RhodeCode

    using Parent::first;

    using Parent::next;

    using Parent::id;

    class Red : public Node {

      friend class BidirBpGraphExtender;

    public:

      Red() {}

      Red(const Node& node) : Node(node) {

                     typename Parent::NodeSetError());

      }

      Red& operator=(const Node& node) {

                     typename Parent::NodeSetError());

        Node::operator=(node);

        return *this;

      }

      Red(Invalid) : Node(INVALID) {}

      Red& operator=(Invalid) {

        Node::operator=(INVALID);

        return *this;

      }

    };

    void first(Red& node) const {

      Parent::nextRed(static_cast<Node&>(node));

    }

    int id(const Red& node) const {

      return Parent::redId(node);

    }

    class Blue : public Node {

      friend class BidirBpGraphExtender;

    public:

      Blue() {}

      Blue(const Node& node) : Node(node) {

                     typename Parent::NodeSetError());

      }

      Blue& operator=(const Node& node) {

                     typename Parent::NodeSetError());

        Node::operator=(node);

        return *this;

      }

      Blue(Invalid) : Node(INVALID) {}

      Blue& operator=(Invalid) {

        Node::operator=(INVALID);

        return *this;

      }

    };

    void first(Blue& node) const {