This is honestly really cool! I've heard praises about Zig's comptime without really understanding what makes it tick. It initially sounds like Rust's constant evaluation which is not particularly capable. The ability to have types represented as values at compilation time, and _only_ at compile time, is clearly very powerful. It approximates dynamic languages or run-time reflection without any of the run-time overhead and without opening the Pandora's box that is full blown macros as in Lisp or Rust's procedural macros.