262 lines
8.3 KiB
C++
262 lines
8.3 KiB
C++
#ifndef BOOST_PP_IS_ITERATING
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///////////////////////////////////////////////////////////////////////////////
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/// \file poly_function.hpp
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/// A wrapper that makes a tr1-style function object that handles const
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/// and non-const refs and reference_wrapper arguments, too, and forwards
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/// the arguments on to the specified implementation.
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//
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// Copyright 2008 Eric Niebler. Distributed under the Boost
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// Software License, Version 1.0. (See accompanying file
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// LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
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#ifndef BOOST_PROTO_DETAIL_POLY_FUNCTION_EAN_2008_05_02
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#define BOOST_PROTO_DETAIL_POLY_FUNCTION_EAN_2008_05_02
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#include <boost/ref.hpp>
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#include <boost/mpl/bool.hpp>
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#include <boost/mpl/void.hpp>
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#include <boost/mpl/eval_if.hpp>
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#include <boost/preprocessor/cat.hpp>
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#include <boost/preprocessor/facilities/intercept.hpp>
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#include <boost/preprocessor/iteration/iterate.hpp>
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#include <boost/preprocessor/repetition/enum.hpp>
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#include <boost/preprocessor/repetition/enum_params.hpp>
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#include <boost/preprocessor/repetition/enum_trailing_params.hpp>
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#include <boost/preprocessor/repetition/enum_binary_params.hpp>
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#include <boost/proto/proto_fwd.hpp>
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#ifdef _MSC_VER
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# pragma warning(push)
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# pragma warning(disable: 4181) // const applied to reference type
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#endif
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namespace boost { namespace proto { namespace detail
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{
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////////////////////////////////////////////////////////////////////////////////////////////////
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template<typename T>
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struct normalize_arg
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{
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typedef T type;
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typedef T const &reference;
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};
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template<typename T>
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struct normalize_arg<T &>
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{
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typedef T type;
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typedef T const &reference;
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};
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template<typename T>
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struct normalize_arg<T const &>
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{
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typedef T type;
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typedef T const &reference;
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};
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template<typename T>
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struct normalize_arg<boost::reference_wrapper<T> >
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{
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typedef T &type;
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typedef T &reference;
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};
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template<typename T>
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struct normalize_arg<boost::reference_wrapper<T> &>
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{
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typedef T &type;
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typedef T &reference;
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};
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template<typename T>
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struct normalize_arg<boost::reference_wrapper<T> const &>
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{
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typedef T &type;
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typedef T &reference;
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};
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////////////////////////////////////////////////////////////////////////////////////////////////
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template<typename T>
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struct arg
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{
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typedef T const &type;
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arg(type t)
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: value(t)
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{}
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operator type() const
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{
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return this->value;
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}
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type operator()() const
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{
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return *this;
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}
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private:
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arg &operator =(arg const &);
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type value;
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};
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template<typename T>
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struct arg<T &>
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{
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typedef T &type;
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arg(type t)
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: value(t)
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{}
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operator type() const
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{
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return this->value;
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}
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type operator()() const
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{
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return *this;
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}
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private:
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arg &operator =(arg const &);
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type value;
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};
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////////////////////////////////////////////////////////////////////////////////////////////////
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template<typename T, typename Void = void>
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struct is_poly_function
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: mpl::false_
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{};
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template<typename T>
