Adding lookbehinds to rust-lang/regex
In a previous blogpost, Erik wrote about how he implemented the linear time matching algorithm from [RegElk+PLDI24] in the popular regex engine RE2. In this one, we're looking at how to do the same thing for the official regex engine from the Rust language. Namely, we add support for unbounded captureless lookbehinds. First, let's discover the newly supported feature and its limitations. Lookbehinds allow regexes to make assertions about things preceding some part of the regex pattern without c