# HG changeset patch
# User Alpar Juttner <alpar@cs.elte.hu>
# Date 2008-05-17 07:30:02
# Node ID e561aa7675de318adf4cefc444d21c9297252201
# Parent  5c3604513ed0256e35e5fd50c54cd0e37362397e

More flexible header names in .lgf + largely improved doc

diff --git a/doc/Makefile.am b/doc/Makefile.am
--- a/doc/Makefile.am
+++ b/doc/Makefile.am
@@ -3,6 +3,7 @@
 	doc/coding_style.dox \
 	doc/dirs.dox \
 	doc/groups.dox \
+	doc/lgf.dox \
 	doc/license.dox \
 	doc/mainpage.dox \
 	doc/namespaces.dox \
diff --git a/doc/groups.dox b/doc/groups.dox
--- a/doc/groups.dox
+++ b/doc/groups.dox
@@ -483,25 +483,6 @@
 */
 
 /**
-@defgroup section_io Section readers and writers
-@ingroup lemon_io
-\brief Section readers and writers for LEMON Input-Output.
-
-This group describes section reader and writer classes that can be 
-attached to \ref LemonReader and \ref LemonWriter.
-*/
-
-/**
-@defgroup item_io Item readers and writers
-@ingroup lemon_io
-\brief Item readers and writers for LEMON Input-Output.
-
-This group describes reader and writer classes for various data types
-(e.g. map or attribute values). These classes can be attached to
-\ref LemonReader and \ref LemonWriter.
-*/
-
-/**
 @defgroup eps_io Postscript exporting
 @ingroup io_group
 \brief General \c EPS drawer and graph exporter
diff --git a/doc/lgf.dox b/doc/lgf.dox
new file mode 100644
--- /dev/null
+++ b/doc/lgf.dox
@@ -0,0 +1,96 @@
+/* -*- C++ -*-
+ *
+ * This file is a part of LEMON, a generic C++ optimization library
+ *
+ * Copyright (C) 2003-2008
+ * Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport
+ * (Egervary Research Group on Combinatorial Optimization, EGRES).
+ *
+ * Permission to use, modify and distribute this software is granted
+ * provided that this copyright notice appears in all copies. For
+ * precise terms see the accompanying LICENSE file.
+ *
+ * This software is provided "AS IS" with no warranty of any kind,
+ * express or implied, and with no claim as to its suitability for any
+ * purpose.
+ *
+ */
+
+namespace lemon {
+/*!
+
+
+
+\page lgf-format Lemon Graph Format (LGF)
+
+The \e LGF is a <em>column oriented</em>
+file format for storing graphs and associated data like
+node and edge maps.
+
+Each line with \c '#' first non-whitespace
+character is considered as a comment line.
+
+Otherwise the file consists of sections starting with
+a header line. The header lines starts with an \c '@' character followed by the
+type of section. The standard section types are \c \@nodes, \c
+\@arcs and \c \@edges
+and \@attributes. Each header line may also have an optional
+\e name, which can be use to distinguish the sections of the same
+type.
+
+The standard sections are column oriented, each line consists of
+<em>token</em>s separated by whitespaces. A token can be \e plain or
+\e quoted. A plain token is just a sequence of non-whitespace characters,
+while a quoted token is a
+character sequence surrounded by double quotes, and it can also
+contain whitespaces and escape sequences. 
+
+The \c \@nodes section describes a set of nodes and associated
+maps. The first is a header line, it columns are the names of the
+maps appearing in the following lines.
+One of the maps must be called \c
+"label", which plays special role in the file.
+The following
+non-empty lines until the next section describes nodes of the
+graph. Each line contains the values of the node maps
+associated to the current node.
+
+\code
+ @nodes
+ label   coordinates size    title
+ 1       (10,20)     10      "First node"
+ 2       (80,80)     8       "Second node"
+ 3       (40,10)     10      "Third node"
+\endcode
+
+The \c \@arcs section is very similar to the \c \@nodes section,
+it again starts with a header line describing the names of the arc,
+but the \c "label" map is not obligatory here. The following lines
+describe the arcs. The first two tokens of each line are
+the source and the target node of the arc, respectively, then come the map
+values. The source and target tokens must be node labels.
+
+\code
+ @arcs
+ 	      capacity
+ 1   2   16
+ 1   3   12
+ 2   3   18
+\endcode
+
+The \c \@edges is just a synonym of \c \@arcs.
+
+The \c \@attributes section contains key-value pairs, each line
+consists of two tokens, an attribute name, and then an attribute value.
+
+\code
+ @attributes
+ source 1
+ target 3
+ caption "LEMON test digraph"
+\endcode
+
+*/
+}
+
+//  LocalWords:  whitespace whitespaces
diff --git a/lemon/lgf_reader.h b/lemon/lgf_reader.h
--- a/lemon/lgf_reader.h
+++ b/lemon/lgf_reader.h
@@ -268,35 +268,58 @@
       str = os.str();
       return is;
     }
-
-    std::istream& readIdentifier(std::istream& is, std::string& str) {
-      std::ostringstream os;
-
-      char c;
-      is >> std::ws;
-      
-      if (!is.get(c))
-	return is;
-
-      if (!isIdentifierFirstChar(c))
-	throw DataFormatError("Wrong char in identifier");
-      
-      os << c;
-      
-      while (is.get(c) && !isWhiteSpace(c)) {
-	if (!isIdentifierChar(c)) 
-	  throw DataFormatError("Wrong char in identifier");	  
-	os << c;
-      }
-      if (!is) is.clear();
-     
-      str = os.str();
-      return is;
-    }
     
