boost_1_45_0/libs/fusion/test/sequence/mutate.hpp

/*=============================================================================
    Copyright (c) 1999-2003 Jaakko Jarvi
    Copyright (c) 2001-2006 Joel de Guzman

    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/sequence/intrinsic/at.hpp>

#if !defined(FUSION_AT)
#define FUSION_AT at_c
#endif

namespace test_detail
{
    // no public default constructor
    class foo
    {
    public:

        explicit foo(int v) : val(v) {}

        bool operator==(const foo& other) const
        {
            return val == other.val;
        }

    private:

        foo() {}
        int val;
    };
}

void
test()
{
    using namespace boost::fusion;
    using namespace test_detail;

    FUSION_SEQUENCE<int, float, bool, foo> t1(5, 12.2f, true, foo(4));
    FUSION_AT<0>(t1) = 6;
    FUSION_AT<1>(t1) = 2.2f;
    FUSION_AT<2>(t1) = false;
    FUSION_AT<3>(t1) = foo(5);

    BOOST_TEST(FUSION_AT<0>(t1) == 6);
    BOOST_TEST(FUSION_AT<1>(t1) > 2.1f && FUSION_AT<1>(t1) < 2.3f);
    BOOST_TEST(FUSION_AT<2>(t1) == false);
    BOOST_TEST(FUSION_AT<3>(t1) == foo(5));
}