// -*- c++ -*-

 #ifndef LEMON_ERASABLE_GRAPH_EXTENDER_H

 #define LEMON_ERASABLE_GRAPH_EXTENDER_H

 #include <lemon/invalid.h>

 namespace lemon {

   template <typename _Base> 

   class ErasableGraphExtender : public _Base {

   public:

     typedef ErasableGraphExtender Graph;

     typedef _Base Parent;

     typedef typename Parent::Node Node;

     typedef typename Parent::Edge Edge;

     void erase(const Node& node) {

       Edge edge;

       Parent::firstOut(edge, node);

       while (edge != INVALID ) {

 	erase(edge);

 	Parent::firstOut(edge, node);

       } 

       Parent::firstIn(edge, node);

       while (edge != INVALID ) {

 	erase(edge);

 	Parent::firstIn(edge, node);

       }

       Parent::getObserverRegistry(Node()).erase(node);

       Parent::erase(node);

     }

     void erase(const Edge& edge) {

       Parent::getObserverRegistry(Edge()).erase(edge);

       Parent::erase(edge);

     }

   };

 }

 #endif