   }
-  
-  /// \e
+
+  /// \ingroup lemon_io
+  ///  
+  /// \brief LGF reader for directed graphs
+  ///
+  /// This utility reads an \ref lgf-format "LGF" file.
+  ///
+  /// The reading method does a batch processing. The user creates a
+  /// reader object, then various reading rules can be added to the
+  /// reader, and eventually the reading is executed with the \c run()
+  /// member function. A map reading rule can be added to the reader
+  /// with the \c nodeMap() or \c arcMap() members. An optional
+  /// converter parameter can also be added as a standard functor converting from
+  /// std::string to the value type of the map. If it is set, it will
+  /// determine how the tokens in the file should be is converted to the map's
+  /// value type. If the functor is not set, then a default conversion
+  /// will be used. One map can be read into multiple map objects at the
+  /// same time. The \c attribute(), \c node() and \c arc() functions
+  /// are used to add attribute reading rules.
+  ///
+  ///\code
+  ///     DigraphReader<Digraph>(std::cin, digraph).
+  ///       nodeMap("coordinates", coord_map).
+  ///       arcMap("capacity", cap_map).
+  ///       node("source", src).
+  ///       node("target", trg).
+  ///       attribute("caption", caption).
+  ///       run();
+  ///\endcode
+  ///
+  /// By default the reader uses the first section in the file of the
+  /// proper type. If a section has an optional name, then it can be
+  /// selected for reading by giving an optional name parameter to
+  /// the \c nodes(), \c arcs() or \c attributes()
+  /// functions.
+  ///
+  /// The \c useNodes() and \c useArcs() functions are used to tell the reader
+  /// that the nodes or arcs should not be constructed (added to the
+  /// graph) during the reading, but instead the label map of the items
+  /// are given as a parameter of these functions. An
+  /// application of these function is multipass reading, which is
+  /// important if two \e \@arcs sections must be read from the
+  /// file. In this example the first phase would read the node set and one
+  /// of the arc sets, while the second phase would read the second arc
+  /// set into an \e ArcSet class (\c SmartArcSet or \c ListArcSet).
+  /// The previously read label node map should be passed to the \c
+  /// useNodes() functions. Another application of multipass reading when
+  /// paths are given as a node map or an arc map. It is impossible read this in
+  /// a single pass, because the arcs are not constructed when the node
+  /// maps are read.
   template <typename _Digraph>
   class DigraphReader {
   public:
@@ -341,23 +364,34 @@
 
   public:
 
-    /// \e
+    /// \brief Constructor
+    ///
+    /// Construct a directed graph reader, which reads from the given
+    /// input stream.
     DigraphReader(std::istream& is, Digraph& digraph) 
       : _is(&is), local_is(false), _digraph(digraph),
 	_use_nodes(false), _use_arcs(false) {}
 
