> It used to many years ago via the regex_macros crate, but I abandoned it mostly because of not having enough resources to dedicate to it and its somewhat niche usage.

As an aside, my impression is that Rust developers are using macros less now than they were even a couple of years ago. It seemed a few years ago, a lot of people coming to Rust were impressed by the power of macros (especially procedural) and used them in a lot of libraries. It seems now, people are realizing the costs of macros to tooling and understandability, and are using them more judiciously.