| //----------------------------------------------------------------------------- |
| // 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); |
| } |
| |
| private: |
| apply_visitor_delayed_t& operator=(const apply_visitor_delayed_t&); |
| |
| }; |
| |
| 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 |