[ijustlovemath]

In case the author comes in, I'm curious about how you designed the registration mechanism. We have a Python application that makes heavy use of decorators to give strong runtime introspection capabilities, and I've always wondered if the same could be done at or near compile time in an equivalent Rust context. I think learning about the drawbacks and boons of the designs you settled on would be really informative!

[terts]

Hi! So for Roto, our introspection needs are actually fairly limited. We only need the `TypeId`, the type name, the size and the alignment. which Rust can give us without any additional traits. It's not possible currently to - for example - access struct fields and enum variants. That is something that I plan to add, but that might require a crate like `bevy_reflect` or `facet`.

Rust is giving me just enough information to pull the current version of. More powerful introspection/reflection is not possible without derive macros. If you're ok with derive macros though, you could look into the 2 crates I mentioned.

Hope that answers your question!

[ijustlovemath]

Did you go through many iterations on the API of the registration? If so, which designs did you disqualify and why?

[terts]

Not many iterations, but a lot of head scratching was involved haha.

I decided against using a trait and a derive macro because I wanted to avoid running into Rust's orphan rule. We have a crate called routecore where most of our types are declared and then a separate crate called Rotonda which uses those types and uses Roto. I wanted Rotonda to be able to register routecore types.

That's also the downside of the current reflection crates; they require each type to have a derive macro.