[inferiorhuman]

Procedural macros have a peek function from the syn crate. macro_rules macros can stuff this into the pattern matching.

e.g.

https://turreta.com/2019/12/24/pattern-matching-declarative-...

[colejohnson66]

But proc macros are limited by requiring another crate (unless things have changed in the last year). Sure, it’s just one extra crate in the project, but why must I be forced to?

[inferiorhuman]

Asked and answered in an adjacent comment.