Changeset 946:c94ef40a22ce in lemon-0.x for src/lemon/skeletons

Timestamp:

10/28/04 00:38:50 (20 years ago)

Author:

Mihaly Barasz

Branch:

default

Phase:

public

Convert:

svn:c9d7d8f5-90d6-0310-b91f-818b3a526b0e/lemon/trunk@1322

Message:

The graph_factory branch (@ 1321) has been merged to trunk.

Location:

src/lemon/skeletons

Files:

• graph.h (modified) (2 diffs)
• graph_component.h (added)
• maps.h (modified) (2 diffs)

src/lemon/skeletons/graph.h

@@ -24 +24 @@
 #include <lemon/invalid.h>
 #include <lemon/skeletons/maps.h>
+#include <lemon/concept_check.h>
+#include <lemon/skeletons/graph_component.h>
 
 namespace lemon {
@@ -31 +33 @@
     /// @{
 
-    /// An empty static graph class.
+//     /// An empty static graph class.
   
-    /// This class provides all the common features of a graph structure,
-    /// however completely without implementations and real data structures
-    /// behind the interface.
-    /// All graph algorithms should compile with this class, but it will not
-    /// run properly, of course.
-    ///
-    /// It can be used for checking the interface compatibility,
-    /// or it can serve as a skeleton of a new graph structure.
-    /// 
-    /// Also, you will find here the full documentation of a certain graph
-    /// feature, the documentation of a real graph imlementation
-    /// like @ref ListGraph or
-    /// @ref SmartGraph will just refer to this structure.
-    ///
-    /// \todo A pages describing the concept of concept description would
-    /// be nice.
-    class StaticGraph
-    {
+//     /// This class provides all the common features of a graph structure,
+//     /// however completely without implementations and real data structures
+//     /// behind the interface.
+//     /// All graph algorithms should compile with this class, but it will not
+//     /// run properly, of course.
+//     ///
+//     /// It can be used for checking the interface compatibility,
+//     /// or it can serve as a skeleton of a new graph structure.
+//     /// 
+//     /// Also, you will find here the full documentation of a certain graph
+//     /// feature, the documentation of a real graph imlementation
+//     /// like @ref ListGraph or
+//     /// @ref SmartGraph will just refer to this structure.
+//     ///
+//     /// \todo A pages describing the concept of concept description would
+//     /// be nice.
+//     class StaticGraph
+//     {
+//     public:
+//       /// Defalult constructor.
+
+//       /// Defalult constructor.
+//       ///
+//       StaticGraph() { }
+//       ///Copy consructor.
+
+// //       ///\todo It is not clear, what we expect from a copy constructor.
+// //       ///E.g. How to assign the nodes/edges to each other? What about maps?
+// //       StaticGraph(const StaticGraph& g) { }
+
+//       /// The base type of node iterators, 
+//       /// or in other words, the trivial node iterator.
+
+//       /// This is the base type of each node iterator,
+//       /// thus each kind of node iterator converts to this.
+//       /// More precisely each kind of node iterator should be inherited 
+//       /// from the trivial node iterator.
+//       class Node {
+//       public:
+//      /// Default constructor
+
+//      /// @warning The default constructor sets the iterator
+//      /// to an undefined value.
+//      Node() { }
+//      /// Copy constructor.
+
+//      /// Copy constructor.
+//      ///
+//      Node(const Node&) { }
+
+//      /// Invalid constructor \& conversion.
+
+//      /// This constructor initializes the iterator to be invalid.
+//      /// \sa Invalid for more details.
+//      Node(Invalid) { }
+//      /// Equality operator
+
+//      /// Two iterators are equal if and only if they point to the
+//      /// same object or both are invalid.
+//      bool operator==(Node) const { return true; }
+
+//      /// Inequality operator
+        
+//      /// \sa operator==(Node n)
+//      ///
+//      bool operator!=(Node) const { return true; }
+
+//      ///Comparison operator.
+
+//      ///This is a strict ordering between the nodes.
+//      ///
+//      ///This ordering can be different from the order in which NodeIt
+//      ///goes through the nodes.
+//      ///\todo Possibly we don't need it.
+//      bool operator<(Node) const { return true; }
+//       };
+    
+//       /// This iterator goes through each node.
+
+//       /// This iterator goes through each node.
+//       /// Its usage is quite simple, for example you can count the number
+//       /// of nodes in graph \c g of type \c Graph like this:
+//       /// \code
+//       /// int count=0;
+//       /// for (Graph::NodeIt n(g); n!=INVALID ++n) ++count;
+//       /// \endcode
+//       class NodeIt : public Node {
+//       public:
+//      /// Default constructor
+
+//      /// @warning The default constructor sets the iterator
+//      /// to an undefined value.
+//      NodeIt() { }
+//      /// Copy constructor.
+        
+//      /// Copy constructor.
+//      ///
+//      NodeIt(const NodeIt&) { }
+//      /// Invalid constructor \& conversion.
+
+//      /// Initialize the iterator to be invalid.
+//      /// \sa Invalid for more details.
+//      NodeIt(Invalid) { }
+//      /// Sets the iterator to the first node.
+
+//      /// Sets the iterator to the first node of \c g.
+//      ///
+//      NodeIt(const StaticGraph& g) { }
+//      /// Node -> NodeIt conversion.
+
+//      /// Sets the iterator to the node of \c g pointed by the trivial 
+//      /// iterator n.
+//      /// This feature necessitates that each time we 
+//      /// iterate the edge-set, the iteration order is the same.
+//      NodeIt(const StaticGraph& g, const Node& n) { }
+//      /// Next node.
+
+//      /// Assign the iterator to the next node.
+//      ///
+//      NodeIt& operator++() { return *this; }
+//       };
+    
+    
+//       /// The base type of the edge iterators.
+
+//       /// The base type of the edge iterators.
+//       ///
+//       class Edge {
+//       public:
+//      /// Default constructor
+
+//      /// @warning The default constructor sets the iterator
+//      /// to an undefined value.
+//      Edge() { }
+//      /// Copy constructor.
+
+//      /// Copy constructor.
+//      ///
+//      Edge(const Edge&) { }
+//      /// Initialize the iterator to be invalid.
+
+//      /// Initialize the iterator to be invalid.
+//      ///
+//      Edge(Invalid) { }
+//      /// Equality operator
+
+//      /// Two iterators are equal if and only if they point to the
+//      /// same object or both are invalid.
+//      bool operator==(Edge) const { return true; }
+//      /// Inequality operator
+
+//      /// \sa operator==(Node n)
+//      ///
+//      bool operator!=(Edge) const { return true; }
+//      ///Comparison operator.
+
+//      ///This is a strict ordering between the nodes.
+//      ///
+//      ///This ordering can be different from the order in which NodeIt
+//      ///goes through the nodes.
+//      ///\todo Possibly we don't need it.
+//      bool operator<(Edge) const { return true; }
+//       };
+    
