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

From: Geoffrey Romer (geoff.romer_at_[hidden])
Date: 2005-10-05 14:23:09

> > If so, doesn't that mean Cromwell's fix is
> > incorrect?
>
> I'm afraid I've not seen his fix.

It was given in the grandparent of your first mail in this thread. If
you like I can forward it to you privately, I'd prefer not to clutter
the list by re-sending it.

> > 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.

Assuming you're referring to Appendix B, I've read it, but I don't
think it addresses my confusion. That appendix addresses the issue of
when the C++ language requires one to use the typename and template
keywords. I think I understand that. What I don't understand is when I
should be saying "typename metafunc<args>::type" and when I should be
using plain "metafunc<args>". This isn't a language-correctness issue,
it's an MPL usage issue.