- virtual void acknowledge_grob (Grob_info);
- virtual bool try_music (Music*);
- virtual void process_music ();
- virtual Spanner *create_ligature_spanner (); /* abstract method */
+ DECLARE_ACKNOWLEDGER (rest);
+ DECLARE_ACKNOWLEDGER (note_head);
+ virtual void listen_ligature (Stream_event *ev);
+ void process_music ();
+ virtual Spanner *create_ligature_spanner () = 0;