variant2/test/get_by_index_cx.cpp

// Copyright 2017 Peter Dimov.
//
// 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/variant2/variant.hpp>

using namespace boost::variant2;

#define STATIC_ASSERT(...) static_assert(__VA_ARGS__, #__VA_ARGS__)

int main()
{
    {
        constexpr variant<int> v;

        STATIC_ASSERT( get<0>(v) == 0 );
        STATIC_ASSERT( get_if<0>(&v) == &get<0>(v) );
    }

    {
        constexpr variant<int> v( 1 );

        STATIC_ASSERT( get<0>(v) == 1 );
        STATIC_ASSERT( get_if<0>(&v) == &get<0>(v) );
    }

    {
        constexpr variant<int, float> v;

        STATIC_ASSERT( get<0>(v) == 0 );
        STATIC_ASSERT( get_if<0>(&v) == &get<0>(v) );

        STATIC_ASSERT( get_if<1>(&v) == nullptr );
    }

    {
        constexpr variant<int, float> v( 1 );

        STATIC_ASSERT( get<0>(v) == 1 );
        STATIC_ASSERT( get_if<0>(&v) == &get<0>(v) );

        STATIC_ASSERT( get_if<1>(&v) == nullptr );
    }

    {
        constexpr variant<int, float> v( 3.14f );

        STATIC_ASSERT( get_if<0>(&v) == nullptr );

        STATIC_ASSERT( get<1>(v) == 3.14f );
        STATIC_ASSERT( get_if<1>(&v) == &get<1>(v) );
    }

    {
        constexpr variant<int, float, float> v;

        STATIC_ASSERT( get<0>(v) == 0 );
        STATIC_ASSERT( get_if<0>(&v) == &get<0>(v) );

        STATIC_ASSERT( get_if<1>(&v) == nullptr );

        STATIC_ASSERT( get_if<2>(&v) == nullptr );
    }

    {
        constexpr variant<int, float, float> v( 1 );

        STATIC_ASSERT( get<0>(v) == 1 );
        STATIC_ASSERT( get_if<0>(&v) == &get<0>(v) );

        STATIC_ASSERT( get_if<1>(&v) == nullptr );

        STATIC_ASSERT( get_if<2>(&v) == nullptr );
    }

    {
        constexpr variant<int, int, float> v( 3.14f );

        STATIC_ASSERT( get_if<0>(&v) == nullptr );

        STATIC_ASSERT( get_if<1>(&v) == nullptr );

        STATIC_ASSERT( get<2>(v) == 3.14f );
        STATIC_ASSERT( get_if<2>(&v) == &get<2>(v) );
    }
}