deba@127: /* -*- C++ -*-
deba@127:  *
deba@127:  * This file is a part of LEMON, a generic C++ optimization library
deba@127:  *
deba@127:  * Copyright (C) 2003-2008
deba@127:  * Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport
deba@127:  * (Egervary Research Group on Combinatorial Optimization, EGRES).
deba@127:  *
deba@127:  * Permission to use, modify and distribute this software is granted
deba@127:  * provided that this copyright notice appears in all copies. For
deba@127:  * precise terms see the accompanying LICENSE file.
deba@127:  *
deba@127:  * This software is provided "AS IS" with no warranty of any kind,
deba@127:  * express or implied, and with no claim as to its suitability for any
deba@127:  * purpose.
deba@127:  *
deba@127:  */
deba@127: 
deba@127: ///\ingroup lemon_io
deba@127: ///\file
deba@127: ///\brief Lemon Graph Format writer.
deba@127: 
deba@127: 
deba@127: #ifndef LEMON_LGF_WRITER_H
deba@127: #define LEMON_LGF_WRITER_H
deba@127: 
deba@127: #include <iostream>
deba@127: #include <fstream>
deba@127: #include <sstream>
deba@127: 
deba@127: #include <algorithm>
deba@127: 
deba@127: #include <vector>
deba@127: #include <functional>
deba@127: 
deba@127: #include <lemon/assert.h>
deba@127: #include <lemon/graph_utils.h>
deba@127: 
deba@127: namespace lemon {
deba@127: 
deba@127:   namespace _writer_bits {
deba@127: 
deba@127:     template <typename Value>
deba@127:     struct DefaultConverter {
deba@127:       std::string operator()(const Value& value) {
deba@127: 	std::ostringstream os;
deba@127: 	os << value;
deba@127: 	return os.str();
deba@127:       }
deba@127:     };
deba@127: 
deba@127:     template <typename T>
deba@127:     bool operator<(const T&, const T&) {
deba@127:       throw DataFormatError("Label map is not comparable");
deba@127:     }
deba@127: 
deba@127:     template <typename _Map>
deba@127:     class MapLess {
deba@127:     public:
deba@127:       typedef _Map Map;
deba@127:       typedef typename Map::Key Item;
deba@127: 
deba@127:     private:
deba@127:       const Map& _map;
deba@127:       
deba@127:     public:
deba@127:       MapLess(const Map& map) : _map(map) {}
deba@127: 
deba@127:       bool operator()(const Item& left, const Item& right) {
deba@127: 	return _map[left] < _map[right];
deba@127:       }
deba@127:     };
deba@127: 
deba@127:     template <typename _Item>    
deba@127:     class MapStorageBase {
deba@127:     public:
deba@127:       typedef _Item Item;
deba@127: 
deba@127:     public:
deba@127:       MapStorageBase() {}
deba@127:       virtual ~MapStorageBase() {}
deba@127: 
deba@127:       virtual std::string get(const Item& item) = 0;
deba@127:       virtual void sort(std::vector<Item>&) = 0;
deba@127:     };
deba@127: 
deba@127:     template <typename _Item, typename _Map, 
deba@127: 	      typename _Converter = DefaultConverter<typename _Map::Value> >
deba@127:     class MapStorage : public MapStorageBase<_Item> {
deba@127:     public:
deba@127:       typedef _Map Map;
deba@127:       typedef _Converter Converter;
deba@127:       typedef _Item Item;
deba@127:       
deba@127:     private:
deba@127:       const Map& _map;
deba@127:       Converter _converter;
deba@127: 
deba@127:     public:
deba@127:       MapStorage(const Map& map, const Converter& converter = Converter()) 
deba@127: 	: _map(map), _converter(converter) {}
deba@127:       virtual ~MapStorage() {}
deba@127: 
deba@127:       virtual std::string get(const Item& item) {
deba@127: 	return _converter(_map[item]);
deba@127:       }
deba@127:       virtual void sort(std::vector<Item>& items) {
deba@127: 	MapLess<Map> less(_map);
deba@127: 	std::sort(items.begin(), items.end(), less);
deba@127:       }
deba@127:     };
deba@127: 
deba@127:     class ValueStorageBase {
deba@127:     public:
deba@127:       ValueStorageBase() {}
deba@127:       virtual ~ValueStorageBase() {}
deba@127: 
deba@127:       virtual std::string get() = 0;      
