void SM_io_parser<Decorator_>::print_vertex(SVertex_handle v) const
{
  // syntax: index { isolated incident_object, mark, point }
  out << index(v) << " { ";
  if ( is_isolated(v) ) out << "1 " << index(v->incident_sface());
  else                  out << "0 " << index(first_out_edge(v));
  out  << ", " << v->mark() << ", " << v->point() <<  "}\n";
}
void SM_io_parser<Decorator_>::print_vertex(SVertex_handle v) const
{
   
  out << index(v) << " { ";
  if ( is_isolated(v) ) out << "1 " << index(v->incident_sface());
  else                  out << "0 " << index(first_out_edge(v));
  out  << ", " << v->mark() << ", " << v->point() <<  "}\n";
}