Index: lemon/bits/alteration_notifier.h
===================================================================
--- lemon/bits/alteration_notifier.h	(revision 314)
+++ lemon/bits/alteration_notifier.h	(revision 373)
@@ -36,59 +36,60 @@
   // a container.
   //
-  // The simple graph's can be refered as two containers, one node container
-  // and one edge container. But they are not standard containers they
-  // does not store values directly they are just key continars for more
-  // value containers which are the node and edge maps.
-  //
-  // The graph's node and edge sets can be changed as we add or erase
+  // The simple graphs can be refered as two containers: a node container
+  // and an edge container. But they do not store values directly, they
+  // are just key continars for more value containers, which are the
+  // node and edge maps.
+  //
+  // The node and edge sets of the graphs can be changed as we add or erase
   // nodes and edges in the graph. LEMON would like to handle easily
   // that the node and edge maps should contain values for all nodes or
   // edges. If we want to check on every indicing if the map contains
   // the current indicing key that cause a drawback in the performance
-  // in the library. We use another solution we notify all maps about
+  // in the library. We use another solution: we notify all maps about
   // an alteration in the graph, which cause only drawback on the
   // alteration of the graph.
   //
-  // This class provides an interface to the container. The \e first() and \e
-  // next() member functions make possible to iterate on the keys of the
-  // container. The \e id() function returns an integer id for each key.
-  // The \e maxId() function gives back an upper bound of the ids.
+  // This class provides an interface to a node or edge container.
+  // The first() and next() member functions make possible
+  // to iterate on the keys of the container.
+  // The id() function returns an integer id for each key.
+  // The maxId() function gives back an upper bound of the ids.
   //
   // For the proper functonality of this class, we should notify it
-  // about each alteration in the container. The alterations have four type
-  // as \e add(), \e erase(), \e build() and \e clear(). The \e add() and
-  // \e erase() signals that only one or few items added or erased to or
-  // from the graph. If all items are erased from the graph or from an empty
-  // graph a new graph is builded then it can be signaled with the
+  // about each alteration in the container. The alterations have four type:
+  // add(), erase(), build() and clear(). The add() and
+  // erase() signal that only one or few items added or erased to or
+  // from the graph. If all items are erased from the graph or if a new graph
+  // is built from an empty graph, then it can be signaled with the
   // clear() and build() members. Important rule that if we erase items
-  // from graph we should first signal the alteration and after that erase
+  // from graphs we should first signal the alteration and after that erase
   // them from the container, on the other way on item addition we should
   // first extend the container and just after that signal the alteration.
   //
   // The alteration can be observed with a class inherited from the
-  // \e ObserverBase nested class. The signals can be handled with
+  // ObserverBase nested class. The signals can be handled with
   // overriding the virtual functions defined in the base class.  The
   // observer base can be attached to the notifier with the
-  // \e attach() member and can be detached with detach() function. The
+  // attach() member and can be detached with detach() function. The
   // alteration handlers should not call any function which signals
   // an other alteration in the same notifier and should not
   // detach any observer from the notifier.
   //
-  // Alteration observers try to be exception safe. If an \e add() or
-  // a \e clear() function throws an exception then the remaining
+  // Alteration observers try to be exception safe. If an add() or
+  // a clear() function throws an exception then the remaining
   // observeres will not be notified and the fulfilled additions will
-  // be rolled back by calling the \e erase() or \e clear()
-  // functions. Thence the \e erase() and \e clear() should not throw
-  // exception. Actullay, it can be throw only \ref ImmediateDetach
-  // exception which detach the observer from the notifier.
-  //
-  // There are some place when the alteration observing is not completly
+  // be rolled back by calling the erase() or clear() functions.
+  // Hence erase() and clear() should not throw exception.
+  // Actullay, they can throw only \ref ImmediateDetach exception,
+  // which detach the observer from the notifier.
+  //
+  // There are some cases, when the alteration observing is not completly
   // reliable. If we want to carry out the node degree in the graph
-  // as in the \ref InDegMap and we use the reverseEdge that cause
+  // as in the \ref InDegMap and we use the reverseArc(), then it cause
   // unreliable functionality. Because the alteration observing signals
-  // only erasing and adding but not the reversing it will stores bad
-  // degrees. The sub graph adaptors cannot signal the alterations because
-  // just a setting in the filter map can modify the graph and this cannot
-  // be watched in any way.
+  // only erasing and adding but not the reversing, it will stores bad
+  // degrees. Apart form that the subgraph adaptors cannot even signal
+  // the alterations because just a setting in the filter map can modify
+  // the graph and this cannot be watched in any way.
   //
   // \param _Container The container which is observed.
@@ -104,11 +105,11 @@
     typedef _Item Item;
 
