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