Crystal is a programming language with the following goals:

- Have a syntax similar to Ruby (but compatibility with it is not a goal)
- Be statically type-checked, but without having to specify the
  type of variables or method arguments.
- Be able to call C code by writing bindings to it in Crystal.
- Have compile-time evaluation and generation of code, to
  avoid boilerplate code.
- Compile to efficient native code.

WWW: https://crystal-lang.org