williamr@2: //-----------------------------------------------------------------------------
williamr@2: // boost variant/detail/apply_visitor_binary.hpp header file
williamr@2: // See http://www.boost.org for updates, documentation, and revision history.
williamr@2: //-----------------------------------------------------------------------------
williamr@2: //
williamr@2: // Copyright (c) 2002-2003
williamr@2: // Eric Friedman
williamr@2: //
williamr@2: // Distributed under the Boost Software License, Version 1.0. (See
williamr@2: // accompanying file LICENSE_1_0.txt or copy at
williamr@2: // http://www.boost.org/LICENSE_1_0.txt)
williamr@2: 
williamr@2: #ifndef BOOST_VARIANT_DETAIL_APPLY_VISITOR_BINARY_HPP
williamr@2: #define BOOST_VARIANT_DETAIL_APPLY_VISITOR_BINARY_HPP
williamr@2: 
williamr@2: #include "boost/config.hpp"
williamr@2: #include "boost/detail/workaround.hpp"
williamr@2: #include "boost/variant/detail/generic_result_type.hpp"
williamr@2: 
williamr@2: #include "boost/variant/detail/apply_visitor_unary.hpp"
williamr@2: 
williamr@2: #include "boost/utility/enable_if.hpp"
williamr@2: 
williamr@2: namespace boost {
williamr@2: 
williamr@2: //////////////////////////////////////////////////////////////////////////
williamr@2: // function template apply_visitor(visitor, visitable1, visitable2)
williamr@2: //
williamr@2: // Visits visitable1 and visitable2 such that their values (which we
williamr@2: // shall call x and y, respectively) are used as arguments in the
williamr@2: // expression visitor(x, y).
williamr@2: //
williamr@2: 
williamr@2: namespace detail { namespace variant {
williamr@2: 
williamr@2: template <typename Visitor, typename Value1>
williamr@2: class apply_visitor_binary_invoke
williamr@2: {
williamr@2: public: // visitor typedefs
williamr@2: 
williamr@2:     typedef typename Visitor::result_type
williamr@2:         result_type;
williamr@2: 
williamr@2: private: // representation
williamr@2: 
williamr@2:     Visitor& visitor_;
williamr@2:     Value1& value1_;
williamr@2: 
williamr@2: public: // structors
williamr@2: 
williamr@2:     apply_visitor_binary_invoke(Visitor& visitor, Value1& value1)
williamr@2:         : visitor_(visitor)
williamr@2:         , value1_(value1)
williamr@2:     {
williamr@2:     }
williamr@2: 
williamr@2: public: // visitor interfaces
williamr@2: 
williamr@2:     template <typename Value2>
williamr@2:         BOOST_VARIANT_AUX_GENERIC_RESULT_TYPE(result_type)
williamr@2:     operator()(Value2& value2)
williamr@2:     {
williamr@2:         return visitor_(value1_, value2);
williamr@2:     }
williamr@2: 
williamr@2: };
williamr@2: 
williamr@2: template <typename Visitor, typename Visitable2>
williamr@2: class apply_visitor_binary_unwrap
williamr@2: {
williamr@2: public: // visitor typedefs
williamr@2: 
williamr@2:     typedef typename Visitor::result_type
williamr@2:         result_type;
williamr@2: 
williamr@2: private: // representation
williamr@2: 
williamr@2:     Visitor& visitor_;
williamr@2:     Visitable2& visitable2_;
williamr@2: 
williamr@2: public: // structors
williamr@2: 
williamr@2:     apply_visitor_binary_unwrap(Visitor& visitor, Visitable2& visitable2)
williamr@2:         : visitor_(visitor)
