# HG changeset patch
# User deba
# Date 1113075333 0
# Node ID 2640cf6547ff188c2b35ae4444653feba91a0352
# Parent  bf228b5f648f7d4198268d5fa01b7a2d1b5a4c47
Functionality changed:
The first map is the id map => The map named "id" is the id map

Documentation improvments

diff -r bf228b5f648f -r 2640cf6547ff doc/graph_io.dox
--- a/doc/graph_io.dox	Sat Apr 09 19:32:06 2005 +0000
+++ b/doc/graph_io.dox	Sat Apr 09 19:35:33 2005 +0000
@@ -2,7 +2,6 @@
 /*!
 
 
-
 \page graph-io-page Graph Input-Output
 
 The standard graph IO makes possible to store graphs and additional maps
@@ -20,8 +19,8 @@
 The nodeset section starts with the \c \@nodeset line.
 The next line contains the names of the maps separated by whitespaces.
 Each following line describes a node in the graph, it contains
-in the right order the values of the maps. The first map should contain
-unique values because it regarded as Id-map. 
+in the right order the values of the maps. The map named "id" should contain
+unique values because it regarded as ID-map. 
 
 \code
 @nodeset
@@ -35,7 +34,7 @@
 same coloumn oriented structure. It starts with the line \c \@edgeset
 The next line contains the whitespace separated list of names of the map.
 Each of the next lines describes one edge. The first two elements in the line
-are the ID of the source and target node as they occur in the first node map. 
+are the ID of the source and target node as they occur in the ID node map. 
 
 \code
 @edgeset
@@ -45,10 +44,10 @@
 3   12       g     3.4      g-edge
 \endcode
 
-The next section contains <em>labeles nodes</em> (i.e. nodes having a special
+The next section contains <em>labeled nodes</em> (i.e. nodes having a special
 label on them). The section starts with
 \c \@nodes. Each of the next lines contains a label for a node in the graph 
-and then the ID described in the first column in the nodeset.
+and then the ID described in the nodeset.
 
 \code
 @nodes 
@@ -56,9 +55,8 @@
 target 12
 \endcode
 
-The last section describes the <em>labeles edges</em>
-(i.e. edges having a special
-label on them). It starts with \c \@edges
+The last section describes the <em>labeled 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.
 
 \code
@@ -88,13 +86,13 @@
 Edge writing.
 
 \code
-GraphWriter<ListGraph> writer(graph);
+GraphWriter<ListGraph> writer(std::cout, graph);
 \endcode
 
 The \c addNodeMap() function declares a \c NodeMap writing command in the
 \c GraphWriter. You should give as parameter the name of the map and the map
-object. The first NodeMap writing command should write a unique map because
-it is regarded as ID map.
+object. The NodeMap writing command with name "id" should write a 
+unique map because it is regarded as ID map.
 
 \see IdMap, DescriptorMap  
 
@@ -108,8 +106,7 @@
 \endcode
 
 With the \c addEdgeMap() member function you can give an edge map
-writing command similar to the NodeMaps. The first map writing command should
-write unique map.
+writing command similar to the NodeMaps.
 
 \see IdMap, DescriptorMap  
 \code
@@ -132,7 +129,7 @@
 \endcode
 
 After you give all write commands you must call the \c run() member
-function, which execute all the write commands.
+function, which execute all the writer commands.
 
 \code
 writer.run();
@@ -151,7 +148,7 @@
 it should skip the values when the string representation contains spaces.
 
 \code
-GraphReader<ListGraph> reader(graph);
+GraphReader<ListGraph> reader(std::cin, graph);
 \endcode
 
 The \c addNodeMap() function reads a map from the \c \@nodeset section.
@@ -206,7 +203,7 @@
 If you want to change the functionality of the reader, you can use
 template parameters to specialize it. When you give a reading
 command for a map you can give a Reader type as template parameter.
-With this template parameter you can control how does read the Reader
+With this template parameter you can control how the Reader reads
 a value from the stream.
 
 The reader has the next structure: 
@@ -244,6 +241,6 @@
 
 The specialization of the writing should be very similar to the reading.
 
