C++ 宇宙飞船算子多级比较？

Question

Does the new C++20 spaceship operator allow a concise way of expressing short-circuited multiple-criteria comparison? Something better than this:

const firstCriteriaComparisonResult = lhs.x <=> rhs.x;
return firstCriteriaComparisonResult != 0 ? firstCriteriaComparisonResult : lhs.y <=> rhs.y;

Answer 1

The usual tie -and-compare approach works with spaceship too:

return std::tie(lhs.x, lhs.y) <=> std::tie(rhs.x, rhs.y);