Thanks for the suggestion. I actually already tested this type of regexp (it was suggested in a previous question I posted about named captures: http://perlmonks.org/?node_id=810388
). Unfortunately, the relatively simple tests I benchmarked weren't "a little slower". They were 7x slower!
So, unfortunately, I think I'm going to have to leave the current code in place meaning that there will be a problem for anyone using Date::Manip in a persistant program. Sooner or later, the problem will be fixed. I'm going to add a note to this affect to the documentation, but for now, I think that's going to be the extent of it.
Thanks again for an incredibly educational and fun (and frustrating... but not due to you) conversation!