deba@127:     };
deba@127: 
deba@127:     template <typename _Value, typename _Converter = DefaultConverter<_Value> >
deba@127:     class ValueStorage : public ValueStorageBase {
deba@127:     public:
deba@127:       typedef _Value Value;
deba@127:       typedef _Converter Converter;
deba@127: 
deba@127:     private:
deba@127:       const Value& _value;
deba@127:       Converter _converter;
deba@127: 
deba@127:     public:
deba@127:       ValueStorage(const Value& value, const Converter& converter = Converter())
deba@127:  	: _value(value), _converter(converter) {}
deba@127: 
deba@127:       virtual std::string get() {
deba@127: 	return _converter(_value);
deba@127:       }
deba@127:     };
deba@127: 
deba@127:     template <typename Value>
deba@127:     struct MapLookUpConverter {
deba@127:       const std::map<Value, std::string>& _map;
deba@127:       
deba@127:       MapLookUpConverter(const std::map<Value, std::string>& map) 
deba@127: 	: _map(map) {}
deba@127:       
deba@127:       std::string operator()(const Value& str) {
deba@127: 	typename std::map<Value, std::string>::const_iterator it = 
deba@127: 	  _map.find(str);
deba@127: 	if (it == _map.end()) {
deba@127: 	  throw DataFormatError("Item not found");
deba@127: 	}
deba@127: 	return it->second;
deba@127:       }
deba@127:     };
deba@127: 
deba@127:     bool isWhiteSpace(char c) {
deba@127:       return c == ' ' || c == '\t' || c == '\v' || 
deba@127:         c == '\n' || c == '\r' || c == '\f'; 
deba@127:     }
deba@127: 
deba@127:     bool isEscaped(char c) {
deba@127:       return c == '\\' || c == '\"' || c == '\'' || 
deba@127: 	c == '\a' || c == '\b';
deba@127:     }
deba@127: 
deba@127:     static void writeEscape(std::ostream& os, char c) {
deba@127:       switch (c) {
deba@127:       case '\\':
deba@127: 	os << "\\\\";
deba@127: 	return;
deba@127:       case '\"':
deba@127: 	os << "\\\"";
deba@127: 	return;
deba@127:       case '\a':
deba@127: 	os << "\\a";
deba@127: 	return;
deba@127:       case '\b':
deba@127: 	os << "\\b";
deba@127: 	return;
deba@127:       case '\f':
deba@127: 	os << "\\f";
deba@127: 	return;
deba@127:       case '\r':
deba@127: 	os << "\\r";
deba@127: 	return;
deba@127:       case '\n':
deba@127: 	os << "\\n";
deba@127: 	return;
deba@127:       case '\t':
deba@127: 	os << "\\t";
deba@127: 	return;
deba@127:       case '\v':
deba@127: 	os << "\\v";
deba@127: 	return;
deba@127:       default:
deba@127: 	if (c < 0x20) {
deba@127: 	  os << '\\' << std::oct << static_cast<int>(c);
deba@127: 	} else {
deba@127: 	  os << c;
deba@127: 	}
deba@127: 	return;
deba@127:       }     
deba@127:     }
deba@127: 
deba@127:     bool requireEscape(const std::string& str) {
deba@127:       std::istringstream is(str);
deba@127:       char c;
deba@127:       while (is.get(c)) {
deba@127: 	if (isWhiteSpace(c) || isEscaped(c)) {
deba@127: 	  return true;
deba@127: 	}
deba@127:       }
deba@127:       return false;
deba@127:     }
deba@127:     
deba@127:     std::ostream& writeToken(std::ostream& os, const std::string& str) {
deba@127: 
deba@127:       if (requireEscape(str)) {
deba@127: 	os << '\"';
deba@127: 	for (std::string::const_iterator it = str.begin(); 
deba@127: 	     it != str.end(); ++it) {
deba@127: 	  writeEscape(os, *it);
deba@127: 	}	
deba@127: 	os << '\"';
deba@127:       } else {
deba@127: 	os << str;
deba@127:       }
deba@127:       return os;
deba@127:     }
deba@127: 
deba@127:   }
deba@127:   
deba@127:   /// \e
deba@127:   template <typename _Digraph>
deba@127:   class DigraphWriter {
deba@127:   public:
deba@127: 
deba@127:     typedef _Digraph Digraph;
deba@127:     GRAPH_TYPEDEFS(typename Digraph);
deba@127:     
deba@127:   private:
deba@127: 
deba@127: 
deba@127:     std::ostream* _os;
deba@127:     bool local_os;
deba@127: 
deba@127:     Digraph& _digraph;
deba@127: 
deba@127:     std::string _nodes_caption;
