Chris@16: //-----------------------------------------------------------------------------
Chris@16: // boost variant/detail/apply_visitor_delayed.hpp header file
Chris@16: // See http://www.boost.org for updates, documentation, and revision history.
Chris@16: //-----------------------------------------------------------------------------
Chris@16: //
Chris@16: // Copyright (c) 2002-2003
Chris@16: // Eric Friedman
Chris@16: //
Chris@16: // Distributed under the Boost Software License, Version 1.0. (See
Chris@16: // accompanying file LICENSE_1_0.txt or copy at
Chris@16: // http://www.boost.org/LICENSE_1_0.txt)
Chris@16: 
Chris@16: #ifndef BOOST_VARIANT_DETAIL_APPLY_VISITOR_DELAYED_HPP
Chris@16: #define BOOST_VARIANT_DETAIL_APPLY_VISITOR_DELAYED_HPP
Chris@16: 
Chris@16: #include "boost/variant/detail/generic_result_type.hpp"
Chris@16: 
Chris@16: #include "boost/variant/detail/apply_visitor_unary.hpp"
Chris@16: #include "boost/variant/detail/apply_visitor_binary.hpp"
Chris@101: #include "boost/variant/variant_fwd.hpp" // for BOOST_VARIANT_DO_NOT_USE_VARIADIC_TEMPLATES
Chris@101: 
Chris@101: 
Chris@101: #include "boost/variant/detail/has_result_type.hpp"
Chris@101: #include <boost/core/enable_if.hpp>
Chris@16: 
Chris@16: namespace boost {
Chris@16: 
Chris@16: //////////////////////////////////////////////////////////////////////////
Chris@16: // function template apply_visitor(visitor)
Chris@16: //
Chris@16: // Returns a function object, overloaded for unary and binary usage, that
Chris@16: // visits its arguments using visitor (or a copy of visitor) via
Chris@16: //  * apply_visitor( visitor, [argument] )
Chris@16: // under unary invocation, or
Chris@16: //  * apply_visitor( visitor, [argument1], [argument2] )
Chris@16: // under binary invocation.
Chris@16: //
Chris@16: // NOTE: Unlike other apply_visitor forms, the visitor object must be
Chris@16: //   non-const; this prevents user from giving temporary, to disastrous
Chris@16: //   effect (i.e., returned function object would have dead reference).
Chris@16: //
Chris@16: 
Chris@16: template <typename Visitor>
Chris@16: class apply_visitor_delayed_t
Chris@16: {
Chris@16: public: // visitor typedefs
Chris@16: 
Chris@16:     typedef typename Visitor::result_type
Chris@16:         result_type;
Chris@16: 
Chris@16: private: // representation
Chris@16: 
Chris@16:     Visitor& visitor_;
Chris@16: 
Chris@16: public: // structors
Chris@16: 
Chris@101:     explicit apply_visitor_delayed_t(Visitor& visitor) BOOST_NOEXCEPT
Chris@16:       : visitor_(visitor)
Chris@16:     {
Chris@16:     }
Chris@16: 
Chris@101: #if !defined(BOOST_VARIANT_DO_NOT_USE_VARIADIC_TEMPLATES)
Chris@101: 
Chris@101: public: // N-ary visitor interface
Chris@101:     template <typename... Visitables>
Chris@101:         BOOST_VARIANT_AUX_GENERIC_RESULT_TYPE(result_type)
Chris@101:     operator()(Visitables&... visitables) const
Chris@101:     {
Chris@101:         return apply_visitor(visitor_, visitables...);
Chris@101:     }
Chris@101: 
Chris@101: #else // !defined(BOOST_VARIANT_DO_NOT_USE_VARIADIC_TEMPLATES)
Chris@101: 
Chris@16: public: // unary visitor interface
Chris@16: 
Chris@16:     template <typename Visitable>
Chris@16:         BOOST_VARIANT_AUX_GENERIC_RESULT_TYPE(result_type)
Chris@16:     operator()(Visitable& visitable) const
Chris@16:     {
Chris@16:         return apply_visitor(visitor_, visitable);
Chris@16:     }
Chris@16: 
Chris@16: public: // binary visitor interface
Chris@16: 
Chris@16:     template <typename Visitable1, typename Visitable2>
Chris@16:         BOOST_VARIANT_AUX_GENERIC_RESULT_TYPE(result_type)
Chris@16:     operator()(Visitable1& visitable1, Visitable2& visitable2) const
Chris@16:     {
Chris@16:         return apply_visitor(visitor_, visitable1, visitable2);
Chris@16:     }
Chris@16: 
Chris@101: #endif // !defined(BOOST_VARIANT_DO_NOT_USE_VARIADIC_TEMPLATES)
Chris@101: 
Chris@16: private:
Chris@16:     apply_visitor_delayed_t& operator=(const apply_visitor_delayed_t&);
Chris@16: 
Chris@16: };
Chris@16: 
Chris@16: template <typename Visitor>
Chris@101: inline typename boost::enable_if<
Chris@101:         boost::detail::variant::has_result_type<Visitor>,
Chris@101:         apply_visitor_delayed_t<Visitor>
Chris@101:     >::type apply_visitor(Visitor& visitor)
Chris@16: {
Chris@16:     return apply_visitor_delayed_t<Visitor>(visitor);
Chris@16: }
Chris@16: 
Chris@101: #if !defined(BOOST_NO_CXX14_DECLTYPE_AUTO) && !defined(BOOST_NO_CXX11_DECLTYPE_N3276) \
Chris@101:     && !defined(BOOST_VARIANT_DO_NOT_USE_VARIADIC_TEMPLATES)
Chris@101: 
Chris@101: template <typename Visitor>
Chris@101: class apply_visitor_delayed_cpp14_t
Chris@101: {
Chris@101: private: // representation
Chris@101:     Visitor& visitor_;
Chris@101: 
Chris@101: public: // structors
Chris@101: 
Chris@101:     explicit apply_visitor_delayed_cpp14_t(Visitor& visitor) BOOST_NOEXCEPT
Chris@101:       : visitor_(visitor)
Chris@101:     {
Chris@101:     }
Chris@101: 
Chris@101: public: // N-ary visitor interface
Chris@101:     template <typename... Visitables>
Chris@101:     decltype(auto) operator()(Visitables&... visitables) const
Chris@101:     {
Chris@101:         return apply_visitor(visitor_, visitables...);
Chris@101:     }
Chris@101: 
Chris@101: private:
Chris@101:     apply_visitor_delayed_cpp14_t& operator=(const apply_visitor_delayed_cpp14_t&);
Chris@101: 
Chris@101: };
Chris@101: 
Chris@101: template <typename Visitor>
Chris@101: inline  typename boost::disable_if<
Chris@101:         boost::detail::variant::has_result_type<Visitor>,
Chris@101:         apply_visitor_delayed_cpp14_t<Visitor>
Chris@101:     >::type apply_visitor(Visitor& visitor)
Chris@101: {
Chris@101:     return apply_visitor_delayed_cpp14_t<Visitor>(visitor);
Chris@101: }
Chris@101: 
Chris@101: #endif // !defined(BOOST_NO_CXX14_DECLTYPE_AUTO) && !defined(BOOST_NO_CXX11_DECLTYPE_N3276)
Chris@101:             // && !defined(BOOST_VARIANT_DO_NOT_USE_VARIADIC_TEMPLATES)
Chris@101: 
Chris@101: 
Chris@16: } // namespace boost
Chris@16: 
Chris@16: #endif // BOOST_VARIANT_DETAIL_APPLY_VISITOR_DELAYED_HPP