williamr@2:         , visitable2_(visitable2)
williamr@2:     {
williamr@2:     }
williamr@2: 
williamr@2: public: // visitor interfaces
williamr@2: 
williamr@2:     template <typename Value1>
williamr@2:         BOOST_VARIANT_AUX_GENERIC_RESULT_TYPE(result_type)
williamr@2:     operator()(Value1& value1)
williamr@2:     {
williamr@2:         apply_visitor_binary_invoke<
williamr@2:               Visitor
williamr@2:             , Value1
williamr@2:             > invoker(visitor_, value1);
williamr@2: 
williamr@2:         return boost::apply_visitor(invoker, visitable2_);
williamr@2:     }
williamr@2: 
williamr@2: };
williamr@2: 
williamr@2: }} // namespace detail::variant
williamr@2: 
williamr@2: //
williamr@2: // nonconst-visitor version:
williamr@2: //
williamr@2: 
williamr@2: #if !BOOST_WORKAROUND(__EDG__, BOOST_TESTED_AT(302))
williamr@2: 
williamr@2: #   define BOOST_VARIANT_AUX_APPLY_VISITOR_NON_CONST_RESULT_TYPE(V) \
williamr@2:     BOOST_VARIANT_AUX_GENERIC_RESULT_TYPE(typename V::result_type) \
williamr@2:     /**/
williamr@2: 
williamr@2: #else // EDG-based compilers
williamr@2: 
williamr@2: #   define BOOST_VARIANT_AUX_APPLY_VISITOR_NON_CONST_RESULT_TYPE(V) \
williamr@2:     typename enable_if< \
williamr@2:           mpl::not_< is_const< V > > \
williamr@2:         , BOOST_VARIANT_AUX_GENERIC_RESULT_TYPE(typename V::result_type) \
williamr@2:         >::type \
williamr@2:     /**/
williamr@2: 
williamr@2: #endif // EDG-based compilers workaround
williamr@2: 
williamr@2: template <typename Visitor, typename Visitable1, typename Visitable2>
williamr@2: inline
williamr@2:     BOOST_VARIANT_AUX_APPLY_VISITOR_NON_CONST_RESULT_TYPE(Visitor)
williamr@2: apply_visitor(
williamr@2:       Visitor& visitor
williamr@2:     , Visitable1& visitable1, Visitable2& visitable2
williamr@2:     )
williamr@2: {
williamr@2:     ::boost::detail::variant::apply_visitor_binary_unwrap<
williamr@2:           Visitor, Visitable2
williamr@2:         > unwrapper(visitor, visitable2);
williamr@2: 
williamr@2:     return boost::apply_visitor(unwrapper, visitable1);
williamr@2: }
williamr@2: 
williamr@2: #undef BOOST_VARIANT_AUX_APPLY_VISITOR_NON_CONST_RESULT_TYPE
williamr@2: 
williamr@2: //
williamr@2: // const-visitor version:
williamr@2: //
williamr@2: 
williamr@2: #if !BOOST_WORKAROUND(BOOST_MSVC, <= 1300)
williamr@2: 
williamr@2: template <typename Visitor, typename Visitable1, typename Visitable2>
williamr@2: inline
williamr@2:     BOOST_VARIANT_AUX_GENERIC_RESULT_TYPE(
williamr@2:           typename Visitor::result_type
williamr@2:         )
williamr@2: apply_visitor(
williamr@2:       const Visitor& visitor
williamr@2:     , Visitable1& visitable1, Visitable2& visitable2
williamr@2:     )
williamr@2: {
williamr@2:     ::boost::detail::variant::apply_visitor_binary_unwrap<
williamr@2:           const Visitor, Visitable2
williamr@2:         > unwrapper(visitor, visitable2);
williamr@2: 
williamr@2:     return boost::apply_visitor(unwrapper, visitable1);
williamr@2: }
williamr@2: 
williamr@2: #endif // MSVC7 and below exclusion
williamr@2: 
williamr@2: } // namespace boost
williamr@2: 
williamr@2: #endif // BOOST_VARIANT_DETAIL_APPLY_VISITOR_BINARY_HPP