// 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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// $Id$
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#if !defined(BOOST_PP_IS_ITERATING)
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#ifndef BOOST_TYPE_ERASURE_DETAIL_EXTRACT_CONCEPT_HPP_INCLUDED
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#define BOOST_TYPE_ERASURE_DETAIL_EXTRACT_CONCEPT_HPP_INCLUDED
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#include <boost/mpl/eval_if.hpp>
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#include <boost/mpl/identity.hpp>
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#include <boost/type_traits/remove_cv.hpp>
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#include <boost/type_traits/remove_reference.hpp>
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#include <boost/preprocessor/cat.hpp>
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#include <boost/preprocessor/inc.hpp>
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#include <boost/preprocessor/iteration/iterate.hpp>
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#include <boost/preprocessor/repetition/repeat.hpp>
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#include <boost/preprocessor/repetition/enum_params.hpp>
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#include <boost/type_erasure/is_placeholder.hpp>
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#include <boost/type_erasure/concept_of.hpp>
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#include <boost/type_erasure/config.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 T, class U>
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struct combine_concepts;
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template<class T>
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struct combine_concepts<T, T> { typedef T type; };
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template<class T>
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struct combine_concepts<T, void> { typedef T type; };
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template<class T>
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struct combine_concepts<void, T> { typedef T type; };
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template<>
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struct combine_concepts<void, void> { typedef void type; };
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#ifdef BOOST_TYPE_ERASURE_USE_MP11
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template<class T, class U>
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using combine_concepts_t = typename ::boost::type_erasure::detail::combine_concepts<T, U>::type;
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template<class T, class U>
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using extract_concept_or_void =
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::boost::mp11::mp_eval_if_c<
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!::boost::type_erasure::is_placeholder<
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::boost::remove_cv_t<
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::boost::remove_reference_t<T>
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>
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>::value,
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void,
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::boost::type_erasure::concept_of_t, U
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>;
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template<class L1, class L2>
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using extract_concept_t =
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::boost::mp11::mp_fold<
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::boost::mp11::mp_transform< ::boost::type_erasure::detail::extract_concept_or_void, L1, L2>,
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void,
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::boost::type_erasure::detail::combine_concepts_t
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>;
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#else
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template<class T, class U>
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struct maybe_extract_concept
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{
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typedef typename ::boost::mpl::eval_if<
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::boost::type_erasure::is_placeholder<
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typename ::boost::remove_cv<
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typename ::boost::remove_reference<T>::type
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>::type
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>,
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::boost::type_erasure::concept_of<typename ::boost::remove_reference<U>::type>,
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::boost::mpl::identity<void>
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>::type type;
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};
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#if !defined(BOOST_NO_CXX11_VARIADIC_TEMPLATES) && !defined(BOOST_NO_CXX11_RVALUE_REFERENCES)
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template<class Args, class... U>
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struct extract_concept;
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template<class R, class T0, class... T, class U0, class... U>
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struct extract_concept<R(T0, T...), U0, U...>
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{
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typedef typename ::boost::type_erasure::detail::combine_concepts<
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typename ::boost::type_erasure::detail::maybe_extract_concept<
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T0, U0
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>::type,
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typename ::boost::type_erasure::detail::extract_concept<
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void(T...),
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U...
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>::type
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>::type type;
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};
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template<>
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struct extract_concept<void()>
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{
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typedef void type;
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};
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#else
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#define BOOST_PP_FILENAME_1 <boost/type_erasure/detail/extract_concept.hpp>
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#define BOOST_PP_ITERATION_LIMITS (1, BOOST_TYPE_ERASURE_MAX_ARITY)
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#include BOOST_PP_ITERATE()
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#endif
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#endif
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}
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}
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}
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#endif
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#else
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#define N BOOST_PP_ITERATION()
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#define BOOST_TYPE_ERASURE_EXTRACT_CONCEPT(z, n, data) \
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typedef typename ::boost::type_erasure::detail::combine_concepts< \
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typename ::boost::type_erasure::detail::maybe_extract_concept< \
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BOOST_PP_CAT(T, n), BOOST_PP_CAT(U, n) \
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>::type, \
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BOOST_PP_CAT(concept, n) \
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>::type BOOST_PP_CAT(concept, BOOST_PP_INC(n));
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template<
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BOOST_PP_ENUM_PARAMS(N, class T),
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BOOST_PP_ENUM_PARAMS(N, class U)>
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struct BOOST_PP_CAT(extract_concept, N)
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{
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typedef void concept0;
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BOOST_PP_REPEAT(N, BOOST_TYPE_ERASURE_EXTRACT_CONCEPT, ~)
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typedef BOOST_PP_CAT(concept, N) type;
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};
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#undef BOOST_TYPE_ERASURE_EXTRACT_CONCEPT
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#undef N
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#endif
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