Edward Diener wrote:
On 4/15/2011 11:13 AM, Jeroen Habraken wrote:
Hi,
Is there a specific yes_type and no_type inside boost that I should be using when writing a SFINAE test? There seem to be quite a few defined already and reinventing the wheel (albeit it being trivial) again doesn't make sense.
For the Boost developer there is:
#include <boost/type_traits/detail/yes_no_type.hpp>
you then have:
boost::type_traits::yes_type boost::type_traits::no_type
Of course the intention of 'detail' for a library is that the code should only be used by that library, but I think, in this case, it is allowable for other Boost library developers to use it also.
But since this is a part of type traits detail it is not meant to be used outside of a Boost library ( ie. by end-users ).
It would perhaps be better if ::boost::type_traits::yes_type and
boost::type_traits::no_type were put into its own utility classes to make it more apparent that Boost library developers and end-users of Boost could use it.
OTOH it might be presumptuous of me to suggest that it be used at all outside of type traits, but I have used it in my own TTI sandbox library anyway since type traits itself is used heavily there.
I think I'm using the one from MPL. If you use MPL for the compile time boolean operations with enable_if then you might as well use the ones in MPL. Actually, it turns out I'm inheriting from the ones in MPL, but it could have been a typedef. struct gtl_no : mpl::bool_<false> {}; struct gtl_yes : mpl::bool_<true> {}; Regards, Luke