251 lines
7.7 KiB
C++
251 lines
7.7 KiB
C++
// Boost.TypeErasure library
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//
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// Copyright 2011 Steven Watanabe
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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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//
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// $Id: binding.hpp 83251 2013-03-02 19:23:44Z steven_watanabe $
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#ifndef BOOST_TYPE_ERASURE_BINDING_HPP_INCLUDED
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#define BOOST_TYPE_ERASURE_BINDING_HPP_INCLUDED
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#include <boost/config.hpp>
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#include <boost/shared_ptr.hpp>
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#include <boost/make_shared.hpp>
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#include <boost/utility/enable_if.hpp>
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#include <boost/mpl/transform.hpp>
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#include <boost/mpl/find_if.hpp>
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#include <boost/mpl/and.hpp>
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#include <boost/mpl/not.hpp>
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#include <boost/mpl/end.hpp>
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#include <boost/mpl/bool.hpp>
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#include <boost/mpl/pair.hpp>
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#include <boost/type_traits/is_same.hpp>
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#include <boost/type_erasure/static_binding.hpp>
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#include <boost/type_erasure/is_subconcept.hpp>
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#include <boost/type_erasure/detail/adapt_to_vtable.hpp>
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#include <boost/type_erasure/detail/null.hpp>
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#include <boost/type_erasure/detail/rebind_placeholders.hpp>
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#include <boost/type_erasure/detail/vtable.hpp>
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#include <boost/type_erasure/detail/normalize.hpp>
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#include <boost/type_erasure/detail/instantiate.hpp>
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#include <boost/type_erasure/detail/check_map.hpp>
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namespace boost {
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namespace type_erasure {
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namespace detail {
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template<class Source, class Dest, class Map>
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struct can_optimize_conversion : ::boost::mpl::and_<
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::boost::is_same<Source, Dest>,
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::boost::is_same<
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typename ::boost::mpl::find_if<
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Map,
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::boost::mpl::not_<
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::boost::is_same<
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::boost::mpl::first< ::boost::mpl::_1>,
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::boost::mpl::second< ::boost::mpl::_1>
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>
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>
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>::type,
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typename ::boost::mpl::end<Map>::type
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>
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>::type
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{};
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}
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/**
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* Stores the binding of a @c Concept to a set of actual types.
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* @c Concept is interpreted in the same way as with @ref any.
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*/
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template<class Concept>
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class binding
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{
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typedef typename ::boost::type_erasure::detail::normalize_concept<
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Concept>::type normalized;
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typedef typename ::boost::mpl::transform<normalized,
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::boost::type_erasure::detail::maybe_adapt_to_vtable< ::boost::mpl::_1>
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>::type actual_concept;
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typedef typename ::boost::type_erasure::detail::make_vtable<
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actual_concept>::type table_type;
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typedef typename ::boost::type_erasure::detail::get_placeholder_normalization_map<
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Concept
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>::type placeholder_subs;
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public:
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/**
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* \pre @ref relaxed must be in @c Concept.
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*
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* \throws Nothing.
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*/
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binding() { BOOST_MPL_ASSERT((::boost::type_erasure::is_relaxed<Concept>)); }
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/**
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* \pre @c Map must be an MPL map with an entry for each placeholder
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* referred to by @c Concept.
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*
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* \throws Nothing.
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*/
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template<class Map>
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explicit binding(const Map&)
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: impl((
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BOOST_TYPE_ERASURE_INSTANTIATE(Concept, Map),
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static_binding<Map>()
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))
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{}
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/**
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* \pre @c Map must be an MPL map with an entry for each placeholder
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* referred to by @c Concept.
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*
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* \throws Nothing.
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*/
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template<class Map>
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binding(const static_binding<Map>&)
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: impl((
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BOOST_TYPE_ERASURE_INSTANTIATE(Concept, Map),
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static_binding<Map>()
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))
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{}
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/**
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* Converts from another set of bindings.
