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

From: David Abrahams (dave_at_[hidden])
Date: 2005-10-05 13:32:21

Geoffrey Romer <geoff.romer_at_[hidden]> 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