/// \brief A skeleton structure for representing directed paths in

     /// \brief A skeleton structure for representing directed paths in

     /// a digraph.

     /// a digraph.

     ///

     ///

     /// A skeleton structure for representing directed paths in a

     /// A skeleton structure for representing directed paths in a

     /// digraph.  

     /// digraph.  

     ///

     ///

     /// In a sense, the path can be treated as a list of arcs. The

     /// In a sense, the path can be treated as a list of arcs. The

     /// lemon path type stores just this list. As a consequence it

     /// lemon path type stores just this list. As a consequence it

     /// cannot enumerate the nodes in the path and the zero length

     /// cannot enumerate the nodes in the path and the zero length

     /// paths cannot store the source.

     /// paths cannot store the source.

     /// algorithms then we should create a temporarly path object. In

     /// algorithms then we should create a temporarly path object. In

     /// Lemon such algorithms gives back a path dumper what can

     /// Lemon such algorithms gives back a path dumper what can

     /// assigned to a real path and the dumpers can be implemented as

     /// assigned to a real path and the dumpers can be implemented as

     /// an adaptor class to the predecessor map.

     /// an adaptor class to the predecessor map.

     ///

     ///

     /// The paths can be constructed from any path type by a

     /// The paths can be constructed from any path type by a

     /// template constructor or a template assignment operator.

     /// template constructor or a template assignment operator.

     /// 

     /// 

     template <typename _Digraph>

     template <typename _Digraph>