That seems like super reasonable approach to factories. I already like that, however it feels a little bit macro heavy.

Actually, command resolver can use whatever code you need. So, you can use something that differs from the actual implementation, like a simplified version of it. But the fact that it is placed in a single centralized place makes it very maintainable.

When I read your comment for the first time, I was surprised why do you think so, as there is only 1 macro – produce/1. Completely forgot that DSL for schema definition is built on macros That’s because the heavy lifting is done by spark (@zachdaniel thank you for the library, support and quick bug fixing!)

I tried to describe the schema using simple structures in my initial implementation. But eventually, current implementation won.

This is great. I’ve tried a bunch of factory approaches, but this one feels quite well executed and seems to cover the needs I generally have quite well. I also really like that it makes it impossible to insert data in a way the codebase wouldn’t.