+//       /// This iterator goes trough the outgoing edges of a node.
+
+//       /// This iterator goes trough the \e outgoing edges of a certain node
+//       /// of a graph.
+//       /// Its usage is quite simple, for example you can count the number
+//       /// of outgoing edges of a node \c n
+//       /// in graph \c g of type \c Graph as follows.
+//       /// \code
+//       /// int count=0;
+//       /// for (Graph::OutEdgeIt e(g, n); e!=INVALID; ++e) ++count;
+//       /// \endcode
+    
+//       class OutEdgeIt : public Edge {
+//       public:
+//      /// Default constructor
+
+//      /// @warning The default constructor sets the iterator
+//      /// to an undefined value.
+//      OutEdgeIt() { }
+//      /// Copy constructor.
+
+//      /// Copy constructor.
+//      ///
+//      OutEdgeIt(const OutEdgeIt&) { }
+//      /// Initialize the iterator to be invalid.
+
+//      /// Initialize the iterator to be invalid.
+//      ///
+//      OutEdgeIt(Invalid) { }
+//      /// This constructor sets the iterator to first outgoing edge.
+    
+//      /// This constructor set the iterator to the first outgoing edge of
+//      /// node
+//      ///@param n the node
+//      ///@param g the graph
+//      OutEdgeIt(const StaticGraph& g, const Node& n) { }
+//      /// Edge -> OutEdgeIt conversion
+
+//      /// Sets the iterator to the value of the trivial iterator \c e.
+//      /// This feature necessitates that each time we 
+//      /// iterate the edge-set, the iteration order is the same.
+//      OutEdgeIt(const StaticGraph& g, const Edge& e) { }
+//      ///Next outgoing edge
+        
+//      /// Assign the iterator to the next 
+//      /// outgoing edge of the corresponding node.
+//      OutEdgeIt& operator++() { return *this; }
+//       };
+
+//       /// This iterator goes trough the incoming edges of a node.
+
+//       /// This iterator goes trough the \e incoming edges of a certain node
+//       /// of a graph.
+//       /// Its usage is quite simple, for example you can count the number
+//       /// of outgoing edges of a node \c n
+//       /// in graph \c g of type \c Graph as follows.
+//       /// \code
+//       /// int count=0;
+//       /// for(Graph::InEdgeIt e(g, n); e!=INVALID; ++e) ++count;
+//       /// \endcode
+
+//       class InEdgeIt : public Edge {
+//       public:
+//      /// Default constructor
+
+//      /// @warning The default constructor sets the iterator
+//      /// to an undefined value.
+//      InEdgeIt() { }
+//      /// Copy constructor.
+
+//      /// Copy constructor.
+//      ///
+//      InEdgeIt(const InEdgeIt&) { }
+//      /// Initialize the iterator to be invalid.
+
+//      /// Initialize the iterator to be invalid.
+//      ///
+//      InEdgeIt(Invalid) { }
+//      /// This constructor sets the iterator to first incoming edge.
+    
+//      /// This constructor set the iterator to the first incoming edge of
+//      /// node
+//      ///@param n the node
+//      ///@param g the graph
+//      InEdgeIt(const StaticGraph& g, const Node& n) { }
+//      /// Edge -> InEdgeIt conversion
+
+//      /// Sets the iterator to the value of the trivial iterator \c e.
+//      /// This feature necessitates that each time we 
+//      /// iterate the edge-set, the iteration order is the same.
+//      InEdgeIt(const StaticGraph& g, const Edge& n) { }
+//      /// Next incoming edge
+
+//      /// Assign the iterator to the next inedge of the corresponding node.
+//      ///
+//      InEdgeIt& operator++() { return *this; }
+//       };
+//       /// This iterator goes through each edge.
+
+//       /// This iterator goes through each edge of a graph.
+//       /// Its usage is quite simple, for example you can count the number
+//       /// of edges in a graph \c g of type \c Graph as follows:
+//       /// \code
+//       /// int count=0;
+//       /// for(Graph::EdgeIt e(g); e!=INVALID; ++e) ++count;
+//       /// \endcode
+//       class EdgeIt : public Edge {
+//       public:
+//      /// Default constructor
+
+//      /// @warning The default constructor sets the iterator
+//      /// to an undefined value.
+//      EdgeIt() { }
+//      /// Copy constructor.
+
+//      /// Copy constructor.
+//      ///
+//      EdgeIt(const EdgeIt&) { }
+//      /// Initialize the iterator to be invalid.
+
+//      /// Initialize the iterator to be invalid.
+//      ///
+//      EdgeIt(Invalid) { }
+//      /// This constructor sets the iterator to first edge.
+    
+//      /// This constructor set the iterator to the first edge of
+//      /// node
+//      ///@param g the graph
+//      EdgeIt(const StaticGraph& g) { }
+//      /// Edge -> EdgeIt conversion
+
+//      /// Sets the iterator to the value of the trivial iterator \c e.
+//      /// This feature necessitates that each time we 
+//      /// iterate the edge-set, the iteration order is the same.
+//      EdgeIt(const StaticGraph&, const Edge&) { } 
+//      ///Next edge
+        
+//      /// Assign the iterator to the next 
+//      /// edge of the corresponding node.
+//      EdgeIt& operator++() { return *this; }
+//       };
+
+//       /// First node of the graph.
+
+//       /// \retval i the first node.
+//       /// \return the first node.
+//       ///
+//       NodeIt& first(NodeIt& i) const { return i; }
+
+//       /// The first incoming edge.
+
+//       /// The first incoming edge.
+//       ///
+//       InEdgeIt& first(InEdgeIt &i, Node) const { return i; }
+//       /// The first outgoing edge.
+
+//       /// The first outgoing edge.
+//       ///
+//       OutEdgeIt& first(OutEdgeIt& i, Node) const { return i; }
+//       /// The first edge of the Graph.
+
+//       /// The first edge of the Graph.
+//       ///
+//       EdgeIt& first(EdgeIt& i) const { return i; }
+
+//       ///Gives back the head node of an edge.
+
+//       ///Gives back the head node of an edge.
+//       ///
+//       Node head(Edge) const { return INVALID; }
+//       ///Gives back the tail node of an edge.
+
+//       ///Gives back the tail node of an edge.
+//       ///
+//       Node tail(Edge) const { return INVALID; }
+  
+//       ///Gives back the \e id of a node.
+
+//       ///\warning Not all graph structures provide this feature.
+//       ///
+//       ///\todo Should each graph provide \c id?
+//       int id(const Node&) const { return 0; }
+//       ///Gives back the \e id of an edge.
+
+//       ///\warning Not all graph structures provide this feature.
+//       ///
+//       ///\todo Should each graph provide \c id?
+//       int id(const Edge&) const { return 0; }
+
+//       ///\e
+      
+//       ///\todo Should it be in the concept?
+//       ///
+//       int nodeNum() const { return 0; }
+//       ///\e
+
+//       ///\todo Should it be in the concept?
+//       ///
+//       int edgeNum() const { return 0; }
+
+
+//       ///Reference map of the nodes to type \c T.
+
+//       /// \ingroup skeletons
+//       ///Reference map of the nodes to type \c T.
+//       /// \sa Reference
+//       /// \warning Making maps that can handle bool type (NodeMap<bool>)
+//       /// needs some extra attention!
