary as opposed to a runtime that interprets or just-in-time compiles the language as it runs. Ruby is interpreted, C is compiled. Generally speaking, compiled languages are more performant but lack some of the flexibility of having a runtime available.

Crystal sacrifices some of Ruby's metaprogramming capabilities for performance and static type assurances.

There are many C interpreters.

I'm aware of PicoC, Cling (nee CINT), and Ch (commercial), but that's only three. What others are there? I'm curious about canonical C interpreters as well as things that aren't quite interpreting C but are somehow related.

Here is another http://compcert.inria.fr

[08/2011] Release of version 1.9 of the Compcert C compiler. Novelties include a reference C interpreter and stronger semantic preservation results.

Question for anyone handing out unofficial legal opinions:

This one is dual-licensed. There are a small kerfuffle of custom licenses that say "no commercial use", but everything is also variously covered by the GPL (v2 or later), LGPL v3, and BSD 3-clause.

Ref: https://github.com/AbsInt/CompCert/blob/master/LICENSE

I'm curious if I could use this in a commercial setting if I perfectly comply with the various GPL and BSD licenses.

If I could, that could be a problem for this group, because the repo readme (at https://github.com/AbsInt/CompCert) explicitly states "this is not free software."