williamr@2: //----------------------------------------------------------------------------- williamr@2: // boost variant/detail/enable_recursive.hpp header file williamr@2: // See http://www.boost.org for updates, documentation, and revision history. williamr@2: //----------------------------------------------------------------------------- williamr@2: // williamr@2: // Copyright (c) 2003 williamr@2: // Eric Friedman williamr@2: // williamr@2: // Distributed under the Boost Software License, Version 1.0. (See williamr@2: // accompanying file LICENSE_1_0.txt or copy at williamr@2: // http://www.boost.org/LICENSE_1_0.txt) williamr@2: williamr@2: #ifndef BOOST_VARIANT_DETAIL_ENABLE_RECURSIVE_HPP williamr@2: #define BOOST_VARIANT_DETAIL_ENABLE_RECURSIVE_HPP williamr@2: williamr@2: #include "boost/variant/detail/enable_recursive_fwd.hpp" williamr@2: #include "boost/variant/variant_fwd.hpp" williamr@2: williamr@2: #if !defined(BOOST_VARIANT_NO_FULL_RECURSIVE_VARIANT_SUPPORT) williamr@2: # include "boost/mpl/apply.hpp" williamr@2: # include "boost/mpl/eval_if.hpp" williamr@2: # include "boost/mpl/lambda.hpp" williamr@2: #endif williamr@2: williamr@2: #include "boost/variant/detail/substitute.hpp" williamr@2: #include "boost/mpl/aux_/config/ctps.hpp" williamr@2: #include "boost/mpl/bool_fwd.hpp" williamr@2: #include "boost/mpl/if.hpp" williamr@2: #include "boost/mpl/or.hpp" williamr@2: #include "boost/type_traits/is_pointer.hpp" williamr@2: #include "boost/type_traits/is_reference.hpp" williamr@2: #include "boost/type_traits/is_same.hpp" williamr@2: williamr@2: #include "boost/variant/recursive_wrapper.hpp" williamr@2: williamr@2: namespace boost { williamr@2: namespace detail { namespace variant { williamr@2: williamr@2: #if !defined(BOOST_VARIANT_DETAIL_NO_SUBSTITUTE) williamr@2: williamr@2: # define BOOST_VARIANT_AUX_ENABLE_RECURSIVE_IMPL(T,Dest,Source) \ williamr@2: substitute< T , Dest , Source > \ williamr@2: /**/ williamr@2: williamr@2: #else // defined(BOOST_VARIANT_DETAIL_NO_SUBSTITUTE) williamr@2: williamr@2: /////////////////////////////////////////////////////////////////////////////// williamr@2: // (detail) class template rebind1 williamr@2: // williamr@2: // Limited workaround in case 'substitute' metafunction unavailable. williamr@2: // williamr@2: williamr@2: template williamr@2: struct rebind1 williamr@2: { williamr@2: private: williamr@2: typedef typename mpl::lambda< williamr@2: mpl::identity williamr@2: >::type le_; williamr@2: williamr@2: public: williamr@2: typedef typename mpl::eval_if< williamr@2: is_same< le_, mpl::identity > williamr@2: , le_ // identity williamr@2: , mpl::apply1 williamr@2: >::type type; williamr@2: }; williamr@2: williamr@2: # define BOOST_VARIANT_AUX_ENABLE_RECURSIVE_IMPL(T,Dest,Source) \ williamr@2: rebind1< T , Dest > \ williamr@2: /**/ williamr@2: williamr@2: #endif // !defined(BOOST_VARIANT_DETAIL_NO_SUBSTITUTE) williamr@2: williamr@2: /////////////////////////////////////////////////////////////////////////////// williamr@2: // (detail) metafunction enable_recursive williamr@2: // williamr@2: // See boost/variant/detail/enable_recursive_fwd.hpp for more information. williamr@2: // williamr@2: williamr@2: #if !defined(BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION) williamr@2: williamr@2: template williamr@2: struct enable_recursive williamr@2: : BOOST_VARIANT_AUX_ENABLE_RECURSIVE_IMPL( williamr@2: T, RecursiveVariant, ::boost::recursive_variant_ williamr@2: ) williamr@2: { williamr@2: }; williamr@2: williamr@2: template williamr@2: struct enable_recursive< T,RecursiveVariant,mpl::false_ > williamr@2: { williamr@2: private: // helpers, for metafunction result (below) williamr@2: williamr@2: typedef typename BOOST_VARIANT_AUX_ENABLE_RECURSIVE_IMPL( williamr@2: T, RecursiveVariant, ::boost::recursive_variant_ williamr@2: )::type t_; williamr@2: williamr@2: public: // metafunction result williamr@2: williamr@2: // [Wrap with recursive_wrapper only if rebind really changed something:] williamr@2: typedef typename mpl::if_< williamr@2: mpl::or_< williamr@2: is_same< t_,T > williamr@2: , is_reference williamr@2: , is_pointer williamr@2: > williamr@2: , t_ williamr@2: , boost::recursive_wrapper williamr@2: >::type type; williamr@2: williamr@2: }; williamr@2: williamr@2: #else // defined(BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION) williamr@2: williamr@2: template williamr@2: struct enable_recursive williamr@2: { williamr@2: private: // helpers, for metafunction result (below) williamr@2: williamr@2: typedef typename BOOST_VARIANT_AUX_ENABLE_RECURSIVE_IMPL( williamr@2: T, RecursiveVariant, ::boost::recursive_variant_ williamr@2: )::type t_; williamr@2: williamr@2: public: // metafunction result williamr@2: williamr@2: // [Wrap with recursive_wrapper only if rebind really changed something:] williamr@2: typedef typename mpl::if_< williamr@2: mpl::or_< williamr@2: NoWrapper williamr@2: , is_same< t_,T > williamr@2: , is_reference williamr@2: , is_pointer williamr@2: > williamr@2: , t_ williamr@2: , boost::recursive_wrapper williamr@2: >::type type; williamr@2: williamr@2: }; williamr@2: williamr@2: #endif // BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION workaround williamr@2: williamr@2: /////////////////////////////////////////////////////////////////////////////// williamr@2: // (detail) metafunction class quoted_enable_recursive williamr@2: // williamr@2: // Same behavior as enable_recursive metafunction (see above). williamr@2: // williamr@2: template williamr@2: struct quoted_enable_recursive williamr@2: { williamr@2: template williamr@2: struct apply williamr@2: : enable_recursive williamr@2: { williamr@2: }; williamr@2: }; williamr@2: williamr@2: }} // namespace detail::variant williamr@2: } // namespace boost williamr@2: williamr@2: #endif // BOOST_VARIANT_DETAIL_ENABLE_RECURSIVE_HPP