Regex used to offer a regex!() macro that did compile-time compilation, but this was removed a while back as it was too much of a maintenance burden and was getting in the way of performance optimization.
IIRC it required basically two separate implementations of the data structures, one that could be constructed at compile-time and was less efficient than the one that could be built at runtime. And the need to support both was becoming a problem.
I feel like there should be a middle ground here, a macro that validates at compile-time but still constructs at runtime. Hopefully the parser could still be shared between the macro and the runtime to ensure the macro can't get out of sync.
