void PM_io_parser<PMDEC>::print_vertex(Vertex_handle v) const
{
  // syntax: index { isolated incident_object, mark, point }
  out << index(v) << " { ";
  if ( is_isolated(v) ) out << "1 " << index(face(v));
  else                  out << "0 " << index(v->halfedge());
  out  << ", " << mark(v) << ", " << point(v) <<  "}\n";
}
void PM_io_parser<PMDEC>::print_vertex(Vertex_handle v) const
{
   
  out << index(v) << " { ";
  if ( is_isolated(v) ) out << "1 " << index(face(v));
  else                  out << "0 " << index(v->halfedge());
  out  << ", " << mark(v) << ", " << point(v) <<  "}\n";
}