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//-----------------------------------------------------------------------------
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// boost variant/detail/apply_visitor_delayed.hpp header file
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// See http://www.boost.org for updates, documentation, and revision history.
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//-----------------------------------------------------------------------------
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//
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// Copyright (c) 2002-2003
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// Eric Friedman
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//
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// Distributed under the Boost Software License, Version 1.0. (See
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// accompanying file LICENSE_1_0.txt or copy at
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// http://www.boost.org/LICENSE_1_0.txt)
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#ifndef BOOST_VARIANT_DETAIL_APPLY_VISITOR_DELAYED_HPP
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#define BOOST_VARIANT_DETAIL_APPLY_VISITOR_DELAYED_HPP
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#include "boost/variant/detail/generic_result_type.hpp"
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#include "boost/variant/detail/apply_visitor_unary.hpp"
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#include "boost/variant/detail/apply_visitor_binary.hpp"
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namespace boost {
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//////////////////////////////////////////////////////////////////////////
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// function template apply_visitor(visitor)
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//
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// Returns a function object, overloaded for unary and binary usage, that
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// visits its arguments using visitor (or a copy of visitor) via
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// * apply_visitor( visitor, [argument] )
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// under unary invocation, or
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// * apply_visitor( visitor, [argument1], [argument2] )
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// under binary invocation.
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//
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// NOTE: Unlike other apply_visitor forms, the visitor object must be
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// non-const; this prevents user from giving temporary, to disastrous
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// effect (i.e., returned function object would have dead reference).
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//
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template <typename Visitor>
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class apply_visitor_delayed_t
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{
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public: // visitor typedefs
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typedef typename Visitor::result_type
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result_type;
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private: // representation
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Visitor& visitor_;
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public: // structors
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explicit apply_visitor_delayed_t(Visitor& visitor)
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: visitor_(visitor)
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{
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}
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public: // unary visitor interface
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template <typename Visitable>
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BOOST_VARIANT_AUX_GENERIC_RESULT_TYPE(result_type)
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operator()(Visitable& visitable)
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{
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return apply_visitor(visitor_, visitable);
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}
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public: // binary visitor interface
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template <typename Visitable1, typename Visitable2>
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BOOST_VARIANT_AUX_GENERIC_RESULT_TYPE(result_type)
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operator()(Visitable1& visitable1, Visitable2& visitable2)
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{
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return apply_visitor(visitor_, visitable1, visitable2);
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}
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};
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template <typename Visitor>
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inline apply_visitor_delayed_t<Visitor> apply_visitor(Visitor& visitor)
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{
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return apply_visitor_delayed_t<Visitor>(visitor);
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}
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} // namespace boost
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#endif // BOOST_VARIANT_DETAIL_APPLY_VISITOR_DELAYED_HPP
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