Changeset 1901:723b2b81d900 in lemon-0.x

Timestamp:

01/24/06 17:07:38 (18 years ago)

Author:

Balazs Dezso

Branch:

default

Phase:

public

Convert:

svn:c9d7d8f5-90d6-0310-b91f-818b3a526b0e/lemon/trunk@2476

Message:

Lemon Graph Format uses label instead of id named map.

Files:

• demo/coloring.lgf (modified) (2 diffs)
• demo/dir_components.lgf (modified) (2 diffs)
• demo/graph_orientation.cc (modified) (4 diffs)
• demo/graph_orientation.lgf (modified) (2 diffs)
• demo/partitions.lgf (modified) (2 diffs)
• demo/route.lgf (modified) (2 diffs)
• demo/sample.lgf (modified) (2 diffs)
• demo/sub_gad_input.lgf (modified) (2 diffs)
• demo/undir_components.lgf (modified) (2 diffs)
• doc/graph_io.dox (modified) (10 diffs)
• gui/graphocska.lgf (modified) (1 diff)
• lemon/graph_reader.h (modified) (4 diffs)
• lemon/graph_writer.h (modified) (4 diffs)
• lemon/lemon_reader.h (modified) (61 diffs)
• lemon/lemon_writer.h (modified) (43 diffs)
• test/Makefile.am (modified) (2 diffs)
• test/dijkstra_test.lgf (modified) (2 diffs)

demo/coloring.lgf

@@ -1 +1 @@
 @nodeset 
-coords  id      
+coords  label   
 (162, 142)      10      
 (169, -35)      9       
@@ -13 +13 @@
 (-282, -149)    0       
 @undiredgeset 
-                id      
+                label   
 9       10      17      
 1       9       15      

demo/dir_components.lgf

@@ -1 +1 @@
 @nodeset 
-coordinates_x   coordinates_y   id      
+coordinates_x   coordinates_y   label   
 218.178 27.2723 19      
 157.79  -130.517        18      
@@ -21 +21 @@
 -389.604        -136.361        1       
 @edgeset 
-                id      
+                label   
 17      19      23      
 19      18      24      

demo/graph_orientation.cc

@@ -50 +50 @@
 
   ListGraph::NodeMap<int> f(g); //in-deg requirement;
-  ListGraph::NodeMap<int> id(g);
+  ListGraph::NodeMap<int> label(g);
   ListGraph::NodeMap<xy<double> > coords(g);
   
@@ -56 +56 @@
     GraphReader<ListGraph> reader(argv[1],g);
     reader.readNodeMap("f",f);
-    reader.readNodeMap("id",id);
+    reader.readNodeMap("label",label);
     reader.readNodeMap("coordinates_x",xMap(coords));
     reader.readNodeMap("coordinates_y",yMap(coords));
@@ -81 +81 @@
   Node act;
   while((act=IterableBoolNodeMap<ListGraph>::TrueIt(active))!=INVALID) {
-    std::cout << "Process node " << id[act]
+    std::cout << "Process node " << label[act]
               << " (def=" << def[act]
               << " lev=" << level[act] << "): ";
@@ -88 +88 @@
     if(e!=INVALID) {
       std::cout << " REVERT EDGE " << g.id(e)
-                << " (" << id[g.source(e)] << "---"
-                << id[g.target(e)] << ")"
+                << " (" << label[g.source(e)] << "---"
+                << label[g.target(e)] << ")"
                 << std::endl;
       if(--def[act]==0) active[act]=false;

demo/graph_orientation.lgf

@@ -1 +1 @@
 @nodeset 
-coordinates_x   coordinates_y   f       id      
+coordinates_x   coordinates_y   f       label   
 -198    -73     2       7       
 120     30      4       6       
@@ -9 +9 @@
 -131    83      3       1       
 @edgeset 
-                id      
+                label   
 7       6       3       
 1       6       2       

demo/partitions.lgf

@@ -1 +1 @@
 @nodeset 
-coordinates_x   coordinates_y   id      
+coordinates_x   coordinates_y   label   
 513.857         -446.322        23      
 393.468         566.711         22      
@@ -25 +25 @@
 -274            -131            1       
 @undiredgeset 
-                id      
+                label   
 12      23      15      
 13      23      14      

demo/route.lgf

@@ -1 +1 @@
 @nodeset
-id      coordinates_x   coordinates_y   
+label   coordinates_x   coordinates_y   
 9       447.907 578.328 
 8       79.2573 909.464 
@@ -12 +12 @@
 0       189.239 92.5316 
 @edgeset
-                length  id      
+                length  label   
 2       3       901.074 0       
 8       5       270.85  1       

demo/sample.lgf

@@ -1 +1 @@
 @nodeset
-id      coordinates_x   coordinates_y
+label      coordinates_x   coordinates_y
 5       796.398 208.035
 4       573.002 63.002
@@ -8 +8 @@
 0       102.239 257.532
 @edgeset
-                id      capacity
+                label      capacity
 4       5       6       8
 3       5       5       8

demo/sub_gad_input.lgf

@@ -1 +1 @@
 @nodeset 
-id
+label
 6
 5
@@ -9 +9 @@
 0
 @edgeset 
-                id      length
+                label      length
 5       6       9       4
 4       6       8       2

demo/undir_components.lgf

@@ -1 +1 @@
 @nodeset 
-coordinates_x   coordinates_y   id      
+coordinates_x   coordinates_y   label   
 574.035 177.301 44      
 694.579 115.483 43      
@@ -45 +45 @@
 -567.302        43.6423 33      
 @undiredgeset 
-                id      
+                label   
 41      42      44      
 40      42      43      

doc/graph_io.dox

@@ -32 +32 @@
 The next line contains the names of the nodemaps, separated by whitespaces.  Each
 following line describes a node in the graph: it contains the values of the
-maps in the right order. The map named "id" should contain unique values
-because it is regarded as an ID-map. These ids need not be numbers but they
+maps in the right order. The map named "label" should contain unique values
+because it is regarded as a label map. These labels need not be numbers but they
 must identify the nodes uniquely for later reference. For example:
 
 \code
 @nodeset
-id  x-coord  y-coord  color
+label  x-coord  y-coord  color
 3   1.0      4.0      blue
 5   2.3      5.7      red
@@ -51 +51 @@
 The next line contains the whitespace separated list of names of the edge
 maps.  Each of the next lines describes one edge. The first two elements in
-the line are the IDs of the source and target (or tail and head) nodes of the
-edge as they occur in the ID node map of the nodeset section. You can also
-have an optional ID map on the edges for later reference (which has to be
+the line are the labels of the source and target (or tail and head) nodes of the
+edge as they occur in the label node map of the nodeset section. You can also
+have an optional label map on the edges for later reference (which has to be
 unique in this case).
 
 \code
 @edgeset
-             id    weight   label
-3   5        a     4.3      a-edge
-5   12       c     2.6      c-edge
-3   12       g     3.4      g-edge
+             label      weight   note
+3   5        a          4.3      a-edge
+5   12       c          2.6      c-edge
+3   12       g          3.4      g-edge
 \endcode
 
@@ -71 +71 @@
 
 Each of the next lines contains a label for a node in the graph 
-and then the ID as described in the \e nodeset section.
+and then the label as described in the \e nodeset section.
 
 \code
@@ -81 +81 @@
 The last section describes the <em>labeled (distinguished) edges</em>
 (i.e. edges having a special label on them). It starts with \c \@edges
-and then each line contains the name of the edge and the ID.
+and then each line contains the name of the edge and the label.
 
 \code
@@ -104 +104 @@
 \endcode
 
-<tt> \@end </tt>
-
-line.
+Finally, the file should be closed with \c \@end line.
 
 
@@ -133 +131 @@
 \ref lemon::GraphWriter "GraphWriter".
 You should give a name to the map and the map
-object as parameters. The NodeMap writing command with name "id" should write a 
-unique map because it will be regarded as an ID map.
+object as parameters. The NodeMap writing command with name "label" should write a 
+unique map because it will be regarded as a label map.
 
 \see IdMap, DescriptorMap  
 
 \code
-IdMap<ListGraph, Node> nodeIdMap;
-writer.writeNodeMap("id", nodeIdMap);
+IdMap<ListGraph, Node> nodeLabelMap;
+writer.writeNodeMap("label", nodeLabelMap);
 
 writer.writeNodeMap("x-coord", xCoordMap);
@@ -158 +156 @@
 
 writer.writeEdgeMap("weight", weightMap);
-writer.writeEdgeMap("label", labelMap);
+writer.writeEdgeMap("note", noteMap);
 \endcode
 
@@ -315 +313 @@
 special template parameter to the GraphReader class. By default, the
 template parameter is \c DefaultReaderTraits. A reader traits class 
-should provide an inner template class Reader for each type, and a 
+should provide a nested template class Reader for each type, and a 
 DefaultReader for skipping a value.
 
-The specialization of  writing is very similar to that of reading.
+The specialization of writing is very similar to that of reading.
 
 \section undir Undirected graphs
@@ -334 +332 @@
 \code
 @undiredgeset
-             id    capacity +flow -flow
-32   2       1     4.3      2.0   0.0
-21   21      5     2.6      0.0   2.6
-21   12      8     3.4      0.0   0.0
+             label      capacity        +flow   -flow
+32   2       1          4.3             2.0     0.0
+21   21      5          2.6             0.0     2.6
+21   12      8          3.4             0.0     0.0
 \endcode
 
@@ -462 +460 @@
 and the \ref lemon::UndirGraphReader "UndirGraphReader" can be converted
 to \ref lemon::LemonReader "LemonReader"
-and it can resolve the ID's of the items, the previous
+and it can resolve the label's of the items, the previous
 result can be achived with the \ref lemon::UndirGraphReader "UndirGraphReader"
 class, too.

gui/graphocska.lgf

@@ -1 +1 @@
 @nodeset
-id      coordinates_x   coordinates_y data
+label   coordinates_x   coordinates_y data
 1       230     -80     1.123
 2       230     100     3.234

lemon/graph_reader.h

@@ -68 +68 @@
   /// reader.readNodeMap("coords", coords);
   ///
-  /// reader.readNodeMap<QuotedStringReader>("label", labelMap);
-  /// reader.skipNodeMap<QuotedStringReader>("description");
+  /// reader.skipNodeMap("description", desc);
   ///
   /// reader.readNodeMap("color", colorMap);
@@ -307 +306 @@
     }
 
-    /// \brief Gives back the node by its id.
-    ///
-    /// It reads an id from the stream and gives back which node belongs to
-    /// it. It is possible only if there was read an "id" named node map.
-    Node readId(std::istream& is, Node) const {
-      return nodeset_reader.readId(is, Node());
+
+    /// \brief Returns true if the reader can give back the items by its label.
+    ///
+    /// \brief Returns true if the reader can give back the items by its label.
+    bool isLabelReader() const {
+      return nodeset_reader.isLabelReader() && edgeset_reader.isLabelReader();
+    }
+
+    /// \brief Gives back the node by its label.
+    ///
+    /// It reads an label from the stream and gives back which node belongs to
+    /// it. It is possible only if there was read an "label" named node map.
+    void readLabel(std::istream& is, Node& node) const {
+      nodeset_reader.readLabel(is, node);
     } 
 
