[uecker]

What do you want to use it for? C++ uses it for the compile-time programming together with templates. Essentially C++ evolves into a language where you write a program that gets interpreted at compile-time to produce some code that then gets compiled. But I am not sure this is a good idea. It adds a lot of complexity, places many responsibilities that belongs into a compiler onto library writers, increases compilation time a lot, and - with all template expansion - causes a lot of bloat that hurts performance. It also makes debugging interesting. But it looks really good in microbenchmarks because you can create optimal code for special cases easily, I just do not see how this translates into real world performance.

[jcelerier]

If it's not in the language it will be in separate preprocessors, which will all be strictly worse.