//-----------------------------------------------------------------------------

 // boost variant/detail/apply_visitor_delayed.hpp header file

 // See http://www.boost.org for updates, documentation, and revision history.

 //-----------------------------------------------------------------------------

 //

 // Copyright (c) 2002-2003

 // 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_APPLY_VISITOR_DELAYED_HPP

 #define BOOST_VARIANT_DETAIL_APPLY_VISITOR_DELAYED_HPP

 #include "boost/variant/detail/generic_result_type.hpp"

 #include "boost/variant/detail/apply_visitor_unary.hpp"

 #include "boost/variant/detail/apply_visitor_binary.hpp"

 namespace boost {

 //////////////////////////////////////////////////////////////////////////

 // function template apply_visitor(visitor)

 //

 // Returns a function object, overloaded for unary and binary usage, that

 // visits its arguments using visitor (or a copy of visitor) via

 //  * apply_visitor( visitor, [argument] )

 // under unary invocation, or

 //  * apply_visitor( visitor, [argument1], [argument2] )

 // under binary invocation.

 //

 // NOTE: Unlike other apply_visitor forms, the visitor object must be

 //   non-const; this prevents user from giving temporary, to disastrous

 //   effect (i.e., returned function object would have dead reference).

 //

 template <typename Visitor>

 class apply_visitor_delayed_t

 {

 public: // visitor typedefs

     typedef typename Visitor::result_type

         result_type;

 private: // representation

     Visitor& visitor_;

 public: // structors

     explicit apply_visitor_delayed_t(Visitor& visitor)

       : visitor_(visitor)

     {

     }

 public: // unary visitor interface

     template <typename Visitable>

         BOOST_VARIANT_AUX_GENERIC_RESULT_TYPE(result_type)

     operator()(Visitable& visitable)

     {

         return apply_visitor(visitor_, visitable);

     }

 public: // binary visitor interface

     template <typename Visitable1, typename Visitable2>

         BOOST_VARIANT_AUX_GENERIC_RESULT_TYPE(result_type)

     operator()(Visitable1& visitable1, Visitable2& visitable2)

     {

         return apply_visitor(visitor_, visitable1, visitable2);

     }

 };

 template <typename Visitor>

 inline apply_visitor_delayed_t<Visitor> apply_visitor(Visitor& visitor)

 {

     return apply_visitor_delayed_t<Visitor>(visitor);

 }

 } // namespace boost

 #endif // BOOST_VARIANT_DETAIL_APPLY_VISITOR_DELAYED_HPP