-    /// \brief Gives back the edge by its id.
-    ///
-    /// It reads an id from the stream and gives back which edge belongs to
-    /// it. It is possible only if there was read an "id" named edge map.
-    Edge readId(std::istream& is, Edge) const {
-      return edgeset_reader.readId(is, Edge());
+    /// \brief Gives back the edge by its label.
+    ///
+    /// It reads an label from the stream and gives back which edge belongs to
+    /// it. It is possible only if there was read an "label" named edge map.
+    void readLabel(std::istream& is, Edge& edge) const {
+      return edgeset_reader.readLabel(is, edge);
     } 
 
@@ -405 +412 @@
   /// reader.readNodeMap("coords", coords);
   ///
-  /// reader.readNodeMap<QuotedStringReader>("label", labelMap);
-  /// reader.skipNodeMap<QuotedStringReader>("description");
+  /// reader.skipNodeMap("description", desc);
   ///
   /// reader.readNodeMap("color", colorMap);
@@ -705 +711 @@
     }
 
-    /// \brief Gives back the node by its id.
-    ///
-    /// It reads an id from the stream and gives back which node belongs to
-    /// it. It is possible only if there was read an "id" named node map.
-    Node readId(std::istream& is, Node) const {
-      return nodeset_reader.readId(is, Node());
+
+    /// \brief Returns true if the reader can give back the items by its label.
+    ///
+    /// \brief Returns true if the reader can give back the items by its label.
+    bool isLabelReader() const {
+      return nodeset_reader.isLabelReader() && 
+        undir_edgeset_reader.isLabelReader();
+    }
+
+    /// \brief Gives back the node by its label.
+    ///
+    /// It reads an label from the stream and gives back which node belongs to
+    /// it. It is possible only if there was read an "label" named node map.
+    void readLabel(std::istream& is, Node& node) const {
+      return nodeset_reader.readLabel(is, node);
     } 
 
-    /// \brief Gives back the edge by its id.
-    ///
-    /// It reads an id from the stream and gives back which edge belongs to
-    /// it. It is possible only if there was read an "id" named edge map.
-    Edge readId(std::istream& is, Edge) const {
-      return undir_edgeset_reader.readId(is, Edge());
+    /// \brief Gives back the edge by its label.
+    ///
+    /// It reads an label from the stream and gives back which edge belongs to
+    /// it. It is possible only if there was read an "label" named edge map.
+    void readLabel(std::istream& is, Edge& edge) const {
+      return undir_edgeset_reader.readLabel(is, edge);
     } 
 
-    /// \brief Gives back the undirected edge by its id.
-    ///
-    /// It reads an id from the stream and gives back which undirected edge 
-    /// belongs to it. It is possible only if there was read an "id" named 
+    /// \brief Gives back the undirected edge by its label.
+    ///
+    /// It reads an label from the stream and gives back which undirected edge 
+    /// belongs to it. It is possible only if there was read an "label" named 
     /// edge map.
-    UndirEdge readId(std::istream& is, UndirEdge) const {
-      return undir_edgeset_reader.readId(is, UndirEdge());
+    void readLabel(std::istream& is, UndirEdge& uedge) const {
+      return undir_edgeset_reader.readLabel(is, uedge);
     } 
     

lemon/graph_writer.h

@@ -55 +55 @@
   /// command in the \c GraphWriter. You should give as parameter 
   /// the name of the map and the map object. The NodeMap writing 
-  /// command with name "id" should write a unique map because it 
-  /// is regarded as ID map (such a map is essential if the graph has edges).
-  ///
-  /// \code
-  /// IdMap<ListGraph, Node> nodeIdMap;
-  /// writer.writeNodeMap("id", nodeIdMap);
+  /// command with name "label" should write a unique map because it 
+  /// is regarded as label map (such a map is essential if the graph has edges).
+  ///
+  /// \code
+  /// IdMap<ListGraph, Node> nodeLabelMap;
+  /// writer.writeNodeMap("label", nodeLabelMap);
   ///
   /// writer.writeNodeMap("coords", coords);
@@ -254 +254 @@
     }
 
-    /// \brief Write the id of the given node.
-    ///
-    /// It writes the id of the given node. If there was written an "id"
+    /// \brief Write the label of the given node.
+    ///
+    /// It writes the label of the given node. If there was written an "label"
     /// named node map then it will write the map value belonging to the node.
-    void writeId(std::ostream& os, const Node& item) const {
-      nodeset_writer.writeId(os, item);
+    void writeLabel(std::ostream& os, const Node& item) const {
+      nodeset_writer.writeLabel(os, item);
     } 
 
-    /// \brief Write the id of the given edge.
-    ///
-    /// It writes the id of the given edge. If there was written an "id"
+    /// \brief Write the label of the given edge.
+    ///
+    /// It writes the label of the given edge. If there was written an "label"
     /// named edge map then it will write the map value belonging to the edge.
-    void writeId(std::ostream& os, const Edge& item) const {
-      edgeset_writer.writeId(os, item);
+    void writeLabel(std::ostream& os, const Edge& item) const {
+      edgeset_writer.writeLabel(os, item);
     } 
 
@@ -328 +328 @@
   /// command in the \c UndirGraphWriter. You should give as parameter 
   /// the name of the map and the map object. The NodeMap writing 
-  /// command with name "id" should write a unique map because it 
-  /// is regarded as ID map.
-  ///
-  /// \code
-  /// IdMap<UndirListGraph, Node> nodeIdMap;
-  /// writer.writeNodeMap("id", nodeIdMap);
+  /// command with name "label" should write a unique map because it 
+  /// is regarded as label map.
+  ///
+  /// \code
+  /// IdMap<UndirListGraph, Node> nodeLabelMap;
+  /// writer.writeNodeMap("label", nodeLabelMap);
   ///
   /// writer.writeNodeMap("coords", coords);
@@ -562 +562 @@
     }
 
-    /// \brief Write the id of the given node.
-    ///
-    /// It writes the id of the given node. If there was written an "id"
+    /// \brief Write the label of the given node.
+    ///
+    /// It writes the label of the given node. If there was written an "label"
     /// named node map then it will write the map value belonging to the node.
-    void writeId(std::ostream& os, const Node& item) const {
-      nodeset_writer.writeId(os, item);
+    void writeLabel(std::ostream& os, const Node& item) const {
+      nodeset_writer.writeLabel(os, item);
     } 
 
-    /// \brief Write the id of the given edge.
-    ///
-    /// It writes the id of the given edge. If there was written an "id"
+    /// \brief Write the label of the given edge.
+    ///
+    /// It writes the label of the given edge. If there was written an "label"
     /// named edge map then it will write the map value belonging to the edge.
-    void writeId(std::ostream& os, const Edge& item) const {
-      undir_edgeset_writer.writeId(os, item);
+    void writeLabel(std::ostream& os, const Edge& item) const {
+      undir_edgeset_writer.writeLabel(os, item);
     } 
 
-    /// \brief Write the id of the given undirected edge.
-    ///
-    /// It writes the id of the given undirected edge. If there was written 
-    /// an "id" named edge map then it will write the map value belonging to 
+    /// \brief Write the label of the given undirected edge.
+    ///
+    /// It writes the label of the given undirected edge. If there was written 
+    /// an "label" named edge map then it will write the map value belonging to 
     /// the edge.
-    void writeId(std::ostream& os, const UndirEdge& item) const {
-      undir_edgeset_writer.writeId(os, item);
+    void writeLabel(std::ostream& os, const UndirEdge& item) const {
+      undir_edgeset_writer.writeLabel(os, item);
     } 
 

lemon/lemon_reader.h

@@ -48 +48 @@
     template <typename T>
     bool operator<(T, T) {
-      throw DataFormatError("Id is not comparable");
+      throw DataFormatError("Label is not comparable");
     }
 
@@ -59 +59 @@
 
     template <typename Item>
-    class ItemIdReader {
+    class ItemLabelReader {
     public:
 
-      bool isIdReader() { return true; }
-
-      void readId(std::istream&, Item&) {}
+      bool isLabelReader() { return true; }
+
+      void readLabel(std::istream&, Item&) {}
       
-      template <class _ItemIdReader>
+      template <class _ItemLabelReader>
       struct Constraints {
         void constraints() {
-          bool b = reader.isIdReader();
+          bool b = reader.isLabelReader();
           ignore_unused_variable_warning(b);
           Item item;
-          reader.readId(is, item);
-        }
-        _ItemIdReader& reader;
+          reader.readLabel(is, item);
+        }
+        _ItemLabelReader& reader;
         std::istream& is;
       };
@@ -242 +242 @@
           inverse.insert(std::make_pair(value, item));
         } else {
-          throw DataFormatError("Multiple ID occurence");
+          throw DataFormatError("Multiple label occurence");
         }
       }
@@ -253 +253 @@
           return it->second;
         } else {
-          throw DataFormatError("Invalid ID error");
+          throw DataFormatError("Invalid label error");
         }
       }      
@@ -280 +280 @@
           inverse.insert(std::make_pair(value, item));
         } else {
-          throw DataFormatError("Multiple ID occurence error");
+          throw DataFormatError("Multiple label occurence error");
         }
       }
@@ -291 +291 @@
           return it->second;
         } else {
-          throw DataFormatError("Invalid ID error");
+          throw DataFormatError("Invalid label error");
         }
       }
@@ -371 +371 @@
 
     template <typename _Item>
-    class IdReaderBase {
+    class LabelReaderBase {
     public:
       typedef _Item Item;
-      virtual ~IdReaderBase() {}
+      virtual ~LabelReaderBase() {}
       virtual Item read(std::istream& is) const = 0;
-      virtual bool isIdReader() const = 0;
-    };
-
-    template <typename _Item, typename _BoxedIdReader>
-    class IdReader : public IdReaderBase<_Item> {
+      virtual bool isLabelReader() const = 0;
+    };
+
+    template <typename _Item, typename _BoxedLabelReader>
+    class LabelReader : public LabelReaderBase<_Item> {
     public:
       typedef _Item Item;
-      typedef _BoxedIdReader BoxedIdReader;
+      typedef _BoxedLabelReader BoxedLabelReader;
       
-      const BoxedIdReader& boxedIdReader;
-
-      IdReader(const BoxedIdReader& _boxedIdReader) 
-        : boxedIdReader(_boxedIdReader) {}
+      const BoxedLabelReader& boxedLabelReader;
+
+      LabelReader(const BoxedLabelReader& _boxedLabelReader) 
+        : boxedLabelReader(_boxedLabelReader) {}
 
       virtual Item read(std::istream& is) const {
         Item item;
-        boxedIdReader.readId(is, item);
+        boxedLabelReader.readLabel(is, item);
         return item;
       }
 
