Re: [review][JSON] Some thoughts on recent reviews

From: Peter Dimov (pdimov_at_[hidden])
Date: 2020-09-23 19:07:31

Niall Douglas wrote:
> Hana's runtime benchmarks showed her regex implementation far outpacing 
> any of those in the standard libraries. Like, an order of magnitude in 
> absolute terms, linear scaling to load instead of exponential for common 
> regex patterns. A whole new world of performance.
>
> Part of why her approach is so fast is because she didn't implement all of 
> regex. But another part is because she encodes the parse into 
> relationships between literal types which the compiler can far more 
> aggressively optimise than complex types. So basically the codegen is way 
> better, because the compiler can eliminate a lot more code.

I've looked at CTRE, I know what it does, how it does it, and how well it 
performs. It is, as I said, a remarkable piece of engineering, and I respect 
Hana for her work. 
https://pdimov.github.io/blog/2020/05/15/its-a-small-world/

Nevertheless, I have a not-entirely-uninformed hunch that a runtime engine 
can perform on par. Of course, until/unless I can substantiate this more 
thoroughly, by for example writing a runtime regex engine that exhibits 
similar performance to CTRE, you can file this under "idle speculation".