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249 lines
8.0 KiB
249 lines
8.0 KiB
//----------------------------------------------------------------------------- |
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// boost variant/detail/initializer.hpp header file |
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// See http://www.boost.org for updates, documentation, and revision history. |
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//----------------------------------------------------------------------------- |
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// |
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// Copyright (c) 2002-2003 |
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// Eric Friedman, Itay Maman |
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// |
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// Distributed under the Boost Software License, Version 1.0. (See |
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// accompanying file LICENSE_1_0.txt or copy at |
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// http://www.boost.org/LICENSE_1_0.txt) |
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#ifndef BOOST_VARIANT_DETAIL_INITIALIZER_HPP |
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#define BOOST_VARIANT_DETAIL_INITIALIZER_HPP |
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#include <new> // for placement new |
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#include <boost/config.hpp> |
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#include <boost/call_traits.hpp> |
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#include <boost/detail/reference_content.hpp> |
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#include <boost/variant/recursive_wrapper_fwd.hpp> |
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#include <boost/variant/detail/move.hpp> |
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#if !defined(BOOST_NO_USING_DECLARATION_OVERLOADS_FROM_TYPENAME_BASE) |
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# include <boost/mpl/aux_/value_wknd.hpp> |
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# include <boost/mpl/int.hpp> |
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# include <boost/mpl/iter_fold.hpp> |
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# include <boost/mpl/next.hpp> |
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# include <boost/mpl/deref.hpp> |
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# include <boost/mpl/pair.hpp> |
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# include <boost/mpl/protect.hpp> |
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#else |
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# include <boost/variant/variant_fwd.hpp> |
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# include <boost/preprocessor/cat.hpp> |
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# include <boost/preprocessor/enum.hpp> |
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# include <boost/preprocessor/repeat.hpp> |
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#endif |
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namespace boost { |
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namespace detail { namespace variant { |
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/////////////////////////////////////////////////////////////////////////////// |
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// (detail) support to simulate standard overload resolution rules |
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// |
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// The below initializers allows variant to follow standard overload |
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// resolution rules over the specified set of bounded types. |
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// |
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// On compilers where using declarations in class templates can correctly |
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// avoid name hiding, use an optimal solution based on the variant's typelist. |
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// |
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// Otherwise, use a preprocessor workaround based on knowledge of the fixed |
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// size of the variant's psuedo-variadic template parameter list. |
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// |
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#if !defined(BOOST_NO_USING_DECLARATION_OVERLOADS_FROM_TYPENAME_BASE) |
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// (detail) quoted metafunction make_initializer_node |
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// |
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// Exposes a pair whose first type is a node in the initializer hierarchy. |
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// |
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struct make_initializer_node |
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{ |
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template <typename BaseIndexPair, typename Iterator> |
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struct apply |
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{ |
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private: // helpers, for metafunction result (below) |
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typedef typename BaseIndexPair::first |
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base; |
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typedef typename BaseIndexPair::second |
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index; |
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class initializer_node |
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: public base |
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{ |
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private: // helpers, for static functions (below) |
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typedef typename mpl::deref<Iterator>::type |
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recursive_enabled_T; |
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typedef typename unwrap_recursive<recursive_enabled_T>::type |
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public_T; |
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#ifndef BOOST_NO_CXX11_RVALUE_REFERENCES |
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typedef boost::is_reference<public_T> |
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is_reference_content_t; |
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typedef typename boost::mpl::if_<is_reference_content_t, public_T, const public_T& >::type |
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param_T; |
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template <class T> struct disable_overload{}; |
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typedef typename boost::mpl::if_<is_reference_content_t, disable_overload<public_T>, public_T&& >::type |
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param2_T; |
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#else |
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typedef typename call_traits<public_T>::param_type |
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param_T; |
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#endif |
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public: // static functions |
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using base::initialize; |
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static int initialize(void* dest, param_T operand) |
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{ |
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typedef typename boost::detail::make_reference_content< |
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recursive_enabled_T |
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>::type internal_T; |
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new(dest) internal_T(operand); |
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return BOOST_MPL_AUX_VALUE_WKND(index)::value; // which |
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} |
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#ifndef BOOST_NO_CXX11_RVALUE_REFERENCES |
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static int initialize(void* dest, param2_T operand) |
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{ |
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// This assert must newer trigger, because all the reference contents are |
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// handled by the initilize(void* dest, param_T operand) function above |
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BOOST_ASSERT(!is_reference_content_t::value); |