-      virtual bool isIdReader() const {
-        return boxedIdReader.isIdReader();
+      virtual bool isLabelReader() const {
+        return boxedLabelReader.isLabelReader();
       }
     };
@@ -728 +728 @@
   ///
   /// The lemon format can store multiple graph nodesets with several maps.
-  /// The nodeset section's header line is \c \@nodeset \c nodeset_id, but the
-  /// \c nodeset_id may be empty.
+  /// The nodeset section's header line is \c \@nodeset \c nodeset_name, but the
+  /// \c nodeset_name may be empty.
   ///
   /// The first line of the section contains the names of the maps separated
@@ -735 +735 @@
   /// contains the mapped values for each map.
   ///
-  /// If the nodeset contains an \c "id" named map then it will be regarded
+  /// If the nodeset contains an \c "label" named map then it will be regarded
   /// as id map. This map should contain only unique values and when the 
-  /// \c readId() member will read a value from the given stream it will
+  /// \c readLabel() member will read a value from the given stream it will
   /// give back that node which is mapped to this value.
   ///
@@ -756 +756 @@
     /// attach it into the given LemonReader. The nodeset reader will
     /// add the readed nodes to the given Graph. The reader will read
-    /// the section when the \c section_id and the \c _id are the same. 
+    /// the section when the \c section_name and the \c _name are the same. 
     NodeSetReader(LemonReader& _reader, 
                   Graph& _graph, 
-                  const std::string& _id = std::string(),
+                  const std::string& _name = std::string(),
                   const DefaultSkipper& _skipper = DefaultSkipper()) 
-      : Parent(_reader), graph(_graph), id(_id), skipper(_skipper) {} 
+      : Parent(_reader), graph(_graph), name(_name), skipper(_skipper) {} 
 
 
@@ -856 +856 @@
     ///
     /// It gives back true when the header line starts with \c \@nodeset,
-    /// and the header line's id and the nodeset's id are the same.
+    /// and the header line's name and the nodeset's name are the same.
     virtual bool header(const std::string& line) {
       std::istringstream ls(line);
       std::string command;
-      std::string name;
+      std::string id;
       ls >> command >> name;
       return command == "@nodeset" && name == id;
@@ -873 +873 @@
 
       getline(is, line);
-      std::istringstream ls(line);      
+      std::istringstream ls(line);
+      std::string id;
       while (ls >> id) {
         typename MapReaders::iterator it = readers.find(id);
@@ -882 +883 @@
           index.push_back(&skipper);
         }
-        if (id == "id" && inverter.get() == 0) {
+        if (id == "label" || (id =="id" && inverter.get() == 0)) {
           inverter.reset(index.back()->getInverter());
           index.back() = inverter.get();
@@ -906 +907 @@
   public:
 
-    /// \brief Returns true if the nodeset can give back the node by its id.
-    ///
-    /// Returns true if the nodeset can give back the node by its id.
-    /// It is possible only if an "id" named map was read.
-    bool isIdReader() const {
+    /// \brief Returns true if the nodeset can give back the node by its label.
+    ///
+    /// Returns true if the nodeset can give back the node by its label.
+    /// It is possible only if an "label" named map was read.
+    bool isLabelReader() const {
       return inverter.get() != 0;
     }
 
-    /// \brief Gives back the node by its id.
+    /// \brief Gives back the node by its label.
     ///
     /// It reads an id from the stream and gives back which node belongs to
-    /// it. It is possible only if there was read an "id" named map.
-    void readId(std::istream& is, Node& node) const {
+    /// it. It is possible only if there was read an "label" named map.
+    void readLabel(std::istream& is, Node& node) const {
       node = inverter->read(is);
     } 
@@ -928 +929 @@
    
     Graph& graph;   
-    std::string id;
+    std::string name;
     _reader_bits::SkipReader<Node, DefaultSkipper> skipper;
 
@@ -938 +939 @@
   ///
   /// The lemon format can store multiple graph edgesets with several maps.
-  /// The edgeset section's header line is \c \@edgeset \c edgeset_id, but the
-  /// \c edgeset_id may be empty.
+  /// The edgeset section's header line is \c \@edgeset \c edgeset_name, but the
+  /// \c edgeset_name may be empty.
   ///
   /// The first line of the section contains the names of the maps separated
@@ -946 +947 @@
   /// values for each map.
   ///
-  /// If the edgeset contains an \c "id" named map then it will be regarded
+  /// If the edgeset contains an \c "label" named map then it will be regarded
   /// as id map. This map should contain only unique values and when the 
-  /// \c readId() member will read a value from the given stream it will
+  /// \c readLabel() member will read a value from the given stream it will
   /// give back that edge which is mapped to this value.
   ///
   /// The edgeset reader needs a node id reader to identify which nodes
-  /// have to be connected. If a NodeSetReader reads an "id" named map,
+  /// have to be connected. If a NodeSetReader reads an "label" named map,
   /// it will be able to resolve the nodes by ids.
   ///
@@ -973 +974 @@
     /// add the readed edges to the given Graph. It will use the given
     /// node id reader to read the source and target nodes of the edges.
-    /// The reader will read the section only if the \c _id and the 
-    /// \c edgset_id are the same. 
-    template <typename NodeIdReader>
+    /// The reader will read the section only if the \c _name and the 
+    /// \c edgset_name are the same. 
+    template <typename NodeLabelReader>
     EdgeSetReader(LemonReader& _reader, 
                   Graph& _graph, 
-                  const NodeIdReader& _nodeIdReader, 
-                  const std::string& _id = std::string(),
+                  const NodeLabelReader& _nodeLabelReader, 
+                  const std::string& _name = std::string(),
                   const DefaultSkipper& _skipper = DefaultSkipper()) 
-      : Parent(_reader), graph(_graph), id(_id), skipper(_skipper) {
-      checkConcept<_reader_bits::ItemIdReader<Node>, NodeIdReader>();
-      nodeIdReader.reset(new _reader_bits::
-                         IdReader<Node, NodeIdReader>(_nodeIdReader));
+      : Parent(_reader), graph(_graph), name(_name), skipper(_skipper) {
+      checkConcept<_reader_bits::ItemLabelReader<Node>, NodeLabelReader>();
+      nodeLabelReader.reset(new _reader_bits::
+                         LabelReader<Node, NodeLabelReader>(_nodeLabelReader));
     }
     /// \brief Destructor.
@@ -1078 +1079 @@
     ///
     /// It gives back true when the header line starts with \c \@edgeset,
-    /// and the header line's id and the edgeset's id are the same.
+    /// and the header line's name and the edgeset's name are the same.
     virtual bool header(const std::string& line) {
       std::istringstream ls(line);
       std::string command;
-      std::string name;
+      std::string id;
       ls >> command >> name;
       return command == "@edgeset" && name == id;
@@ -1091 +1092 @@
     /// It reads the content of the section.
     virtual void read(std::istream& is) {
-      if (!nodeIdReader->isIdReader()) {
-        throw DataFormatError("Cannot find nodeset or ID map");
+      if (!nodeLabelReader->isLabelReader()) {
+        throw DataFormatError("Cannot find nodeset or label map");
       }
       std::vector<_reader_bits::MapReaderBase<Edge>* > index;
@@ -1099 +1100 @@
       getline(is, line);
       std::istringstream ls(line);      
+      std::string id;
       while (ls >> id) {
         typename MapReaders::iterator it = readers.find(id);
@@ -1107 +1109 @@
           index.push_back(&skipper);
         }
-        if (id == "id" && inverter.get() == 0) {
+        if (id == "label" || (id =="id" && inverter.get() == 0)) {
           inverter.reset(index.back()->getInverter());
           index.back() = inverter.get();
@@ -1122 +1124 @@
       while (getline(is, line)) {       
         std::istringstream ls(line);
-        Node from = nodeIdReader->read(ls);
-        Node to = nodeIdReader->read(ls);
+        Node from = nodeLabelReader->read(ls);
+        Node to = nodeLabelReader->read(ls);
         Edge edge = graph.addEdge(from, to);
         for (int i = 0; i < (int)index.size(); ++i) {
@@ -1133 +1135 @@
   public:
 
-    /// \brief Returns true if the edgeset can give back the edge by its id.
-    ///
-    /// Returns true if the edgeset can give back the edge by its id.
-    /// It is possible only if an "id" named map was read.
-    bool isIdReader() const {
+    /// \brief Returns true if the edgeset can give back the edge by its label.
+    ///
+    /// Returns true if the edgeset can give back the edge by its label.
+    /// It is possible only if an "label" named map was read.
+    bool isLabelReader() const {
       return inverter.get() != 0;
     }
 
-    /// \brief Gives back the edge by its id.
+    /// \brief Gives back the edge by its label.
     ///
     /// It reads an id from the stream and gives back which edge belongs to
-    /// it. It is possible only if there was read an "id" named map.
-    void readId(std::istream& is, Edge& edge) const {
+    /// it. It is possible only if there was read an "label" named map.
+    void readLabel(std::istream& is, Edge& edge) const {
       edge = inverter->read(is);
     } 
@@ -1155 +1157 @@
    
     Graph& graph;   
-    std::string id;
+    std::string name;
     _reader_bits::SkipReader<Edge, DefaultSkipper> skipper;
 
     std::auto_ptr<_reader_bits::MapInverterBase<Edge> > inverter;
-    std::auto_ptr<_reader_bits::IdReaderBase<Node> > nodeIdReader;
+    std::auto_ptr<_reader_bits::LabelReaderBase<Node> > nodeLabelReader;
   };
 
