Question

Basically, I am looking for a library solution that does this:

#include <boost/type_traits.hpp>

template<bool>
struct bool_to_bool_type;

template<>
struct bool_to_bool_type<false>
{
    typedef boost::false_type type;
};

template<>
struct bool_to_bool_type<true>
{
    typedef boost::true_type type;
};

Is there such a metafunction?

Answer 1

Oh wait, true_type is just a typedef for std::integral_constant<bool, true>? Then there’s an obvious solution:

boost::integral_constant<bool, input_value>