deba@127:     std::string _arcs_caption;
deba@127:     std::string _attributes_caption;
deba@127:     
deba@127:     typedef std::map<Node, std::string> NodeIndex;
deba@127:     NodeIndex _node_index;
deba@127:     typedef std::map<Arc, std::string> ArcIndex;
deba@127:     ArcIndex _arc_index;
deba@127: 
deba@127:     typedef std::vector<std::pair<std::string, 
deba@127:       _writer_bits::MapStorageBase<Node>* > > NodeMaps;    
deba@127:     NodeMaps _node_maps; 
deba@127: 
deba@127:     typedef std::vector<std::pair<std::string, 
deba@127:       _writer_bits::MapStorageBase<Arc>* > >ArcMaps;
deba@127:     ArcMaps _arc_maps;
deba@127: 
deba@127:     typedef std::vector<std::pair<std::string, 
deba@127:       _writer_bits::ValueStorageBase*> > Attributes;
deba@127:     Attributes _attributes;
deba@127: 
deba@127:     bool _skip_nodes;
deba@127:     bool _skip_arcs;
deba@127: 
deba@127:   public:
deba@127: 
deba@127:     /// \e
deba@127:     DigraphWriter(std::ostream& is, Digraph& digraph) 
deba@127:       : _os(&is), local_os(false), _digraph(digraph),
deba@127: 	_skip_nodes(false), _skip_arcs(false) {}
deba@127: 
deba@127:     /// \e
deba@127:     DigraphWriter(const std::string& fn, Digraph& digraph) 
deba@127:       : _os(new std::ofstream(fn.c_str())), local_os(true), _digraph(digraph),
deba@127: 	_skip_nodes(false), _skip_arcs(false) {}
deba@127: 
deba@127:     /// \e
deba@127:     DigraphWriter(const char* fn, Digraph& digraph) 
deba@127:       : _os(new std::ofstream(fn)), local_os(true), _digraph(digraph),
deba@127: 	_skip_nodes(false), _skip_arcs(false) {}
deba@127: 
deba@127:     DigraphWriter(DigraphWriter& other) 
deba@127:       : _os(other._os), local_os(other.local_os), _digraph(other._digraph),
deba@127: 	_skip_nodes(other._skip_nodes), _skip_arcs(other._skip_arcs) {
deba@127: 
deba@127:       other.is = 0;
deba@127:       other.local_os = false;
deba@127: 
deba@127:       _node_index.swap(other._node_index);
deba@127:       _arc_index.swap(other._arc_index);
deba@127: 
deba@127:       _node_maps.swap(other._node_maps);
deba@127:       _arc_maps.swap(other._arc_maps);
deba@127:       _attributes.swap(other._attributes);
deba@127: 
deba@127:       _nodes_caption = other._nodes_caption;
deba@127:       _arcs_caption = other._arcs_caption;
deba@127:       _attributes_caption = other._attributes_caption;
deba@127:     }
deba@127: 
deba@127:     /// \e
deba@127:     ~DigraphWriter() {
deba@127:       for (typename NodeMaps::iterator it = _node_maps.begin(); 
deba@127: 	   it != _node_maps.end(); ++it) {
deba@127: 	delete it->second;
deba@127:       }
deba@127: 
deba@127:       for (typename ArcMaps::iterator it = _arc_maps.begin(); 
deba@127: 	   it != _arc_maps.end(); ++it) {
deba@127: 	delete it->second;
deba@127:       }
deba@127: 
deba@127:       for (typename Attributes::iterator it = _attributes.begin(); 
deba@127: 	   it != _attributes.end(); ++it) {
deba@127: 	delete it->second;
deba@127:       }
deba@127: 
deba@127:       if (local_os) {
deba@127: 	delete _os;
deba@127:       }
deba@127:     }
deba@127: 
deba@127:   private:
deba@127:     
deba@127:     DigraphWriter& operator=(const DigraphWriter&);
deba@127: 
deba@127:   public:
deba@127: 
deba@127:     /// \e
deba@127:     template <typename Map>
deba@127:     DigraphWriter& nodeMap(const std::string& caption, const Map& map) {
deba@127:       checkConcept<concepts::ReadMap<Node, typename Map::Value>, Map>();
deba@127:       _writer_bits::MapStorageBase<Node>* storage = 
deba@127: 	new _writer_bits::MapStorage<Node, Map>(map);
deba@127:       _node_maps.push_back(std::make_pair(caption, storage));
deba@127:       return *this;
deba@127:     }
deba@127: 
deba@127:     /// \e
deba@127:     template <typename Map, typename Converter>
deba@127:     DigraphWriter& nodeMap(const std::string& caption, const Map& map, 
deba@127: 			   const Converter& converter = Converter()) {