@@ -1167 +1169 @@
   /// The lemon format can store multiple undirected edgesets with several 
   /// maps. The undirected edgeset section's header line is \c \@undiredgeset 
-  /// \c undiredgeset_id, but the \c undiredgeset_id may be empty.
+  /// \c undiredgeset_name, but the \c undiredgeset_name may be empty.
   ///
   /// The first line of the section contains the names of the maps separated
@@ -1179 +1181 @@
   /// difference.
   ///
-  /// If the edgeset contains an \c "id" named map then it will be regarded
+  /// If the edgeset contains an \c "label" named map then it will be regarded
   /// as id map. This map should contain only unique values and when the 
-  /// \c readId() member will read a value from the given stream it will
+  /// \c readLabel() member will read a value from the given stream it will
   /// give back that undiricted edge which is mapped to this value.
   ///
   /// The undirected edgeset reader needs a node id reader to identify which 
-  /// nodes have to be connected. If a NodeSetReader reads an "id" named map,
+  /// nodes have to be connected. If a NodeSetReader reads an "label" named map,
   /// it will be able to resolve the nodes by ids.
   ///
@@ -1208 +1210 @@
     /// will use the given node id reader to read the source and target 
     /// nodes of the edges. The reader will read the section only if the 
-    /// \c _id and the \c undiredgset_id are the same. 
-    template <typename NodeIdReader>
+    /// \c _name and the \c undiredgset_name are the same. 
+    template <typename NodeLabelReader>
     UndirEdgeSetReader(LemonReader& _reader, 
                        Graph& _graph, 
-                       const NodeIdReader& _nodeIdReader, 
-                       const std::string& _id = std::string(),
+                       const NodeLabelReader& _nodeLabelReader, 
+                       const std::string& _name = std::string(),
                        const DefaultSkipper& _skipper = DefaultSkipper()) 
-      : Parent(_reader), graph(_graph), id(_id), skipper(_skipper) {
-      checkConcept<_reader_bits::ItemIdReader<Node>, NodeIdReader>();
-      nodeIdReader.reset(new _reader_bits::
-                         IdReader<Node, NodeIdReader>(_nodeIdReader));
+      : Parent(_reader), graph(_graph), name(_name), skipper(_skipper) {
+      checkConcept<_reader_bits::ItemLabelReader<Node>, NodeLabelReader>();
+      nodeLabelReader.reset(new _reader_bits::
+                         LabelReader<Node, NodeLabelReader>(_nodeLabelReader));
     }
     /// \brief Destructor.
@@ -1373 +1375 @@
     ///
     /// It gives back true when the header line starts with \c \@undiredgeset,
-    /// and the header line's id and the edgeset's id are the same.
+    /// and the header line's name and the edgeset's name are the same.
     virtual bool header(const std::string& line) {
       std::istringstream ls(line);
       std::string command;
-      std::string name;
+      std::string id;
       ls >> command >> name;
       return command == "@undiredgeset" && name == id;
@@ -1386 +1388 @@
     /// It reads the content of the section.
     virtual void read(std::istream& is) {
-      if (!nodeIdReader->isIdReader()) {
-        throw DataFormatError("Cannot find nodeset or ID map");
+      if (!nodeLabelReader->isLabelReader()) {
+        throw DataFormatError("Cannot find nodeset or label map");
       }
       std::vector<_reader_bits::MapReaderBase<UndirEdge>* > index;
@@ -1394 +1396 @@
       getline(is, line);
       std::istringstream ls(line);      
+      std::string id;
       while (ls >> id) {
         typename MapReaders::iterator it = readers.find(id);
@@ -1402 +1405 @@
           index.push_back(&skipper);
         }
-        if (id == "id" && inverter.get() == 0) {
+        if (id == "label" || (id =="id" && inverter.get() == 0)) {
           inverter.reset(index.back()->getInverter());
           index.back() = inverter.get();
@@ -1417 +1420 @@
       while (getline(is, line)) {       
         std::istringstream ls(line);
-        Node from = nodeIdReader->read(ls);
-        Node to = nodeIdReader->read(ls);
+        Node from = nodeLabelReader->read(ls);
+        Node to = nodeLabelReader->read(ls);
         UndirEdge edge = graph.addEdge(from, to);
         for (int i = 0; i < (int)index.size(); ++i) {
@@ -1428 +1431 @@
   public:
 
-    /// \brief Returns true if the edgeset can give back the edge by its id.
+    /// \brief Returns true if the edgeset can give back the edge by its label.
     ///
     /// Returns true if the edgeset can give back the undirected edge by its 
-    /// id. It is possible only if an "id" named map was read.
-    bool isIdReader() const {
+    /// id. It is possible only if an "label" named map was read.
+    bool isLabelReader() const {
       return inverter.get() != 0;
     }
 
-    /// \brief Gives back the undirected edge by its id.
+    /// \brief Gives back the undirected edge by its label.
     ///
     /// It reads an id from the stream and gives back which undirected edge 
-    /// belongs to it. It is possible only if there was read an "id" named map.
-    void readId(std::istream& is, UndirEdge& undirEdge) const {
+    /// belongs to it. It is possible only if there was read an "label" named map.
+    void readLabel(std::istream& is, UndirEdge& undirEdge) const {
       undirEdge = inverter->read(is);
     } 
 
-    /// \brief Gives back the directed edge by its id.
+    /// \brief Gives back the directed edge by its label.
     ///
     /// It reads an id from the stream and gives back which directed edge 
     /// belongs to it. The directed edge id is the \c '+' or \c '-' character
     /// and the undirected edge id. It is possible only if there was read 
-    /// an "id" named map.
-    void readId(std::istream& is, Edge& edge) const {
+    /// an "label" named map.
+    void readLabel(std::istream& is, Edge& edge) const {
       char c;
       is >> c;
@@ -1471 +1474 @@
    
     Graph& graph;   
-    std::string id;
+    std::string name;
     _reader_bits::SkipReader<UndirEdge, DefaultSkipper> skipper;
 
     std::auto_ptr<_reader_bits::MapInverterBase<UndirEdge> > inverter;
-    std::auto_ptr<_reader_bits::IdReaderBase<Node> > nodeIdReader;
+    std::auto_ptr<_reader_bits::LabelReaderBase<Node> > nodeLabelReader;
   };
 
@@ -1481 +1484 @@
   /// \brief SectionReader for reading labeled nodes.
   ///
-  /// The nodes section's header line is \c \@nodes \c nodes_id, but the
-  /// \c nodes_id may be empty.
+  /// The nodes section's header line is \c \@nodes \c nodes_name, but the
+  /// \c nodes_name may be empty.
   ///
   /// Each line in the section contains the name of the node 
@@ -1500 +1503 @@
     /// attach it into the given LemonReader. It will use the given
     /// node id reader to give back the nodes. The reader will read the 
-    /// section only if the \c _id and the \c nodes_id are the same. 
-    template <typename _IdReader>
-    NodeReader(LemonReader& _reader, const _IdReader& _idReader, 
-               const std::string& _id = std::string()) 
-      : Parent(_reader), id(_id) {
-      checkConcept<_reader_bits::ItemIdReader<Node>, _IdReader>();
-      nodeIdReader.reset(new _reader_bits::
-                         IdReader<Node, _IdReader>(_idReader));
+    /// section only if the \c _name and the \c nodes_name are the same. 
+    template <typename _LabelReader>
+    NodeReader(LemonReader& _reader, const _LabelReader& _labelReader, 
+               const std::string& _name = std::string()) 
+      : Parent(_reader), name(_name) {
+      checkConcept<_reader_bits::ItemLabelReader<Node>, _LabelReader>();
+      nodeLabelReader.reset(new _reader_bits::
+                         LabelReader<Node, _LabelReader>(_labelReader));
     }
 
@@ -1539 +1542 @@
     ///
     /// It gives back true when the header line start with \c \@nodes,
-    /// and the header line's id and the reader's id are the same.
+    /// and the header line's name and the reader's name are the same.
     virtual bool header(const std::string& line) {
       std::istringstream ls(line);
       std::string command;
-      std::string name;
+      std::string id;
       ls >> command >> name;
       return command == "@nodes" && name == id;
@@ -1552 +1555 @@
     /// It reads the content of the section.
     virtual void read(std::istream& is) {
-      if (!nodeIdReader->isIdReader()) {
-        throw DataFormatError("Cannot find nodeset or ID map");
+      if (!nodeLabelReader->isLabelReader()) {
+        throw DataFormatError("Cannot find nodeset or label map");
       }
       std::string line;
@@ -1562 +1565 @@
         typename NodeReaders::iterator it = readers.find(id);
         if (it != readers.end()) {
-          it->second.read(nodeIdReader->read(ls));
+          it->second.read(nodeLabelReader->read(ls));
           it->second.touch();
         }       
@@ -1578 +1581 @@
   private:
 
-    std::string id;
+    std::string name;
 
     typedef std::map<std::string, _reader_bits::ItemStore<Node> > NodeReaders;
     NodeReaders readers;
-    std::auto_ptr<_reader_bits::IdReaderBase<Node> > nodeIdReader;
+    std::auto_ptr<_reader_bits::LabelReaderBase<Node> > nodeLabelReader;
   };
 
@@ -1588 +1591 @@
   /// \brief SectionReader for reading labeled edges.
   ///
-  /// The edges section's header line is \c \@edges \c edges_id, but the
-  /// \c edges_id may be empty.
+  /// The edges section's header line is \c \@edges \c edges_name, but the
+  /// \c edges_name may be empty.
   ///
   /// Each line in the section contains the name of the edge 
@@ -1607 +1610 @@
     /// attach it into the given LemonReader. It will use the given
     /// edge id reader to give back the edges. The reader will read the 
-    /// section only if the \c _id and the \c edges_id are the same. 
-    template <typename _IdReader>
-    EdgeReader(LemonReader& _reader, const _IdReader& _idReader, 
-               const std::string& _id = std::string()) 
-      : Parent(_reader), id(_id) {
-      checkConcept<_reader_bits::ItemIdReader<Edge>, _IdReader>();
-      edgeIdReader.reset(new _reader_bits::
-                         IdReader<Edge, _IdReader>(_idReader));
+    /// section only if the \c _name and the \c edges_name are the same. 
+    template <typename _LabelReader>
+    EdgeReader(LemonReader& _reader, const _LabelReader& _labelReader, 
+               const std::string& _name = std::string()) 
+      : Parent(_reader), name(_name) {
+      checkConcept<_reader_bits::ItemLabelReader<Edge>, _LabelReader>();
+      edgeLabelReader.reset(new _reader_bits::
+                         LabelReader<Edge, _LabelReader>(_labelReader));
     }
 
@@ -1645 +1648 @@
     ///
     /// It gives back true when the header line start with \c \@edges,
-    /// and the header line's id and the reader's id are the same.
+    /// and the header line's name and the reader's name are the same.
     virtual bool header(const std::string& line) {
       std::istringstream ls(line);
       std::string command;
-      std::string name;
+      std::string id;
       ls >> command >> name;
       return command == "@edges" && name == id;
@@ -1658 +1661 @@
     /// It reads the content of the section.
     virtual void read(std::istream& is) {
-      if (!edgeIdReader->isIdReader()) {
-        throw DataFormatError("Cannot find edgeset or ID map");
+      if (!edgeLabelReader->isLabelReader()) {
+        throw DataFormatError("Cannot find edgeset or label map");
       }
       std::string line;
@@ -1668 +1671 @@
         typename EdgeReaders::iterator it = readers.find(id);
         if (it != readers.end()) {
-          it->second.read(edgeIdReader->read(ls));
+          it->second.read(edgeLabelReader->read(ls));
           it->second.touch();
         }       
@@ -1684 +1687 @@
   private:
 
