/*=============================================================================
    Copyright (c) 2001-2014 Joel de Guzman
    http://spirit.sourceforge.net/

    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)
=============================================================================*/
#if !defined(BOOST_SPIRIT_X3_IS_VARIANT_JAN_10_2012_0823AM)
#define BOOST_SPIRIT_X3_IS_VARIANT_JAN_10_2012_0823AM

#include <boost/variant.hpp>
#include <boost/mpl/has_xxx.hpp>
#include <boost/mpl/bool.hpp>

namespace boost {
namespace spirit {
namespace x3 {
namespace traits {
namespace detail {
// By declaring a nested struct in your class/struct, you tell
// spirit that it is regarded as a variant type. The minimum
// required interface for such a variant is that it has constructors
// for various types supported by your variant and a typedef 'types'
// which is an mpl sequence of the contained types.
//
// This is an intrusive interface. For a non-intrusive interface,
// use the is_variant trait.
BOOST_MPL_HAS_XXX_TRAIT_DEF(adapted_variant_tag)
}

template <typename T, typename Enable = void>
struct is_variant
    : detail::has_adapted_variant_tag<T>
{};

template <BOOST_VARIANT_ENUM_PARAMS(typename T)>
struct is_variant<boost::variant<BOOST_VARIANT_ENUM_PARAMS(T)>>
            : mpl::true_
{};
}
}
}
}

#endif
