| 31 | #if 0 |
| 32 | template <typename T> |
| 33 | void Node<T>::balance() |
| 34 | { |
| 35 | using namespace matchit; |
| 36 | |
| 37 | constexpr auto dsN = [](auto &&color, auto &&lhs, auto &&value, auto &&rhs) |
| 38 | { |
| 39 | return and_(app(&Node<T>::color, color), app(&Node<T>::lhs, lhs), |
| 40 | app(&Node<T>::value, value), app(&Node<T>::rhs, rhs)); |
| 41 | }; |
| 42 | |
| 43 | Id<std::shared_ptr<Node<T>>> a, b, c, d; |
| 44 | Id<T> x, y, z; |
| 45 | Id<Node> self; |
| 46 | *this = match(*this)( |
| 47 | pattern | dsN(Black, some(dsN(Red, some(dsN(Red, a, x, b)), y, c)), z, |
| 48 | d) // left-left case |
| 49 | = |
| 50 | [&] |
| 51 | { |
| 52 | return Node{Red, std::make_shared<Node>(Black, *a, *x, *b), *y, |
| 53 | std::make_shared<Node>(Black, *c, *z, *d)}; |
| 54 | }, |
| 55 | pattern | dsN(Black, some(dsN(Red, a, x, some(dsN(Red, b, y, c)))), z, |
| 56 | d) // left-right case |
| 57 | = |
| 58 | [&] |
| 59 | { |
| 60 | return Node{Red, std::make_shared<Node>(Black, *a, *x, *b), *y, |
| 61 | std::make_shared<Node>(Black, *c, *z, *d)}; |
| 62 | }, |
| 63 | pattern | |
| 64 | dsN(Black, a, x, |
| 65 | some(dsN(Red, some(dsN(Red, b, y, c)), z, d))) // right-left case |
| 66 | = |
| 67 | [&] |
| 68 | { |
| 69 | return Node{Red, std::make_shared<Node>(Black, *a, *x, *b), *y, |
| 70 | std::make_shared<Node>(Black, *c, *z, *d)}; |
| 71 | }, |
| 72 | pattern | |
| 73 | dsN(Black, a, x, |
| 74 | some(dsN(Red, b, y, some(dsN(Red, c, z, d))))) // right-right case |
| 75 | = |
| 76 | [&] |
| 77 | { |
| 78 | return Node{Red, std::make_shared<Node>(Black, *a, *x, *b), *y, |
| 79 | std::make_shared<Node>(Black, *c, *z, *d)}; |
| 80 | }, |
| 81 | pattern | self = expr(self) // do nothing |
| 82 | ); |
| 83 | } |
| 84 | |
| 85 | #else |
| 86 | |