mirror/example/meta_prog_06.cpp

This example shows the usage of the meta-programming utilities and the intrinsic meta-functions and tagging with members of a namespace.

Copyright 2008-2010 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>
#include "./classes.hpp"

MIRROR_NAMESPACE_BEGIN

// Helper functor class used by the for_each_ii algorithm
// in the print_public_types_in<>() function
struct name_printer
{
    template <typename IterInfo>
    void operator()(IterInfo) const
    {
        typedef typename IterInfo::type MetaObject;
        // print the full name of the current element
        std::cout << MetaObject::full_name();
        // if this is the last element in the traversal
        // then print the final dot or print a separating comma
        // otherwise
        if(IterInfo::is_last::value)
            std::cout << ".";
        else    std::cout << ", ";
    }
};

template <typename MetaNamespace>
void print_public_types_in(void)
{
    using namespace mirror;
    std::cout << "Public types in the '"
        << MetaNamespace::full_name()
        << "' namespace: ";
    // Get the members of the passed MetaNamespace, filter only
    // meta-types and then filter only those that lack the 'hidden' tag
    mirror::mp::for_each_ii<
        mp::only_if<
            mp::only_if<
                members<MetaNamespace>,
                mp::is_a<
                    mp::arg<1>,
                    meta_type_tag
                >
            >,
            mp::lacks<
                tags<
                    mp::arg<1>
                >,
                MIRROR_OBJECT_TAG(hidden)
            >
        >
    >(name_printer());
    std::cout << std::endl;
}


MIRROR_NAMESPACE_END


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

/* Example of output:
Public types in the 'std' namespace: std::string, std::wstring, std::tm.
Public types in the 'test' namespace: test::C, test::D, test::E, test::F, test::G, test::H, test::Ch.
*/