Regex Tester & Validator

This PCRE regex matches date or time-like strings containing five pairs of digits separated by a consistent delimiter. It utilizes a branch reset group `(?|...)` to ensure the captured delimiter—either three hyphens, one hyphen, any single character, or a colon—is always assigned to group 1. A backreference `\1` then guarantees that the exact same separator is used between all digit pairs. It is typically used in programming challenges to test advanced PCRE features and backreferences.