williamr@2: //-----------------------------------------------------------------------------
williamr@2: // boost variant/detail/apply_visitor_delayed.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_DELAYED_HPP
williamr@2: #define BOOST_VARIANT_DETAIL_APPLY_VISITOR_DELAYED_HPP
williamr@2: 
williamr@2: #include "boost/variant/detail/generic_result_type.hpp"
williamr@2: 
williamr@2: #include "boost/variant/detail/apply_visitor_unary.hpp"
williamr@2: #include "boost/variant/detail/apply_visitor_binary.hpp"
williamr@2: 
williamr@2: namespace boost {
williamr@2: 
williamr@2: //////////////////////////////////////////////////////////////////////////
williamr@2: // function template apply_visitor(visitor)
williamr@2: //
williamr@2: // Returns a function object, overloaded for unary and binary usage, that
williamr@2: // visits its arguments using visitor (or a copy of visitor) via
williamr@2: //  * apply_visitor( visitor, [argument] )
williamr@2: // under unary invocation, or
williamr@2: //  * apply_visitor( visitor, [argument1], [argument2] )
williamr@2: // under binary invocation.
williamr@2: //
williamr@2: // NOTE: Unlike other apply_visitor forms, the visitor object must be
williamr@2: //   non-const; this prevents user from giving temporary, to disastrous
williamr@2: //   effect (i.e., returned function object would have dead reference).
williamr@2: //
williamr@2: 
williamr@2: template <typename Visitor>
williamr@2: class apply_visitor_delayed_t
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: 
williamr@2: public: // structors
williamr@2: 
williamr@2:     explicit apply_visitor_delayed_t(Visitor& visitor)
williamr@2:       : visitor_(visitor)
williamr@2:     {
williamr@2:     }
williamr@2: 
williamr@2: public: // unary visitor interface
williamr@2: 
williamr@2:     template <typename Visitable>
williamr@2:         BOOST_VARIANT_AUX_GENERIC_RESULT_TYPE(result_type)
williamr@2:     operator()(Visitable& visitable)
williamr@2:     {
williamr@2:         return apply_visitor(visitor_, visitable);
williamr@2:     }
williamr@2: 
williamr@2: public: // binary visitor interface
williamr@2: 
williamr@2:     template <typename Visitable1, typename Visitable2>
williamr@2:         BOOST_VARIANT_AUX_GENERIC_RESULT_TYPE(result_type)
williamr@2:     operator()(Visitable1& visitable1, Visitable2& visitable2)
williamr@2:     {
williamr@2:         return apply_visitor(visitor_, visitable1, visitable2);
williamr@2:     }
williamr@2: 
williamr@2: };
williamr@2: 
williamr@2: template <typename Visitor>
williamr@2: inline apply_visitor_delayed_t<Visitor> apply_visitor(Visitor& visitor)
williamr@2: {
williamr@2:     return apply_visitor_delayed_t<Visitor>(visitor);
williamr@2: }
williamr@2: 
williamr@2: } // namespace boost
williamr@2: 
williamr@2: #endif // BOOST_VARIANT_DETAIL_APPLY_VISITOR_DELAYED_HPP