The problem is with distance<begin, end>::value. My distance_impl<> doesn't provide a nested value. It provides a nested type. If this were distance<begin, end>::type::value, it works. It also works if I change my distance_impl<> specialization, but I don't think I should have to. Bug?
From what I can see in the MPL docs, a numeric metafunction is only required to return ::type, and ::value is just a convenience that I shouldn't count on. So I agree, a bug. I'll patch up shortly, thanks for picking this up.
The defect above should now be fixed on HEAD. Cheers Dan ___________________________________________________________ Yahoo! Answers - Got a question? Someone out there knows the answer. Try it now. http://uk.answers.yahoo.com/