Some say a set of regular expressions comprises a domain-specific language, or DSL; essentially, a mini-programming language. A full-blown programming language like Java or Python can do many things, ...

If you’ve programmed in Perl or any other language with built-in regular-expression capabilities, then you probably know how much easier regular expressions make text processing and pattern matching.

Just to remind you, Google added the regex information to the Search Console documentation and then pulled it. But it did say "if you choose the Custom (regex) filter, you can filter by a regular ...