The author discusses the rewrite of Rust’s regex crate, which aims to improve internal composition and make it easier to add optimizations while maintaining correctness. This led to the creation of the regex-automata crate, which exposes the regex crate internals as separate APIs. The post highlights the problems that prompted the rewrite, including difficulties with composition, testing, and requests for niche APIs. The author also mentions the birth of regex-automata, which originally aimed to build fully compiled DFAs but expanded to include a variety of regex engines. The post concludes by mentioning the availability of the regex-cli program for command line access to the regex crate’s APIs.
https://blog.burntsushi.net/regex-internals/