diff -r d8475431bbbb -r 8e85e6bbefdf lemon/bits/clearable_graph_extender.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/lemon/bits/clearable_graph_extender.h	Mon May 23 04:48:14 2005 +0000
@@ -0,0 +1,49 @@
+// -*- c++ -*-
+
+#ifndef LEMON_CLEARABLE_GRAPH_EXTENDER_H
+#define LEMON_CLEARABLE_GRAPH_EXTENDER_H
+
+#include <lemon/invalid.h>
+
+
+namespace lemon {
+
+  template <typename _Base> 
+  class ClearableGraphExtender : public _Base {
+  public:
+
+    typedef ClearableGraphExtender Graph;
+    typedef _Base Parent;
+    typedef typename Parent::Node Node;
+    typedef typename Parent::Edge Edge;
+
+    void clear() {
+      Parent::getNotifier(Node()).clear();
+      Parent::getNotifier(Edge()).clear();
+      Parent::clear();
+    }
+
+  };
+
+  template <typename _Base> 
+  class ClearableUndirGraphExtender : public _Base {
+  public:
+
+    typedef ClearableUndirGraphExtender Graph;
+    typedef _Base Parent;
+    typedef typename Parent::Node Node;
+    typedef typename Parent::UndirEdge UndirEdge;
+    typedef typename Parent::Edge Edge;
+
+    void clear() {
+      Parent::getNotifier(Node()).clear();
+      Parent::getNotifier(UndirEdge()).clear();
+      Parent::getNotifier(Edge()).clear();
+      Parent::clear();
+    }
+
+  };
+
+}
+
+#endif