- virtual void do_print () const;
- virtual void do_process_and_next (Moment);
- virtual Music_iterator *try_music_in_children (Music const *) const;
+ virtual void process (Moment);
+ virtual Music_iterator *try_music_in_children (Music *) const;
+
+private:
+ Music_iterator * main_iter_p_;
+ Music_iterator * alternative_iter_p_;
+
+ Moment main_length_mom_;