RhodeCode

      Graph,

      typename enable_if<typename Graph::BuildTag, void>::type>

    {

      template <typename From, typename NodeRefMap, typename EdgeRefMap>

      static void copy(const From& from, Graph &to,

                       NodeRefMap& nodeRefMap, EdgeRefMap& edgeRefMap) {

        to.build(from, nodeRefMap, edgeRefMap);

      }

    };

  }

  /// \brief Class to copy a digraph.

  ///

  /// Class to copy a digraph to another digraph (duplicate a digraph). The

  /// simplest way of using it is through the \c digraphCopy() function.

  ///

  /// This class not only make a copy of a digraph, but it can create

  /// references and cross references between the nodes and arcs of

  /// the two digraphs, and it can copy maps to use with the newly created

  /// digraph.

  ///

  /// To make a copy from a digraph, first an instance of DigraphCopy

  /// should be created, then the data belongs to the digraph should