mirror/example/meta_prog_04.cpp

This example shows the usage of the meta-programming utilities and the intrinsic meta-functions for various meta-objects

Copyright 2008-2011 Matus Chochlik. Distributed under the Boost Software License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)

#include <mirror/mirror.hpp>
#include <iostream>

MIRROR_NAMESPACE_BEGIN

// see also mirror/example/meta_prog_01.cpp for an alternate implementation
template <typename MetaNamespace>
void count_integral_types_in(void)
{
    using namespace mirror;
    // Get the members of the MetaNamespace, filter only those which
    // are meta-types and get the type reflected by each meta-type
    // and then filter only those types that are integral
    // finally get the size of the resulting range
    std::cout <<
        mp::size<
            mp::only_if<
                mp::transform<
                    mp::only_if<
                        members<MetaNamespace>,
                        mp::is_a<
                            mp::arg<1>,
                            meta_type_tag
                        >
                    >,
                    original_type<
                        mp::arg<1>
                    >
                >,
                std::is_integral< mp::arg<1> >
            >
        >::value
    << " integral types in namespace '"
    << MetaNamespace::full_name()
    << "'"
    << std::endl;
}


MIRROR_NAMESPACE_END


int main(void)
{
    using namespace mirror;
    count_integral_types_in<
        MIRRORED_GLOBAL_SCOPE()
    >();
    count_integral_types_in<
        MIRRORED_NAMESPACE(std)
    >();
    //
    return 0;
}

/* Example of output:
10 integral types in namespace ''
0 integral types in namespace 'std'
*/