+//       template<class T> class NodeMap : public ReferenceMap< Node, T >
+//       {
+//       public:
+
+//      ///\e
+//      NodeMap(const StaticGraph&) { }
+//      ///\e
+//      NodeMap(const StaticGraph&, T) { }
+
+//      ///Copy constructor
+//      template<typename TT> NodeMap(const NodeMap<TT>&) { }
+//      ///Assignment operator
+//      template<typename TT> NodeMap& operator=(const NodeMap<TT>&)
+//      { return *this; }
+//       };
+
+//       ///Reference map of the edges to type \c T.
+
+//       /// \ingroup skeletons
+//       ///Reference map of the edges to type \c T.
+//       /// \sa Reference
+//       /// \warning Making maps that can handle bool type (EdgeMap<bool>)
+//       /// needs some extra attention!
+//       template<class T> class EdgeMap
+//      : public ReferenceMap<Edge,T>
+//       {
+//       public:
+
+//      ///\e
+//      EdgeMap(const StaticGraph&) { }
+//      ///\e
+//      EdgeMap(const StaticGraph&, T) { }
+    
+//      ///Copy constructor
+//      template<typename TT> EdgeMap(const EdgeMap<TT>&) { }
+//      ///Assignment operator
+//      template<typename TT> EdgeMap &operator=(const EdgeMap<TT>&)
+//      { return *this; }
+//       };
+//     };
+
+//     struct DummyType {
+//       int value;
+//       DummyType() {}
+//       DummyType(int p) : value(p) {}
+//       DummyType& operator=(int p) { value = p; return *this;}
+//     };
+    
+//     ///\brief Checks whether \c G meets the
+//     ///\ref lemon::skeleton::StaticGraph "StaticGraph" concept
+//     template<class Graph> void checkCompileStaticGraph(Graph &G) 
+//     {
+//       typedef typename Graph::Node Node;
+//       typedef typename Graph::NodeIt NodeIt;
+//       typedef typename Graph::Edge Edge;
+//       typedef typename Graph::EdgeIt EdgeIt;
+//       typedef typename Graph::InEdgeIt InEdgeIt;
+//       typedef typename Graph::OutEdgeIt OutEdgeIt;
+  
+//       {
+//      Node i; Node j(i); Node k(INVALID);
+//      i=j;
+//      bool b; b=true;
+//      b=(i==INVALID); b=(i!=INVALID);
+//      b=(i==j); b=(i!=j); b=(i<j);
+//       }
+//       {
+//      NodeIt i; NodeIt j(i); NodeIt k(INVALID); NodeIt l(G);
+//      i=j;
+//      j=G.first(i);
+//      j=++i;
+//      bool b; b=true;
+//      b=(i==INVALID); b=(i!=INVALID);
+//      Node n(i);
+//      n=i;
+//      b=(i==j); b=(i!=j); b=(i<j);
+//      //Node ->NodeIt conversion
+//      NodeIt ni(G,n);
+//       }
+//       {
+//      Edge i; Edge j(i); Edge k(INVALID);
+//      i=j;
+//      bool b; b=true;
+//      b=(i==INVALID); b=(i!=INVALID);
+//      b=(i==j); b=(i!=j); b=(i<j);
+//       }
+//       {
+//      EdgeIt i; EdgeIt j(i); EdgeIt k(INVALID); EdgeIt l(G);
+//      i=j;
+//      j=G.first(i);
+//      j=++i;
+//      bool b; b=true;
+//      b=(i==INVALID); b=(i!=INVALID);
+//      Edge e(i);
+//      e=i;
+//      b=(i==j); b=(i!=j); b=(i<j);
+//      //Edge ->EdgeIt conversion
+//      EdgeIt ei(G,e);
+//       }
+//       {
+//      Node n;
+//      InEdgeIt i; InEdgeIt j(i); InEdgeIt k(INVALID); InEdgeIt l(G,n);
+//      i=j;
+//      j=G.first(i,n);
+//      j=++i;
+//      bool b; b=true;
+//      b=(i==INVALID); b=(i!=INVALID);
+//      Edge e(i);
+//      e=i;
+//      b=(i==j); b=(i!=j); b=(i<j);
+//      //Edge ->InEdgeIt conversion
+//      InEdgeIt ei(G,e);
+//       }
+//       {
+//      Node n;
+//      OutEdgeIt i; OutEdgeIt j(i); OutEdgeIt k(INVALID); OutEdgeIt l(G,n);
+//      i=j;
+//      j=G.first(i,n);
+//      j=++i;
+//      bool b; b=true;
+//      b=(i==INVALID); b=(i!=INVALID);
+//      Edge e(i);
+//      e=i;
+//      b=(i==j); b=(i!=j); b=(i<j);
+//      //Edge ->OutEdgeIt conversion
+//      OutEdgeIt ei(G,e);
+//       }
+//       {
+//      Node n,m;
+//      n=m=INVALID;
+//      Edge e;
+//      e=INVALID;
+//      n=G.tail(e);
+//      n=G.head(e);
+//       }
+//       // id tests
+//       { Node n; int i=G.id(n); i=i; }
+//       { Edge e; int i=G.id(e); i=i; }
+//       //NodeMap tests
+//       {
+//      Node k;
+//      typename Graph::template NodeMap<int> m(G);
+//      //Const map
+//      typename Graph::template NodeMap<int> const &cm = m;
+//      //Inicialize with default value
+//      typename Graph::template NodeMap<int> mdef(G,12);
+//      //Copy
+//      typename Graph::template NodeMap<int> mm(cm);
+//      //Copy from another type
+//      typename Graph::template NodeMap<double> dm(cm);
+//      //Copy to more complex type
+//      typename Graph::template NodeMap<DummyType> em(cm);
+//      int v;
+//      v=m[k]; m[k]=v; m.set(k,v);
+//      v=cm[k];
+    
+//      m=cm;  
+//      dm=cm; //Copy from another type  
+//      em=cm; //Copy to more complex type
+//      {
+//        //Check the typedef's
+//        typename Graph::template NodeMap<int>::ValueType val;
+//        val=1;
+//        typename Graph::template NodeMap<int>::KeyType key;
+//        key = typename Graph::NodeIt(G);
+//      }
+//       }  
+//       { //bool NodeMap
+//      Node k;
+//      typename Graph::template NodeMap<bool> m(G);
+//      typename Graph::template NodeMap<bool> const &cm = m;  //Const map
+//      //Inicialize with default value
+//      typename Graph::template NodeMap<bool> mdef(G,12);
+//      typename Graph::template NodeMap<bool> mm(cm);   //Copy
+//      typename Graph::template NodeMap<int> dm(cm); //Copy from another type
+//      bool v;
+//      v=m[k]; m[k]=v; m.set(k,v);
+//      v=cm[k];
+    
+//      m=cm;  
+//      dm=cm; //Copy from another type
+//      m=dm; //Copy to another type
+
+//      {
+//        //Check the typedef's
+//        typename Graph::template NodeMap<bool>::ValueType val;
+//        val=true;
+//        typename Graph::template NodeMap<bool>::KeyType key;
+//        key= typename Graph::NodeIt(G);
+//      }
+//       }
+//       //EdgeMap tests
+//       {
+//      Edge k;
+//      typename Graph::template EdgeMap<int> m(G);
+//      typename Graph::template EdgeMap<int> const &cm = m;  //Const map
+//      //Inicialize with default value
+//      typename Graph::template EdgeMap<int> mdef(G,12);
+//      typename Graph::template EdgeMap<int> mm(cm);   //Copy
+//      typename Graph::template EdgeMap<double> dm(cm);//Copy from another type
+//      int v;
+//      v=m[k]; m[k]=v; m.set(k,v);
+//      v=cm[k];
+    
+//      m=cm;  
+//      dm=cm; //Copy from another type
+//      {
+//        //Check the typedef's
+//        typename Graph::template EdgeMap<int>::ValueType val;
+//        val=1;
+//        typename Graph::template EdgeMap<int>::KeyType key;
+//        key= typename Graph::EdgeIt(G);
+//      }
+//       }  
+//       { //bool EdgeMap
+//      Edge k;
+//      typename Graph::template EdgeMap<bool> m(G);
+//      typename Graph::template EdgeMap<bool> const &cm = m;  //Const map
+//      //Inicialize with default value
+//      typename Graph::template EdgeMap<bool> mdef(G,12);
+//      typename Graph::template EdgeMap<bool> mm(cm);   //Copy
+//      typename Graph::template EdgeMap<int> dm(cm); //Copy from another type
+//      bool v;
+//      v=m[k]; m[k]=v; m.set(k,v);
+//      v=cm[k];
+    
+//      m=cm;  
+//      dm=cm; //Copy from another type
