43 lines
1.2 KiB
C++
43 lines
1.2 KiB
C++
#ifndef RFL_INTERNAL_DEFINEVARIANT_HPP_
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#define RFL_INTERNAL_DEFINEVARIANT_HPP_
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#include <variant>
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namespace rfl {
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namespace internal {
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/// Allows you to combine several variants.
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template <class... Vars>
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struct define_variant;
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/// Recursive case - both variants.
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template <class... Vars1, class... Vars2, class... Tail>
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struct define_variant<std::variant<Vars1...>, std::variant<Vars2...>, Tail...> {
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using type = typename define_variant<std::variant<Vars1..., Vars2...>,
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Tail...>::type;
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};
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/// Recursive case - variant plus other type.
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template <class... Vars, class Head, class... Tail>
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struct define_variant<std::variant<Vars...>, Head, Tail...> {
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using type =
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typename define_variant<std::variant<Vars..., Head>, Tail...>::type;
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};
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/// Recursive case - other type.
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template <class Head, class... Tail>
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struct define_variant<Head, Tail...> {
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using type = typename define_variant<std::variant<Head>, Tail...>::type;
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};
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/// Special case - only a single variant is left.
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template <class... Vars>
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struct define_variant<std::variant<Vars...>> {
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using type = std::variant<Vars...>;
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};
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} // namespace internal
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} // namespace rfl
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#endif
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