on Wed Jun 03 2009, Larry Evans <cppljevans-AT-suddenlink.net> wrote:
Anything that can be done with the backward predicate can be done by passing an appropriate boolean flag along with the result. Unlike the forward predicate, there are no big-O gains from having the algorithm know about it.
Why not? It seems there should be. After all, if the backward predicate is satisfied by the last element in the sequence, wouldn't that avoid going back up the recursion stack?
How can you possibly "avoid going back up the recursion stack?" That's like asking the recursive metafunction invocations not to "return." I suppose we could cause a compiler error, but I doubt that's what you had in mind! -- Dave Abrahams BoostPro Computing http://www.boostpro.com