-    // \brief Exception which can be called from \e clear() and
-    // \e erase().
-    //
-    // From the \e clear() and \e erase() function only this
+    // \brief Exception which can be called from clear() and
+    // erase().
+    //
+    // From the clear() and erase() function only this
     // exception is allowed to throw. The exception immediatly
     // detaches the current observer from the notifier. Because the
-    // \e clear() and \e erase() should not throw other exceptions
+    // clear() and erase() should not throw other exceptions
     // it can be used to invalidate the observer.
     struct ImmediateDetach {};
@@ -122,6 +123,5 @@
     // The observer interface contains some pure virtual functions
     // to override. The add() and erase() functions are
-    // to notify the oberver when one item is added or
-    // erased.
+    // to notify the oberver when one item is added or erased.
     //
     // The build() and clear() members are to notify the observer
Index: lemon/bits/array_map.h
===================================================================
--- lemon/bits/array_map.h	(revision 314)
+++ lemon/bits/array_map.h	(revision 373)
@@ -37,10 +37,9 @@
   // \brief Graph map based on the array storage.
   //
-  // The ArrayMap template class is graph map structure what
-  // automatically updates the map when a key is added to or erased from
-  // the map. This map uses the allocators to implement
-  // the container functionality.
+  // The ArrayMap template class is graph map structure that automatically
+  // updates the map when a key is added to or erased from the graph.
+  // This map uses the allocators to implement the container functionality.
   //
-  // The template parameters are the Graph the current Item type and
+  // The template parameters are the Graph, the current Item type and
   // the Value type of the map.
   template <typename _Graph, typename _Item, typename _Value>
@@ -48,12 +47,12 @@
     : public ItemSetTraits<_Graph, _Item>::ItemNotifier::ObserverBase {
   public:
-    // The graph type of the maps.
+    // The graph type.
     typedef _Graph Graph;
-    // The item type of the map.
+    // The item type.
     typedef _Item Item;
     // The reference map tag.
     typedef True ReferenceMapTag;
 
-    // The key type of the maps.
+    // The key type of the map.
     typedef _Item Key;
     // The value type of the map.
@@ -201,5 +200,5 @@
     // \brief Adds a new key to the map.
     //
-    // It adds a new key to the map. It called by the observer notifier
+    // It adds a new key to the map. It is called by the observer notifier
     // and it overrides the add() member function of the observer base.
     virtual void add(const Key& key) {
@@ -229,5 +228,5 @@
     // \brief Adds more new keys to the map.
     //
-    // It adds more new keys to the map. It called by the observer notifier
+    // It adds more new keys to the map. It is called by the observer notifier
     // and it overrides the add() member function of the observer base.
     virtual void add(const std::vector<Key>& keys) {
@@ -273,5 +272,5 @@
     // \brief Erase a key from the map.
     //
-    // Erase a key from the map. It called by the observer notifier
+    // Erase a key from the map. It is called by the observer notifier
     // and it overrides the erase() member function of the observer base.
     virtual void erase(const Key& key) {
@@ -282,5 +281,5 @@
     // \brief Erase more keys from the map.
     //
-    // Erase more keys from the map. It called by the observer notifier
+    // Erase more keys from the map. It is called by the observer notifier
     // and it overrides the erase() member function of the observer base.
     virtual void erase(const std::vector<Key>& keys) {
@@ -291,7 +290,7 @@
     }
 
-    // \brief Buildes the map.
-    //
-    // It buildes the map. It called by the observer notifier
+    // \brief Builds the map.
+    //
+    // It builds the map. It is called by the observer notifier
     // and it overrides the build() member function of the observer base.
     virtual void build() {
@@ -307,5 +306,5 @@
     // \brief Clear the map.
     //
-    // It erase all items from the map. It called by the observer notifier
+    // It erase all items from the map. It is called by the observer notifier
     // and it overrides the clear() member function of the observer base.
     virtual void clear() {
Index: lemon/bits/base_extender.h
===================================================================
--- lemon/bits/base_extender.h	(revision 314)
+++ lemon/bits/base_extender.h	(revision 373)
@@ -31,5 +31,5 @@
 //\ingroup digraphbits
 //\file
-//\brief Extenders for the digraph types
+//\brief Extenders for the graph types
 namespace lemon {
 
Index: lemon/bits/graph_extender.h
===================================================================
--- lemon/bits/graph_extender.h	(revision 314)
+++ lemon/bits/graph_extender.h	(revision 373)
@@ -30,10 +30,10 @@
 //\ingroup graphbits
 //\file
-//\brief Extenders for the digraph types
+//\brief Extenders for the graph types
 namespace lemon {
 
