arabica/include/Arabica/getparam.hpp

39 lines
747 B
C++

#ifndef ARABICA_UTILS_GET_PARAM_HPP
#define ARABICA_UTILS_GET_PARAM_HPP
#ifdef HAVE_BOOST
#include <boost/mpl/if.hpp>
#include <boost/type_traits/is_base_and_derived.hpp>
#endif
namespace Arabica
{
struct nil_t { };
#ifdef HAVE_BOOST
template <typename BaseT, typename DefaultT, typename T0, typename T1>
struct get_param
{
typedef typename boost::mpl::if_<
boost::is_base_and_derived<BaseT, T0>
, T0
, typename boost::mpl::if_<
boost::is_base_and_derived<BaseT, T1>
, T1
, DefaultT
>::type
>::type type;
}; // get_param
#else
template <typename BaseT, typename DefaultT, typename T0, typename T1>
struct get_param
{
typedef T0 type;
};
#endif
} // namespace Arabica
#endif