-    std::string id;
+    std::string name;
 
     typedef std::map<std::string, _reader_bits::ItemStore<Edge> > EdgeReaders;
     EdgeReaders readers;
-    std::auto_ptr<_reader_bits::IdReaderBase<Edge> > edgeIdReader;
+    std::auto_ptr<_reader_bits::LabelReaderBase<Edge> > edgeLabelReader;
   };
 
@@ -1695 +1698 @@
   ///
   /// The undirected edges section's header line is \c \@undiredges 
-  /// \c undiredges_id, but the \c undiredges_id may be empty.
+  /// \c undiredges_name, but the \c undiredges_name may be empty.
   ///
   /// Each line in the section contains the name of the undirected edge 
@@ -1714 +1717 @@
     /// attach it into the given LemonReader. It will use the given
     /// undirected edge id reader to give back the edges. The reader will 
-    /// read the section only if the \c _id and the \c undiredges_id are 
+    /// read the section only if the \c _name and the \c undiredges_name are 
     /// the same. 
-    template <typename _IdReader>
-    UndirEdgeReader(LemonReader& _reader, const _IdReader& _idReader, 
-               const std::string& _id = std::string()) 
-      : Parent(_reader), id(_id) {
-      checkConcept<_reader_bits::ItemIdReader<UndirEdge>, _IdReader>();
-      checkConcept<_reader_bits::ItemIdReader<Edge>, _IdReader>();
-      undirEdgeIdReader.reset(new _reader_bits::
-                              IdReader<UndirEdge, _IdReader>(_idReader));
-      edgeIdReader.reset(new _reader_bits::
-                         IdReader<Edge, _IdReader>(_idReader));
+    template <typename _LabelReader>
+    UndirEdgeReader(LemonReader& _reader, const _LabelReader& _labelReader, 
+               const std::string& _name = std::string()) 
+      : Parent(_reader), name(_name) {
+      checkConcept<_reader_bits::ItemLabelReader<UndirEdge>, _LabelReader>();
+      checkConcept<_reader_bits::ItemLabelReader<Edge>, _LabelReader>();
+      undirEdgeLabelReader.reset(new _reader_bits::
+                              LabelReader<UndirEdge, _LabelReader>(_labelReader));
+      edgeLabelReader.reset(new _reader_bits::
+                         LabelReader<Edge, _LabelReader>(_labelReader));
     }
 
@@ -1769 +1772 @@
     ///
     /// It gives back true when the header line start with \c \@edges,
-    /// and the header line's id and the reader's id are the same.
+    /// and the header line's name and the reader's name are the same.
     virtual bool header(const std::string& line) {
       std::istringstream ls(line);
       std::string command;
-      std::string name;
+      std::string id;
       ls >> command >> name;
       return command == "@undiredges" && name == id;
@@ -1782 +1785 @@
     /// It reads the content of the section.
     virtual void read(std::istream& is) {
-      if (!edgeIdReader->isIdReader()) {
-        throw DataFormatError("Cannot find undirected edgeset or ID map");
-      }
-      if (!undirEdgeIdReader->isIdReader()) {
-        throw DataFormatError("Cannot find undirected edgeset or ID map");
+      if (!edgeLabelReader->isLabelReader()) {
+        throw DataFormatError("Cannot find undirected edgeset or label map");
+      }
+      if (!undirEdgeLabelReader->isLabelReader()) {
+        throw DataFormatError("Cannot find undirected edgeset or label map");
       }
       std::string line;
@@ -1796 +1799 @@
           typename UndirEdgeReaders::iterator it = undirEdgeReaders.find(id);
           if (it != undirEdgeReaders.end()) {
-            it->second.read(undirEdgeIdReader->read(ls));
+            it->second.read(undirEdgeLabelReader->read(ls));
             it->second.touch();
             continue;
@@ -1803 +1806 @@
           typename EdgeReaders::iterator it = edgeReaders.find(id);
           if (it != edgeReaders.end()) {
-            it->second.read(edgeIdReader->read(ls));
+            it->second.read(edgeLabelReader->read(ls));
             it->second.touch();
             continue;
@@ -1829 +1832 @@
   private:
 
-    std::string id;
+    std::string name;
 
     typedef std::map<std::string, 
                      _reader_bits::ItemStore<UndirEdge> > UndirEdgeReaders;
     UndirEdgeReaders undirEdgeReaders;
-    std::auto_ptr<_reader_bits::IdReaderBase<UndirEdge> > undirEdgeIdReader;
+    std::auto_ptr<_reader_bits::LabelReaderBase<UndirEdge> > undirEdgeLabelReader;
 
     typedef std::map<std::string, _reader_bits::ItemStore<Edge> > EdgeReaders;
     EdgeReaders edgeReaders;
-    std::auto_ptr<_reader_bits::IdReaderBase<Edge> > edgeIdReader;
+    std::auto_ptr<_reader_bits::LabelReaderBase<Edge> > edgeLabelReader;
   };
 
@@ -1845 +1848 @@
   ///
   /// The lemon format can store multiple attribute set. Each set has
-  /// the header line \c \@attributes \c attributeset_id, but the 
-  /// attributeset_id may be empty.
+  /// the header line \c \@attributes \c attributeset_name, but the 
+  /// attributeset_name may be empty.
   ///
   /// The attributeset section contains several lines. Each of them starts
@@ -1861 +1864 @@
     /// Constructor for AttributeReader. It creates the AttributeReader and
     /// attach it into the given LemonReader. The reader process a section
-    /// only if the \c section_id and the \c _id are the same.
+    /// only if the \c section_name and the \c _name are the same.
     AttributeReader(LemonReader& _reader, 
-                    const std::string& _id = std::string()) 
-      : Parent(_reader), id(_id) {}
+                    const std::string& _name = std::string()) 
+      : Parent(_reader), name(_name) {}
 
     /// \brief Destructor.
@@ -1917 +1920 @@
       std::istringstream ls(line);
       std::string command;
-      std::string name;
+      std::string id;
       ls >> command >> name;
       return command == "@attributes" && name == id;
@@ -1934 +1937 @@
         if (it != readers.end()) {
           it->second->read(ls);
-          it->second->touch();
+          it->second->touch();
         }
       }
@@ -1948 +1951 @@
 
   private:
-    std::string id;
+    std::string name;
 
     typedef std::map<std::string, _reader_bits::ValueReaderBase*> Readers;
@@ -2204 +2207 @@
 
     void readMapNames(std::istream& is, std::vector<std::string>& maps) {
-      std::string line, id;
+      std::string line, name;
       std::getline(is, line);
       std::istringstream ls(line);
-      while (ls >> id) {
-        maps.push_back(id);
+      while (ls >> name) {
+        maps.push_back(name);
       }
       while (getline(is, line));
@@ -2214 +2217 @@
 
     void readItemNames(std::istream& is, std::vector<std::string>& maps) {
-      std::string line, id;
+      std::string line, name;
       while (std::getline(is, line)) {
         std::istringstream ls(line);
-        ls >> id;
-        maps.push_back(id);
+        ls >> name;
+        maps.push_back(name);
       }
     }

lemon/lemon_writer.h

@@ -47 +47 @@
     
     template <typename Item>
-    class ItemIdWriter {
+    class ItemLabelWriter {
     public:
 
-      bool isIdWriter() { return true; }
-
-      void writeId(std::ostream&, const Item&) {}
+      bool isLabelWriter() { return true; }
+
+      void writeLabel(std::ostream&, const Item&) {}
       
-      template <class _ItemIdWriter>
+      template <class _ItemLabelWriter>
       struct Constraints {
         void constraints() {
-          bool b = writer.isIdWriter();
+          bool b = writer.isLabelWriter();
           ignore_unused_variable_warning(b);
-          writer.writeId(os, item);
+          writer.writeLabel(os, item);
         }
-        _ItemIdWriter& writer;
+        _ItemLabelWriter& writer;
         std::ostream& os;
         const Item& item;
@@ -226 +226 @@
 
     template <typename _Item>
-    class IdWriterBase {
+    class LabelWriterBase {
     public:
       typedef _Item Item;
-      virtual ~IdWriterBase() {}
+      virtual ~LabelWriterBase() {}
       virtual void write(std::ostream&, const Item&) const = 0;
-      virtual bool isIdWriter() const = 0;
-    };
-
-    template <typename _Item, typename _BoxedIdWriter>
-    class IdWriter : public IdWriterBase<_Item> {
+      virtual bool isLabelWriter() const = 0;
+    };
+
+    template <typename _Item, typename _BoxedLabelWriter>
+    class LabelWriter : public LabelWriterBase<_Item> {
     public:
       typedef _Item Item;
-      typedef _BoxedIdWriter BoxedIdWriter;
-
-      const BoxedIdWriter& idWriter;
-
-      IdWriter(const BoxedIdWriter& _idWriter) 
-        : idWriter(_idWriter) {}
+      typedef _BoxedLabelWriter BoxedLabelWriter;
+
+      const BoxedLabelWriter& labelWriter;
+
+      LabelWriter(const BoxedLabelWriter& _labelWriter) 
+        : labelWriter(_labelWriter) {}
 
       virtual void write(std::ostream& os, const Item& item) const {
-        idWriter.writeId(os, item);
-      }
-
-      virtual bool isIdWriter() const {
-        return idWriter.isIdWriter();
+        labelWriter.writeLabel(os, item);
+      }
+
+      virtual bool isLabelWriter() const {
+        return labelWriter.isLabelWriter();
       }
     };
@@ -375 +375 @@
   ///
   /// The lemon format can store multiple graph nodesets with several maps.
-  /// The nodeset section's header line is \c \@nodeset \c nodeset_id, but the
-  /// \c nodeset_id may be empty.
+  /// The nodeset section's header line is \c \@nodeset \c nodeset_name, but 
+  /// the \c nodeset_name may be empty.
   ///
   /// The first line of the section contains the names of the maps separated
@@ -382 +382 @@
   /// contains the mapped values for each map.
   ///
-  /// If the nodeset contains an \c "id" named map then it will be regarded
-  /// as id map. This map should contain only unique values and when the 
-  /// \c writeId() member will be called with a node it will write it's id.
-  /// Otherwise if the \c _forceIdMap constructor parameter is true then
-  /// the id map will be the id in the graph.
+  /// If the nodeset contains an \c "label" named map then it will be regarded
+  /// as label map. This map should contain only unique values and when the 
+  /// \c writeLabel() member will be called with a node it will write it's 
+  /// label. Otherwise if the \c _forceLabelMap constructor parameter is true 
+  /// then the label map will be the id in the graph.
   ///
   /// \relates LemonWriter
@@ -401 +401 @@
     ///
     /// Constructor for NodeSetWriter. It creates the NodeSetWriter and
-    /// attach it into the given LemonWriter. If the \c _forceIdMap
-    /// parameter is true then the writer will write own id map when
-    /// the user does not give "id" named map.
+    /// attach it into the given LemonWriter. If the \c _forceLabelMap
+    /// parameter is true then the writer will write own label map when
+    /// the user does not give "label" named map.
     NodeSetWriter(LemonWriter& _writer, const Graph& _graph, 
-                  const std::string& _id = std::string(), 
-                  bool _forceIdMap = true) 
-      : Parent(_writer), idMap(0), forceIdMap(_forceIdMap), 
-        graph(_graph), id(_id) {}
+                  const std::string& _name = std::string(), 
+                  bool _forceLabelMap = true) 
+      : Parent(_writer), labelMap(0), forceLabelMap(_forceLabelMap), 
+        graph(_graph), name(_name) {}
 
