[857] | 1 | //-----------------------------------------------------------------------------
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| 2 | // boost variant/detail/apply_visitor_delayed.hpp header file
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| 3 | // See http://www.boost.org for updates, documentation, and revision history.
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| 4 | //-----------------------------------------------------------------------------
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| 5 | //
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| 6 | // Copyright (c) 2002-2003
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| 7 | // Eric Friedman
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| 8 | //
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| 9 | // Distributed under the Boost Software License, Version 1.0. (See
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| 10 | // accompanying file LICENSE_1_0.txt or copy at
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| 11 | // http://www.boost.org/LICENSE_1_0.txt)
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| 12 |
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| 13 | #ifndef BOOST_VARIANT_DETAIL_APPLY_VISITOR_DELAYED_HPP
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| 14 | #define BOOST_VARIANT_DETAIL_APPLY_VISITOR_DELAYED_HPP
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| 15 |
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| 16 | #include "boost/variant/detail/generic_result_type.hpp"
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| 17 |
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| 18 | #include "boost/variant/detail/apply_visitor_unary.hpp"
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| 19 | #include "boost/variant/detail/apply_visitor_binary.hpp"
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| 20 |
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| 21 | namespace boost {
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| 22 |
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| 23 | //////////////////////////////////////////////////////////////////////////
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| 24 | // function template apply_visitor(visitor)
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| 25 | //
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| 26 | // Returns a function object, overloaded for unary and binary usage, that
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| 27 | // visits its arguments using visitor (or a copy of visitor) via
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| 28 | // * apply_visitor( visitor, [argument] )
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| 29 | // under unary invocation, or
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| 30 | // * apply_visitor( visitor, [argument1], [argument2] )
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| 31 | // under binary invocation.
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| 32 | //
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| 33 | // NOTE: Unlike other apply_visitor forms, the visitor object must be
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| 34 | // non-const; this prevents user from giving temporary, to disastrous
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| 35 | // effect (i.e., returned function object would have dead reference).
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| 36 | //
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| 37 |
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| 38 | template <typename Visitor>
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| 39 | class apply_visitor_delayed_t
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| 40 | {
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| 41 | public: // visitor typedefs
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| 42 |
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| 43 | typedef typename Visitor::result_type
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| 44 | result_type;
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| 45 |
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| 46 | private: // representation
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| 47 |
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| 48 | Visitor& visitor_;
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| 49 |
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| 50 | public: // structors
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| 51 |
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| 52 | explicit apply_visitor_delayed_t(Visitor& visitor)
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| 53 | : visitor_(visitor)
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| 54 | {
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| 55 | }
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| 56 |
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| 57 | public: // unary visitor interface
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| 58 |
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| 59 | template <typename Visitable>
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| 60 | BOOST_VARIANT_AUX_GENERIC_RESULT_TYPE(result_type)
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| 61 | operator()(Visitable& visitable)
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| 62 | {
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| 63 | return apply_visitor(visitor_, visitable);
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| 64 | }
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| 65 |
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| 66 | public: // binary visitor interface
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| 67 |
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| 68 | template <typename Visitable1, typename Visitable2>
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| 69 | BOOST_VARIANT_AUX_GENERIC_RESULT_TYPE(result_type)
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| 70 | operator()(Visitable1& visitable1, Visitable2& visitable2)
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| 71 | {
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| 72 | return apply_visitor(visitor_, visitable1, visitable2);
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| 73 | }
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| 74 |
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| 75 | };
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| 76 |
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| 77 | template <typename Visitor>
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| 78 | inline apply_visitor_delayed_t<Visitor> apply_visitor(Visitor& visitor)
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| 79 | {
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| 80 | return apply_visitor_delayed_t<Visitor>(visitor);
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| 81 | }
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| 82 |
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| 83 | } // namespace boost
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| 84 |
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| 85 | #endif // BOOST_VARIANT_DETAIL_APPLY_VISITOR_DELAYED_HPP
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