Adding lookbehinds to rust-lang/regex, https://systemf.epfl.ch/blog/rust-regex-lookbehinds/.
The feature of lookbehinds is very often absent in linear regex engines. These researchers bring them in the `regex` crate. The benchmarks show a reasonable and usable performance making it ready for real-world applications.
The article gives all pointers to the research article and the patches for `regex` (on github.com).
The prevention of unnecessary lookbehind scanning till the end of the haystack is neat!