     /// \brief Destructor.
@@ -455 +455 @@
     /// It gives back the header of the section.
     virtual std::string header() {
-      return "@nodeset " + id;
+      return "@nodeset " + name;
     }
 
@@ -463 +463 @@
     virtual void write(std::ostream& os) {
       for (int i = 0; i < (int)writers.size(); ++i) {
-        if (writers[i].first == "id") {
-          idMap = writers[i].second;
-          forceIdMap = false;
+        if (writers[i].first == "label" || (writers[i].first == "id" && labelMap == 0)) {
+          labelMap = writers[i].second;
+          forceLabelMap = false;
           break;
         }
       }
-      if (forceIdMap) {
-        os << "id\t";
+      if (forceLabelMap) {
+        os << "label\t";
       }
       for (int i = 0; i < (int)writers.size(); ++i) {
@@ -477 +477 @@
       os << std::endl;
       for (typename Graph::NodeIt it(graph); it != INVALID; ++it) {
-        if (forceIdMap) {
+        if (forceLabelMap) {
           os << graph.id(it) << '\t';
         }
@@ -490 +490 @@
   public:
 
-    /// \brief Returns true if the nodeset can write the ids of the nodes.
-    ///
-    /// Returns true if the nodeset can write the ids of the nodes.
-    /// It is possible only if an "id" named map was written or the 
-    /// \c _forceIdMap constructor parameter was true.
-    bool isIdWriter() const {
-      return idMap != 0 || forceIdMap;
-    }
-
-    /// \brief Write the id of the given node.
-    ///
-    /// It writes the id of the given node. If there was written an "id"
+    /// \brief Returns true if the nodeset can write the labels of the nodes.
+    ///
+    /// Returns true if the nodeset can write the labels of the nodes.
+    /// It is possible only if an "label" named map was written or the 
+    /// \c _forceLabelMap constructor parameter was true.
+    bool isLabelWriter() const {
+      return labelMap != 0 || forceLabelMap;
+    }
+
+    /// \brief Write the label of the given node.
+    ///
+    /// It writes the label of the given node. If there was written an "label"
     /// named map then it will write the map value belongs to the node.
-    /// Otherwise if the \c forceId parameter was true it will write
-    /// its id in the graph. 
-    void writeId(std::ostream& os, const Node& item) const {
-      if (forceIdMap) {
+    /// Otherwise if the \c forceLabel parameter was true it will write
+    /// its label in the graph. 
+    void writeLabel(std::ostream& os, const Node& item) const {
+      if (forceLabelMap) {
         os << graph.id(item);
       } else {
-        idMap->write(os, item);
+        labelMap->write(os, item);
       }
     }
@@ -519 +519 @@
     MapWriters writers;
 
-    _writer_bits::MapWriterBase<Node>* idMap;
-    bool forceIdMap;
+    _writer_bits::MapWriterBase<Node>* labelMap;
+    bool forceLabelMap;
    
     const Graph& graph;   
-    std::string id;
+    std::string name;
 
   };
@@ -531 +531 @@
   ///
   /// The lemon format can store multiple graph edgesets with several maps. 
-  /// The edgeset section's header line is \c \@edgeset \c edgeset_id, but the
-  /// \c edgeset_id may be empty.
+  /// The edgeset section's header line is \c \@edgeset \c edgeset_name, but 
+  /// the \c edgeset_name may be empty.
   ///
   /// The first line of the section contains the names of the maps separated
   /// with white spaces. Each next lines describes a edge in the edgeset. The
-  /// line contains the source and the target nodes' id and the mapped 
+  /// line contains the source and the target nodes' label and the mapped 
   /// values for each map.
   ///
-  /// If the edgeset contains an \c "id" named map then it will be regarded
-  /// as id map. This map should contain only unique values and when the 
-  /// \c writeId() member will be called with an edge it will write it's id.
-  /// Otherwise if the \c _forceIdMap constructor parameter is true then
-  /// the id map will be the id in the graph.
-  ///
-  /// The edgeset writer needs a node id writer to identify which nodes
-  /// have to be connected. If a NodeSetWriter can write the nodes' id,
+  /// If the edgeset contains an \c "label" named map then it will be regarded
+  /// as label map. This map should contain only unique values and when the 
+  /// \c writeLabel() member will be called with an edge it will write it's 
+  /// label. Otherwise if the \c _forceLabelMap constructor parameter is true 
+  /// then the label map will be the id in the graph.
+  ///
+  /// The edgeset writer needs a node label writer to identify which nodes
+  /// have to be connected. If a NodeSetWriter can write the nodes' label,
   /// it will be able to use with this class.
   ///
@@ -563 +563 @@
     ///
     /// Constructor for EdgeSetWriter. It creates the EdgeSetWriter and
-    /// attach it into the given LemonWriter. It will write node ids by
-    /// the \c _nodeIdWriter. If the \c _forceIdMap parameter is true 
-    /// then the writer will write own id map if the user does not give 
-    /// "id" named map.
-    template <typename NodeIdWriter>
+    /// attach it into the given LemonWriter. It will write node labels by
+    /// the \c _nodeLabelWriter. If the \c _forceLabelMap parameter is true 
+    /// then the writer will write own label map if the user does not give 
+    /// "label" named map.
+    template <typename NodeLabelWriter>
     EdgeSetWriter(LemonWriter& _writer, const Graph& _graph, 
-                  const NodeIdWriter& _nodeIdWriter, 
-                  const std::string& _id = std::string(),
-                  bool _forceIdMap = true)
-      : Parent(_writer), idMap(0), forceIdMap(_forceIdMap),
-        graph(_graph), id(_id) {
-      checkConcept<_writer_bits::ItemIdWriter<Node>, NodeIdWriter>();
-      nodeIdWriter.reset(new _writer_bits::
-                         IdWriter<Node, NodeIdWriter>(_nodeIdWriter));
+                  const NodeLabelWriter& _nodeLabelWriter, 
+                  const std::string& _name = std::string(),
+                  bool _forceLabelMap = true)
+      : Parent(_writer), labelMap(0), forceLabelMap(_forceLabelMap),
+        graph(_graph), name(_name) {
+      checkConcept<_writer_bits::ItemLabelWriter<Node>, NodeLabelWriter>();
+      nodeLabelWriter.reset(new _writer_bits::
+                         LabelWriter<Node, NodeLabelWriter>(_nodeLabelWriter));
     } 
 
@@ -624 +624 @@
     /// It gives back the header of the section.
     virtual std::string header() {
-      return "@edgeset " + id;
+      return "@edgeset " + name;
     }
 
@@ -631 +631 @@
     /// Write the content of the section.
     virtual void write(std::ostream& os) {
-      if (!nodeIdWriter->isIdWriter()) {
-        throw DataFormatError("Cannot find nodeset or ID map");
+      if (!nodeLabelWriter->isLabelWriter()) {
+        throw DataFormatError("Cannot find nodeset or label map");
       }
       for (int i = 0; i < (int)writers.size(); ++i) {
-        if (writers[i].first == "id") {
-          idMap = writers[i].second;
-          forceIdMap = false;
+        if (writers[i].first == "label" || (writers[i].first == "id" && labelMap == 0)) {
+          labelMap = writers[i].second;
+          forceLabelMap = false;
           break;
         }
       }
       os << "\t\t";
-      if (forceIdMap) {
-        os << "id\t";
+      if (forceLabelMap) {
+        os << "label\t";
       }
       for (int i = 0; i < (int)writers.size(); ++i) {
@@ -650 +650 @@
       os << std::endl;
       for (typename Graph::EdgeIt it(graph); it != INVALID; ++it) {
-        nodeIdWriter->write(os, graph.source(it));
+        nodeLabelWriter->write(os, graph.source(it));
         os << '\t';
-        nodeIdWriter->write(os, graph.target(it));
+        nodeLabelWriter->write(os, graph.target(it));
         os << '\t';
-        if (forceIdMap) {
+        if (forceLabelMap) {
           os << graph.id(it) << '\t';
         }
@@ -667 +667 @@
   public:
 
-    /// \brief Returns true if the edgeset can write the ids of the edges.
-    ///
-    /// Returns true if the edgeset can write the ids of the edges.
-    /// It is possible only if an "id" named map was written or the 
-    /// \c _forceIdMap constructor parameter was true.
-    bool isIdWriter() const {
-      return forceIdMap || idMap != 0;
-    }
-
-    /// \brief Write the id of the given edge.
-    ///
-    /// It writes the id of the given edge. If there was written an "id"
+    /// \brief Returns true if the edgeset can write the labels of the edges.
+    ///
+    /// Returns true if the edgeset can write the labels of the edges.
+    /// It is possible only if an "label" named map was written or the 
+    /// \c _forceLabelMap constructor parameter was true.
+    bool isLabelWriter() const {
+      return forceLabelMap || labelMap != 0;
+    }
+
+    /// \brief Write the label of the given edge.
+    ///
+    /// It writes the label of the given edge. If there was written an "label"
     /// named map then it will write the map value belongs to the edge.
-    /// Otherwise if the \c forceId parameter was true it will write
-    /// its id in the graph. 
-    void writeId(std::ostream& os, const Edge& item) const {
-      if (forceIdMap) {
+    /// Otherwise if the \c forceLabel parameter was true it will write
+    /// its label in the graph. 
+    void writeLabel(std::ostream& os, const Edge& item) const {
+      if (forceLabelMap) {
         os << graph.id(item);
       } else {
-        idMap->write(os, item);
+        labelMap->write(os, item);
       }
     } 
@@ -696 +696 @@
     MapWriters writers;
 
-    _writer_bits::MapWriterBase<Edge>* idMap;
-    bool forceIdMap;
+    _writer_bits::MapWriterBase<Edge>* labelMap;
+    bool forceLabelMap;
    
     const Graph& graph;   
-    std::string id;
-
-    std::auto_ptr<_writer_bits::IdWriterBase<Node> > nodeIdWriter;
+    std::string name;
+
+    std::auto_ptr<_writer_bits::LabelWriterBase<Node> > nodeLabelWriter;
   };
 