deba@127:       checkConcept<concepts::ReadMap<Node, typename Map::Value>, Map>();
deba@127:       _writer_bits::MapStorageBase<Node>* storage = 
deba@127: 	new _writer_bits::MapStorage<Node, Map, Converter>(map, converter);
deba@127:       _node_maps.push_back(std::make_pair(caption, storage));
deba@127:       return *this;
deba@127:     }
deba@127: 
deba@127:     /// \e
deba@127:     template <typename Map>
deba@127:     DigraphWriter& arcMap(const std::string& caption, const Map& map) {
deba@127:       checkConcept<concepts::ReadMap<Arc, typename Map::Value>, Map>();
deba@127:       _writer_bits::MapStorageBase<Arc>* storage = 
deba@127: 	new _writer_bits::MapStorage<Arc, Map>(map);
deba@127:       _arc_maps.push_back(std::make_pair(caption, storage));
deba@127:       return *this;
deba@127:     }
deba@127: 
deba@127:     /// \e
deba@127:     template <typename Map, typename Converter>
deba@127:     DigraphWriter& arcMap(const std::string& caption, const Map& map, 
deba@127: 			  const Converter& converter = Converter()) {
deba@127:       checkConcept<concepts::ReadMap<Arc, typename Map::Value>, Map>();
deba@127:       _writer_bits::MapStorageBase<Arc>* storage = 
deba@127: 	new _writer_bits::MapStorage<Arc, Map, Converter>(map, converter);
deba@127:       _arc_maps.push_back(std::make_pair(caption, storage));
deba@127:       return *this;
deba@127:     }
deba@127: 
deba@127:     /// \e
deba@127:     template <typename Value>
deba@127:     DigraphWriter& attribute(const std::string& caption, const Value& value) {
deba@127:       _writer_bits::ValueStorageBase* storage = 
deba@127: 	new _writer_bits::ValueStorage<Value>(value);
deba@127:       _attributes.push_back(std::make_pair(caption, storage));
deba@127:       return *this;
deba@127:     }
deba@127: 
deba@127:     /// \e
deba@127:     template <typename Value, typename Converter>
deba@127:     DigraphWriter& attribute(const std::string& caption, const Value& value, 
deba@127: 			     const Converter& converter = Converter()) {
deba@127:       _writer_bits::ValueStorageBase* storage = 
deba@127: 	new _writer_bits::ValueStorage<Value, Converter>(value, converter);
deba@127:       _attributes.push_back(std::make_pair(caption, storage));
deba@127:       return *this;
deba@127:     }
deba@127: 
deba@127:     /// \e
deba@127:     DigraphWriter& node(const std::string& caption, const Node& node) {
deba@127:       typedef _writer_bits::MapLookUpConverter<Node> Converter;
deba@127:       Converter converter(_node_index);
deba@127:       _writer_bits::ValueStorageBase* storage = 
deba@127: 	new _writer_bits::ValueStorage<Node, Converter>(node, converter);
deba@127:       _attributes.push_back(std::make_pair(caption, storage));
deba@127:       return *this;
deba@127:     }
deba@127: 
deba@127:     /// \e
deba@127:     DigraphWriter& arc(const std::string& caption, const Arc& arc) {
deba@127:       typedef _writer_bits::MapLookUpConverter<Arc> Converter;
deba@127:       Converter converter(_arc_index);
deba@127:       _writer_bits::ValueStorageBase* storage = 
deba@127: 	new _writer_bits::ValueStorage<Arc, Converter>(arc, converter);
deba@127:       _attributes.push_back(std::make_pair(caption, storage));
deba@127:       return *this;
deba@127:     }
deba@127: 
deba@127:     /// \e
deba@127:     DigraphWriter& nodes(const std::string& caption) {
deba@127:       _nodes_caption = caption;
deba@127:       return *this;
deba@127:     }
deba@127: 
deba@127:     /// \e
deba@127:     DigraphWriter& arcs(const std::string& caption) {
deba@127:       _arcs_caption = caption;
deba@127:       return *this;
deba@127:     }
deba@127: 
deba@127:     /// \e
deba@127:     DigraphWriter& attributes(const std::string& caption) {
deba@127:       _attributes_caption = caption;
deba@127:       return *this;
deba@127:     }
deba@127: 
deba@127:     DigraphWriter& skipNodes() {
deba@127:       LEMON_ASSERT(!_skip_nodes, "Multiple usage of skipNodes() member");