-    /// \e
+    /// \brief Constructor
+    ///
+    /// Construct a directed graph reader, which reads from the given
+    /// file.
     DigraphReader(const std::string& fn, Digraph& digraph) 
       : _is(new std::ifstream(fn.c_str())), local_is(true), _digraph(digraph),
     	_use_nodes(false), _use_arcs(false) {}
-
-
-    /// \e
+    
+    /// \brief Constructor
+    ///
+    /// Construct a directed graph reader, which reads from the given
+    /// file.
     DigraphReader(const char* fn, Digraph& digraph) 
       : _is(new std::ifstream(fn)), local_is(true), _digraph(digraph),
     	_use_nodes(false), _use_arcs(false) {}
 
-    /// \e
+    /// \brief Copy constructor
+    ///
+    /// The copy constructor transfers all data from the other reader,
+    /// therefore the copied reader will not be usable more. 
     DigraphReader(DigraphReader& other) 
       : _is(other._is), local_is(other.local_is), _digraph(other._digraph),
 	_use_nodes(other._use_nodes), _use_arcs(other._use_arcs) {
@@ -377,7 +411,7 @@
       _attributes_caption = other._attributes_caption;
     }
 
-    /// \e
+    /// \brief Destructor
     ~DigraphReader() {
       for (typename NodeMaps::iterator it = _node_maps.begin(); 
 	   it != _node_maps.end(); ++it) {
@@ -406,7 +440,12 @@
 
   public:
 
-    /// \e
+    /// \name Reading rules
+    /// @{
+    
+    /// \brief Node map reading rule
+    ///
+    /// Add a node map reading rule to the reader.
     template <typename Map>
     DigraphReader& nodeMap(const std::string& caption, Map& map) {
       checkConcept<concepts::WriteMap<Node, typename Map::Value>, Map>();
@@ -416,7 +455,10 @@
       return *this;
     }
 
-    /// \e
+    /// \brief Node map reading rule
+    ///
+    /// Add a node map reading rule with specialized converter to the
+    /// reader.
     template <typename Map, typename Converter>
     DigraphReader& nodeMap(const std::string& caption, Map& map, 
 			   const Converter& converter = Converter()) {
@@ -427,7 +469,9 @@
       return *this;
     }
 
-    /// \e
+    /// \brief Arc map reading rule
+    ///
+    /// Add an arc map reading rule to the reader.
     template <typename Map>
     DigraphReader& arcMap(const std::string& caption, Map& map) {
       checkConcept<concepts::WriteMap<Arc, typename Map::Value>, Map>();
@@ -437,7 +481,10 @@
       return *this;
     }
 
-    /// \e
+    /// \brief Arc map reading rule
+    ///
+    /// Add an arc map reading rule with specialized converter to the
+    /// reader.
     template <typename Map, typename Converter>
     DigraphReader& arcMap(const std::string& caption, Map& map, 
 			  const Converter& converter = Converter()) {
@@ -448,7 +495,9 @@
       return *this;
     }
 
-    /// \e
+    /// \brief Attribute reading rule
+    ///
+    /// Add an attribute reading rule to the reader.
     template <typename Value>
     DigraphReader& attribute(const std::string& caption, Value& value) {
       _reader_bits::ValueStorageBase* storage = 
@@ -457,7 +506,10 @@
       return *this;
     }
 
-    /// \e
+    /// \brief Attribute reading rule
+    ///
+    /// Add an attribute reading rule with specialized converter to the
+    /// reader.
     template <typename Value, typename Converter>
     DigraphReader& attribute(const std::string& caption, Value& value, 
 			     const Converter& converter = Converter()) {
@@ -467,7 +519,9 @@
       return *this;
     }
 
-    /// \e
+    /// \brief Node reading rule
+    ///
+    /// Add a node reading rule to reader.
     DigraphReader& node(const std::string& caption, Node& node) {
       typedef _reader_bits::MapLookUpConverter<Node> Converter;
       Converter converter(_node_index);
@@ -477,7 +531,9 @@
       return *this;
     }
 
-    /// \e
+    /// \brief Arc reading rule
+    ///
+    /// Add an arc reading rule to reader.
     DigraphReader& arc(const std::string& caption, Arc& arc) {
       typedef _reader_bits::MapLookUpConverter<Arc> Converter;
       Converter converter(_arc_index);
@@ -487,25 +543,44 @@
       return *this;
     }
 