@@ -710 +710 @@
   /// The lemon format can store multiple undirected edgesets with several 
   /// maps. The undirected edgeset section's header line is \c \@undiredgeset 
-  /// \c undiredgeset_id, but the \c undiredgeset_id may be empty.
+  /// \c undiredgeset_name, but the \c undiredgeset_name may be empty.
   ///
   /// The first line of the section contains the names of the maps separated
   /// with white spaces. Each next lines describes an undirected edge in the 
-  /// edgeset. The line contains the two connected nodes' id and the mapped 
+  /// edgeset. The line contains the two connected nodes' label and the mapped 
   /// values for each undirected map.
   ///
@@ -723 +723 @@
   /// difference.
   ///
-  /// If the edgeset contains an \c "id" named map then it will be regarded
-  /// as id map. This map should contain only unique values and when the 
-  /// \c writeId() member will be called with an undirected edge it will 
-  /// write it's id. Otherwise if the \c _forceIdMap constructor parameter
-  /// is true then the id map will be the id in the graph.
-  ///
-  /// The undirected edgeset writer needs a node id writer to identify 
+  /// If the edgeset contains an \c "label" named map then it will be regarded
+  /// as label map. This map should contain only unique values and when the 
+  /// \c writeLabel() member will be called with an undirected edge it will 
+  /// write it's label. Otherwise if the \c _forceLabelMap constructor 
+  /// parameter is true then the label map will be the id in the graph.
+  ///
+  /// The undirected edgeset writer needs a node label writer to identify 
   /// which nodes have to be connected. If a NodeSetWriter can write the 
-  /// nodes' id, it will be able to use with this class.
+  /// nodes' label, it will be able to use with this class.
   ///
   /// \relates LemonWriter
@@ -748 +748 @@
     ///
     /// Constructor for UndirEdgeSetWriter. It creates the UndirEdgeSetWriter
-    /// and attach it into the given LemonWriter. It will write node ids by
-    /// the \c _nodeIdWriter. If the \c _forceIdMap parameter is true 
-    /// then the writer will write own id map if the user does not give 
-    /// "id" named map.
-    template <typename NodeIdWriter>
+    /// and attach it into the given LemonWriter. It will write node labels by
+    /// the \c _nodeLabelWriter. If the \c _forceLabelMap parameter is true 
+    /// then the writer will write own label map if the user does not give 
+    /// "label" named map.
+    template <typename NodeLabelWriter>
     UndirEdgeSetWriter(LemonWriter& _writer, const Graph& _graph, 
-                       const NodeIdWriter& _nodeIdWriter, 
-                       const std::string& _id = std::string(),
-                       bool _forceIdMap = true)
-      : Parent(_writer), idMap(0), forceIdMap(_forceIdMap),
-        graph(_graph), id(_id) {
-      checkConcept<_writer_bits::ItemIdWriter<Node>, NodeIdWriter>();
-      nodeIdWriter.reset(new _writer_bits::
-                         IdWriter<Node, NodeIdWriter>(_nodeIdWriter));
+                       const NodeLabelWriter& _nodeLabelWriter, 
+                       const std::string& _name = std::string(),
+                       bool _forceLabelMap = true)
+      : Parent(_writer), labelMap(0), forceLabelMap(_forceLabelMap),
+        graph(_graph), name(_name) {
+      checkConcept<_writer_bits::ItemLabelWriter<Node>, NodeLabelWriter>();
+      nodeLabelWriter.reset(new _writer_bits::
+                         LabelWriter<Node, NodeLabelWriter>(_nodeLabelWriter));
     } 
 
@@ -833 +833 @@
     /// It gives back the header of the section.
     virtual std::string header() {
-      return "@undiredgeset " + id;
+      return "@undiredgeset " + name;
     }
 
@@ -840 +840 @@
     /// Write the content of the section.
     virtual void write(std::ostream& os) {
-      if (!nodeIdWriter->isIdWriter()) {
-        throw DataFormatError("Cannot find nodeset or ID map");
+      if (!nodeLabelWriter->isLabelWriter()) {
+        throw DataFormatError("Cannot find nodeset or label map");
       }
       for (int i = 0; i < (int)writers.size(); ++i) {
-        if (writers[i].first == "id") {
-          idMap = writers[i].second;
-          forceIdMap = false;
+        if (writers[i].first == "label") {
+          labelMap = writers[i].second;
+          forceLabelMap = false;
           break;
         }
       }
       os << "\t\t";
-      if (forceIdMap) {
-        os << "id\t";
+      if (forceLabelMap) {
+        os << "label\t";
       }
       for (int i = 0; i < (int)writers.size(); ++i) {
@@ -859 +859 @@
       os << std::endl;
       for (typename Graph::UndirEdgeIt it(graph); it != INVALID; ++it) {
-        nodeIdWriter->write(os, graph.source(it));
+        nodeLabelWriter->write(os, graph.source(it));
         os << '\t';
-        nodeIdWriter->write(os, graph.target(it));
+        nodeLabelWriter->write(os, graph.target(it));
         os << '\t';
-        if (forceIdMap) {
+        if (forceLabelMap) {
           os << graph.id(it) << '\t';
         }
@@ -876 +876 @@
   public:
 
-    /// \brief Returns true if the undirected edgeset can write the ids of 
+    /// \brief Returns true if the undirected edgeset can write the labels of 
     /// the edges.
     ///
-    /// Returns true if the undirected edgeset can write the ids of the 
-    /// undirected edges. It is possible only if an "id" named map was 
-    /// written or the \c _forceIdMap constructor parameter was true.
-    bool isIdWriter() const {
-      return forceIdMap || idMap != 0;
-    }
-
-    /// \brief Write the id of the given undirected edge.
-    ///
-    /// It writes the id of the given undirected edge. If there was written 
-    /// an "id" named map then it will write the map value belongs to the 
-    /// undirected edge. Otherwise if the \c forceId parameter was true it 
+    /// Returns true if the undirected edgeset can write the labels of the 
+    /// undirected edges. It is possible only if an "label" named map was 
+    /// written or the \c _forceLabelMap constructor parameter was true.
+    bool isLabelWriter() const {
+      return forceLabelMap || labelMap != 0;
+    }
+
+    /// \brief Write the label of the given undirected edge.
+    ///
+    /// It writes the label of the given undirected edge. If there was written 
+    /// an "label" named map then it will write the map value belongs to the 
+    /// undirected edge. Otherwise if the \c forceLabel parameter was true it 
     /// will write its id in the graph. 
-    void writeId(std::ostream& os, const UndirEdge& item) const {
-      if (forceIdMap) {
+    void writeLabel(std::ostream& os, const UndirEdge& item) const {
+      if (forceLabelMap) {
         os << graph.id(item);
       } else {
-        idMap->write(os, item);
+        labelMap->write(os, item);
       }
     } 
 
-    /// \brief Write the id of the given edge.
-    ///
-    /// It writes the id of the given edge. If there was written 
-    /// an "id" named map then it will write the map value belongs to the 
-    /// edge. Otherwise if the \c forceId parameter was true it 
+    /// \brief Write the label of the given edge.
+    ///
+    /// It writes the label of the given edge. If there was written 
+    /// an "label" named map then it will write the map value belongs to the 
+    /// edge. Otherwise if the \c forceLabel parameter was true it 
     /// will write its id in the graph. If the edge is forward map
     /// then its prefix character is \c '+' elsewhere \c '-'.
-    void writeId(std::ostream& os, const Edge& item) const {
+    void writeLabel(std::ostream& os, const Edge& item) const {
       if (graph.direction(item)) {
         os << "+ ";
@@ -913 +913 @@
         os << "- ";
       }
-      if (forceIdMap) {
+      if (forceLabelMap) {
         os << graph.id(item);
       } else {
-        idMap->write(os, item);
+        labelMap->write(os, item);
       }
     } 
@@ -926 +926 @@
     MapWriters writers;
 
-    _writer_bits::MapWriterBase<UndirEdge>* idMap;
-    bool forceIdMap;
+    _writer_bits::MapWriterBase<UndirEdge>* labelMap;
+    bool forceLabelMap;
    
     const Graph& graph;   
-    std::string id;
-
-    std::auto_ptr<_writer_bits::IdWriterBase<Node> > nodeIdWriter;
+    std::string name;
+
+    std::auto_ptr<_writer_bits::LabelWriterBase<Node> > nodeLabelWriter;
   };
 
   /// \ingroup io_group
-  /// \brief SectionWriter for writing labeled nodes.
-  ///
-  /// The nodes section's header line is \c \@nodes \c nodes_id, but the
-  /// \c nodes_id may be empty.
-  ///
-  /// Each line in the section contains the label of the node and 
-  /// then the node id. 
+  /// \brief SectionWriter for writing named nodes.
+  ///
+  /// The nodes section's header line is \c \@nodes \c nodes_name, but the
+  /// \c nodes_name may be empty.
+  ///
+  /// Each line in the section contains the name of the node and 
+  /// then the node label. 
   ///
   /// \relates LemonWriter
@@ -955 +955 @@
     ///
     /// Constructor for NodeWriter. It creates the NodeWriter and
-    /// attach it into the given LemonWriter. The given \c _IdWriter
-    /// will write the nodes' id what can be a nodeset writer.
-    template <typename _IdWriter>
-    NodeWriter(LemonWriter& _writer, const _IdWriter& _idWriter, 
-               const std::string& _id = std::string()) 
-      : Parent(_writer), id(_id) {
-      checkConcept<_writer_bits::ItemIdWriter<Node>, _IdWriter>();
-      idWriter.reset(new _writer_bits::IdWriter<Node, _IdWriter>(_idWriter));
+    /// attach it into the given LemonWriter. The given \c _LabelWriter
+    /// will write the nodes' label what can be a nodeset writer.
+    template <typename _LabelWriter>
+    NodeWriter(LemonWriter& _writer, const _LabelWriter& _labelWriter, 
+               const std::string& _name = std::string()) 
+      : Parent(_writer), name(_name) {
+      checkConcept<_writer_bits::ItemLabelWriter<Node>, _LabelWriter>();
+      labelWriter.reset(new _writer_bits::LabelWriter<Node, _LabelWriter>
+                        (_labelWriter));
     }
 
@@ -986 +987 @@
   protected:
 
-    /// \brief Header checking function.
-    ///
-    /// It gives back true when the header line start with \c \@nodes,
-    /// and the header line's id and the writer's id are the same.
+    /// \brief The header of the section.
+    ///
+    /// It gives back the header of the section.
     virtual std::string header() {
-      return "@nodes " + id;
+      return "@nodes " + name;
     }
 
@@ -998 +998 @@
     /// Write the content of the section.
     virtual void write(std::ostream& os) {
-      if (!idWriter->isIdWriter()) {
-        throw DataFormatError("Cannot find nodeset or ID map");
+      if (!labelWriter->isLabelWriter()) {
+        throw DataFormatError("Cannot find nodeset or label map");
       }
       for (int i = 0; i < (int)writers.size(); ++i) {
         os << writers[i].first << ' ';
-        idWriter->write(os, *(writers[i].second));
+        labelWriter->write(os, *(writers[i].second));
         os << std::endl;
       }
@@ -1010 +1010 @@
   private:
 
