Note that that benchmark is against the code that still does the whole 'foreach' thing, only in different way.

I'm sorry, but I don't understand how can I accomplish this simple task of mapping 'physical match back to the pattern or patterns that match'.

This is the task that we're trying to accomplish at first place, so how is it 'simple' if after a bunch of lines of ingenious code we reduce the problem to itself?

Either I'm missing something, or I described the problem in confusing way?