-    /// \e
+    /// @}
+
+    /// \name Select section by name
+    /// @{
+
+    /// \brief Set \c \@nodes section to be read
+    ///
+    /// Set \c \@nodes section to be read
     DigraphReader& nodes(const std::string& caption) {
       _nodes_caption = caption;
       return *this;
     }
 
-    /// \e
+    /// \brief Set \c \@arcs section to be read
+    ///
+    /// Set \c \@arcs section to be read
     DigraphReader& arcs(const std::string& caption) {
       _arcs_caption = caption;
       return *this;
     }
 
-    /// \e
+    /// \brief Set \c \@attributes section to be read
+    ///
+    /// Set \c \@attributes section to be read
     DigraphReader& attributes(const std::string& caption) {
       _attributes_caption = caption;
       return *this;
     }
 
-    /// \e
+    /// @}
+
+    /// \name Using previously constructed node or arc set
+    /// @{
+
+    /// \brief Use previously constructed node set
+    ///
+    /// Use previously constructed node set, and specify the node
+    /// label map.
     template <typename Map>
     DigraphReader& useNodes(const Map& map) {
       checkConcept<concepts::ReadMap<Node, typename Map::Value>, Map>();
@@ -518,7 +593,11 @@
       return *this;
     }
 
-    /// \e
+    /// \brief Use previously constructed node set
+    ///
+    /// Use previously constructed node set, and specify the node
+    /// label map and a functor which converts the label map values to
+    /// std::string.
     template <typename Map, typename Converter>
     DigraphReader& useNodes(const Map& map, 
 			    const Converter& converter = Converter()) {
@@ -531,7 +610,10 @@
       return *this;
     }
 
-    /// \e
+    /// \brief Use previously constructed arc set
+    ///
+    /// Use previously constructed arc set, and specify the arc
+    /// label map.
     template <typename Map>
     DigraphReader& useArcs(const Map& map) {
       checkConcept<concepts::ReadMap<Arc, typename Map::Value>, Map>();
@@ -544,7 +626,11 @@
       return *this;
     }
 
-    /// \e
+    /// \brief Use previously constructed arc set
+    ///
+    /// Use previously constructed arc set, and specify the arc
+    /// label map and a functor which converts the label map values to
+    /// std::string.
     template <typename Map, typename Converter>
     DigraphReader& useArcs(const Map& map, 
 			    const Converter& converter = Converter()) {
@@ -557,6 +643,8 @@
       return *this;
     }
 
+    /// @}
+
   private:
 
     bool readLine() {
@@ -597,7 +685,7 @@
 	
 	std::string map;
 	int index = 0;
-	while (_reader_bits::readIdentifier(line, map)) {
+	while (_reader_bits::readToken(line, map)) {
 	  if (maps.find(map) != maps.end()) {
 	    std::ostringstream msg;
 	    msg << "Multiple occurence of node map: " << map;
@@ -680,7 +768,7 @@
 	
 	std::string map;
 	int index = 0;
-	while (_reader_bits::readIdentifier(line, map)) {
+	while (_reader_bits::readToken(line, map)) {
 	  if (maps.find(map) != maps.end()) {
 	    std::ostringstream msg;
 	    msg << "Multiple occurence of arc map: " << map;
@@ -787,7 +875,7 @@
 	line.putback(c);
 	
 	std::string attr, token;
-	if (!_reader_bits::readIdentifier(line, attr))
+	if (!_reader_bits::readToken(line, attr))
 	  throw DataFormatError("Attribute name not found");
 	if (!_reader_bits::readToken(line, token))
 	  throw DataFormatError("Attribute value not found");
@@ -827,8 +915,13 @@
     }
 
   public:
-    
-    /// \e
+
+    /// \name Execution of the reader    
+    /// @{
+
+    /// \brief Start the batch processing
+    ///
+    /// This function starts the batch processing
     void run() {
       
       LEMON_ASSERT(_is != 0, "This reader assigned to an other reader");
@@ -846,8 +939,8 @@
 	  char c;
 	  std::string section, caption;
 	  line >> c;
-	  _reader_bits::readIdentifier(line, section);
-	  _reader_bits::readIdentifier(line, caption);
+	  _reader_bits::readToken(line, section);
+	  _reader_bits::readToken(line, caption);
 
 	  if (line >> c) 
 	    throw DataFormatError("Extra character on the end of line");
@@ -891,20 +984,25 @@
       }
 