deba@127:       return *this;
deba@127:     }
deba@127: 
deba@127:     DigraphWriter& skipArcs() {
deba@127:       LEMON_ASSERT(!_skip_arcs, "Multiple usage of skipArcs() member");
deba@127:       return *this;
deba@127:     }
deba@127: 
deba@127:   private:
deba@127: 
deba@127:     void writeNodes() {
deba@127:       _writer_bits::MapStorageBase<Node>* label = 0;
deba@127:       for (typename NodeMaps::iterator it = _node_maps.begin();
deba@127: 	   it != _node_maps.end(); ++it) {
deba@127:         if (it->first == "label") {
deba@127: 	  label = it->second;
deba@127: 	  break;
deba@127: 	}
deba@127:       }
deba@127: 
deba@127:       *_os << "@nodes";
deba@127:       if (!_nodes_caption.empty()) {
deba@127: 	*_os << ' ' << _nodes_caption;
deba@127:       }
deba@127:       *_os << std::endl;
deba@127: 
deba@127:       if (label == 0) {
deba@127: 	*_os << "label" << '\t';
deba@127:       }
deba@127:       for (typename NodeMaps::iterator it = _node_maps.begin();
deba@127: 	   it != _node_maps.end(); ++it) {
deba@127: 	*_os << it->first << '\t';
deba@127:       }
deba@127:       *_os << std::endl;
deba@127: 
deba@127:       std::vector<Node> nodes;
deba@127:       for (NodeIt n(_digraph); n != INVALID; ++n) {
deba@127: 	nodes.push_back(n);
deba@127:       }
deba@127:       
deba@127:       if (label == 0) {
deba@127: 	IdMap<Digraph, Node> id_map(_digraph);
deba@127: 	_writer_bits::MapLess<IdMap<Digraph, Node> > id_less(id_map);
deba@127: 	std::sort(nodes.begin(), nodes.end(), id_less);
deba@127:       } else {
deba@127: 	label->sort(nodes);
deba@127:       }
deba@127: 
deba@127:       for (int i = 0; i < static_cast<int>(nodes.size()); ++i) {
deba@127: 	Node n = nodes[i];
deba@127: 	if (label == 0) {
deba@127: 	  std::ostringstream os;
deba@127: 	  os << _digraph.id(n);
deba@127: 	  _writer_bits::writeToken(*_os, os.str());
deba@127: 	  *_os << '\t';
deba@127: 	  _node_index.insert(std::make_pair(n, os.str()));
deba@127: 	}
deba@127: 	for (typename NodeMaps::iterator it = _node_maps.begin();
deba@127: 	     it != _node_maps.end(); ++it) {
deba@127: 	  std::string value = it->second->get(n);
deba@127: 	  _writer_bits::writeToken(*_os, value);
deba@127: 	  if (it->first == "label") {
deba@127: 	    _node_index.insert(std::make_pair(n, value));
deba@127: 	  }
deba@127: 	  *_os << '\t';
deba@127: 	}
deba@127: 	*_os << std::endl;
deba@127:       }
deba@127:     }
deba@127: 
deba@127:     void writeArcs() {
deba@127:       _writer_bits::MapStorageBase<Arc>* label = 0;
deba@127:       for (typename ArcMaps::iterator it = _arc_maps.begin();
deba@127: 	   it != _arc_maps.end(); ++it) {
deba@127:         if (it->first == "label") {
deba@127: 	  label = it->second;
deba@127: 	  break;
deba@127: 	}
deba@127:       }
deba@127: 
deba@127:       *_os << "@arcs";
deba@127:       if (!_arcs_caption.empty()) {
deba@127: 	*_os << ' ' << _arcs_caption;
deba@127:       }
deba@127:       *_os << std::endl;
deba@127: 
deba@127:       *_os << '\t' << '\t';
deba@127:       if (label == 0) {
deba@127: 	*_os << "label" << '\t';
deba@127:       }
deba@127:       for (typename ArcMaps::iterator it = _arc_maps.begin();
deba@127: 	   it != _arc_maps.end(); ++it) {
deba@127: 	*_os << it->first << '\t';
deba@127:       }
deba@127:       *_os << std::endl;
deba@127: 
deba@127:       std::vector<Arc> arcs;
deba@127:       for (ArcIt n(_digraph); n != INVALID; ++n) {
deba@127: 	arcs.push_back(n);
deba@127:       }
deba@127:       
deba@127:       if (label == 0) {
deba@127: 	IdMap<Digraph, Arc> id_map(_digraph);
deba@127: 	_writer_bits::MapLess<IdMap<Digraph, Arc> > id_less(id_map);
deba@127: 	std::sort(arcs.begin(), arcs.end(), id_less);
deba@127:       } else {
deba@127: 	label->sort(arcs);
deba@127:       }
deba@127: 
deba@127:       for (int i = 0; i < static_cast<int>(arcs.size()); ++i) {
deba@127: 	Arc a = arcs[i];
deba@127: 	_writer_bits::writeToken(*_os, _node_index.
