diff -r 908a1a6f0752 -r 289d80c33f04 src/lemon/concept/graph.h
--- a/src/lemon/concept/graph.h	Thu Nov 04 21:28:55 2004 +0000
+++ b/src/lemon/concept/graph.h	Thu Nov 04 22:04:51 2004 +0000
@@ -765,26 +765,6 @@
     /************* New GraphBase stuff **************/
 
 
-    /// \bug The nodes and edges are not allowed to inherit from the
-    /// same baseclass.
-
-    class BaseGraphItem {
-    public:
-      BaseGraphItem() {}
-      BaseGraphItem(Invalid) {}
-
-      // We explicitely list these:
-      BaseGraphItem(BaseGraphItem const&) {}
-      BaseGraphItem& operator=(BaseGraphItem const&) { return *this; }
-
-      bool operator==(BaseGraphItem) const { return false; }
-      bool operator!=(BaseGraphItem) const { return false; }
-
-      // Technical requirement. Do we really need this?
-      bool operator<(BaseGraphItem) const { return false; }
-    };
-
-
     /// A minimal GraphBase concept
 
     /// This class describes a minimal concept which can be extended to a
@@ -794,11 +774,14 @@
 
       GraphBase() {}
 
+      /// \bug Should we demand that Node and Edge be subclasses of the
+      /// Graph class???
 
-      /// \bug Nodes and Edges are comparable each other
-      
-      class Node : public BaseGraphItem {};
-      class Edge : public BaseGraphItem {};
+      typedef GraphItem<'n'> Node;
+      typedef GraphItem<'e'> Edge;
+
+//       class Node : public BaseGraphItem<'n'> {};
+//       class Edge : public BaseGraphItem<'e'> {};
 
       // Graph operation
       void firstNode(Node &n) const { }
@@ -840,27 +823,13 @@
 
 
 
-    /**************** Concept checking classes ****************/
 
-    template<typename BGI>
-    struct BaseGraphItemConcept {
-      void constraints() {
-	BGI i1;
-	BGI i2 = i1;
-	BGI i3 = INVALID;
-	
-	i1 = i3;
-	if( i1 == i3 ) {
-	  if ( i2 != i3 && i3 < i2 )
-	    return;
-	}
-      }
-    };
+    /**************** The full-featured graph concepts ****************/
 
     
-    
     class StaticGraph 
-      :  virtual public BaseGraphComponent, public IterableGraphComponent, public MappableGraphComponent {
+      :  virtual public BaseGraphComponent,
+	 public IterableGraphComponent, public MappableGraphComponent {
     public:
       typedef BaseGraphComponent::Node Node;
       typedef BaseGraphComponent::Edge Edge;
@@ -869,15 +838,14 @@
     template <typename Graph>
     struct StaticGraphConcept {
       void constraints() {
-	function_requires<BaseGraphComponentConcept<Graph> >();
 	function_requires<IterableGraphComponentConcept<Graph> >();
 	function_requires<MappableGraphComponentConcept<Graph> >();
       }
-      Graph& graph;
     };
 
     class ExtendableGraph 
-      :  virtual public BaseGraphComponent, public StaticGraph, public ExtendableGraphComponent, public ClearableGraphComponent {
+      :  virtual public BaseGraphComponent, public StaticGraph,
+	 public ExtendableGraphComponent, public ClearableGraphComponent {
     public:
       typedef BaseGraphComponent::Node Node;
       typedef BaseGraphComponent::Edge Edge;
@@ -890,11 +858,11 @@
 	function_requires<ExtendableGraphComponentConcept<Graph> >();
 	function_requires<ClearableGraphComponentConcept<Graph> >();
       }
-      Graph& graph;
     };
 
     class ErasableGraph 
-      :  virtual public BaseGraphComponent, public ExtendableGraph, public ErasableGraphComponent {
+      :  virtual public BaseGraphComponent, public ExtendableGraph,
+	 public ErasableGraphComponent {
     public:
       typedef BaseGraphComponent::Node Node;
       typedef BaseGraphComponent::Edge Edge;
@@ -906,7 +874,6 @@
 	function_requires<ExtendableGraphConcept<Graph> >();
 	function_requires<ErasableGraphComponentConcept<Graph> >();
       }
-      Graph& graph;
     };
 
     // @}