Chris@102: /*=============================================================================
Chris@102:     Copyright (c) 2001-2014 Joel de Guzman
Chris@102:     Copyright (c) 2013 Agustín Bergé
Chris@102:     http://spirit.sourceforge.net/
Chris@102: 
Chris@102:     Distributed under the Boost Software License, Version 1.0. (See accompanying
Chris@102:     file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
Chris@102: =============================================================================*/
Chris@102: #if !defined(BOOST_SPIRIT_X3_SUBCONTEXT_APR_15_2013_0840AM)
Chris@102: #define BOOST_SPIRIT_X3_SUBCONTEXT_APR_15_2013_0840AM
Chris@102: 
Chris@102: #if defined(_MSC_VER)
Chris@102: #pragma once
Chris@102: #endif
Chris@102: 
Chris@102: #include <boost/fusion/support/pair.hpp>
Chris@102: #include <boost/spirit/home/x3/support/context.hpp>
Chris@102: #include <boost/spirit/home/x3/support/unused.hpp>
Chris@102: 
Chris@102: namespace boost { namespace spirit { namespace x3
Chris@102: {
Chris@102:     template <typename... T>
Chris@102:     struct subcontext;
Chris@102: 
Chris@102:     template <>
Chris@102:     struct subcontext<>
Chris@102:     {
Chris@102:         template <typename Context>
Chris@102:         subcontext(Context const& /*context*/)
Chris@102:         {}
Chris@102:         
Chris@102:         template <typename ID_, typename Unused = void>
Chris@102:         struct get_result
Chris@102:         {
Chris@102:             typedef unused_type type;
Chris@102:         };
Chris@102: 
Chris@102:         template <typename ID_>
Chris@102:         unused_type
Chris@102:         get(ID_) const
Chris@102:         {
Chris@102:             return unused;
Chris@102:         }
Chris@102:     };
Chris@102: 
Chris@102:     template <typename T>
Chris@102:     struct subcontext<T>
Chris@102:       : context<typename T::first_type, typename T::second_type>
Chris@102:     {
Chris@102:         typedef context<
Chris@102:             typename T::first_type, typename T::second_type
Chris@102:         > context_type;
Chris@102: 
Chris@102:         template <typename Context>
Chris@102:         subcontext(Context const& context)
Chris@102:           : context_type(x3::get<typename T::first_type>(context))
Chris@102:         {}
Chris@102: 
Chris@102:         using context_type::get;
Chris@102:     };
Chris@102: 
Chris@102:     template <typename T, typename... Tail>
Chris@102:     struct subcontext<T, Tail...>
Chris@102:       : subcontext<Tail...>
Chris@102:       , context<
Chris@102:             typename T::first_type, typename T::second_type
Chris@102:           , subcontext<Tail...>
Chris@102:         >
Chris@102:     {
Chris@102:         typedef subcontext<Tail...> base_type;
Chris@102:         typedef context<
Chris@102:             typename T::first_type, typename T::second_type
Chris@102:           , base_type
Chris@102:         > context_type;
Chris@102: 
Chris@102:         template <typename Context>
Chris@102:         subcontext(Context const& context)
Chris@102:           : base_type(context)
Chris@102:           , context_type(
Chris@102:                 x3::get<typename T::first_type>(context)
Chris@102:               , *static_cast<base_type*>(this))
Chris@102:         {}
Chris@102: 
Chris@102:         using context_type::get;
Chris@102:     };
Chris@102: 
Chris@102: }}}
Chris@102: 
Chris@102: #endif