- bool can_create_slur (string, vsize, vsize *, Stream_event *);
- void create_slur (string spanner_id, Stream_event *ev_cause, Grob *g_cause, Direction dir, bool left_broken);
+ bool can_create_slur (const string&, vsize, vsize *, Stream_event *);
+ void create_slur (const string &spanner_id, Stream_event *ev_cause, Grob *g_cause, Direction dir, bool left_broken);