/Src/Dependencies/Boost/boost/accumulators/framework/accumulators/reference_accumulator.hpp
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- ///////////////////////////////////////////////////////////////////////////////
- // reference_accumulator.hpp
- //
- // Copyright 2005 Eric Niebler. Distributed under the Boost
- // Software License, Version 1.0. (See accompanying file
- // LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
- #ifndef BOOST_ACCUMULATORS_FRAMEWORK_ACCUMULATORS_REFERENCE_ACCUMULATOR_HPP_EAN_03_23_2006
- #define BOOST_ACCUMULATORS_FRAMEWORK_ACCUMULATORS_REFERENCE_ACCUMULATOR_HPP_EAN_03_23_2006
- #include <boost/ref.hpp>
- #include <boost/mpl/always.hpp>
- #include <boost/parameter/keyword.hpp>
- #include <boost/accumulators/framework/depends_on.hpp> // for feature_tag
- #include <boost/accumulators/framework/accumulator_base.hpp>
- #include <boost/accumulators/framework/extractor.hpp>
- namespace boost { namespace accumulators
- {
- namespace impl
- {
- //////////////////////////////////////////////////////////////////////////
- // reference_accumulator_impl
- //
- template<typename Referent, typename Tag>
- struct reference_accumulator_impl
- : accumulator_base
- {
- typedef Referent &result_type;
- template<typename Args>
- reference_accumulator_impl(Args const &args)
- : ref(args[parameter::keyword<Tag>::get()])
- {
- }
- result_type result(dont_care) const
- {
- return this->ref;
- }
- private:
- reference_wrapper<Referent> ref;
- };
- } // namespace impl
- namespace tag
- {
- //////////////////////////////////////////////////////////////////////////
- // reference_tag
- template<typename Tag>
- struct reference_tag
- {
- };
- //////////////////////////////////////////////////////////////////////////
- // reference
- template<typename Referent, typename Tag>
- struct reference
- : depends_on<>
- {
- /// INTERNAL ONLY
- ///
- typedef mpl::always<accumulators::impl::reference_accumulator_impl<Referent, Tag> > impl;
- };
- }
- namespace extract
- {
- BOOST_ACCUMULATORS_DEFINE_EXTRACTOR(tag, reference, (typename)(typename))
- BOOST_ACCUMULATORS_DEFINE_EXTRACTOR(tag, reference_tag, (typename))
- }
- using extract::reference;
- using extract::reference_tag;
- // Map all reference<V,T> features to reference_tag<T> so
- // that references can be extracted using reference_tag<T>
- // without specifying the referent type.
- template<typename ValueType, typename Tag>
- struct feature_of<tag::reference<ValueType, Tag> >
- : feature_of<tag::reference_tag<Tag> >
- {
- };
- }} // namespace boost::accumulators
- #endif