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


#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

private: // representation

    Visitor& visitor_;

public: // structors

    explicit apply_visitor_delayed_t(Visitor& visitor)
      : visitor_(visitor)

public: // unary visitor interface

    template <typename Visitable>
    operator()(Visitable& visitable) const
        return apply_visitor(visitor_, visitable);

public: // binary visitor interface

    template <typename Visitable1, typename Visitable2>
    operator()(Visitable1& visitable1, Visitable2& visitable2) const
        return apply_visitor(visitor_, visitable1, visitable2);

    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