Re: [Boost-users] [mpl] trouble with conditionals

Geoffrey Romer writes:

Right, exactly, and as I understand it, that metafunction is never actually evaluated (at least, not in the above code), so the result is, as I said, a pair consisting of char and a nullary metafunction, not a char and an int_.

That's correct.

If so, doesn't that mean Cromwell's fix is incorrect?

I'm afraid I've not seen his fix.

I'm feeling generally very confused about the circumstances in which one does and does not use the typename...::type syntax.

C++ Template Metaprogramming has a whole appendix dedicated to that question, which some have told me is the clearest explanation they've seen. -- Dave Abrahams Boost Consulting www.boost-consulting.com