@MartinEnder I'm confused! I'm trying to get to grips with Retina, I thought I was close, but I'm getting some trailing 0s. I wondered if you could point out my stupidity here: retina.tryitonline.net/…

Any clues would be much appreciated! Sorry if it's a stupid question... :/

Hmm, seems that ^ and $ fix that, I guess I was hitting a zero-length match at the end! retina.tryitonline.net/… I imagine I can still improve this I thought perhaps using M% somehow...

@DomHastings yes exactly. When your regex allows zero length matches you'll always get one at the end.

You usually don't need $ to fix that though, ^ should be enough.