diff -r 4ea2147274db -r d4acebef7276 src/lemon/bits/extendable_graph_extender.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/lemon/bits/extendable_graph_extender.h	Tue Apr 05 12:30:46 2005 +0000
@@ -0,0 +1,65 @@
+// -*- c++ -*-
+
+#ifndef LEMON_EXTENDABLE_GRAPH_EXTENDER_H
+#define LEMON_EXTENDABLE_GRAPH_EXTENDER_H
+
+namespace lemon {
+
+  template <typename _Base> 
+  class ExtendableGraphExtender : public _Base {
+  public:
+
+    typedef ExtendableGraphExtender Graph;
+    typedef _Base Parent;
+
+    typedef typename Parent::Node Node;
+    typedef typename Parent::Edge Edge;
+
+    Node addNode() {
+      Node node = Parent::addNode();
+      Parent::getNotifier(Node()).add(node);
+      return node;
+    }
+    
+    Edge addEdge(const Node& from, const Node& to) {
+      Edge edge = Parent::addEdge(from, to);
+      Parent::getNotifier(Edge()).add(edge);
+      return edge;
+    }
+
+  };
+
+  template <typename _Base> 
+  class ExtendableUndirGraphExtender : public _Base {
+  public:
+
+    typedef ExtendableUndirGraphExtender Graph;
+    typedef _Base Parent;
+
+    typedef typename Parent::Node Node;
+    typedef typename Parent::Edge Edge;
+    typedef typename Parent::UndirEdge UndirEdge;
+
+    Node addNode() {
+      Node node = Parent::addNode();
+      Parent::getNotifier(Node()).add(node);
+      return node;
+    }
+
+    UndirEdge addEdge(const Node& from, const Node& to) {
+      UndirEdge uedge = Parent::addEdge(from, to);
+      Parent::getNotifier(UndirEdge()).add(uedge);
+
+      Edge edge_forward(uedge, true);
+      Edge edge_backward(uedge, false);
+      Parent::getNotifier(Edge()).add(edge_forward);
+      Parent::getNotifier(Edge()).add(edge_backward);
+
+      return uedge;
+    }
+
+  };
+
+}
+
+#endif