+//      m=dm; //Copy to another type
+//      {
+//        //Check the typedef's
+//        typename Graph::template EdgeMap<bool>::ValueType val;
+//        val=true;
+//        typename Graph::template EdgeMap<bool>::KeyType key;
+//        key= typename Graph::EdgeIt(G);
+//      }
+//       }
+//     }
+    
+//     /// An empty non-static graph class.
+    
+//     /// This class provides everything that \ref StaticGraph
+//     /// with additional functionality which enables to build a
+//     /// graph from scratch.
+//     class ExtendableGraph : public StaticGraph
+//     {
+//     public:
+//       /// Defalult constructor.
+
+//       /// Defalult constructor.
+//       ///
+//       ExtendableGraph() { }
+//       ///Add a new node to the graph.
+
+//       /// \return the new node.
+//       ///
+//       Node addNode() { return INVALID; }
+//       ///Add a new edge to the graph.
+
+//       ///Add a new edge to the graph with tail node \c t
+//       ///and head node \c h.
+//       ///\return the new edge.
+//       Edge addEdge(Node h, Node t) { return INVALID; }
+    
+//       /// Resets the graph.
+
+//       /// This function deletes all edges and nodes of the graph.
+//       /// It also frees the memory allocated to store them.
+//       /// \todo It might belong to \ref ErasableGraph.
+//       void clear() { }
+//     };
+
+    
+//     ///\brief Checks whether \c G meets the
+//     ///\ref lemon::skeleton::ExtendableGraph "ExtendableGraph" concept
+//     template<class Graph> void checkCompileExtendableGraph(Graph &G) 
+//     {
+//       checkCompileStaticGraph(G);
+
+//       typedef typename Graph::Node Node;
+//       typedef typename Graph::NodeIt NodeIt;
+//       typedef typename Graph::Edge Edge;
+//       typedef typename Graph::EdgeIt EdgeIt;
+//       typedef typename Graph::InEdgeIt InEdgeIt;
+//       typedef typename Graph::OutEdgeIt OutEdgeIt;
+  
+//       Node n,m;
+//       n=G.addNode();
+//       m=G.addNode();
+//       Edge e;
+//       e=G.addEdge(n,m); 
+  
+//       //  G.clear();
+//     }
+
+
+//     /// An empty erasable graph class.
+  
+//     /// This class is an extension of \ref ExtendableGraph. It also makes it
+//     /// possible to erase edges or nodes.
+//     class ErasableGraph : public ExtendableGraph
+//     {
+//     public:
+//       /// Defalult constructor.
+
+//       /// Defalult constructor.
+//       ///
+//       ErasableGraph() { }
+//       /// Deletes a node.
+
+//       /// Deletes node \c n node.
+//       ///
+//       void erase(Node n) { }
+//       /// Deletes an edge.
+
+//       /// Deletes edge \c e edge.
+//       ///
+//       void erase(Edge e) { }
+//     };
+    
+//     template<class Graph> void checkCompileGraphEraseEdge(Graph &G) 
+//     {
+//       typename Graph::Edge e;
+//       G.erase(e);
+//     }
+
+//     template<class Graph> void checkCompileGraphEraseNode(Graph &G) 
+//     {
+//       typename Graph::Node n;
+//       G.erase(n);
+//     }
+
+//     ///\brief Checks whether \c G meets the
+//     ///\ref lemon::skeleton::EresableGraph "EresableGraph" concept
+//     template<class Graph> void checkCompileErasableGraph(Graph &G) 
+//     {
+//       checkCompileExtendableGraph(G);
+//       checkCompileGraphEraseNode(G);
+//       checkCompileGraphEraseEdge(G);
+//     }
+
+//     ///Checks whether a graph has findEdge() member function.
+    
+//     ///\todo findEdge() might be a global function.
+//     ///
+//     template<class Graph> void checkCompileGraphFindEdge(Graph &G) 
+//     {
+//       typedef typename Graph::NodeIt Node;
+//       typedef typename Graph::NodeIt NodeIt;
+
+//       G.findEdge(NodeIt(G),++NodeIt(G),G.findEdge(NodeIt(G),++NodeIt(G)));
+//       G.findEdge(Node(),Node(),G.findEdge(Node(),Node()));  
+//     }
+
+
+
+    /************* New GraphBase stuff **************/
+
+
+    /// \bug The nodes and edges are not allowed to inherit from the
+    /// same baseclass.
+
+    class BaseGraphItem {
     public:
-      /// Defalult constructor.
-
-      /// Defalult constructor.
-      ///
-      StaticGraph() { }
-      ///Copy consructor.
-
-//       ///\todo It is not clear, what we expect from a copy constructor.
-//       ///E.g. How to assign the nodes/edges to each other? What about maps?
-//       StaticGraph(const StaticGraph& g) { }
-
-      /// The base type of node iterators, 
-      /// or in other words, the trivial node iterator.
-
-      /// This is the base type of each node iterator,
-      /// thus each kind of node iterator converts to this.
-      /// More precisely each kind of node iterator should be inherited 
-      /// from the trivial node iterator.
-      class Node {
-      public:
-        /// Default constructor
-
-        /// @warning The default constructor sets the iterator
-        /// to an undefined value.
-        Node() { }
-        /// Copy constructor.
-
-        /// Copy constructor.
-        ///
-        Node(const Node&) { }
-
-        /// Invalid constructor \& conversion.
-
-        /// This constructor initializes the iterator to be invalid.
-        /// \sa Invalid for more details.
-        Node(Invalid) { }
-        /// Equality operator
-
-        /// Two iterators are equal if and only if they point to the
-        /// same object or both are invalid.
-        bool operator==(Node) const { return true; }
-
-        /// Inequality operator
+      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
+    /// full-featured graph with \ref GraphFactory.
+    class GraphBase {
+    public:
+
+      GraphBase() {}
+
+
+      /// \bug Nodes and Edges are comparable each other
+      
+      class Node : public BaseGraphItem {};
+      class Edge : public BaseGraphItem {};
+
+      // Graph operation
+      void firstNode(Node &n) const { }
+      void firstEdge(Edge &e) const { }
+
+      void firstOutEdge(Edge &e, Node) const { }
+      void firstInEdge(Edge &e, Node) const { }
+
+      void nextNode(Node &n) const { }
+      void nextEdge(Edge &e) const { }
+
+
+      // Question: isn't it reasonable if this methods have a Node
+      // parameter? Like this:
+      // Edge& nextOut(Edge &e, Node) const { return e; }
+      void nextOutEdge(Edge &e) const { }
+      void nextInEdge(Edge &e) const { }
+
+      Node head(Edge) const { return Node(); }
+      Node tail(Edge) const { return Node(); }
+      
+
+      // Do we need id, nodeNum, edgeNum and co. in this basic graphbase
+      // concept?
+
+
+      // Maps.
+      //
+      // We need a special slimer concept which does not provide maps (it
+      // wouldn't be strictly slimer, cause for map-factory id() & friends
+      // a required...)
+
+      template<typename T>
+      class NodeMap : public GraphMap<Node, T, GraphBase> {};
+
+      template<typename T>
+      class EdgeMap : public GraphMap<Edge, T, GraphBase> {};
+    };
+
+
+
+    /**************** Concept checking classes ****************/
+
+    template<typename BGI>
+    struct BaseGraphItemConcept {
+      void constraints() {
+        BGI i1;
+        BGI i2 = i1;
+        BGI i3 = INVALID;
         