-
+\author Balazs Dezso
 */
-}
\ No newline at end of file
+}
diff -r bf228b5f648f -r 2640cf6547ff src/lemon/graph_reader.h
--- a/src/lemon/graph_reader.h	Sat Apr 09 19:32:06 2005 +0000
+++ b/src/lemon/graph_reader.h	Sat Apr 09 19:35:33 2005 +0000
@@ -34,16 +34,20 @@
 
 namespace lemon {
 
+  /// \addtogroup io_group
+  /// @{
 
   /// \brief Standard ReaderTraits for the GraphReader class.
   ///
   /// Standard ReaderTraits for the GraphReader class.
   /// It defines standard reading method for all type of value. 
+  /// \author Balazs Dezso
   struct DefaultReaderTraits {
 
-   /// \brief Template class for reading an value.
+    /// \brief Template class for reading an value.
     ///
     /// Template class for reading an value.
+    /// \author Balazs Dezso
     template <typename _Value>
     struct Reader {
       /// The value type.
@@ -57,6 +61,13 @@
       }
     };
 
+    /// \brief Returns wheter this name is an ID map name.
+    ///
+    /// Returns wheter this name is an ID map name.
+    static bool idMapName(const std::string& name) {
+      return name == "id";
+    }
+
     /// The reader class for the not needed maps.
     typedef Reader<std::string> DefaultReader;
 
@@ -66,6 +77,7 @@
   ///
   /// Reader class for quoted strings. It can process the escape
   /// sequences in the string.
+  /// \author Balazs Dezso
   class QuotedStringReader {
   public:
     typedef std::string Value;
@@ -171,12 +183,69 @@
 
   /// \brief The graph reader class.
   ///
-  /// \ingroup io_group
-  /// The reader class for the graph input.
+  ///
+  /// The given file format may contain several maps and labeled nodes or 
+  /// edges.
+  ///
+  /// If you read a graph you need not read all the maps and items just those
+  /// that you need. The interface of the \c GraphReader is very similar to
+  /// the GraphWriter but the reading method does not depend on the order the
+  /// given commands.
+  ///
+  /// The reader object suppose that each not readed value does not contain 
+  /// whitespaces, therefore it has some extra possibilities to control how
+  /// it should skip the values when the string representation contains spaces.
+  ///
+  /// \code
+  /// GraphReader<ListGraph> reader(std::cin, graph);
+  /// \endcode
+  ///
+  /// The \c addNodeMap() function reads a map from the \c \@nodeset section.
+  /// If there is a map that you do not want to read from the file and there is
+  /// whitespace in the string represenation of the values then you should
+  /// call the \c skipNodeMap() template member function with proper 
+  /// parameters.
+  ///
+  /// \code
+  /// reader.addNodeMap("x-coord", xCoordMap);
+  /// reader.addNodeMap("y-coord", yCoordMap);
+  ///
+  /// reader.addNodeMap<QuotedStringReader>("label", labelMap);
+  /// reader.skipNodeMap<QuotedStringReader>("description");
+  ///
+  /// reader.addNodeMap("color", colorMap);
+  /// \endcode
+  ///
+  /// With the \c addEdgeMap() member function you can give an edge map
+  /// reading command similar to the NodeMaps. 
+  ///
+  /// \code
+  /// reader.addEdgeMap("weight", weightMap);
+  /// reader.addEdgeMap("label", labelMap);
+  /// \endcode
+  ///
+  /// With \c addNode() and \c addEdge() functions you can read labeled Nodes 
+  /// and Edges.
+  ///
+  /// \code
+  /// reader.addNode("source", sourceNode);
+  /// reader.addNode("target", targetNode);
+  ///
+  /// reader.addEdge("observed", edge);
+  /// \endcode
+  ///
+  /// After you give all read commands you must call the \c run() member
+  /// function, which execute all the commands.
+  ///
+  /// \code
+  /// reader.run();
+  /// \endcode
+  ///
   /// \see DefaultReaderTraits
   /// \see QuotedStringReader
   /// \see \ref GraphWriter
   /// \see \ref graph-io-page
+  /// \author Balazs Dezso
   template <typename _Graph, typename _ReaderTraits = DefaultReaderTraits> 
   class GraphReader {
   public:
@@ -200,7 +269,6 @@
     ///
     /// Destruct the graph reader.
     ~GraphReader() {
-
       for (typename NodeMapReaders::iterator it = node_map_readers.begin(); 
 	   it != node_map_readers.end(); ++it) {
 	delete it->second;
@@ -364,7 +432,6 @@
 	std::string id;
 	std::istringstream ls(line);	
 	while (ls >> id) {
-	  if (id[0] == '#') break;
 	  typename NodeMapReaders::iterator it = node_map_readers.find(id);
 	  if (it != node_map_readers.end()) {
 	    index.push_back(it->second);
@@ -372,21 +439,24 @@
 	  } else {
 	    index.push_back(&nodeSkipper);
 	  }
+	  if (ReaderTraits::idMapName(id) && nodeInverter.get() == 0) {
+	    nodeInverter.reset(index.back()->getInverter());
+	    index.back() = nodeInverter.get();
+	  }
 	}
       }
 