   // \ingroup graphbits
   //
-  // \brief Extender for the Digraphs
+  // \brief Extender for the digraph implementations
   template <typename Base>
   class DigraphExtender : public Base {
Index: lemon/bits/traits.h
===================================================================
--- lemon/bits/traits.h	(revision 314)
+++ lemon/bits/traits.h	(revision 372)
@@ -219,4 +219,17 @@
 
   template <typename Graph, typename Enable = void>
+  struct ArcNumTagIndicator {
+    static const bool value = false;
+  };
+
+  template <typename Graph>
+  struct ArcNumTagIndicator<
+    Graph,
+    typename enable_if<typename Graph::ArcNumTag, void>::type
+  > {
+    static const bool value = true;
+  };
+
+  template <typename Graph, typename Enable = void>
   struct EdgeNumTagIndicator {
     static const bool value = false;
@@ -232,4 +245,17 @@
 
   template <typename Graph, typename Enable = void>
+  struct FindArcTagIndicator {
+    static const bool value = false;
+  };
+
+  template <typename Graph>
+  struct FindArcTagIndicator<
+    Graph,
+    typename enable_if<typename Graph::FindArcTag, void>::type
+  > {
+    static const bool value = true;
+  };
+
+  template <typename Graph, typename Enable = void>
   struct FindEdgeTagIndicator {
     static const bool value = false;
Index: lemon/bits/vector_map.h
===================================================================
--- lemon/bits/vector_map.h	(revision 314)
+++ lemon/bits/vector_map.h	(revision 373)
@@ -39,7 +39,7 @@
   // \brief Graph map based on the std::vector storage.
   //
-  // The VectorMap template class is graph map structure what
-  // automatically updates the map when a key is added to or erased from
-  // the map. This map type uses the std::vector to store the values.
+  // The VectorMap template class is graph map structure that automatically
+  // updates the map when a key is added to or erased from the graph.
+  // This map type uses std::vector to store the values.
   //
   // \tparam _Graph The graph this map is attached to.
@@ -170,5 +170,5 @@
     // \brief Adds a new key to the map.
     //
-    // It adds a new key to the map. It called by the observer notifier
+    // It adds a new key to the map. It is called by the observer notifier
     // and it overrides the add() member function of the observer base.
     virtual void add(const Key& key) {
@@ -181,5 +181,5 @@
     // \brief Adds more new keys to the map.
     //
-    // It adds more new keys to the map. It called by the observer notifier
+    // It adds more new keys to the map. It is called by the observer notifier
     // and it overrides the add() member function of the observer base.
     virtual void add(const std::vector<Key>& keys) {
@@ -196,5 +196,5 @@
     // \brief Erase a key from the map.
     //
-    // Erase a key from the map. It called by the observer notifier
+    // Erase a key from the map. It is called by the observer notifier
     // and it overrides the erase() member function of the observer base.
     virtual void erase(const Key& key) {
@@ -204,5 +204,5 @@
     // \brief Erase more keys from the map.
     //
-    // Erase more keys from the map. It called by the observer notifier
+    // It erases more keys from the map. It is called by the observer notifier
     // and it overrides the erase() member function of the observer base.
     virtual void erase(const std::vector<Key>& keys) {
@@ -212,7 +212,7 @@
     }
 
-    // \brief Buildes the map.
-    //
-    // It buildes the map. It called by the observer notifier
+    // \brief Build the map.
+    //
+    // It builds the map. It is called by the observer notifier
     // and it overrides the build() member function of the observer base.
     virtual void build() {
@@ -224,5 +224,5 @@
     // \brief Clear the map.
     //
-    // It erase all items from the map. It called by the observer notifier
+    // It erases all items from the map. It is called by the observer notifier
     // and it overrides the clear() member function of the observer base.
     virtual void clear() {
Index: lemon/full_graph.h
===================================================================
--- lemon/full_graph.h	(revision 367)
+++ lemon/full_graph.h	(revision 372)
@@ -307,4 +307,5 @@
 
     typedef True NodeNumTag;
+    typedef True ArcNumTag;
     typedef True EdgeNumTag;
 
@@ -344,4 +345,5 @@
 
     typedef True FindEdgeTag;
+    typedef True FindArcTag;
 
     Edge findEdge(Node u, Node v, Edge prev = INVALID) const {
Index: lemon/grid_graph.h
===================================================================
--- lemon/grid_graph.h	(revision 350)
+++ lemon/grid_graph.h	(revision 372)
@@ -83,4 +83,5 @@
 
     typedef True NodeNumTag;
+    typedef True EdgeNumTag;
     typedef True ArcNumTag;
 
@@ -128,4 +129,5 @@
 
     typedef True FindEdgeTag;
+    typedef True FindArcTag;
 
     Edge findEdge(Node u, Node v, Edge prev = INVALID) const {
Index: lemon/smart_graph.h
===================================================================
--- lemon/smart_graph.h	(revision 341)
+++ lemon/smart_graph.h	(revision 372)
@@ -68,5 +68,5 @@
 
     typedef True NodeNumTag;
-    typedef True EdgeNumTag;
+    typedef True ArcNumTag;
 
     int nodeNum() const { return nodes.size(); }