     }
+
+    /// @}
     
   };
 
+  /// \relates DigraphReader
   template <typename Digraph>
   DigraphReader<Digraph> digraphReader(std::istream& is, Digraph& digraph) {
     return DigraphReader<Digraph>(is, digraph);
   }
 
+  /// \relates DigraphReader
   template <typename Digraph>
   DigraphReader<Digraph> digraphReader(const std::string& fn, 
 				       Digraph& digraph) {
     return DigraphReader<Digraph>(fn, digraph);
   }
 
+  /// \relates DigraphReader
   template <typename Digraph>
   DigraphReader<Digraph> digraphReader(const char* fn, Digraph& digraph) {
     return DigraphReader<Digraph>(fn, digraph);
diff --git a/lemon/lgf_writer.h b/lemon/lgf_writer.h
--- a/lemon/lgf_writer.h
+++ b/lemon/lgf_writer.h
@@ -204,6 +204,7 @@
     }
 
     bool requireEscape(const std::string& str) {
+      if (str.empty() || str[0] == '@') return true;
       std::istringstream is(str);
       char c;
       while (is.get(c)) {
@@ -231,7 +232,50 @@
 
   }
   
-  /// \e
+  /// \ingroup lemon_io
+  ///  
+  /// \brief LGF writer for directed graphs
+  ///
+  /// This utility writes an \ref lgf-format "LGF" file.
+  ///
+  /// The writing method does a batch processing. The user creates a
+  /// writer object, then various writing rules can be added to the
+  /// writer, and eventually the writing is executed with the \c run()
+  /// member function. A map writing rule can be added to the writer
+  /// with the \c nodeMap() or \c arcMap() members. An optional
+  /// converter parameter can also be added as a standard functor converting from
+  /// the value type of the map to std::string. If it is set, it will
+  /// determine how the map's value type is written to the output
+  /// stream. If the functor is not set, then a default conversion
+  /// will be used. The \c attribute(), \c node() and \c arc() functions
+  /// are used to add attribute writing rules.
+  ///
+  ///\code
+  ///     DigraphWriter<Digraph>(std::cout, digraph).
+  ///       nodeMap("coordinates", coord_map).
+  ///       nodeMap("size", size).
+  ///       nodeMap("title", title).
+  ///       arcMap("capacity", cap_map).
+  ///       node("source", src).
+  ///       node("target", trg).
+  ///       attribute("caption", caption).
+  ///       run();
+  ///\endcode
+  ///
+  ///
+  /// By default, the writer does not write additional captions to the
+  /// sections, but they can be give as an optional parameter of
+  /// the \c nodes(), \c arcs() or \c
+  /// attributes() functions.
+  ///
+  /// The \c skipNodes() and \c skipArcs() functions forbid the
+  /// writing of the sections. If two arc sections should be written to the
+  /// output, it can be done in two passes, the first pass writes the
+  /// node section and the first arc section, then the second pass
+  /// skips the node section and writes just the arc section to the
+  /// stream. The output stream can be retrieved with the \c ostream()
+  /// function, hence the second pass can append its output to the output of the
+  /// first pass.
   template <typename _Digraph>
   class DigraphWriter {
   public:
@@ -273,21 +317,34 @@
 
   public:
 
-    /// \e
+    /// \brief Constructor
+    ///
+    /// Construct a directed graph writer, which writes to the given
+    /// output stream.
     DigraphWriter(std::ostream& is, Digraph& digraph) 
       : _os(&is), local_os(false), _digraph(digraph),
 	_skip_nodes(false), _skip_arcs(false) {}
 
-    /// \e
+    /// \brief Constructor
+    ///
+    /// Construct a directed graph writer, which writes to the given
+    /// output file.
     DigraphWriter(const std::string& fn, Digraph& digraph) 
       : _os(new std::ofstream(fn.c_str())), local_os(true), _digraph(digraph),
 	_skip_nodes(false), _skip_arcs(false) {}
 
-    /// \e
+    /// \brief Constructor
+    ///
+    /// Construct a directed graph writer, which writes to the given
+    /// output file.
     DigraphWriter(const char* fn, Digraph& digraph) 
       : _os(new std::ofstream(fn)), local_os(true), _digraph(digraph),
 	_skip_nodes(false), _skip_arcs(false) {}
 