-      if (index.size() == 0) {
-	throw DataFormatError("Cannot find node id map");
-      }
+//       if (index.size() == 0) {
+// 	throw DataFormatError("Cannot find node id map");
+//       }
 
-      nodeInverter = 
-	std::auto_ptr<InverterBase<Node> >(index[0]->getInverter());
+//       nodeInverter = 
+// 	std::auto_ptr<InverterBase<Node> >(index[0]->getInverter());
       std::string line;
       while (line = readNotEmptyLine(is, line_num), line[0] != '@') {
 	Node node = graph.addNode();
 	std::istringstream ls(line);
-	nodeInverter->read(ls, node);
-	for (int i = 1; i < (int)index.size(); ++i) {
+	for (int i = 0; i < (int)index.size(); ++i) {
 	  index[i]->read(ls, node);
 	}
       }
@@ -402,7 +472,6 @@
 	std::string id;
 	std::istringstream ls(line);	
 	while (ls >> id) {
-	  if (id[0] == '#') break;
 	  typename EdgeMapReaders::iterator it = edge_map_readers.find(id);
 	  if (it != edge_map_readers.end()) {
 	    index.push_back(it->second);
@@ -410,23 +479,29 @@
 	  } else {
 	    index.push_back(&edgeSkipper);
 	  }
+	  if (ReaderTraits::idMapName(id) && edgeInverter.get() == 0) {
+	    edgeInverter.reset(index.back()->getInverter());
+	    index.back() = edgeInverter.get();
+	  }
 	}
       }
+      
+      if (nodeInverter.get() == 0) {
+ 	throw DataFormatError("Cannot find node id map");
+      }
+//       if (index.size() == 0) {
+// 	throw DataFormatError("Cannot find edge id map");
+//       }
 
-      if (index.size() == 0) {
-	throw DataFormatError("Cannot find edge id map");
-      }
-
-      edgeInverter = 
-	std::auto_ptr<InverterBase<Edge> >(index[0]->getInverter());
+//       edgeInverter = 
+// 	std::auto_ptr<InverterBase<Edge> >(index[0]->getInverter());
       std::string line;
       while (line = readNotEmptyLine(is, line_num), line[0] != '@') {	
 	std::istringstream ls(line);
 	Node source = nodeInverter->read(ls);
 	Node target = nodeInverter->read(ls);
 	Edge edge = graph.addEdge(source, target);
-	edgeInverter->read(ls, edge);
-	for (int i = 1; i < (int)index.size(); ++i) {
+	for (int i = 0; i < (int)index.size(); ++i) {
 	  index[i]->read(ls, edge);
 	}
       }      
@@ -436,6 +511,9 @@
     std::string readNodes(int& line_num, 
 			  std::auto_ptr<InverterBase<Node> >& nodeInverter) {
       std::string line;
+      if (nodeInverter.get() == 0) {
+ 	throw DataFormatError("Cannot find node id map");
+      }
       while (line = readNotEmptyLine(is, line_num), line[0] != '@') {
 	std::istringstream ls(line);
 	std::string name;
@@ -451,6 +529,9 @@
     std::string readEdges(int& line_num, 
 			  std::auto_ptr<InverterBase<Edge> >& edgeInverter) {
       std::string line;
+      if (edgeInverter.get() == 0) {
+ 	throw DataFormatError("Cannot find edge id map");
+      }
       while (line = readNotEmptyLine(is, line_num), line[0] != '@') {
 	std::istringstream ls(line);
 	std::string name;
@@ -466,23 +547,32 @@
     std::string readNotEmptyLine(std::istream& is, int& line_num) {
       std::string line;
       while (++line_num, getline(is, line)) {	
-	int vi = line.find_first_not_of(" \t");
-	if (vi != (int)std::string::npos && line[vi] != '#') {
+	int vi = line.find('#');
+	if (vi != (int)::std::string::npos) {
+	  line = line.substr(0, vi);
+	}
+	vi = line.find_first_not_of(" \t");
+	if (vi != (int)std::string::npos) { 
+	  std::cerr << "Line: " << line.substr(vi) << std::endl;
 	  return line.substr(vi);
 	}
       }
       throw DataFormatError("End of stream error");
     }
     