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struct is_poly_function<T, typename T::is_poly_function_base_>
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: mpl::true_
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{};
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////////////////////////////////////////////////////////////////////////////////////////////////
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#define BOOST_PROTO_POLY_FUNCTION() \
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typedef void is_poly_function_base_; \
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/**/
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////////////////////////////////////////////////////////////////////////////////////////////////
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struct poly_function_base
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{
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/// INTERNAL ONLY
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BOOST_PROTO_POLY_FUNCTION()
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};
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////////////////////////////////////////////////////////////////////////////////////////////////
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template<typename Derived, typename NullaryResult = void>
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struct poly_function
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: poly_function_base
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{
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template<typename Sig>
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struct result;
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template<typename This>
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struct result<This()>
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: Derived::template impl<>
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{
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typedef typename result::result_type type;
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};
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NullaryResult operator()() const
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{
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result<Derived const()> impl;
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return impl();
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}
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#define BOOST_PP_ITERATION_PARAMS_1 (4, (1, BOOST_PROTO_MAX_ARITY, <boost/proto/detail/poly_function.hpp>, 0))
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#include BOOST_PP_ITERATE()
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};
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////////////////////////////////////////////////////////////////////////////////////////////////
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template<typename PolyFunSig, bool IsPoly>
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struct as_mono_function_impl;
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////////////////////////////////////////////////////////////////////////////////////////////////
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template<typename PolyFunSig>
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struct as_mono_function;
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#define BOOST_PP_ITERATION_PARAMS_1 (4, (1, BOOST_PROTO_MAX_ARITY, <boost/proto/detail/poly_function.hpp>, 1))
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#include BOOST_PP_ITERATE()
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}}} // namespace boost::proto::detail
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#ifdef _MSC_VER
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# pragma warning(pop)
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#endif
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#endif
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#elif 0 == BOOST_PP_ITERATION_FLAGS()
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#define N BOOST_PP_ITERATION()
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template<typename This BOOST_PP_ENUM_TRAILING_PARAMS(N, typename A)>
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struct result<This(BOOST_PP_ENUM_PARAMS(N, A))>
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: Derived::template impl<
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BOOST_PP_ENUM_BINARY_PARAMS(
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N
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, typename normalize_arg<A
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, >::type BOOST_PP_INTERCEPT
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)
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>
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{
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typedef typename result::result_type type;
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};
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template<BOOST_PP_ENUM_PARAMS(N, typename A)>
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typename result<
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Derived const(
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BOOST_PP_ENUM_BINARY_PARAMS(N, A, const & BOOST_PP_INTERCEPT)
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)
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>::type
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operator ()(BOOST_PP_ENUM_BINARY_PARAMS(N, A, const &a)) const
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{
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result<
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Derived const(
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BOOST_PP_ENUM_BINARY_PARAMS(N, A, const & BOOST_PP_INTERCEPT)
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)
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> impl;
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#define M0(Z, N, DATA) \
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static_cast<typename normalize_arg<BOOST_PP_CAT(A, N) const &> \
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::reference>(BOOST_PP_CAT(a, N))
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return impl(BOOST_PP_ENUM(N, M0, ~));
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#undef M0
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}
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#undef N
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#elif 1 == BOOST_PP_ITERATION_FLAGS()
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#define N BOOST_PP_ITERATION()
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////////////////////////////////////////////////////////////////////////////////////////////////
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template<typename PolyFun, BOOST_PP_ENUM_PARAMS(N, typename A)>
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struct as_mono_function_impl<PolyFun(BOOST_PP_ENUM_PARAMS(N, A)), true>
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{
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typedef typename PolyFun::template impl<BOOST_PP_ENUM_PARAMS(N, const A)> type;
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};
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////////////////////////////////////////////////////////////////////////////////////////////////
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template<typename PolyFun, BOOST_PP_ENUM_PARAMS(N, typename A)>
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struct as_mono_function_impl<PolyFun(BOOST_PP_ENUM_PARAMS(N, A)), false>
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{
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typedef PolyFun type;
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};
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////////////////////////////////////////////////////////////////////////////////////////////////
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template<typename PolyFun, BOOST_PP_ENUM_PARAMS(N, typename A)>
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struct as_mono_function<PolyFun(BOOST_PP_ENUM_PARAMS(N, A))>
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: as_mono_function_impl<PolyFun(BOOST_PP_ENUM_PARAMS(N, A)), is_poly_function<PolyFun>::value>
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{};
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#undef N
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#endif
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