third_party/boost/fusion/test/sequence/adapt_tpl_struct_empty.cpp

/*=============================================================================
    Copyright (c) 2016 Kohei Takahashi

    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 <boost/detail/lightweight_test.hpp>
#include <boost/fusion/adapted/struct/adapt_struct.hpp>
#include <boost/fusion/sequence/intrinsic/size.hpp>
#include <boost/fusion/sequence/intrinsic/empty.hpp>
#include <boost/fusion/sequence/intrinsic/begin.hpp>
#include <boost/fusion/sequence/intrinsic/end.hpp>
#include <boost/fusion/sequence/io/out.hpp>
#include <boost/fusion/iterator/equal_to.hpp>
#include <boost/fusion/container/vector/vector.hpp>
#include <boost/fusion/container/list/list.hpp>
#include <boost/fusion/container/generation/make_vector.hpp>
#include <boost/fusion/sequence/comparison/equal_to.hpp>
#include <boost/fusion/sequence/comparison/not_equal_to.hpp>
#include <boost/fusion/sequence/comparison/less.hpp>
#include <boost/fusion/sequence/comparison/less_equal.hpp>
#include <boost/fusion/sequence/comparison/greater.hpp>
#include <boost/fusion/sequence/comparison/greater_equal.hpp>
#include <boost/fusion/mpl.hpp>
#include <boost/fusion/support/is_view.hpp>
#include <boost/mpl/is_sequence.hpp>
#include <boost/mpl/assert.hpp>
#include <iostream>

template <typename T>
class empty_struct{};
BOOST_FUSION_ADAPT_TPL_STRUCT((T), (empty_struct)(T),)

int
main()
{
    using namespace boost::fusion;
    using namespace boost;

    std::cout << tuple_open('[');
    std::cout << tuple_close(']');
    std::cout << tuple_delimiter(", ");

    {
        BOOST_MPL_ASSERT_NOT((traits::is_view<empty_struct<void> >));
        empty_struct<void> e;

        std::cout << e << std::endl;
        BOOST_TEST(e == make_vector());

        BOOST_STATIC_ASSERT(fusion::result_of::size<empty_struct<void> >::value == 0);
        BOOST_MPL_ASSERT((fusion::result_of::empty<empty_struct<void> >));

        BOOST_MPL_ASSERT((fusion::result_of::equal_to<
            fusion::result_of::begin<empty_struct<void> >::type,
            fusion::result_of::end<empty_struct<void> >::type>));
    }

    {
        fusion::vector<> v;
        empty_struct<void> e;
        BOOST_TEST(v == e);
        BOOST_TEST_NOT(v != e);
        BOOST_TEST_NOT(v < e);
        BOOST_TEST(v <= e);
        BOOST_TEST_NOT(v > e);
        BOOST_TEST(v >= e);
    }

    {
        empty_struct<void> e;

        // conversion from empty_struct to vector
        fusion::vector<> v(e);
        v = e;

        // FIXME
        // conversion from empty_struct to list
        //fusion::list<> l(e);
        //l = e;
    }

    BOOST_MPL_ASSERT((mpl::is_sequence<empty_struct<void> >));

    return boost::report_errors();
}