-        /// \sa operator==(Node n)
-        ///
-        bool operator!=(Node) const { return true; }
-
-        ///Comparison operator.
-
-        ///This is a strict ordering between the nodes.
-        ///
-        ///This ordering can be different from the order in which NodeIt
-        ///goes through the nodes.
-        ///\todo Possibly we don't need it.
-        bool operator<(Node) const { return true; }
-      };
-    
-      /// This iterator goes through each node.
-
-      /// This iterator goes through each node.
-      /// Its usage is quite simple, for example you can count the number
-      /// of nodes in graph \c g of type \c Graph like this:
-      /// \code
-      /// int count=0;
-      /// for (Graph::NodeIt n(g); n!=INVALID; ++n) ++count;
-      /// \endcode
-      class NodeIt : public Node {
-      public:
-        /// Default constructor
-
-        /// @warning The default constructor sets the iterator
-        /// to an undefined value.
-        NodeIt() { }
-        /// Copy constructor.
-        
-        /// Copy constructor.
-        ///
-        NodeIt(const NodeIt&) { }
-        /// Invalid constructor \& conversion.
-
-        /// Initialize the iterator to be invalid.
-        /// \sa Invalid for more details.
-        NodeIt(Invalid) { }
-        /// Sets the iterator to the first node.
-
-        /// Sets the iterator to the first node of \c g.
-        ///
-        NodeIt(const StaticGraph& g) { }
-        /// Node -> NodeIt conversion.
-
-        /// Sets the iterator to the node of \c g pointed by the trivial 
-        /// iterator n.
-        /// This feature necessitates that each time we 
-        /// iterate the edge-set, the iteration order is the same.
-        NodeIt(const StaticGraph& g, const Node& n) { }
-        /// Next node.
-
-        /// Assign the iterator to the next node.
-        ///
-        NodeIt& operator++() { return *this; }
-      };
-    
-    
-      /// The base type of the edge iterators.
-
-      /// The base type of the edge iterators.
-      ///
-      class Edge {
-      public:
-        /// Default constructor
-
-        /// @warning The default constructor sets the iterator
-        /// to an undefined value.
-        Edge() { }
-        /// Copy constructor.
-
-        /// Copy constructor.
-        ///
-        Edge(const Edge&) { }
-        /// Initialize the iterator to be invalid.
-
-        /// Initialize the iterator to be invalid.
-        ///
-        Edge(Invalid) { }
-        /// Equality operator
-
-        /// Two iterators are equal if and only if they point to the
-        /// same object or both are invalid.
-        bool operator==(Edge) const { return true; }
-        /// Inequality operator
-
-        /// \sa operator==(Node n)
-        ///
-        bool operator!=(Edge) const { return true; }
-        ///Comparison operator.
-
-        ///This is a strict ordering between the nodes.
-        ///
-        ///This ordering can be different from the order in which NodeIt
-        ///goes through the nodes.
-        ///\todo Possibly we don't need it.
-        bool operator<(Edge) const { return true; }
-      };
-    
-      /// This iterator goes trough the outgoing edges of a node.
-
-      /// This iterator goes trough the \e outgoing edges of a certain node
-      /// of a graph.
-      /// Its usage is quite simple, for example you can count the number
-      /// of outgoing edges of a node \c n
-      /// in graph \c g of type \c Graph as follows.
-      /// \code
-      /// int count=0;
-      /// for (Graph::OutEdgeIt e(g, n); e!=INVALID; ++e) ++count;
-      /// \endcode
-    
-      class OutEdgeIt : public Edge {
-      public:
-        /// Default constructor
-
-        /// @warning The default constructor sets the iterator
-        /// to an undefined value.
-        OutEdgeIt() { }
-        /// Copy constructor.
-
-        /// Copy constructor.
-        ///
-        OutEdgeIt(const OutEdgeIt&) { }
-        /// Initialize the iterator to be invalid.
-
-        /// Initialize the iterator to be invalid.
-        ///
-        OutEdgeIt(Invalid) { }
-        /// This constructor sets the iterator to first outgoing edge.
-    
-        /// This constructor set the iterator to the first outgoing edge of
-        /// node
-        ///@param n the node
-        ///@param g the graph
-        OutEdgeIt(const StaticGraph& g, const Node& n) { }
-        /// Edge -> OutEdgeIt conversion
-
-        /// Sets the iterator to the value of the trivial iterator \c e.
-        /// This feature necessitates that each time we 
-        /// iterate the edge-set, the iteration order is the same.
-        OutEdgeIt(const StaticGraph& g, const Edge& e) { }
-        ///Next outgoing edge
-        
-        /// Assign the iterator to the next 
-        /// outgoing edge of the corresponding node.
-        OutEdgeIt& operator++() { return *this; }
-      };
-
-      /// This iterator goes trough the incoming edges of a node.
-
-      /// This iterator goes trough the \e incoming edges of a certain node
-      /// of a graph.
-      /// Its usage is quite simple, for example you can count the number
-      /// of outgoing edges of a node \c n
-      /// in graph \c g of type \c Graph as follows.
-      /// \code
-      /// int count=0;
-      /// for(Graph::InEdgeIt e(g, n); e!=INVALID; ++e) ++count;
-      /// \endcode
-
-      class InEdgeIt : public Edge {
-      public:
-        /// Default constructor
-
-        /// @warning The default constructor sets the iterator
-        /// to an undefined value.
-        InEdgeIt() { }
-        /// Copy constructor.
-
-        /// Copy constructor.
-        ///
-        InEdgeIt(const InEdgeIt&) { }
-        /// Initialize the iterator to be invalid.
-
-        /// Initialize the iterator to be invalid.
-        ///
-        InEdgeIt(Invalid) { }
-        /// This constructor sets the iterator to first incoming edge.
-    
-        /// This constructor set the iterator to the first incoming edge of
-        /// node
-        ///@param n the node
-        ///@param g the graph
-        InEdgeIt(const StaticGraph& g, const Node& n) { }
-        /// Edge -> InEdgeIt conversion
-
-        /// Sets the iterator to the value of the trivial iterator \c e.
-        /// This feature necessitates that each time we 
-        /// iterate the edge-set, the iteration order is the same.
-        InEdgeIt(const StaticGraph& g, const Edge& n) { }
-        /// Next incoming edge
-
-        /// Assign the iterator to the next inedge of the corresponding node.
-        ///
-        InEdgeIt& operator++() { return *this; }
-      };
-      /// This iterator goes through each edge.
-
-      /// This iterator goes through each edge of a graph.
-      /// Its usage is quite simple, for example you can count the number
-      /// of edges in a graph \c g of type \c Graph as follows:
-      /// \code
-      /// int count=0;
-      /// for(Graph::EdgeIt e(g); e!=INVALID; ++e) ++count;
-      /// \endcode
-      class EdgeIt : public Edge {
-      public:
-        /// Default constructor
-
-        /// @warning The default constructor sets the iterator
-        /// to an undefined value.
-        EdgeIt() { }
-        /// Copy constructor.
-
-        /// Copy constructor.
-        ///
-        EdgeIt(const EdgeIt&) { }
-        /// Initialize the iterator to be invalid.
-
-        /// Initialize the iterator to be invalid.
-        ///
-        EdgeIt(Invalid) { }
-        /// This constructor sets the iterator to first edge.
-    
-        /// This constructor set the iterator to the first edge of
-        /// node
-        ///@param g the graph
-        EdgeIt(const StaticGraph& g) { }
-        /// Edge -> EdgeIt conversion
-
-        /// Sets the iterator to the value of the trivial iterator \c e.
-        /// This feature necessitates that each time we 
-        /// iterate the edge-set, the iteration order is the same.
-        EdgeIt(const StaticGraph&, const Edge&) { } 
-        ///Next edge
-        
-        /// Assign the iterator to the next 
-        /// edge of the corresponding node.
-        EdgeIt& operator++() { return *this; }
-      };
-
-      /// First node of the graph.
-
-      /// \retval i the first node.
-      /// \return the first node.
-      ///
-      NodeIt& first(NodeIt& i) const { return i; }
-
-      /// The first incoming edge.
-
-      /// The first incoming edge.
-      ///
-      InEdgeIt& first(InEdgeIt &i, Node) const { return i; }
-      /// The first outgoing edge.
-
-      /// The first outgoing edge.
-      ///
-      OutEdgeIt& first(OutEdgeIt& i, Node) const { return i; }
-      /// The first edge of the Graph.
-
-      /// The first edge of the Graph.
-      ///
-      EdgeIt& first(EdgeIt& i) const { return i; }
-
-      ///Gives back the head node of an edge.
-
-      ///Gives back the head node of an edge.
-      ///
-      Node head(Edge) const { return INVALID; }
-      ///Gives back the tail node of an edge.
-
-      ///Gives back the tail node of an edge.
-      ///
-      Node tail(Edge) const { return INVALID; }
-  
-      ///Gives back the \e id of a node.
-
-      ///\warning Not all graph structures provide this feature.
-      ///
-      ///\todo Should each graph provide \c id?
-      int id(const Node&) const { return 0; }
-      ///Gives back the \e id of an edge.
-
-      ///\warning Not all graph structures provide this feature.
-      ///
-      ///\todo Should each graph provide \c id?
-      int id(const Edge&) const { return 0; }
-
-      ///\e
-      
-      ///\todo Should it be in the concept?
-      ///
-      int nodeNum() const { return 0; }