+    /// \brief Copy constructor
+    ///
+    /// The copy constructor transfers all data from the other writer,
+    /// therefore the copied writer will not be usable more. 
     DigraphWriter(DigraphWriter& other) 
       : _os(other._os), local_os(other.local_os), _digraph(other._digraph),
 	_skip_nodes(other._skip_nodes), _skip_arcs(other._skip_arcs) {
@@ -307,7 +364,7 @@
       _attributes_caption = other._attributes_caption;
     }
 
-    /// \e
+    /// \brief Destructor
     ~DigraphWriter() {
       for (typename NodeMaps::iterator it = _node_maps.begin(); 
 	   it != _node_maps.end(); ++it) {
@@ -335,7 +392,12 @@
 
   public:
 
-    /// \e
+    /// \name Writing rules
+    /// @{
+    
+    /// \brief Node map reading rule
+    ///
+    /// Add a node map reading rule to the writer.
     template <typename Map>
     DigraphWriter& nodeMap(const std::string& caption, const Map& map) {
       checkConcept<concepts::ReadMap<Node, typename Map::Value>, Map>();
@@ -345,7 +407,10 @@
       return *this;
     }
 
-    /// \e
+    /// \brief Node map writing rule
+    ///
+    /// Add a node map writing rule with specialized converter to the
+    /// writer.
     template <typename Map, typename Converter>
     DigraphWriter& nodeMap(const std::string& caption, const Map& map, 
 			   const Converter& converter = Converter()) {
@@ -356,7 +421,9 @@
       return *this;
     }
 
-    /// \e
+    /// \brief Arc map writing rule
+    ///
+    /// Add an arc map writing rule to the writer.
     template <typename Map>
     DigraphWriter& arcMap(const std::string& caption, const Map& map) {
       checkConcept<concepts::ReadMap<Arc, typename Map::Value>, Map>();
@@ -366,7 +433,10 @@
       return *this;
     }
 
-    /// \e
+    /// \brief Arc map writing rule
+    ///
+    /// Add an arc map writing rule with specialized converter to the
+    /// writer.
     template <typename Map, typename Converter>
     DigraphWriter& arcMap(const std::string& caption, const Map& map, 
 			  const Converter& converter = Converter()) {
@@ -377,7 +447,9 @@
       return *this;
     }
 
-    /// \e
+    /// \brief Attribute writing rule
+    ///
+    /// Add an attribute writing rule to the writer.
     template <typename Value>
     DigraphWriter& attribute(const std::string& caption, const Value& value) {
       _writer_bits::ValueStorageBase* storage = 
@@ -386,7 +458,10 @@
       return *this;
     }
 
-    /// \e
+    /// \brief Attribute writing rule
+    ///
+    /// Add an attribute writing rule with specialized converter to the
+    /// writer.
     template <typename Value, typename Converter>
     DigraphWriter& attribute(const std::string& caption, const Value& value, 
 			     const Converter& converter = Converter()) {
@@ -396,7 +471,9 @@
       return *this;
     }
 
-    /// \e
+    /// \brief Node writing rule
+    ///
+    /// Add a node writing rule to the writer.
     DigraphWriter& node(const std::string& caption, const Node& node) {
       typedef _writer_bits::MapLookUpConverter<Node> Converter;
       Converter converter(_node_index);
@@ -406,7 +483,9 @@
       return *this;
     }
 
-    /// \e
+    /// \brief Arc writing rule
+    ///
+    /// Add an arc writing rule to writer.
     DigraphWriter& arc(const std::string& caption, const Arc& arc) {
       typedef _writer_bits::MapLookUpConverter<Arc> Converter;
       Converter converter(_arc_index);
@@ -416,34 +495,54 @@
       return *this;
     }
 
-    /// \e
+    /// \name Select section by name
+    /// @{
+
+    /// \brief Set \c \@nodes section to be read
+    ///
+    /// Set \c \@nodes section to be read
     DigraphWriter& nodes(const std::string& caption) {
       _nodes_caption = caption;
       return *this;
     }
 
