forked from Qortal/Brooklyn
44 lines
946 B
C++
44 lines
946 B
C++
#ifndef MAPBOX_UTIL_VARIANT_VISITOR_HPP
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#define MAPBOX_UTIL_VARIANT_VISITOR_HPP
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#include <utility>
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namespace mapbox {
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namespace util {
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template <typename... Fns>
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struct visitor;
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template <typename Fn>
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struct visitor<Fn> : Fn
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{
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using Fn::operator();
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template<typename T>
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visitor(T&& fn) : Fn(std::forward<T>(fn)) {}
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};
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template <typename Fn, typename... Fns>
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struct visitor<Fn, Fns...> : Fn, visitor<Fns...>
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{
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using Fn::operator();
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using visitor<Fns...>::operator();
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template<typename T, typename... Ts>
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visitor(T&& fn, Ts&&... fns)
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: Fn(std::forward<T>(fn))
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, visitor<Fns...>(std::forward<Ts>(fns)...) {}
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};
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template <typename... Fns>
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visitor<typename std::decay<Fns>::type...> make_visitor(Fns&&... fns)
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{
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return visitor<typename std::decay<Fns>::type...>
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(std::forward<Fns>(fns)...);
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}
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} // namespace util
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} // namespace mapbox
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#endif // MAPBOX_UTIL_VARIANT_VISITOR_HPP
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