-      ///\e
-
-      ///\todo Should it be in the concept?
-      ///
-      int edgeNum() const { return 0; }
-
-
-      ///Reference map of the nodes to type \c T.
-
-      /// \ingroup skeletons
-      ///Reference map of the nodes to type \c T.
-      /// \sa Reference
-      /// \warning Making maps that can handle bool type (NodeMap<bool>)
-      /// needs some extra attention!
-      template<class T> class NodeMap : public ReferenceMap< Node, T >
-      {
-      public:
-
-        ///\e
-        NodeMap(const StaticGraph&) { }
-        ///\e
-        NodeMap(const StaticGraph&, T) { }
-
-        ///Copy constructor
-        template<typename TT> NodeMap(const NodeMap<TT>&) { }
-        ///Assignment operator
-        template<typename TT> NodeMap& operator=(const NodeMap<TT>&)
-        { return *this; }
-      };
-
-      ///Reference map of the edges to type \c T.
-
-      /// \ingroup skeletons
-      ///Reference map of the edges to type \c T.
-      /// \sa Reference
-      /// \warning Making maps that can handle bool type (EdgeMap<bool>)
-      /// needs some extra attention!
-      template<class T> class EdgeMap
-        : public ReferenceMap<Edge,T>
-      {
-      public:
-
-        ///\e
-        EdgeMap(const StaticGraph&) { }
-        ///\e
-        EdgeMap(const StaticGraph&, T) { }
-    
-        ///Copy constructor
-        template<typename TT> EdgeMap(const EdgeMap<TT>&) { }
-        ///Assignment operator
-        template<typename TT> EdgeMap &operator=(const EdgeMap<TT>&)
-        { return *this; }
-      };
-    };
-
-    struct DummyType {
-      int value;
-      DummyType() {}
-      DummyType(int p) : value(p) {}
-      DummyType& operator=(int p) { value = p; return *this;}
-    };
-    
-    ///\brief Checks whether \c G meets the
-    ///\ref lemon::skeleton::StaticGraph "StaticGraph" concept
-    template<class Graph> void checkCompileStaticGraph(Graph &G) 
-    {
-      typedef typename Graph::Node Node;
-      typedef typename Graph::NodeIt NodeIt;
-      typedef typename Graph::Edge Edge;
-      typedef typename Graph::EdgeIt EdgeIt;
-      typedef typename Graph::InEdgeIt InEdgeIt;
-      typedef typename Graph::OutEdgeIt OutEdgeIt;
-  
-      {
-        Node i; Node j(i); Node k(INVALID);
-        i=j;
-        bool b; b=true;
-        b=(i==INVALID); b=(i!=INVALID);
-        b=(i==j); b=(i!=j); b=(i<j);
-      }
-      {
-        NodeIt i; NodeIt j(i); NodeIt k(INVALID); NodeIt l(G);
-        i=j;
-        j=G.first(i);
-        j=++i;
-        bool b; b=true;
-        b=(i==INVALID); b=(i!=INVALID);
-        Node n(i);
-        n=i;
-        b=(i==j); b=(i!=j); b=(i<j);
-        //Node ->NodeIt conversion
-        NodeIt ni(G,n);
-      }
-      {
-        Edge i; Edge j(i); Edge k(INVALID);
-        i=j;
-        bool b; b=true;
-        b=(i==INVALID); b=(i!=INVALID);
-        b=(i==j); b=(i!=j); b=(i<j);
-      }
-      {
-        EdgeIt i; EdgeIt j(i); EdgeIt k(INVALID); EdgeIt l(G);
-        i=j;
-        j=G.first(i);
-        j=++i;
-        bool b; b=true;
-        b=(i==INVALID); b=(i!=INVALID);
-        Edge e(i);
-        e=i;
-        b=(i==j); b=(i!=j); b=(i<j);
-        //Edge ->EdgeIt conversion
-        EdgeIt ei(G,e);
-      }
-      {
-        Node n;
-        InEdgeIt i; InEdgeIt j(i); InEdgeIt k(INVALID); InEdgeIt l(G,n);
-        i=j;
-        j=G.first(i,n);
-        j=++i;
-        bool b; b=true;
-        b=(i==INVALID); b=(i!=INVALID);
-        Edge e(i);
-        e=i;
-        b=(i==j); b=(i!=j); b=(i<j);
-        //Edge ->InEdgeIt conversion
-        InEdgeIt ei(G,e);
-      }
-      {
-        Node n;
-        OutEdgeIt i; OutEdgeIt j(i); OutEdgeIt k(INVALID); OutEdgeIt l(G,n);
-        i=j;
-        j=G.first(i,n);
-        j=++i;
-        bool b; b=true;
-        b=(i==INVALID); b=(i!=INVALID);
-        Edge e(i);
-        e=i;
-        b=(i==j); b=(i!=j); b=(i<j);
-        //Edge ->OutEdgeIt conversion
-        OutEdgeIt ei(G,e);
-      }
-      {
-        Node n,m;
-        n=m=INVALID;
-        Edge e;
-        e=INVALID;
-        n=G.tail(e);
-        n=G.head(e);
-      }
-      // id tests
-      { Node n; int i=G.id(n); i=i; }
-      { Edge e; int i=G.id(e); i=i; }
-      //NodeMap tests
-      {
-        Node k;
-        typename Graph::template NodeMap<int> m(G);
-        //Const map
-        typename Graph::template NodeMap<int> const &cm = m;
-        //Inicialize with default value
-        typename Graph::template NodeMap<int> mdef(G,12);
-        //Copy
-        typename Graph::template NodeMap<int> mm(cm);
-        //Copy from another type
-        typename Graph::template NodeMap<double> dm(cm);
-        //Copy to more complex type
-        typename Graph::template NodeMap<DummyType> em(cm);
-        int v;
-        v=m[k]; m[k]=v; m.set(k,v);
-        v=cm[k];
-    
-        m=cm;  
-        dm=cm; //Copy from another type  
-        em=cm; //Copy to more complex type
-        {
-          //Check the typedef's
-          typename Graph::template NodeMap<int>::ValueType val;
-          val=1;
-          typename Graph::template NodeMap<int>::KeyType key;
-          key = typename Graph::NodeIt(G);
-        }
-      }  
-      { //bool NodeMap
-        Node k;
-        typename Graph::template NodeMap<bool> m(G);
-        typename Graph::template NodeMap<bool> const &cm = m;  //Const map
-        //Inicialize with default value
-        typename Graph::template NodeMap<bool> mdef(G,12);
-        typename Graph::template NodeMap<bool> mm(cm);   //Copy
-        typename Graph::template NodeMap<int> dm(cm); //Copy from another type
-        bool v;
-        v=m[k]; m[k]=v; m.set(k,v);
-        v=cm[k];
-    
-        m=cm;  
-        dm=cm; //Copy from another type
-        m=dm; //Copy to another type
-
-        {
-          //Check the typedef's
-          typename Graph::template NodeMap<bool>::ValueType val;
-          val=true;
-          typename Graph::template NodeMap<bool>::KeyType key;
-          key= typename Graph::NodeIt(G);
+        i1 = i3;
+        if( i1 == i3 ) {
+          if ( i2 != i3 && i3 < i2 )
+            return;
         }
       }
-      //EdgeMap tests
-      {
-        Edge k;
-        typename Graph::template EdgeMap<int> m(G);
-        typename Graph::template EdgeMap<int> const &cm = m;  //Const map
-        //Inicialize with default value
-        typename Graph::template EdgeMap<int> mdef(G,12);
-        typename Graph::template EdgeMap<int> mm(cm);   //Copy
-        typename Graph::template EdgeMap<double> dm(cm);//Copy from another type
-        int v;
-        v=m[k]; m[k]=v; m.set(k,v);
-        v=cm[k];
-    
-        m=cm;  
-        dm=cm; //Copy from another type
-        {
-          //Check the typedef's
-          typename Graph::template EdgeMap<int>::ValueType val;
-          val=1;
-          typename Graph::template EdgeMap<int>::KeyType key;
-          key= typename Graph::EdgeIt(G);
-        }
-      }  
-      { //bool EdgeMap
-        Edge k;
-        typename Graph::template EdgeMap<bool> m(G);
-        typename Graph::template EdgeMap<bool> const &cm = m;  //Const map
-        //Inicialize with default value
-        typename Graph::template EdgeMap<bool> mdef(G,12);
-        typename Graph::template EdgeMap<bool> mm(cm);   //Copy
-        typename Graph::template EdgeMap<int> dm(cm); //Copy from another type
-        bool v;
-        v=m[k]; m[k]=v; m.set(k,v);
-        v=cm[k];
-    
-        m=cm;  
-        dm=cm; //Copy from another type
-        m=dm; //Copy to another type
-        {
-          //Check the typedef's
-          typename Graph::template EdgeMap<bool>::ValueType val;
-          val=true;
-          typename Graph::template EdgeMap<bool>::KeyType key;
-          key= typename Graph::EdgeIt(G);
-        }
+    };
+
+    
+    
+    class StaticGraph 
+      :  virtual public BaseGraphComponent, public IterableGraphComponent, public MappableGraphComponent {
+    public:
+      typedef BaseGraphComponent::Node Node;
+      typedef BaseGraphComponent::Edge Edge;
+    };
+
+    template <typename Graph>
+    struct StaticGraphConcept {
+      void constraints() {
+        function_requires<BaseGraphComponentConcept<Graph> >();
+        function_requires<IterableGraphComponentConcept<Graph> >();
+        function_requires<MappableGraphComponentConcept<Graph> >();
       }
-    }
-    
-    /// An empty non-static graph class.
-    
-    /// This class provides everything that \ref StaticGraph
-    /// with additional functionality which enables to build a
-    /// graph from scratch.
-    class ExtendableGraph : public StaticGraph
-    {
+      Graph& graph;
+    };
+
+    class ExtendableGraph 
+      :  virtual public BaseGraphComponent, public StaticGraph, public ExtendableGraphComponent, public ClearableGraphComponent {
     public:
-      /// Defalult constructor.
-
-      /// Defalult constructor.
-      ///
-      ExtendableGraph() { }
-      ///Add a new node to the graph.
-
-      /// \return the new node.
-      ///
-      Node addNode() { return INVALID; }
-      ///Add a new edge to the graph.
-
-      ///Add a new edge to the graph with tail node \c t
-      ///and head node \c h.
-      ///\return the new edge.
-      Edge addEdge(Node h, Node t) { return INVALID; }
-    
-      /// Resets the graph.
-
-      /// This function deletes all edges and nodes of the graph.
-      /// It also frees the memory allocated to store them.
-      /// \todo It might belong to \ref ErasableGraph.
-      void clear() { }
+      typedef BaseGraphComponent::Node Node;
+      typedef BaseGraphComponent::Edge Edge;
     };
 
