134 lines
3.8 KiB
Plaintext
134 lines
3.8 KiB
Plaintext
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//-----------------------------------------------------------------------------
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// boost variant/detail/enable_recursive.hpp header file
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// See http://www.boost.org for updates, documentation, and revision history.
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//-----------------------------------------------------------------------------
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//
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// Copyright (c) 2003
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// Eric Friedman
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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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#ifndef BOOST_VARIANT_DETAIL_ENABLE_RECURSIVE_HPP
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#define BOOST_VARIANT_DETAIL_ENABLE_RECURSIVE_HPP
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#include <boost/variant/detail/enable_recursive_fwd.hpp>
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#include <boost/variant/variant_fwd.hpp>
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#if !defined(BOOST_VARIANT_NO_FULL_RECURSIVE_VARIANT_SUPPORT)
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# include <boost/mpl/apply.hpp>
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# include <boost/mpl/eval_if.hpp>
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# include <boost/mpl/lambda.hpp>
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#endif
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#include <boost/variant/detail/substitute.hpp>
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#include <boost/mpl/aux_/config/ctps.hpp>
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#include <boost/mpl/bool_fwd.hpp>
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#include <boost/mpl/if.hpp>
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#include <boost/mpl/or.hpp>
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#include <boost/type_traits/is_pointer.hpp>
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#include <boost/type_traits/is_reference.hpp>
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#include <boost/type_traits/is_same.hpp>
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#include <boost/variant/recursive_wrapper.hpp>
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namespace boost {
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namespace detail { namespace variant {
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#if !defined(BOOST_VARIANT_DETAIL_NO_SUBSTITUTE)
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# define BOOST_VARIANT_AUX_ENABLE_RECURSIVE_IMPL(T,Dest,Source) \
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substitute< T , Dest , Source > \
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/**/
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#else // defined(BOOST_VARIANT_DETAIL_NO_SUBSTITUTE)
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///////////////////////////////////////////////////////////////////////////////
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// (detail) class template rebind1
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//
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// Limited workaround in case 'substitute' metafunction unavailable.
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//
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template <typename T, typename U1>
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struct rebind1
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{
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private:
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typedef typename mpl::lambda<
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mpl::identity<T>
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>::type le_;
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public:
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typedef typename mpl::eval_if<
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is_same< le_, mpl::identity<T> >
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, le_ // identity<T>
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, mpl::apply1<le_, U1>
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>::type type;
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};
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# define BOOST_VARIANT_AUX_ENABLE_RECURSIVE_IMPL(T,Dest,Source) \
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rebind1< T , Dest > \
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/**/
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#endif // !defined(BOOST_VARIANT_DETAIL_NO_SUBSTITUTE)
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///////////////////////////////////////////////////////////////////////////////
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// (detail) metafunction enable_recursive
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//
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// See boost/variant/detail/enable_recursive_fwd.hpp for more information.
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//
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template <typename T, typename RecursiveVariant, typename NoWrapper>
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struct enable_recursive
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: BOOST_VARIANT_AUX_ENABLE_RECURSIVE_IMPL(
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T, RecursiveVariant, ::boost::recursive_variant_
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)
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{
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};
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template <typename T, typename RecursiveVariant>
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struct enable_recursive< T,RecursiveVariant,mpl::false_ >
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{
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private: // helpers, for metafunction result (below)
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typedef typename BOOST_VARIANT_AUX_ENABLE_RECURSIVE_IMPL(
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T, RecursiveVariant, ::boost::recursive_variant_
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)::type t_;
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public: // metafunction result
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// [Wrap with recursive_wrapper only if rebind really changed something:]
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typedef typename mpl::if_<
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mpl::or_<
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is_same< t_,T >
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, is_reference<t_>
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, is_pointer<t_>
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>
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, t_
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, boost::recursive_wrapper<t_>
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>::type type;
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};
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///////////////////////////////////////////////////////////////////////////////
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// (detail) metafunction class quoted_enable_recursive
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//
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// Same behavior as enable_recursive metafunction (see above).
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//
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template <typename RecursiveVariant, typename NoWrapper>
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struct quoted_enable_recursive
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{
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template <typename T>
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struct apply
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: enable_recursive<T, RecursiveVariant, NoWrapper>
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{
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};
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};
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}} // namespace detail::variant
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} // namespace boost
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#endif // BOOST_VARIANT_DETAIL_ENABLE_RECURSIVE_HPP
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