ext-boost/boost/variant/detail/apply_visitor_binary.hpp
2017-03-12 21:30:15 -07:00

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7.3 KiB
C++

//-----------------------------------------------------------------------------
// boost variant/detail/apply_visitor_binary.hpp header file
// See http://www.boost.org for updates, documentation, and revision history.
//-----------------------------------------------------------------------------
//
// Copyright (c) 2002-2003 Eric Friedman
// Copyright (c) 2014 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_DETAIL_APPLY_VISITOR_BINARY_HPP
#define BOOST_VARIANT_DETAIL_APPLY_VISITOR_BINARY_HPP
#include <boost/config.hpp>
#include <boost/detail/workaround.hpp>
#include <boost/variant/detail/generic_result_type.hpp>
#include <boost/variant/detail/apply_visitor_unary.hpp>
#if BOOST_WORKAROUND(__EDG__, BOOST_TESTED_AT(302))
#include <boost/utility/enable_if.hpp>
#include <boost/mpl/not.hpp>
#include <boost/type_traits/is_const.hpp>
#endif
#if !defined(BOOST_NO_CXX14_DECLTYPE_AUTO) && !defined(BOOST_NO_CXX11_DECLTYPE_N3276)
# include <boost/variant/detail/has_result_type.hpp>
#endif
namespace boost {
//////////////////////////////////////////////////////////////////////////
// function template apply_visitor(visitor, visitable1, visitable2)
//
// Visits visitable1 and visitable2 such that their values (which we
// shall call x and y, respectively) are used as arguments in the
// expression visitor(x, y).
//
namespace detail { namespace variant {
template <typename Visitor, typename Value1>
class apply_visitor_binary_invoke
{
public: // visitor typedefs
typedef typename Visitor::result_type
result_type;
private: // representation
Visitor& visitor_;
Value1& value1_;
public: // structors
apply_visitor_binary_invoke(Visitor& visitor, Value1& value1) BOOST_NOEXCEPT
: visitor_(visitor)
, value1_(value1)
{
}
public: // visitor interfaces
template <typename Value2>
BOOST_VARIANT_AUX_GENERIC_RESULT_TYPE(result_type)
operator()(Value2& value2)
{
return visitor_(value1_, value2);
}
private:
apply_visitor_binary_invoke& operator=(const apply_visitor_binary_invoke&);
};
template <typename Visitor, typename Visitable2>
class apply_visitor_binary_unwrap
{
public: // visitor typedefs
typedef typename Visitor::result_type
result_type;
private: // representation
Visitor& visitor_;
Visitable2& visitable2_;
public: // structors
apply_visitor_binary_unwrap(Visitor& visitor, Visitable2& visitable2) BOOST_NOEXCEPT
: visitor_(visitor)
, visitable2_(visitable2)
{
}
public: // visitor interfaces
template <typename Value1>
BOOST_VARIANT_AUX_GENERIC_RESULT_TYPE(result_type)
operator()(Value1& value1)
{
apply_visitor_binary_invoke<
Visitor
, Value1
> invoker(visitor_, value1);
return boost::apply_visitor(invoker, visitable2_);
}
private:
apply_visitor_binary_unwrap& operator=(const apply_visitor_binary_unwrap&);
};
}} // namespace detail::variant
//
// nonconst-visitor version:
//
#if !BOOST_WORKAROUND(__EDG__, BOOST_TESTED_AT(302))
# define BOOST_VARIANT_AUX_APPLY_VISITOR_NON_CONST_RESULT_TYPE(V) \
BOOST_VARIANT_AUX_GENERIC_RESULT_TYPE(typename V::result_type) \
/**/
#else // EDG-based compilers
# define BOOST_VARIANT_AUX_APPLY_VISITOR_NON_CONST_RESULT_TYPE(V) \
typename enable_if< \
mpl::not_< is_const< V > > \
, BOOST_VARIANT_AUX_GENERIC_RESULT_TYPE(typename V::result_type) \
>::type \
/**/
#endif // EDG-based compilers workaround
