on Sat Apr 07 2007, "Ford, Rich" <Rich.Ford-AT-amd.com> wrote:
Thanks. I hadn't thought of that, but of course one could find the begin of the filtered sequence by constructing it from the begin of the base sequence. Then an algorithm doing decrementing could check to see if begin had been reached and avoid decrementing beyond that.
But what would the point be? An iterator, after decrementation, must point at a valid element. If you're decrementing past the beginning of the filtered sequence, there's no element (of the filtered sequence) to stop on. Sure, I guess we could make decrementation a no-op at the beginning of the sequence, but again, I don't see the point. -- Dave Abrahams Boost Consulting www.boost-consulting.com Don't Miss BoostCon 2007! ==> http://www.boostcon.com