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Re: [v3] ext/type_traits.h
Howard Hinnant wrote:
On Sep 28, 2006, at 4:45 PM, Martin Sebor wrote:
Peter Dimov wrote:
Martin Sebor wrote:
The standalone add_unsigned critters would be okay too. They
would be in line with all the other little traits classes. I
don't see a big advantage of one approach over the other.
The standalone to_unsigned can be used as a metafunction.
Ah, neat. I hadn't thought of that. And the limits one couldn't
because...? It doesn't have the right name?
Iiuc, yes. Here's a trivial trait that takes a metafunction as a
template template parameter (F):
Cool. Thanks for the demo!
[...]
One might imagine some similar test or trait where supplying
add_unsigned would work, because it has a nested "type", and
numeric_limits would fail.
Hmm, looks like we need a "metafunction adapter" for legacy
interfaces:
template <class T>
struct make_type { typedef T type; };
That way make_type<numeric_limits<T>::unsigned_type>::type could
be used as a metafunction too ;-)
Martin