As to question #2: Abigail-II used the cut operator (?>) recently in Matching nested begin/ends. I've seen it used in that manner before, but can't remember exactly where.
The cut operator was only used there for performance reasons.
And I did it only because I _think_ it's faster, not because
I know for sure. It certainly didn't change the meaning of
the regex, it would still match the same set of strings.