) ? "-" : "+") << endl;  #endif                         }                     });                 }                                  if (!frame.todo.empty()) {                     // Now do an edge                     handle_t edge_into = frame.todo.back();                     handle_t connected_head = find(edge_into);                     frame.todo.pop_back();                      #ifdef debug                     cerr << "\tFollow " << graph->get_id(edge_into) << (graph->get_is_reverse(edge_into) ? "-" : "+") 