-    // Inverters store and give back the Item from the id,
-    // and may put the ids into a map.
+    template <typename _Item>
+    class ReaderBase;
     
     template <typename _Item>
-    class InverterBase {
+    class InverterBase : public ReaderBase<_Item> {
     public:
       typedef _Item Item;
       virtual void read(std::istream&, const Item&) = 0;
       virtual Item read(std::istream&) = 0;
+
+      virtual InverterBase<_Item>* getInverter() {
+	return this;
+      }
     };
 
     template <typename _Item, typename _Map, typename _Reader>
@@ -651,7 +741,15 @@
 
   };
 
-  /// Ready to use reader function.  
+  /// \brief Read a graph from the input.
+  ///
+  /// Read a graph from the input.
+  /// \param is The input stream.
+  /// \param g The graph.
+  /// \param capacity The capacity map.
+  /// \param s The source node.
+  /// \param t The target node.
+  /// \param cost The cost map.
   template<typename Graph, typename CapacityMap, typename CostMap>
   void readGraph(std::istream& is, Graph &g, CapacityMap& capacity, 
 		  typename Graph::Node &s, typename Graph::Node &t, 
@@ -664,6 +762,14 @@
     reader.run();
   }
 
+  /// \brief Read a graph from the input.
+  ///
+  /// Read a graph from the input.
+  /// \param is The input stream.
+  /// \param g The graph.
+  /// \param capacity The capacity map.
+  /// \param s The source node.
+  /// \param t The target node.
   template<typename Graph, typename CapacityMap>
   void readGraph(std::istream& is, Graph &g, CapacityMap& capacity, 
 		  typename Graph::Node &s, typename Graph::Node &t) {
@@ -674,6 +780,13 @@
     reader.run();
   }
 
+  /// \brief Read a graph from the input.
+  ///
+  /// Read a graph from the input.
+  /// \param is The input stream.
+  /// \param g The graph.
+  /// \param capacity The capacity map.
+  /// \param s The source node.
   template<typename Graph, typename CapacityMap>
   void readGraph(std::istream& is, Graph &g, CapacityMap& capacity, 
 		  typename Graph::Node &s) {
@@ -683,6 +796,12 @@
     reader.run();
   }
 
+  /// \brief Read a graph from the input.
+  ///
+  /// Read a graph from the input.
+  /// \param is The input stream.
+  /// \param g The graph.
+  /// \param capacity The capacity map.
   template<typename Graph, typename CapacityMap>
   void readGraph(std::istream& is, Graph &g, CapacityMap& capacity) {
     GraphReader<Graph> reader(is, g);
@@ -690,12 +809,18 @@
     reader.run();
   }
 
+  /// \brief Read a graph from the input.
+  ///
+  /// Read a graph from the input.
+  /// \param is The input stream.
+  /// \param g The graph.
   template<typename Graph>
   void readGraph(std::istream& is, Graph &g) {
     GraphReader<Graph> reader(is, g);
     reader.run();
   }
 
