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//-----------------------------------------------------------------------------
// boost variant/recursive_variant.hpp header file
// See http://www.boost.org for updates, documentation, and revision history.
//-----------------------------------------------------------------------------
//
// Copyright (c) 2003 Eric Friedman
// Copyright (c) 2013 Antony Polukhin
//
// 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_VARIANT_RECURSIVE_VARIANT_HPP
#define BOOST_VARIANT_RECURSIVE_VARIANT_HPP
#include "boost/variant/variant_fwd.hpp"
#include "boost/variant/detail/enable_recursive.hpp"
#include "boost/variant/detail/substitute_fwd.hpp"
#include "boost/variant/detail/make_variant_list.hpp"
#include "boost/variant/detail/over_sequence.hpp"
#include "boost/mpl/aux_/lambda_arity_param.hpp"
#include "boost/mpl/equal.hpp"
#include "boost/mpl/eval_if.hpp"
#include "boost/mpl/identity.hpp"
#include "boost/mpl/if.hpp"
#include "boost/mpl/protect.hpp"
#include "boost/mpl/transform.hpp"
#include "boost/type_traits/is_same.hpp"
#include "boost/preprocessor/cat.hpp"
#include "boost/preprocessor/repeat.hpp"
#include "boost/mpl/bool.hpp"
#include "boost/mpl/is_sequence.hpp"
#include "boost/variant/variant.hpp"
namespace boost {
namespace detail { namespace variant {
///////////////////////////////////////////////////////////////////////////////
// (detail) metafunction specialization substitute
//
// Handles embedded variant types when substituting for recursive_variant_.
//
#if !defined(BOOST_VARIANT_DETAIL_NO_SUBSTITUTE)
template <
BOOST_VARIANT_ENUM_PARAMS(typename T)
, typename RecursiveVariant
BOOST_MPL_AUX_LAMBDA_ARITY_PARAM(typename Arity)
>
struct substitute<
::boost::variant<
recursive_flag< T0 >
, BOOST_VARIANT_ENUM_SHIFTED_PARAMS(T)
>
, RecursiveVariant
, ::boost::recursive_variant_
BOOST_MPL_AUX_LAMBDA_ARITY_PARAM(Arity)
>
{
typedef ::boost::variant<
recursive_flag< T0 >
, BOOST_VARIANT_ENUM_SHIFTED_PARAMS(T)
> type;
};
template <
BOOST_VARIANT_ENUM_PARAMS(typename T)
, typename RecursiveVariant
BOOST_MPL_AUX_LAMBDA_ARITY_PARAM(typename Arity)
>
struct substitute<
::boost::variant<
::boost::detail::variant::over_sequence< T0 >
, BOOST_VARIANT_ENUM_SHIFTED_PARAMS(T)
>
, RecursiveVariant
, ::boost::recursive_variant_
BOOST_MPL_AUX_LAMBDA_ARITY_PARAM(Arity)
>
{
private:
typedef T0 initial_types;
typedef typename mpl::transform<
initial_types
, mpl::protect< quoted_enable_recursive<RecursiveVariant,mpl::true_> >
>::type types;
public:
typedef typename mpl::if_<
mpl::equal<initial_types, types, ::boost::is_same<mpl::_1, mpl::_2> >
, ::boost::variant<
::boost::detail::variant::over_sequence< T0 >
, BOOST_VARIANT_ENUM_SHIFTED_PARAMS(T)
>
, ::boost::variant< over_sequence<types> >
>::type type;
};
template <
BOOST_VARIANT_ENUM_PARAMS(typename T)
, typename RecursiveVariant
BOOST_MPL_AUX_LAMBDA_ARITY_PARAM(typename Arity)
>
struct substitute<
::boost::variant< BOOST_VARIANT_ENUM_PARAMS(T) >
, RecursiveVariant
, ::boost::recursive_variant_
BOOST_MPL_AUX_LAMBDA_ARITY_PARAM(Arity)
>
{
#if !defined(BOOST_VARIANT_DO_NOT_USE_VARIADIC_TEMPLATES)
typedef ::boost::variant<
typename enable_recursive<
T0
, RecursiveVariant
, mpl::true_
>::type,
typename enable_recursive<
TN
, RecursiveVariant
, mpl::true_
>::type...
> type;
#else // defined(BOOST_VARIANT_DO_NOT_USE_VARIADIC_TEMPLATES)
private: // helpers, for metafunction result (below)
#define BOOST_VARIANT_AUX_ENABLE_RECURSIVE_TYPEDEFS(z,N,_) \
typedef typename enable_recursive< \
BOOST_PP_CAT(T,N) \
, RecursiveVariant \
, mpl::true_ \
>::type BOOST_PP_CAT(wknd_T,N); \
/**/
BOOST_PP_REPEAT(
BOOST_VARIANT_LIMIT_TYPES
, BOOST_VARIANT_AUX_ENABLE_RECURSIVE_TYPEDEFS
, _
)
#undef BOOST_VARIANT_AUX_ENABLE_RECURSIVE_TYPEDEFS
public: // metafunction result
typedef ::boost::variant< BOOST_VARIANT_ENUM_PARAMS(wknd_T) > type;
#endif // BOOST_VARIANT_DO_NOT_USE_VARIADIC_TEMPLATES workaround
};
#else // defined(BOOST_VARIANT_DETAIL_NO_SUBSTITUTE)
//
// no specializations: embedded variants unsupported on these compilers!
//
#endif // !defined(BOOST_VARIANT_DETAIL_NO_SUBSTITUTE)
}} // namespace detail::variant
///////////////////////////////////////////////////////////////////////////////
// metafunction make_recursive_variant
//
// See docs and boost/variant/variant_fwd.hpp for more information.
//
template < BOOST_VARIANT_ENUM_PARAMS(typename T) >
struct make_recursive_variant
{
public: // metafunction result
typedef boost::variant<
detail::variant::recursive_flag< T0 >
, BOOST_VARIANT_ENUM_SHIFTED_PARAMS(T)
> type;
};
///////////////////////////////////////////////////////////////////////////////
// metafunction make_recursive_variant_over
//
// See docs and boost/variant/variant_fwd.hpp for more information.
//
template <typename Types>
struct make_recursive_variant_over
{
private: // precondition assertions
BOOST_STATIC_ASSERT(( ::boost::mpl::is_sequence<Types>::value ));
public: // metafunction result
typedef typename make_recursive_variant<
detail::variant::over_sequence< Types >
>::type type;
};
} // namespace boost
#endif // BOOST_VARIANT_RECURSIVE_VARIANT_HPP
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