boost/variant/multivisitors.hpp
// Boost.Varaint
// Multivisitors defined here
//
// See http://www.boost.org for most recent version, including documentation.
//
// Copyright Antony Polukhin, 2013.
//
// 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_MULTIVISITORS_HPP
#define BOOST_VARIANT_MULTIVISITORS_HPP
#if defined(_MSC_VER) && (_MSC_VER >= 1020)
# pragma once
#endif
#include <boost/variant.hpp>
#include <boost/bind.hpp>
#include <boost/preprocessor/repetition.hpp>
#include <boost/preprocessor/punctuation/comma_if.hpp>
#include <boost/preprocessor/arithmetic/add.hpp>
#include <boost/preprocessor/arithmetic/sub.hpp>
#ifndef BOOST_VARAINT_MAX_MULTIVIZITOR_PARAMS
# define BOOST_VARAINT_MAX_MULTIVIZITOR_PARAMS 4
#endif
namespace boost {
namespace detail { namespace variant {
template <class VisitorT, class Visitable1T, class Visitable2T>
struct two_variables_holder {
private:
VisitorT& visitor_;
Visitable1T& visitable1_;
Visitable2T& visitable2_;
// required to supress warnings and enshure that we do not copy
// this visitor
two_variables_holder& operator=(const two_variables_holder&);
public:
typedef BOOST_DEDUCED_TYPENAME VisitorT::result_type result_type;
explicit two_variables_holder(VisitorT& visitor, Visitable1T& visitable1, Visitable2T& visitable2) BOOST_NOEXCEPT
: visitor_(visitor)
, visitable1_(visitable1)
, visitable2_(visitable2)
{}
#define BOOST_VARIANT_OPERATOR_BEG() \
return ::boost::apply_visitor( \
::boost::bind<result_type>(boost::ref(visitor_), _1, _2 \
/**/
#define BOOST_VARIANT_OPERATOR_END() \
), visitable1_, visitable2_); \
/**/
#define BOOST_VARANT_VISITORS_VARIABLES_PRINTER(z, n, data) \
BOOST_PP_COMMA() boost::ref( BOOST_PP_CAT(vis, n) ) \
/**/
#define BOOST_VARIANT_VISIT(z, n, data) \
template <BOOST_PP_ENUM_PARAMS(BOOST_PP_ADD(n, 1), class VisitableUnwrapped)> \
BOOST_VARIANT_AUX_GENERIC_RESULT_TYPE(result_type) operator()( \
BOOST_PP_ENUM_BINARY_PARAMS(BOOST_PP_ADD(n, 1), VisitableUnwrapped, & vis) \
) const \
{ \
BOOST_VARIANT_OPERATOR_BEG() \
BOOST_PP_REPEAT(BOOST_PP_ADD(n, 1), BOOST_VARANT_VISITORS_VARIABLES_PRINTER, ~) \
BOOST_VARIANT_OPERATOR_END() \
} \
/**/
BOOST_PP_REPEAT( BOOST_PP_SUB(BOOST_VARAINT_MAX_MULTIVIZITOR_PARAMS, 2), BOOST_VARIANT_VISIT, ~)
#undef BOOST_VARIANT_OPERATOR_BEG
#undef BOOST_VARIANT_OPERATOR_END
#undef BOOST_VARANT_VISITORS_VARIABLES_PRINTER
#undef BOOST_VARIANT_VISIT
};
template <class VisitorT, class Visitable1T, class Visitable2T>
inline two_variables_holder<VisitorT, Visitable1T, Visitable2T> make_two_variables_holder(
VisitorT& visitor, Visitable1T& visitable1, Visitable2T& visitable2
) BOOST_NOEXCEPT
{
return two_variables_holder<VisitorT, Visitable1T, Visitable2T>(visitor, visitable1, visitable2);
}
template <class VisitorT, class Visitable1T, class Visitable2T>
inline two_variables_holder<const VisitorT, Visitable1T, Visitable2T> make_two_variables_holder(
const VisitorT& visitor, Visitable1T& visitable1, Visitable2T& visitable2
) BOOST_NOEXCEPT
{
return two_variables_holder<const VisitorT, Visitable1T, Visitable2T>(visitor, visitable1, visitable2);
}
}} // namespace detail::variant
#define BOOST_VARIANT_APPLY_VISITOR_BEG() \
return ::boost::apply_visitor( \
boost::detail::variant::make_two_variables_holder(visitor, var0 , var1), \
var2 \
/**/
#define BOOST_VARIANT_APPLY_VISITOR_END() \
); \
/**/
#define BOOST_VARANT_VISITORS_VARIABLES_PRINTER(z, n, data) \
BOOST_PP_COMMA() BOOST_PP_CAT(var, BOOST_PP_ADD(n, 3)) \
/**/
#define BOOST_VARIANT_VISIT(z, n, data) \
template <class Visitor BOOST_PP_COMMA() BOOST_PP_ENUM_PARAMS(BOOST_PP_ADD(n, 3), class T)> \
inline BOOST_VARIANT_AUX_GENERIC_RESULT_TYPE(BOOST_DEDUCED_TYPENAME Visitor::result_type) apply_visitor( \
data BOOST_PP_COMMA() BOOST_PP_ENUM_BINARY_PARAMS(BOOST_PP_ADD(n, 3), T, & var) \
) \
{ \
BOOST_VARIANT_APPLY_VISITOR_BEG() \
BOOST_PP_REPEAT(n, BOOST_VARANT_VISITORS_VARIABLES_PRINTER, ~) \
BOOST_VARIANT_APPLY_VISITOR_END() \
} \
/**/
BOOST_PP_REPEAT( BOOST_PP_SUB(BOOST_VARAINT_MAX_MULTIVIZITOR_PARAMS, 2), BOOST_VARIANT_VISIT, const Visitor& visitor)
BOOST_PP_REPEAT( BOOST_PP_SUB(BOOST_VARAINT_MAX_MULTIVIZITOR_PARAMS, 2), BOOST_VARIANT_VISIT, Visitor& visitor)
#undef BOOST_VARIANT_APPLY_VISITOR_BEG
#undef BOOST_VARIANT_APPLY_VISITOR_END
#undef BOOST_VARANT_VISITORS_VARIABLES_PRINTER
#undef BOOST_VARIANT_VISIT
} // namespace boost
#endif // BOOST_VARIANT_MULTIVISITORS_HPP