#2954: Provide std::conjunction and std::disjunction substitutes

This commit is contained in:
Daniel Krügler 2022-07-02 18:59:49 +02:00
parent c12b4c0cf1
commit 5eeeb317fc

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@ -292,6 +292,32 @@ template <typename T> using type_identity_t = typename type_identity<T>::type;
template <typename T>
using underlying_t = typename std::underlying_type<T>::type;
template <typename...>
struct disjunction;
template <>
struct disjunction<> : std::false_type {};
template <typename P>
struct disjunction<P> : P {};
template <typename P1, typename P2>
struct disjunction<P1, P2> : std::conditional<P1::value, P1, P2>::type {};
template <typename P1, typename P2, typename P3, typename... Pn>
struct disjunction<P1, P2, P3, Pn...>
: std::conditional<P1::value, P1, disjunction<P2, P3, Pn...>>::type {
};
template <typename...>
struct conjunction;
template <>
struct conjunction<> : std::true_type {};
template <typename P>
struct conjunction<P> : P {};
template <typename P1, typename P2>
struct conjunction<P1, P2> : std::conditional<P1::value, P2, P1>::type {};
template <typename P1, typename P2, typename P3, typename... Pn>
struct conjunction<P1, P2, P3, Pn...>
: std::conditional<P1::value, conjunction<P2, P3, Pn...>, P1>::type {
};
struct monostate {
constexpr monostate() {}
};