Chris@16: //-----------------------------------------------------------------------------
Chris@16: // boost variant/detail/enable_recursive.hpp header file
Chris@16: // See http://www.boost.org for updates, documentation, and revision history.
Chris@16: //-----------------------------------------------------------------------------
Chris@16: //
Chris@16: // Copyright (c) 2003
Chris@16: // Eric Friedman
Chris@16: //
Chris@16: // Distributed under the Boost Software License, Version 1.0. (See
Chris@16: // accompanying file LICENSE_1_0.txt or copy at
Chris@16: // http://www.boost.org/LICENSE_1_0.txt)
Chris@16: 
Chris@16: #ifndef BOOST_VARIANT_DETAIL_ENABLE_RECURSIVE_HPP
Chris@16: #define BOOST_VARIANT_DETAIL_ENABLE_RECURSIVE_HPP
Chris@16: 
Chris@16: #include "boost/variant/detail/enable_recursive_fwd.hpp"
Chris@16: #include "boost/variant/variant_fwd.hpp"
Chris@16: 
Chris@16: #if !defined(BOOST_VARIANT_NO_FULL_RECURSIVE_VARIANT_SUPPORT)
Chris@16: #   include "boost/mpl/apply.hpp"
Chris@16: #   include "boost/mpl/eval_if.hpp"
Chris@16: #   include "boost/mpl/lambda.hpp"
Chris@16: #endif
Chris@16: 
Chris@16: #include "boost/variant/detail/substitute.hpp"
Chris@16: #include "boost/mpl/aux_/config/ctps.hpp"
Chris@16: #include "boost/mpl/bool_fwd.hpp"
Chris@16: #include "boost/mpl/if.hpp"
Chris@16: #include "boost/mpl/or.hpp"
Chris@16: #include "boost/type_traits/is_pointer.hpp"
Chris@16: #include "boost/type_traits/is_reference.hpp"
Chris@16: #include "boost/type_traits/is_same.hpp"
Chris@16: 
Chris@16: #include "boost/variant/recursive_wrapper.hpp"
Chris@16: 
Chris@16: namespace boost {
Chris@16: namespace detail { namespace variant {
Chris@16: 
Chris@16: #if !defined(BOOST_VARIANT_DETAIL_NO_SUBSTITUTE)
Chris@16: 
Chris@16: #   define BOOST_VARIANT_AUX_ENABLE_RECURSIVE_IMPL(T,Dest,Source) \
Chris@16:     substitute< T , Dest , Source > \
Chris@16:     /**/
Chris@16: 
Chris@16: #else // defined(BOOST_VARIANT_DETAIL_NO_SUBSTITUTE)
Chris@16: 
Chris@16: ///////////////////////////////////////////////////////////////////////////////
Chris@16: // (detail) class template rebind1
Chris@16: //
Chris@16: // Limited workaround in case 'substitute' metafunction unavailable.
Chris@16: //
Chris@16: 
Chris@16: template <typename T, typename U1>
Chris@16: struct rebind1
Chris@16: {
Chris@16: private:
Chris@16:     typedef typename mpl::lambda<
Chris@16:           mpl::identity<T>
Chris@16:         >::type le_;
Chris@16: 
Chris@16: public:
Chris@16:     typedef typename mpl::eval_if<
Chris@16:           is_same< le_, mpl::identity<T> >
Chris@16:         , le_ // identity<T>
Chris@16:         , mpl::apply1<le_, U1>
Chris@16:         >::type type;
Chris@16: };
Chris@16: 
Chris@16: #   define BOOST_VARIANT_AUX_ENABLE_RECURSIVE_IMPL(T,Dest,Source) \
Chris@16:     rebind1< T , Dest > \
Chris@16:     /**/
Chris@16: 
Chris@16: #endif // !defined(BOOST_VARIANT_DETAIL_NO_SUBSTITUTE)
Chris@16: 
Chris@16: ///////////////////////////////////////////////////////////////////////////////
Chris@16: // (detail) metafunction enable_recursive
Chris@16: //
Chris@16: // See boost/variant/detail/enable_recursive_fwd.hpp for more information.
Chris@16: //
Chris@16: 
Chris@16: 
Chris@16: template <typename T, typename RecursiveVariant, typename NoWrapper>
Chris@16: struct enable_recursive
Chris@16:     : BOOST_VARIANT_AUX_ENABLE_RECURSIVE_IMPL(
Chris@16:           T, RecursiveVariant, ::boost::recursive_variant_
Chris@16:         )
Chris@16: {
Chris@16: };
Chris@16: 
Chris@16: template <typename T, typename RecursiveVariant>
Chris@16: struct enable_recursive< T,RecursiveVariant,mpl::false_ >
Chris@16: {
Chris@16: private: // helpers, for metafunction result (below)
Chris@16: 
Chris@16:     typedef typename BOOST_VARIANT_AUX_ENABLE_RECURSIVE_IMPL(
Chris@16:           T, RecursiveVariant, ::boost::recursive_variant_
Chris@16:         )::type t_;
Chris@16: 
Chris@16: public: // metafunction result
Chris@16: 
Chris@16:     // [Wrap with recursive_wrapper only if rebind really changed something:]
Chris@16:     typedef typename mpl::if_<
Chris@16:           mpl::or_<
Chris@16:               is_same< t_,T >
Chris@16:             , is_reference<t_>
Chris@16:             , is_pointer<t_>
Chris@16:             >
Chris@16:         , t_
Chris@16:         , boost::recursive_wrapper<t_>
Chris@16:         >::type type;
Chris@16: 
Chris@16: };
Chris@16: 
Chris@16: 
Chris@16: ///////////////////////////////////////////////////////////////////////////////
Chris@16: // (detail) metafunction class quoted_enable_recursive
Chris@16: //
Chris@16: // Same behavior as enable_recursive metafunction (see above).
Chris@16: //
Chris@16: template <typename RecursiveVariant, typename NoWrapper>
Chris@16: struct quoted_enable_recursive
Chris@16: {
Chris@16:     template <typename T>
Chris@16:     struct apply
Chris@16:         : enable_recursive<T, RecursiveVariant, NoWrapper>
Chris@16:     {
Chris@16:     };
Chris@16: };
Chris@16: 
Chris@16: }} // namespace detail::variant
Chris@16: } // namespace boost
Chris@16: 
Chris@16: #endif // BOOST_VARIANT_DETAIL_ENABLE_RECURSIVE_HPP