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typedef typename boost::mpl::if_<is_reference_content_t, param2_T, recursive_enabled_T>::type value_T; |
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new(dest) value_T( boost::detail::variant::move(operand) ); |
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return BOOST_MPL_AUX_VALUE_WKND(index)::value; // which |
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} |
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#endif |
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}; |
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friend class initializer_node; |
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public: // metafunction result |
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typedef mpl::pair< |
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initializer_node |
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, typename mpl::next< index >::type |
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> type; |
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}; |
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}; |
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// (detail) class initializer_root |
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// |
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// Every level of the initializer hierarchy must expose the name |
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// "initialize," so initializer_root provides a dummy function: |
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// |
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class initializer_root |
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{ |
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public: // static functions |
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static void initialize(); |
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}; |
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#else // defined(BOOST_NO_USING_DECLARATION_OVERLOADS_FROM_TYPENAME_BASE) |
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// Obsolete. Remove. |
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#define BOOST_VARIANT_AUX_PP_INITIALIZER_TEMPLATE_PARAMS \ |
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BOOST_VARIANT_ENUM_PARAMS(typename recursive_enabled_T) \ |
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/**/ |
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// Obsolete. Remove. |
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#define BOOST_VARIANT_AUX_PP_INITIALIZER_DEFINE_PARAM_T(N) \ |
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typedef typename unwrap_recursive< \ |
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BOOST_PP_CAT(recursive_enabled_T,N) \ |
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>::type BOOST_PP_CAT(public_T,N); \ |
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typedef typename call_traits< \ |
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BOOST_PP_CAT(public_T,N) \ |
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>::param_type BOOST_PP_CAT(param_T,N); \ |
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/**/ |
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template < BOOST_VARIANT_ENUM_PARAMS(typename recursive_enabled_T) > |
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struct preprocessor_list_initializer |
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{ |
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public: // static functions |
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#define BOOST_VARIANT_AUX_PP_INITIALIZE_FUNCTION(z,N,_) \ |
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typedef typename unwrap_recursive< \ |
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BOOST_PP_CAT(recursive_enabled_T,N) \ |
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>::type BOOST_PP_CAT(public_T,N); \ |
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typedef typename call_traits< \ |
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BOOST_PP_CAT(public_T,N) \ |
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>::param_type BOOST_PP_CAT(param_T,N); \ |
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static int initialize( \ |
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void* dest \ |
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, BOOST_PP_CAT(param_T,N) operand \ |
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) \ |
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{ \ |
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typedef typename boost::detail::make_reference_content< \ |
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BOOST_PP_CAT(recursive_enabled_T,N) \ |
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>::type internal_T; \ |
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\ |
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new(dest) internal_T(operand); \ |
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return (N); /*which*/ \ |
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} \ |
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/**/ |
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BOOST_PP_REPEAT( |
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BOOST_VARIANT_LIMIT_TYPES |
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, BOOST_VARIANT_AUX_PP_INITIALIZE_FUNCTION |
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, _ |
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) |
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#undef BOOST_VARIANT_AUX_PP_INITIALIZE_FUNCTION |
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}; |
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#endif // BOOST_NO_USING_DECLARATION_OVERLOADS_FROM_TYPENAME_BASE workaround |
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}} // namespace detail::variant |
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} // namespace boost |
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/////////////////////////////////////////////////////////////////////////////// |
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// macro BOOST_VARIANT_AUX_INITIALIZER_T |
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// |
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// Given both the variant's typelist and a basename for forming the list of |
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// bounded types (i.e., T becomes T1, T2, etc.), exposes the initializer |
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// most appropriate to the current compiler. |
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// |
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#if !defined(BOOST_NO_USING_DECLARATION_OVERLOADS_FROM_TYPENAME_BASE) |
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#define BOOST_VARIANT_AUX_INITIALIZER_T( mpl_seq, typename_base ) \ |
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::boost::mpl::iter_fold< \ |
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mpl_seq \ |
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, ::boost::mpl::pair< \ |
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::boost::detail::variant::initializer_root \ |
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, ::boost::mpl::int_<0> \ |
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> \ |
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, ::boost::mpl::protect< \ |
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::boost::detail::variant::make_initializer_node \ |
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> \ |
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>::type::first \ |
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/**/ |
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#else // defined(BOOST_NO_USING_DECLARATION_OVERLOADS_FROM_TYPENAME_BASE) |
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// Obsolete. Remove. |
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#define BOOST_VARIANT_AUX_PP_INITIALIZER_TEMPLATE_ARGS(typename_base) \ |
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BOOST_VARIANT_ENUM_PARAMS(typename_base) \ |
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/**/ |
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#define BOOST_VARIANT_AUX_INITIALIZER_T( mpl_seq, typename_base ) \ |
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::boost::detail::variant::preprocessor_list_initializer< \ |
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BOOST_VARIANT_ENUM_PARAMS(typename_base) \ |
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> \ |
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/**/ |
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#endif // BOOST_NO_USING_DECLARATION_OVERLOADS_FROM_TYPENAME_BASE workaround |
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#endif // BOOST_VARIANT_DETAIL_INITIALIZER_HPP
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