public:

struct Mate {

int plies;

};

struct Tablebase {

int plies;

bool win;

};

struct InternalUnits {

int value;

};

Score() : score(InternalUnits{ VALUE_ZERO }) {};

Score(Value v);

template <typename T> bool is() const { return std::holds_alternative<T>(score); }

template <typename T> T get() const { return std::get<T>(score); }

template <typename F> decltype(auto) visit(F &&f) const { return std::visit(std::forward<F>(f), score); }

private:

std::variant<Mate, Tablebase, InternalUnits> score;