+  /// @}
 }
 
 #endif
diff -r bf228b5f648f -r 2640cf6547ff src/lemon/graph_writer.h
--- a/src/lemon/graph_writer.h	Sat Apr 09 19:32:06 2005 +0000
+++ b/src/lemon/graph_writer.h	Sat Apr 09 19:35:33 2005 +0000
@@ -37,15 +37,20 @@
 
 namespace lemon {
 
+  /// \addtogroup io_group
+  /// @{
+
   /// \brief Standard WriterTraits for the GraphWriter class.
   ///
   /// Standard WriterTraits for the GraphWriter class.
   /// It defines standard writing method for all type of value. 
+  /// \author Balazs Dezso
   struct DefaultWriterTraits {
 
     /// \brief Template class for writing an value.
     ///
     /// Template class for writing an value.
+    /// \author Balazs Dezso
     template <typename _Value>
     struct Writer {
       /// The value type.
@@ -59,6 +64,13 @@
       }
     };
 
+    /// \brief Returns wheter this name is an ID map name.
+    ///
+    /// Returns wheter this name is an ID map name.
+    static bool idMapName(const std::string& name) {
+      return name == "id";
+    }
+
   };
 
 
@@ -66,6 +78,7 @@
   ///
   /// Writer class for quoted strings. It can process the escape
   /// sequences in the string.
+  /// \author Balazs Dezso
   class QuotedStringWriter {
   public:
     typedef std::string Value;
@@ -146,12 +159,66 @@
   
   /// \brief The graph writer class.
   ///
-  ///\ingroup io_group
-  /// The writer class for the graph output.
+  /// The \c GraphWriter class provides the graph output. To write a graph
+  /// you should first give writing commands for the writer. You can declare
+  /// write command as \c NodeMap or \c EdgeMap writing and labeled Node and
+  /// Edge writing.
+  ///
+  /// \code
+  /// GraphWriter<ListGraph> writer(std::cout, graph);
+  /// \endcode
+  ///
+  /// The \c addNodeMap() function declares a \c NodeMap writing 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.
+  ///
+  /// \code
+  /// IdMap<ListGraph, Node> nodeIdMap;
+  /// writer.addNodeMap("id", nodeIdMap);
+  ///
+  /// writer.addNodeMap("x-coord", xCoordMap);
+  /// writer.addNodeMap("y-coord", yCoordMap);
+  /// writer.addNodeMap("color", colorMap);
+  /// \endcode
+  ///
+  /// With the \c addEdgeMap() member function you can give an edge map
+  /// writing command similar to the NodeMaps.
+  ///
+  /// \code
+  /// DescriptorMap<ListGraph, Edge, ListGraph::EdgeMap<int> > 
+  ///   edgeDescMap(graph);
+  /// writer.addEdgeMap("descriptor", edgeDescMap);
+  ///
+  /// writer.addEdgeMap("weight", weightMap);
+  /// writer.addEdgeMap("label", labelMap);
+  /// \endcode
+  ///
+  /// With \c addNode() and \c addEdge() functions you can point out Nodes and
+  /// Edges in the graph. By example, you can write out the source and target
+  /// of the graph.
+  ///
+  /// \code
+  /// writer.addNode("source", sourceNode);
+  /// writer.addNode("target", targetNode);
+  ///
+  /// writer.addEdge("observed", edge);
+  /// \endcode
+  ///
+  /// After you give all write commands you must call the \c run() member
+  /// function, which execute all the writer commands.
+  ///
+  /// \code
+  /// writer.run();
+  /// \endcode
+  ///
   /// \see DefaultWriterTraits
   /// \see QuotedStringWriter
+  /// \see IdMap
+  /// \see DescriptorMap
   /// \see \ref GraphReader
   /// \see \ref graph-io-page
+  /// \author Balazs Dezso
   template <typename _Graph, typename _WriterTraits = DefaultWriterTraits> 
   class GraphWriter {
   public:
@@ -254,82 +321,17 @@
     ///
     /// Executes the writer commands.
     void run() {   
-      writeNodeSet();
-      writeEdgeSet();
-      writeNodes();
-      writeEdges();
+      WriterBase<Node>* nodeWriter = 0;
+      WriterBase<Edge>* edgeWriter = 0;
+      writeNodeSet(nodeWriter);
+      writeEdgeSet(nodeWriter, edgeWriter);
+      writeNodes(nodeWriter);
+      writeEdges(edgeWriter);
       os << "@end" << std::endl;
     }
 
   private:
 