deba@127: 				 find(_digraph.source(a))->second);
deba@127: 	*_os << '\t';
deba@127: 	_writer_bits::writeToken(*_os, _node_index.
deba@127: 				 find(_digraph.target(a))->second);
deba@127: 	*_os << '\t';
deba@127: 	if (label == 0) {
deba@127: 	  std::ostringstream os;
deba@127: 	  os << _digraph.id(a);
deba@127: 	  _writer_bits::writeToken(*_os, os.str());
deba@127: 	  *_os << '\t';
deba@127: 	  _arc_index.insert(std::make_pair(a, os.str()));
deba@127: 	}
deba@127: 	for (typename ArcMaps::iterator it = _arc_maps.begin();
deba@127: 	     it != _arc_maps.end(); ++it) {
deba@127: 	  std::string value = it->second->get(a);
deba@127: 	  _writer_bits::writeToken(*_os, value);
deba@127: 	  if (it->first == "label") {
deba@127: 	    _arc_index.insert(std::make_pair(a, value));
deba@127: 	  }
deba@127: 	  *_os << '\t';
deba@127: 	}
deba@127: 	*_os << std::endl;
deba@127:       }
deba@127:     }
deba@127: 
deba@127:     void writeAttributes() {
deba@127:       if (_attributes.empty()) return;
deba@127:       *_os << "@attributes";
deba@127:       if (!_attributes_caption.empty()) {
deba@127: 	*_os << ' ' << _attributes_caption;
deba@127:       }
deba@127:       *_os << std::endl;
deba@127:       for (typename Attributes::iterator it = _attributes.begin();
deba@127: 	   it != _attributes.end(); ++it) {
deba@127: 	*_os << it->first << ' ';
deba@127: 	_writer_bits::writeToken(*_os, it->second->get());
deba@127: 	*_os << std::endl;
deba@127:       }
deba@127:     }
deba@127:     
deba@127:   public:
deba@127:     
deba@127:     /// \e
deba@127:     void run() {
deba@127:       if (!_skip_nodes) {
deba@127: 	writeNodes();
deba@127:       }
deba@127:       if (!_skip_arcs) {      
deba@127: 	writeArcs();
deba@127:       }
deba@127:       writeAttributes();
deba@127:     }
deba@127: 
deba@127:     /// \e
deba@127:     std::ostream& stream() {
deba@127:       return *_os;
deba@127:     }
deba@127:   };
deba@127: 
deba@127:   template <typename Digraph>
deba@127:   DigraphWriter<Digraph> digraphWriter(std::istream& is, Digraph& digraph) {
deba@127:     return DigraphWriter<Digraph>(is, digraph);
deba@127:   }
deba@127: 
deba@127:   template <typename Digraph>
deba@127:   DigraphWriter<Digraph> digraphWriter(const std::string& fn, 
deba@127: 				       Digraph& digraph) {
deba@127:     return DigraphWriter<Digraph>(fn, digraph);
deba@127:   }
deba@127: 
deba@127:   template <typename Digraph>
deba@127:   DigraphWriter<Digraph> digraphWriter(const char* fn, Digraph& digraph) {
deba@127:     return DigraphWriter<Digraph>(fn, digraph);
deba@127:   }
deba@127: }
deba@127: 
deba@127: #endif