void SM_io_parser<Decorator_>::debug_loop(SHalfloop_const_handle l) const
{
  out << index(l) << " "
      << index(l->twin()) << " " << index(l->incident_sface())
      << " ["<< l->mark() << "] " << l->circle() << std::endl;
}
void SM_io_parser<Decorator_>::debug_loop(SHalfloop_const_handle l) const
{
  out << index(l) << " "
      << index(l->twin()) << " " << index(l->incident_sface())
      << " ["<< l->mark() << "] " << l->circle() << std::endl;
}