| //----------------------------------------------------------------------------- |
| // boost variant/recursive_variant.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_RECURSIVE_VARIANT_HPP |
| #define BOOST_VARIANT_RECURSIVE_VARIANT_HPP |
| |
| #include "boost/variant/variant_fwd.hpp" |
| #include "boost/variant/detail/enable_recursive.hpp" |
| #include "boost/variant/detail/substitute_fwd.hpp" |
| #include "boost/variant/detail/make_variant_list.hpp" |
| #include "boost/variant/detail/over_sequence.hpp" |
| |
| #include "boost/mpl/aux_/lambda_arity_param.hpp" |
| |
| #if !defined(BOOST_VARIANT_NO_TYPE_SEQUENCE_SUPPORT) |
| # include "boost/mpl/eval_if.hpp" |
| # include "boost/mpl/identity.hpp" |
| # include "boost/mpl/protect.hpp" |
| # include "boost/mpl/transform.hpp" |
| #else |
| # include "boost/preprocessor/cat.hpp" |
| # include "boost/preprocessor/repeat.hpp" |
| #endif |
| |
| #include "boost/mpl/bool.hpp" |
| #include "boost/mpl/is_sequence.hpp" |
| #include "boost/variant/variant.hpp" |
| |
| namespace boost { |
| |
| namespace detail { namespace variant { |
| |
| /////////////////////////////////////////////////////////////////////////////// |
| // (detail) metafunction specialization substitute |
| // |
| // Handles embedded variant types when substituting for recursive_variant_. |
| // |
| |
| #if !defined(BOOST_VARIANT_DETAIL_NO_SUBSTITUTE) |
| |
| template < |
| BOOST_VARIANT_ENUM_PARAMS(typename T) |
| , typename RecursiveVariant |
| BOOST_MPL_AUX_LAMBDA_ARITY_PARAM(typename Arity) |
| > |
| struct substitute< |
| ::boost::variant< |
| recursive_flag< T0 > |
| , BOOST_VARIANT_ENUM_SHIFTED_PARAMS(T) |
| > |
| , RecursiveVariant |
| , ::boost::recursive_variant_ |
| BOOST_MPL_AUX_LAMBDA_ARITY_PARAM(Arity) |
| > |
| { |
| typedef ::boost::variant< |
| recursive_flag< T0 > |
| , BOOST_VARIANT_ENUM_SHIFTED_PARAMS(T) |
| > type; |
| }; |
| |
| template < |
| BOOST_VARIANT_ENUM_PARAMS(typename T) |
| , typename RecursiveVariant |
| BOOST_MPL_AUX_LAMBDA_ARITY_PARAM(typename Arity) |
| > |
| struct substitute< |
| ::boost::variant< BOOST_VARIANT_ENUM_PARAMS(T) > |
| , RecursiveVariant |
| , ::boost::recursive_variant_ |
| BOOST_MPL_AUX_LAMBDA_ARITY_PARAM(Arity) |
| > |
| { |
| |
| #if !defined(BOOST_VARIANT_NO_TYPE_SEQUENCE_SUPPORT) |
| |
| private: // helpers, for metafunction result (below) |
| |
| typedef typename mpl::eval_if< |
| ::boost::detail::variant::is_over_sequence<T0> |
| , mpl::identity< T0 > |
| , make_variant_list< BOOST_VARIANT_ENUM_PARAMS(T) > |
| >::type initial_types; |
| |
| typedef typename mpl::transform< |
| initial_types |
| , mpl::protect< quoted_enable_recursive<RecursiveVariant,mpl::true_> > |
| >::type types; |
| |
| public: // metafunction result |
| |
| typedef ::boost::variant< types > type; |
| |
| #else // defined(BOOST_VARIANT_NO_TYPE_SEQUENCE_SUPPORT) |
| |
| private: // helpers, for metafunction result (below) |
| |
| #define BOOST_VARIANT_AUX_ENABLE_RECURSIVE_TYPEDEFS(z,N,_) \ |
| typedef typename enable_recursive< \ |
| BOOST_PP_CAT(T,N) \ |
| , RecursiveVariant \ |
| , mpl::true_ \ |
| >::type BOOST_PP_CAT(wknd_T,N); \ |
| /**/ |
| |
| BOOST_PP_REPEAT( |
| BOOST_VARIANT_LIMIT_TYPES |
| , BOOST_VARIANT_AUX_ENABLE_RECURSIVE_TYPEDEFS |
| , _ |
| ) |
| |
| #undef BOOST_VARIANT_AUX_ENABLE_RECURSIVE_TYPEDEFS |
| |
| public: // metafunction result |
| |
| typedef ::boost::variant< BOOST_VARIANT_ENUM_PARAMS(wknd_T) > type; |
| |
| #endif // BOOST_VARIANT_NO_TYPE_SEQUENCE_SUPPORT workaround |
| |
| }; |
| |
| #else // defined(BOOST_VARIANT_DETAIL_NO_SUBSTITUTE) |
| |
| // |
| // no specializations: embedded variants unsupported on these compilers! |
| // |
| |
| #endif // !defined(BOOST_VARIANT_DETAIL_NO_SUBSTITUTE) |
| |
| }} // namespace detail::variant |
| |
| /////////////////////////////////////////////////////////////////////////////// |
| // metafunction make_recursive_variant |
| // |
| // See docs and boost/variant/variant_fwd.hpp for more information. |
| // |
| template < BOOST_VARIANT_ENUM_PARAMS(typename T) > |
| struct make_recursive_variant |
| { |
| public: // metafunction result |
| |
| typedef boost::variant< |
| detail::variant::recursive_flag< T0 > |
| , BOOST_VARIANT_ENUM_SHIFTED_PARAMS(T) |
| > type; |
| |
| }; |
| |
| /////////////////////////////////////////////////////////////////////////////// |
| // metafunction make_recursive_variant_over |
| // |
| // See docs and boost/variant/variant_fwd.hpp for more information. |
| // |
| template <typename Types> |
| struct make_recursive_variant_over |
| { |
| private: // precondition assertions |
| |
| #if !BOOST_WORKAROUND(BOOST_MSVC, <= 1300) |
| BOOST_STATIC_ASSERT(( ::boost::mpl::is_sequence<Types>::value )); |
| #endif |
| |
| public: // metafunction result |
| |
| typedef typename make_recursive_variant< |
| detail::variant::over_sequence< Types > |
| >::type type; |
| |
| }; |
| |
| } // namespace boost |
| |
| #endif // BOOST_VARIANT_RECURSIVE_VARIANT_HPP |