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