-    void writeNodeSet() {
-      if (node_map_writers.size() == 0) return;
-      os << "@nodeset" << std::endl;
-      for (int i = 0; i < (int)node_map_writers.size(); ++i) {
-	os << node_map_writers[i].first << '\t';
-      } 
-      os << std::endl;
-      for (NodeIt it(graph); it != INVALID; ++it) {
-	for (int i = 0; i < (int)node_map_writers.size(); ++i) {
-	  node_map_writers[i].second->write(os, it);
-	}
-	os << std::endl;
-      }
-
-    }
-
-    void writeEdgeSet() {
-      if (edge_map_writers.size() == 0) return;
-      if (node_map_writers.size() == 0) {
-	//	ErrorMessage message;
-	//	message << "Missing node id map";
-	//	throw IOLogicError(message);
-      }
-      os << "@edgeset" << std::endl;
-      os << "\t\t";
-      for (int i = 0; i < (int)edge_map_writers.size(); ++i) {
-	os << edge_map_writers[i].first << '\t';
-      } 
-      os << std::endl;
-      for (EdgeIt it(graph); it != INVALID; ++it) {
-	node_map_writers[0].second->write(os, graph.source(it));
-	node_map_writers[0].second->write(os, graph.target(it));
-	for (int i = 0; i < (int)edge_map_writers.size(); ++i) {
-	  edge_map_writers[i].second->write(os, it);
-	}
-	os << std::endl;
-      }
-    }
-
-    void writeNodes() {
-      if (node_writers.size() == 0) return;
-      if (node_map_writers.size() == 0) {
-	//	throw Exception() << "Missing node id map";
-      }
-      os << "@nodes" << std::endl;
-      for (int i = 0; i < (int)node_writers.size(); ++i) {
-	os << node_writers[i].first << '\t';
-	node_map_writers[0].second->write(os, node_writers[i].second);
-	os << std::endl;
-      } 
-    }
-
-    void writeEdges() {
-      if (edge_writers.size() == 0) return;
-      if (edge_map_writers.size() == 0) {
-	//	throw Exception() << "Missing edge id map";
-      }
-      os << "@edges" << std::endl;
-      for (int i = 0; i < (int)edge_writers.size(); ++i) {
-	os << edge_writers[i].first << '\t';
-	edge_map_writers[0].second->write(os, edge_writers[i].second);
-	os << std::endl;
-      } 
-    }
-    
-    // Writers
-
     template <class _Item>
     class WriterBase {
     public:
@@ -358,6 +360,76 @@
 
     };
 