-    /// \e
+    /// \brief Set \c \@arcs section to be read
+    ///
+    /// Set \c \@arcs section to be read
     DigraphWriter& arcs(const std::string& caption) {
       _arcs_caption = caption;
       return *this;
     }
 
-    /// \e
+    /// \brief Set \c \@attributes section to be read
+    ///
+    /// Set \c \@attributes section to be read
     DigraphWriter& attributes(const std::string& caption) {
       _attributes_caption = caption;
       return *this;
     }
 
+    /// \name Skipping section
+    /// @{
+
+    /// \brief Skip writing the node set
+    ///
+    /// The \c \@nodes section will be not written to the stream.
     DigraphWriter& skipNodes() {
       LEMON_ASSERT(!_skip_nodes, "Multiple usage of skipNodes() member");
       return *this;
     }
 
+    /// \brief Skip writing arc set
+    ///
+    /// The \c \@arcs section will be not written to the stream.
     DigraphWriter& skipArcs() {
       LEMON_ASSERT(!_skip_arcs, "Multiple usage of skipArcs() member");
       return *this;
     }
 
+    /// @}
+
   private:
 
     void writeNodes() {
@@ -458,7 +557,7 @@
 
       *_os << "@nodes";
       if (!_nodes_caption.empty()) {
-	*_os << ' ' << _nodes_caption;
+	_writer_bits::writeToken(*_os << ' ', _nodes_caption);
       }
       *_os << std::endl;
 
@@ -467,7 +566,7 @@
       }
       for (typename NodeMaps::iterator it = _node_maps.begin();
 	   it != _node_maps.end(); ++it) {
-	*_os << it->first << '\t';
+	_writer_bits::writeToken(*_os, it->first) << '\t';
       }
       *_os << std::endl;
 
@@ -518,7 +617,7 @@
 
       *_os << "@arcs";
       if (!_arcs_caption.empty()) {
-	*_os << ' ' << _arcs_caption;
+	_writer_bits::writeToken(*_os << ' ', _arcs_caption);
       }
       *_os << std::endl;
 
@@ -528,7 +627,7 @@
       }
       for (typename ArcMaps::iterator it = _arc_maps.begin();
 	   it != _arc_maps.end(); ++it) {
-	*_os << it->first << '\t';
+	_writer_bits::writeToken(*_os, it->first) << '\t';
       }
       *_os << std::endl;
 
@@ -577,12 +676,12 @@
       if (_attributes.empty()) return;
       *_os << "@attributes";
       if (!_attributes_caption.empty()) {
-	*_os << ' ' << _attributes_caption;
+	_writer_bits::writeToken(*_os << ' ', _attributes_caption);
       }
       *_os << std::endl;
       for (typename Attributes::iterator it = _attributes.begin();
 	   it != _attributes.end(); ++it) {
-	*_os << it->first << ' ';
+	_writer_bits::writeToken(*_os, it->first) << ' ';
 	_writer_bits::writeToken(*_os, it->second->get());
 	*_os << std::endl;
       }
@@ -590,7 +689,12 @@
     
   public:
     
-    /// \e
+    /// \name Execution of the writer    
+    /// @{
+
+    /// \brief Start the batch processing
+    ///
+    /// This function starts the batch processing
     void run() {
       if (!_skip_nodes) {
 	writeNodes();
@@ -601,23 +705,30 @@
       writeAttributes();
     }
 
-    /// \e
-    std::ostream& stream() {
+    /// \brief Gives back the stream of the writer
+    ///
+    /// Gives back the stream of the writer
+    std::ostream& ostream() {
       return *_os;
     }
+
+    /// @}
   };
 
+  /// \relates DigraphWriter
   template <typename Digraph>
   DigraphWriter<Digraph> digraphWriter(std::istream& is, Digraph& digraph) {
     return DigraphWriter<Digraph>(is, digraph);
   }
 
+  /// \relates DigraphWriter
   template <typename Digraph>
   DigraphWriter<Digraph> digraphWriter(const std::string& fn, 
 				       Digraph& digraph) {
     return DigraphWriter<Digraph>(fn, digraph);
   }
 
+  /// \relates DigraphWriter
   template <typename Digraph>
   DigraphWriter<Digraph> digraphWriter(const char* fn, Digraph& digraph) {
     return DigraphWriter<Digraph>(fn, digraph);