-    
-    ///\brief Checks whether \c G meets the
-    ///\ref lemon::skeleton::ExtendableGraph "ExtendableGraph" concept
-    template<class Graph> void checkCompileExtendableGraph(Graph &G) 
-    {
-      checkCompileStaticGraph(G);
-
-      typedef typename Graph::Node Node;
-      typedef typename Graph::NodeIt NodeIt;
-      typedef typename Graph::Edge Edge;
-      typedef typename Graph::EdgeIt EdgeIt;
-      typedef typename Graph::InEdgeIt InEdgeIt;
-      typedef typename Graph::OutEdgeIt OutEdgeIt;
-  
-      Node n,m;
-      n=G.addNode();
-      m=G.addNode();
-      Edge e;
-      e=G.addEdge(n,m); 
-  
-      //  G.clear();
-    }
-
-
-    /// An empty erasable graph class.
-  
-    /// This class is an extension of \ref ExtendableGraph. It also makes it
-    /// possible to erase edges or nodes.
-    class ErasableGraph : public ExtendableGraph
-    {
+    template <typename Graph>
+    struct ExtendableGraphConcept {
+      void constraints() {
+        function_requires<StaticGraphConcept<Graph> >();
+        function_requires<ExtendableGraphComponentConcept<Graph> >();
+        function_requires<ClearableGraphComponentConcept<Graph> >();
+      }
+      Graph& graph;
+    };
+
+    class ErasableGraph 
+      :  virtual public BaseGraphComponent, public ExtendableGraph, public ErasableGraphComponent {
     public:
-      /// Defalult constructor.
-
-      /// Defalult constructor.
-      ///
-      ErasableGraph() { }
-      /// Deletes a node.
-
-      /// Deletes node \c n node.
-      ///
-      void erase(Node n) { }
-      /// Deletes an edge.
-
-      /// Deletes edge \c e edge.
-      ///
-      void erase(Edge e) { }
+      typedef BaseGraphComponent::Node Node;
+      typedef BaseGraphComponent::Edge Edge;
     };
-    
-    template<class Graph> void checkCompileGraphEraseEdge(Graph &G) 
-    {
-      typename Graph::Edge e;
-      G.erase(e);
-    }
-
-    template<class Graph> void checkCompileGraphEraseNode(Graph &G) 
-    {
-      typename Graph::Node n;
-      G.erase(n);
-    }
-
-    ///\brief Checks whether \c G meets the
-    ///\ref lemon::skeleton::EresableGraph "EresableGraph" concept
-    template<class Graph> void checkCompileErasableGraph(Graph &G) 
-    {
-      checkCompileExtendableGraph(G);
-      checkCompileGraphEraseNode(G);
-      checkCompileGraphEraseEdge(G);
-    }
-
-    ///Checks whether a graph has findEdge() member function.
-    
-    ///\todo findEdge() might be a global function.
-    ///
-    template<class Graph> void checkCompileGraphFindEdge(Graph &G) 
-    {
-      typedef typename Graph::NodeIt Node;
-      typedef typename Graph::NodeIt NodeIt;
-
-      G.findEdge(NodeIt(G),++NodeIt(G),G.findEdge(NodeIt(G),++NodeIt(G)));
-      G.findEdge(Node(),Node(),G.findEdge(Node(),Node()));  
-    }
- 
+
+    template <typename Graph>
+    struct ErasableGraphConcept {
+      void constraints() {
+        function_requires<ExtendableGraphConcept<Graph> >();
+        function_requires<ErasableGraphComponentConcept<Graph> >();
+      }
+      Graph& graph;
+    };
+
     // @}
   } //namespace skeleton  