-    std::string id;
+    std::string name;
 
     typedef std::vector<std::pair<std::string, const Node*> > NodeWriters;
     NodeWriters writers;
-    std::auto_ptr<_writer_bits::IdWriterBase<Node> > idWriter;
+    std::auto_ptr<_writer_bits::LabelWriterBase<Node> > labelWriter;
   };
 
   /// \ingroup io_group
-  /// \brief SectionWriter for writing labeled edges.
-  ///
-  /// The edges section's header line is \c \@edges \c edges_id, but the
-  /// \c edges_id may be empty.
-  ///
-  /// Each line in the section contains the label of the edge and 
-  /// then the edge id. 
+  /// \brief SectionWriter for writing named edges.
+  ///
+  /// The edges section's header line is \c \@edges \c edges_name, but the
+  /// \c edges_name may be empty.
+  ///
+  /// Each line in the section contains the name of the edge and 
+  /// then the edge label. 
   ///
   /// \relates LemonWriter
@@ -1037 +1037 @@
     ///
     /// Constructor for EdgeWriter. It creates the EdgeWriter and
-    /// attach it into the given LemonWriter. The given \c _IdWriter
-    /// will write the edges' id what can be a edgeset writer.
-    template <typename _IdWriter>
-    EdgeWriter(LemonWriter& _writer, const _IdWriter& _idWriter, 
-               const std::string& _id = std::string()) 
-      : Parent(_writer), id(_id) {
-      checkConcept<_writer_bits::ItemIdWriter<Edge>, _IdWriter>();
-      idWriter.reset(new _writer_bits::IdWriter<Edge, _IdWriter>(_idWriter));
+    /// attach it into the given LemonWriter. The given \c _LabelWriter
+    /// will write the edges' label what can be a edgeset writer.
+    template <typename _LabelWriter>
+    EdgeWriter(LemonWriter& _writer, const _LabelWriter& _labelWriter, 
+               const std::string& _name = std::string()) 
+      : Parent(_writer), name(_name) {
+      checkConcept<_writer_bits::ItemLabelWriter<Edge>, _LabelWriter>();
+      labelWriter.reset(new _writer_bits::LabelWriter<Edge, _LabelWriter>(_labelWriter));
     }
 
@@ -1066 +1066 @@
   protected:
 
-    /// \brief Header checking function.
-    ///
-    /// It gives back true when the header line start with \c \@edges,
-    /// and the header line's id and the writer's id are the same.
+    /// \brief The header of the section.
+    ///
+    /// It gives back the header of the section.
     virtual std::string header() {
-      return "@edges " + id;
+      return "@edges " + name;
     }
 
@@ -1078 +1077 @@
     /// Write the content of the section.
     virtual void write(std::ostream& os) {
-      if (!idWriter->isIdWriter()) {
-        throw DataFormatError("Cannot find edgeset or ID map");
+      if (!labelWriter->isLabelWriter()) {
+        throw DataFormatError("Cannot find edgeset or label map");
       }
       for (int i = 0; i < (int)writers.size(); ++i) {
         os << writers[i].first << ' ';
-        idWriter->write(os, *(writers[i].second));
+        labelWriter->write(os, *(writers[i].second));
         os << std::endl;
       }
@@ -1090 +1089 @@
   private:
 
-    std::string id;
+    std::string name;
 
     typedef std::vector<std::pair<std::string, const Edge*> > EdgeWriters;
     EdgeWriters writers;
 
-    std::auto_ptr<_writer_bits::IdWriterBase<Edge> > idWriter;
+    std::auto_ptr<_writer_bits::LabelWriterBase<Edge> > labelWriter;
   };
 
   /// \ingroup io_group
-  /// \brief SectionWriter for writing labeled undirected edges.
+  /// \brief SectionWriter for writing named undirected edges.
   ///
   /// The undirected edges section's header line is \c \@undiredges 
-  /// \c undiredges_id, but the \c undiredges_id may be empty.
-  ///
-  /// Each line in the section contains the label of the undirected edge and 
-  /// then the undirected edge id. 
+  /// \c undiredges_name, but the \c undiredges_name may be empty.
+  ///
+  /// Each line in the section contains the name of the undirected edge and 
+  /// then the undirected edge label. 
   ///
   /// \relates LemonWriter
@@ -1120 +1119 @@
     ///
     /// Constructor for UndirEdgeWriter. It creates the UndirEdgeWriter and
-    /// attach it into the given LemonWriter. The given \c _IdWriter
-    /// will write the undirected edges' id what can be an undirected 
+    /// attach it into the given LemonWriter. The given \c _LabelWriter
+    /// will write the undirected edges' label what can be an undirected 
     /// edgeset writer.
-    template <typename _IdWriter>
-    UndirEdgeWriter(LemonWriter& _writer, const _IdWriter& _idWriter, 
-               const std::string& _id = std::string()) 
-      : Parent(_writer), id(_id) {
-      checkConcept<_writer_bits::ItemIdWriter<Edge>, _IdWriter>();
-      checkConcept<_writer_bits::ItemIdWriter<UndirEdge>, _IdWriter>();
-      undirEdgeIdWriter.reset(new _writer_bits::
-                              IdWriter<UndirEdge, _IdWriter>(_idWriter));
-      edgeIdWriter.reset(new _writer_bits::
-                         IdWriter<Edge, _IdWriter>(_idWriter));
+    template <typename _LabelWriter>
+    UndirEdgeWriter(LemonWriter& _writer, const _LabelWriter& _labelWriter, 
+               const std::string& _name = std::string()) 
+      : Parent(_writer), name(_name) {
+      checkConcept<_writer_bits::ItemLabelWriter<Edge>, _LabelWriter>();
+      checkConcept<_writer_bits::ItemLabelWriter<UndirEdge>, _LabelWriter>();
+      undirEdgeLabelWriter.reset(new _writer_bits::
+                              LabelWriter<UndirEdge, _LabelWriter>(_labelWriter));
+      edgeLabelWriter.reset(new _writer_bits::
+                         LabelWriter<Edge, _LabelWriter>(_labelWriter));
     }
 
@@ -1161 +1160 @@
   protected:
 
-    /// \brief Header checking function.
-    ///
-    /// It gives back true when the header line start with \c \@undiredges,
-    /// and the header line's id and the writer's id are the same.
+    /// \brief The header of the section.
+    ///
+    /// It gives back the header of the section.
     virtual std::string header() {
-      return "@undiredges " + id;
+      return "@undiredges " + name;
     }
 
@@ -1173 +1171 @@
     /// Write the content of the section.
     virtual void write(std::ostream& os) {
-      if (!edgeIdWriter->isIdWriter()) {
-        throw DataFormatError("Cannot find undirected edgeset or ID map");
-      }
-      if (!undirEdgeIdWriter->isIdWriter()) {
-        throw DataFormatError("Cannot find undirected edgeset or ID map");
+      if (!edgeLabelWriter->isLabelWriter()) {
+        throw DataFormatError("Cannot find undirected edgeset or label map");
+      }
+      if (!undirEdgeLabelWriter->isLabelWriter()) {
+        throw DataFormatError("Cannot find undirected edgeset or label map");
       }
       for (int i = 0; i < (int)undirEdgeWriters.size(); ++i) {
         os << undirEdgeWriters[i].first << ' ';
-        undirEdgeIdWriter->write(os, *(undirEdgeWriters[i].second));
+        undirEdgeLabelWriter->write(os, *(undirEdgeWriters[i].second));
         os << std::endl;
       }
       for (int i = 0; i < (int)edgeWriters.size(); ++i) {
         os << edgeWriters[i].first << ' ';
-        edgeIdWriter->write(os, *(edgeWriters[i].second));
+        edgeLabelWriter->write(os, *(edgeWriters[i].second));
         os << std::endl;
       }
@@ -1193 +1191 @@
   private:
 
-    std::string id;
+    std::string name;
 
     typedef std::vector<std::pair<std::string, 
                                   const UndirEdge*> > UndirEdgeWriters;
     UndirEdgeWriters undirEdgeWriters;
-    std::auto_ptr<_writer_bits::IdWriterBase<UndirEdge> > undirEdgeIdWriter;
+    std::auto_ptr<_writer_bits::LabelWriterBase<UndirEdge> > undirEdgeLabelWriter;
 
     typedef std::vector<std::pair<std::string, const Edge*> > EdgeWriters;
     EdgeWriters edgeWriters;
-    std::auto_ptr<_writer_bits::IdWriterBase<Edge> > edgeIdWriter;
+    std::auto_ptr<_writer_bits::LabelWriterBase<Edge> > edgeLabelWriter;
 
   };
@@ -1210 +1208 @@
   ///
   /// The lemon format can store multiple attribute set. Each set has
-  /// the header line \c \@attributes \c attributeset_id, but the 
-  /// attributeset_id may be empty.
+  /// the header line \c \@attributes \c attributes_name, but the 
+  /// attributeset_name may be empty.
   ///
   /// The attributeset section contains several lines. Each of them starts
@@ -1227 +1225 @@
     /// attach it into the given LemonWriter.
     AttributeWriter(LemonWriter& _writer, 
-                    const std::string& _id = std::string()) 
-      : Parent(_writer), id(_id) {}
+                    const std::string& _name = std::string()) 
+      : Parent(_writer), name(_name) {}
 
     /// \brief Destructor.
@@ -1249 +1247 @@
     /// Add an attribute writer command for the writer.
     template <typename Value>
-    AttributeWriter& writeAttribute(const std::string& id, 
+    AttributeWriter& writeAttribute(const std::string& name, 
                                     const Value& value) {
       return 
-        writeAttribute<typename Traits::template Writer<Value> >(id, value);
+        writeAttribute<typename Traits::template Writer<Value> >(name, value);
     }
 
@@ -1274 +1272 @@
     /// It gives back the header of the section.
     std::string header() {
-      return "@attributes " + id;
+      return "@attributes " + name;
     }
 
@@ -1290 +1288 @@
 
   private:
-    std::string id;
+    std::string name;
 
     typedef std::vector<std::pair<std::string, 

test/Makefile.am

@@ -11 +11 @@
         heap_test.h
 
+
 check_PROGRAMS = \
         all_pairs_shortest_path_test \
@@ -21 +22 @@
         graph_utils_test \
         kruskal_test \
-        max_matching_test \
         maps_test \
         matrix_maps_test \
+        max_matching_test \
         min_cost_flow_test \
         suurballe_test \

test/dijkstra_test.lgf

@@ -1 +1 @@
 @nodeset
-id      
+label   
 999     
 998     
@@ -1002 +1002 @@
 0       
 @edgeset
-                id      capacity        
+                label   capacity        
 75      377     6906    27      
 417     515     6905    69