88 lines
2.5 KiB
C++
88 lines
2.5 KiB
C++
// Copyright David Abrahams, Daniel Wallin 2003.
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// Distributed under the Boost Software License, Version 1.0.
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// (See 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_PARAMETER_AUX_PACK_PREDICATE_HPP
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#define BOOST_PARAMETER_AUX_PACK_PREDICATE_HPP
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namespace boost { namespace parameter { namespace aux {
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// helper for get_predicate<...>, below
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template <typename T>
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struct get_predicate_or_default
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{
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typedef T type;
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};
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// helper for predicate<...>, below
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template <typename T>
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struct get_predicate
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: ::boost::parameter::aux
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::get_predicate_or_default<typename T::predicate>
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{
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};
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}}} // namespace boost::parameter::aux
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#include <boost/parameter/aux_/use_default.hpp>
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#include <boost/parameter/aux_/always_true_predicate.hpp>
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namespace boost { namespace parameter { namespace aux {
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template <>
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struct get_predicate_or_default< ::boost::parameter::aux::use_default>
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{
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typedef ::boost::parameter::aux::always_true_predicate type;
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};
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}}} // namespace boost::parameter::aux
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#include <boost/parameter/required.hpp>
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#include <boost/parameter/optional.hpp>
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#include <boost/parameter/config.hpp>
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#if defined(BOOST_PARAMETER_CAN_USE_MP11)
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#include <boost/mp11/integral.hpp>
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#include <boost/mp11/utility.hpp>
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#else
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#include <boost/mpl/bool.hpp>
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#include <boost/mpl/if.hpp>
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#include <boost/mpl/eval_if.hpp>
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#include <boost/mpl/identity.hpp>
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#endif
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namespace boost { namespace parameter { namespace aux {
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template <typename T>
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#if defined(BOOST_PARAMETER_CAN_USE_MP11)
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using predicate = ::boost::mp11::mp_if<
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::boost::mp11::mp_if<
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::boost::parameter::aux::is_optional<T>
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, ::boost::mp11::mp_true
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, ::boost::parameter::aux::is_required<T>
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>
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, ::boost::parameter::aux::get_predicate<T>
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, ::boost::mp11::mp_identity<
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::boost::parameter::aux::always_true_predicate
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>
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>;
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#else
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struct predicate
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: ::boost::mpl::eval_if<
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typename ::boost::mpl::if_<
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::boost::parameter::aux::is_optional<T>
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, ::boost::mpl::true_
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, ::boost::parameter::aux::is_required<T>
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>::type
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, ::boost::parameter::aux::get_predicate<T>
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, ::boost::mpl::identity<
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::boost::parameter::aux::always_true_predicate
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>
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>
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{
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};
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#endif // BOOST_PARAMETER_CAN_USE_MP11
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}}} // namespace boost::parameter::aux
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#endif // include guard
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