Oh, serde is interesting. I was specifically thinking about compile-time reflection but apparently rust's macros are more powerful than I realized. I'm inspired to look into this more, thanks!
Serde (https://github.com/serde-rs/serde) is my baby, so let me know if you need any help with it. In a sense serde is a compile time reflection library. It's designed to recursively walk through a structure while calling a function on each component. While the primary purpose is to do serialization, it could be used to do other reflection-y things, like build a UI widget for arbitrary structures. To really support full reflection though serde would have to be modified to support in-place modification. It wouldn't trivial, but it's certainly not impossible.
