/*=============================================================================
    Copyright (c) 2001-2014 Joel de Guzman
    Copyright (c) 2013 Agustin Berge
    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_SUBCONTEXT_APR_15_2013_0840AM)
#define BOOST_SPIRIT_X3_SUBCONTEXT_APR_15_2013_0840AM

#include <boost/spirit/home/x3/support/context.hpp>
#include <boost/spirit/home/x3/support/unused.hpp>

namespace boost {
namespace spirit {
namespace x3 {
template <typename... T>
struct subcontext;

template <>
struct subcontext<>
{
    template <typename Context>
    subcontext(Context const& /*context*/)
    {}

    template <typename ID_>
    unused_type
    get(ID_) const
    {
        return unused;
    }
};

template <typename T>
struct subcontext<T>
    : context<typename T::first_type, typename T::second_type>
{
    typedef context<
    typename T::first_type, typename T::second_type
    > context_type;

    template <typename Context>
    subcontext(Context const& context)
        : context_type(x3::get<typename T::first_type>(context))
    {}

    using context_type::get;
};

template <typename T, typename... Tail>
struct subcontext<T, Tail...>
    : subcontext<Tail...>
    , context<
    typename T::first_type, typename T::second_type
    , subcontext<Tail...>
    >
{
    typedef subcontext<Tail...> base_type;
    typedef context<
    typename T::first_type, typename T::second_type
    , base_type
    > context_type;

    template <typename Context>
    subcontext(Context const& context)
        : base_type(context)
        , context_type(
            x3::get<typename T::first_type>(context)
        , *static_cast<base_type*>(this))
    {}

    using context_type::get;
};

}
}
}

#endif