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*
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* \pre Map must be an MPL map with an entry for each placeholder
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* referred to by @c Concept. The mapped type should be the
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* corresponding placeholder in Concept2.
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*
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* \throws std::bad_alloc
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*/
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template<class Concept2, class Map>
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binding(const binding<Concept2>& other, const Map&
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#ifndef BOOST_TYPE_ERASURE_DOXYGEN
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, typename ::boost::enable_if<
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::boost::mpl::and_<
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::boost::type_erasure::detail::check_map<Concept, Map>,
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::boost::type_erasure::is_subconcept<Concept, Concept2, Map>
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>
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>::type* = 0
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#endif
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)
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: impl(
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other,
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static_binding<Map>(),
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::boost::type_erasure::detail::can_optimize_conversion<Concept2, Concept, Map>()
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)
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{}
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/**
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* Converts from another set of bindings.
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*
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* \pre Map must be an MPL map with an entry for each placeholder
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* referred to by @c Concept. The mapped type should be the
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* corresponding placeholder in Concept2.
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*
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* \throws std::bad_alloc
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*/
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template<class Concept2, class Map>
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binding(const binding<Concept2>& other, const static_binding<Map>&
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#ifndef BOOST_TYPE_ERASURE_DOXYGEN
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, typename ::boost::enable_if<
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::boost::mpl::and_<
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::boost::type_erasure::detail::check_map<Concept, Map>,
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::boost::type_erasure::is_subconcept<Concept, Concept2, Map>
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>
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>::type* = 0
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#endif
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)
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: impl(
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other,
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static_binding<Map>(),
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::boost::type_erasure::detail::can_optimize_conversion<Concept2, Concept, Map>()
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)
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{}
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/**
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* \return true iff the sets of types that the placeholders
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* bind to are the same for both arguments.
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*
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* \throws Nothing.
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*/
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friend bool operator==(const binding& lhs, const binding& rhs)
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{ return *lhs.impl.table == *rhs.impl.table; }
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/**
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* \return true iff the arguments do not map to identical
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* sets of types.
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*
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* \throws Nothing.
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*/
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friend bool operator!=(const binding& lhs, const binding& rhs)
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{ return !(lhs == rhs); }
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/** INTERNAL ONLY */
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template<class T>
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typename T::type find() const { return impl.table->lookup((T*)0); }
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private:
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template<class C2>
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friend class binding;
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/** INTERNAL ONLY */
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struct impl_type
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{
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impl_type() {
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table = &::boost::type_erasure::detail::make_vtable_init<
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typename ::boost::mpl::transform<
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actual_concept,
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::boost::type_erasure::detail::get_null_vtable_entry<
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::boost::mpl::_1
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>
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>::type,
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table_type
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>::type::value;
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}
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template<class Map>
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impl_type(const static_binding<Map>&)
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{
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table = &::boost::type_erasure::detail::make_vtable_init<
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typename ::boost::mpl::transform<
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actual_concept,
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::boost::type_erasure::detail::rebind_placeholders<
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::boost::mpl::_1,
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typename ::boost::type_erasure::detail::add_deductions<
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Map,
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placeholder_subs
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>::type
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>
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>::type,
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table_type
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>::type::value;
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}
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template<class Concept2, class Map>
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impl_type(const binding<Concept2>& other, const static_binding<Map>&, boost::mpl::false_)
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: manager(new table_type)
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{
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manager->template convert_from<
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typename ::boost::type_erasure::detail::convert_deductions<
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Map,
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placeholder_subs,
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typename binding<Concept2>::placeholder_subs
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>::type
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>(*other.impl.table);
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table = manager.get();
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}
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template<class Concept2, class Map>
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impl_type(const binding<Concept2>& other, const static_binding<Map>&, boost::mpl::true_)
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: table(other.impl.table),
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manager(other.impl.manager)
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{}
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const table_type* table;
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::boost::shared_ptr<table_type> manager;
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} impl;
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};
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}
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}
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#endif
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