- Link_array<Music> time_scaled_musics_;
- /// when does the scaled music stop? Array order is synced with time_scaled_musics_
- Array<Rational> stop_moments_;
- /// when does the current spanner stop? Array order is synced with time_scaled_musics_
- