Comment by penteract

I'm not the person you're replying to, but it looks like it's possible to carry around a finite state machine, hence get the power of regular expressions (with caveats). I made an example that should highlight quoted text: https://news.ycombinator.com/item?id=41254638

It doesn't check that there's a closing quote, but it should work for highlighting syntactically valid code (once you fix my mistakes). I don't see a way for a character to affect others arbitrarily far back unless some fancier features like ignoring certain classes can be abused.