Two reasons: captures, and it needs to know which of the regexes matched. I meant to but forgot to mention in my original comment that the reason Sublime's buil

Two reasons: captures, and it needs to know which of the regexes matched. I meant to but forgot to mention in my original comment that the reason Sublime's built-in highlighter is the fastest is they wrote a custom regex engine which basically does the equivalent of or-ing them together but unlike all other regex engines handles captures and information about which one matched properly while doing so. The custom engine doesn't do backtracking and it falls back to Oniguruma for regexes that use fancy features. So yah it's in theory possible you just need to write a custom regex engine to do it.