If you're interested in Rust regex implementations, you may be interested in the one that I wrote in a macro: https://crates.io/crates/safe-regex . At build time, the macro generates the matcher as Rust code. The compiler then compiles and optimizes the matcher code as part of your Rust binary.

I wanted to see if it was possible to make a fast Rust regex library without using any unsafe code. It turns out that it is. Russ Cox's paper was very helpful.