+    void writeNodeSet(WriterBase<Node>* & nodeWriter) {
+      if (node_map_writers.size() == 0) return;
+      os << "@nodeset" << std::endl;
+      for (int i = 0; i < (int)node_map_writers.size(); ++i) {
+	const std::string& id = node_map_writers[i].first;
+	os << id << '\t';
+	if (WriterTraits::idMapName(id) && nodeWriter == 0) {
+	  nodeWriter = node_map_writers[i].second;
+	}
+      } 
+      os << std::endl;
+      for (NodeIt it(graph); it != INVALID; ++it) {
+	for (int i = 0; i < (int)node_map_writers.size(); ++i) {
+	  node_map_writers[i].second->write(os, it);
+	}
+	os << std::endl;
+      }
+
+    }
+
+    void writeEdgeSet(WriterBase<Node>* nodeWriter, 
+		      WriterBase<Edge>* & edgeWriter) {
+      if (nodeWriter == 0) {
+	throw DataFormatError("Cannot find node id map");
+      }
+      os << "@edgeset" << std::endl;
+      os << "\t\t";
+      for (int i = 0; i < (int)edge_map_writers.size(); ++i) {
+	const std::string& id = edge_map_writers[i].first;
+	os << id << '\t';
+	if (WriterTraits::idMapName(id) && edgeWriter == 0) {
+	  edgeWriter = edge_map_writers[i].second;
+	}
+      } 
+      os << std::endl;
+      for (EdgeIt it(graph); it != INVALID; ++it) {
+	nodeWriter->write(os, graph.source(it));
+	nodeWriter->write(os, graph.target(it));
+	for (int i = 0; i < (int)edge_map_writers.size(); ++i) {
+	  edge_map_writers[i].second->write(os, it);
+	}
+	os << std::endl;
+      }
+    }
+
+    void writeNodes(WriterBase<Node>* nodeWriter) {
+      if (nodeWriter == 0) {
+	throw DataFormatError("Cannot find node id map");
+      }
+      os << "@nodes" << std::endl;
+      for (int i = 0; i < (int)node_writers.size(); ++i) {
+	os << node_writers[i].first << '\t';
+	nodeWriter->write(os, node_writers[i].second);
+	os << std::endl;
+      } 
+    }
+
+    void writeEdges(WriterBase<Edge>* edgeWriter) {
+      if (edgeWriter == 0) {
+	throw DataFormatError("Cannot find node id map");
+      }
+      os << "@edges" << std::endl;
+      for (int i = 0; i < (int)edge_writers.size(); ++i) {
+	os << edge_writers[i].first << '\t';
+        edgeWriter->write(os, edge_writers[i].second);
+	os << std::endl;
+      } 
+    }
+    
+
 
 
     typedef std::vector< std::pair<std::string, WriterBase<Node>*> > 
@@ -379,7 +451,15 @@
 
   };
 
-  /// Ready to use writer function.  
+  /// \brief Write a graph to the output.
+  ///
+  /// Write a graph to the output.
+  /// \param os The output stream.
+  /// \param g The graph.
+  /// \param capacity The capacity map.
+  /// \param s The source node.
+  /// \param t The target node.
+  /// \param cost The cost map.
   template<typename Graph, typename CapacityMap, typename CostMap>
   void writeGraph(std::ostream& os, const Graph &g, 
 		  const CapacityMap& capacity, const typename Graph::Node &s,
@@ -396,7 +476,14 @@
     reader.run();
   }
 
-  /// Ready to use writer function.  
+  /// \brief Write a graph to the output.
+  ///
+  /// Write a graph to the output.
+  /// \param os The output stream.
+  /// \param g The graph.
+  /// \param capacity The capacity map.
+  /// \param s The source node.
+  /// \param t The target node.
   template<typename Graph, typename CapacityMap>
   void writeGraph(std::ostream& os, const Graph &g, 
 		  const CapacityMap& capacity, const typename Graph::Node &s,
@@ -412,7 +499,13 @@
     reader.run();
   }
 
-  /// Ready to use writer function.  
+  /// \brief Write a graph to the output.
+  ///
+  /// Write a graph to the output.
+  /// \param os The output stream.
+  /// \param g The graph.
+  /// \param capacity The capacity map.
+  /// \param s The source node.
   template<typename Graph, typename CapacityMap>
   void writeGraph(std::ostream& os, const Graph &g, 
 		  const CapacityMap& capacity, const typename Graph::Node &s) {
@@ -425,7 +518,13 @@
     reader.addNode("source", s);
     reader.run();
   }
-  /// Ready to use writer function.  
+
+  /// \brief Write a graph to the output.
+  ///
+  /// Write a graph to the output.
+  /// \param os The output stream.
+  /// \param g The graph.
+  /// \param capacity The capacity map.
   template<typename Graph, typename CapacityMap>
   void writeGraph(std::ostream& os, const Graph &g, 
 		  const CapacityMap& capacity) {
@@ -437,7 +536,12 @@
     reader.addEdgeMap("capacity", capacity);
     reader.run();
   }
-  /// Ready to use writer function.  
+
+  /// \brief Write a graph to the output.
+  ///
+  /// Write a graph to the output.
+  /// \param os The output stream.
+  /// \param g The graph.
   template<typename Graph>
   void writeGraph(std::ostream& os, const Graph &g) {
     GraphWriter<Graph> reader(os, g);
@@ -448,6 +552,7 @@
     reader.run();
   }
 
+  /// @}
 
 }