src/lemon/skeletons/maps.h

@@ -17 +17 @@
 #ifndef LEMON_MAPSKELETON_H
 #define LEMON_MAPSKELETON_H
+
+#include <lemon/concept_check.h>
 
 ///\ingroup skeletons
@@ -114 +116 @@
     };
 
+
+    template<typename Item, typename T, typename Graph>
+    class GraphMap : public ReadWriteMap<Item, T> {
+      // I really, really don't like the idea that every graph should have
+      // reference maps! --klao
+
+    private:
+      // We state explicitly that graph maps have no default constructor?
+      GraphMap();
+
+    public:
+      explicit GraphMap(Graph const&) {}
+      // value for initializing
+      GraphMap(Graph const&, T) {}
+
+      // this probably should be required:
+      GraphMap(GraphMap const&) {}
+      GraphMap& operator=(GraphMap const&) { return *this; }
+
+      // but this is a absolute no-op! We should provide a more generic
+      // graph-map-copy operation.
+      //
+      // template<typename TT>
+      // GraphMap(GraphMap<TT> const&);
+      //
+      // template<typename TT>
+      // GraphMap& operator=(const GraphMap<TT>&);
+    };
+
+
+    /****************  Concept-checking classes  ****************/
+
+    template<typename ReadMap>
+    struct ReadMapConcept {
+      typedef typename ReadMap::KeyType KeyType;
+      typedef typename ReadMap::ValueType ValueType;
+
+      void constraints() {
+        // No constraints for constructor.
+
+        // What are the requirement for the ValueType?
+        // CopyConstructible? Assignable? None of these?
+        ValueType v = m[k];
+        v = m[k];
+
+        // FIXME:
+        ignore_unused_variable_warning(v);
+      }
+
+      ReadMap m;
+      KeyType k;
+    };
+
+    template<typename WriteMap>
+    struct WriteMapConcept {
+      typedef typename WriteMap::KeyType KeyType;
+      typedef typename WriteMap::ValueType ValueType;
+
+      void constraints() {
+        // No constraints for constructor.
+
+        m.set(k, v);
+      }
+
+      WriteMap m;
+      KeyType k;
+      ValueType v;
+    };
+
+    template<typename ReadWriteMap>
+    struct ReadWriteMapConcept {
+      void constraints() {
+        function_requires< ReadMapConcept<ReadWriteMap> >();
+        function_requires< WriteMapConcept<ReadWriteMap> >();
+      }
+    };
+
+    template<typename ReferenceMap>
+    struct ReferenceMapConcept {
+      typedef typename ReferenceMap::KeyType KeyType;
+      typedef typename ReferenceMap::ValueType ValueType;
+      typedef typename ReferenceMap::ReferenceType ReferenceType;
+
+      // What for is this?
+      typedef typename ReferenceMap::ConstReferenceType ConstReferenceType;
+
+      void constraints() {
+        function_requires< ReadWriteMapConcept<ReferenceMap> >();
+
+        m[k] = v;
+        // Or should we require real reference?
+        // Like this:
+        // ValueType &vv = m[k];
+        // ignore_unused_variable_warning(vv);
+      }
+
+      ReferenceMap m;
+      KeyType k;
+      ValueType v;
+    };
+
+    /// \todo GraphMapConceptCheck
+
+    template<typename GraphMap, typename Graph>
+    struct GraphMapConcept {
+      void constraints() {
+        function_requires< ReadWriteMapConcept<GraphMap> >();
+        // Construction with a graph parameter
+        GraphMap a(g);
+        // Ctor with a graph and a default value parameter
+        GraphMap a2(g,t);
+        // Copy ctor. Do we need it?
+        GraphMap b=c;
+        // Copy operator. Do we need it?
+        a=b;
+
+        ignore_unused_variable_warning(a2);
+      }
+      const GraphMap &c;
+      const Graph &g;
+      const typename GraphMap::ValueType &t;
+    };
+    
+
     // @}