template <typename Visitor, typename Visitable1, typename Visitable2>
inline
BOOST_VARIANT_AUX_APPLY_VISITOR_NON_CONST_RESULT_TYPE(Visitor)
apply_visitor(
Visitor& visitor
, Visitable1& visitable1, Visitable2& visitable2
)
{
::boost::detail::variant::apply_visitor_binary_unwrap<
Visitor, Visitable2
> unwrapper(visitor, visitable2);
return boost::apply_visitor(unwrapper, visitable1);
}
#undef BOOST_VARIANT_AUX_APPLY_VISITOR_NON_CONST_RESULT_TYPE
//
// const-visitor version:
//
template <typename Visitor, typename Visitable1, typename Visitable2>
inline
BOOST_VARIANT_AUX_GENERIC_RESULT_TYPE(
typename Visitor::result_type
)
apply_visitor(
const Visitor& visitor
, Visitable1& visitable1, Visitable2& visitable2
)
{
::boost::detail::variant::apply_visitor_binary_unwrap<
const Visitor, Visitable2
> unwrapper(visitor, visitable2);
return boost::apply_visitor(unwrapper, visitable1);
}
#if !defined(BOOST_NO_CXX14_DECLTYPE_AUTO) && !defined(BOOST_NO_CXX11_DECLTYPE_N3276)
//////////////////////////////////////////////////////////////////////////
// function template apply_visitor(visitor, visitable1, visitable2)
//
// C++14 part.
//
namespace detail { namespace variant {
template <typename Visitor, typename Value1>
class apply_visitor_binary_invoke_cpp14
{
Visitor& visitor_;
Value1& value1_;
public: // structors
apply_visitor_binary_invoke_cpp14(Visitor& visitor, Value1& value1) BOOST_NOEXCEPT
: visitor_(visitor)
, value1_(value1)
{
}
public: // visitor interfaces
template <typename Value2>
decltype(auto) operator()(Value2& value2)
{
return visitor_(value1_, value2);
}
private:
apply_visitor_binary_invoke_cpp14& operator=(const apply_visitor_binary_invoke_cpp14&);
};
template <typename Visitor, typename Visitable2>
class apply_visitor_binary_unwrap_cpp14
{
Visitor& visitor_;
Visitable2& visitable2_;
public: // structors
apply_visitor_binary_unwrap_cpp14(Visitor& visitor, Visitable2& visitable2) BOOST_NOEXCEPT
: visitor_(visitor)
, visitable2_(visitable2)
{
}
public: // visitor interfaces
template <typename Value1>
decltype(auto) operator()(Value1& value1)
{
apply_visitor_binary_invoke_cpp14<
Visitor
, Value1
> invoker(visitor_, value1);
return boost::apply_visitor(invoker, visitable2_);
}
private:
apply_visitor_binary_unwrap_cpp14& operator=(const apply_visitor_binary_unwrap_cpp14&);
};
}} // namespace detail::variant
template <typename Visitor, typename Visitable1, typename Visitable2>
inline decltype(auto) apply_visitor(Visitor& visitor, Visitable1& visitable1, Visitable2& visitable2,
typename boost::disable_if<
boost::detail::variant::has_result_type<Visitor>
>::type* = 0)
{
::boost::detail::variant::apply_visitor_binary_unwrap_cpp14<
Visitor, Visitable2
> unwrapper(visitor, visitable2);
return boost::apply_visitor(unwrapper, visitable1);
}
template <typename Visitor, typename Visitable1, typename Visitable2>
inline decltype(auto) apply_visitor(const Visitor& visitor, Visitable1& visitable1, Visitable2& visitable2,
typename boost::disable_if<
boost::detail::variant::has_result_type<Visitor>
>::type* = 0)
{
::boost::detail::variant::apply_visitor_binary_unwrap_cpp14<
const Visitor, Visitable2
> unwrapper(visitor, visitable2);
return boost::apply_visitor(unwrapper, visitable1);
}
#endif // !defined(BOOST_NO_CXX14_DECLTYPE_AUTO) && !defined(BOOST_NO_CXX11_DECLTYPE_N3276)
} // namespace boost
#endif // BOOST_VARIANT_DETAIL_APPLY_VISITOR_BINARY_HPP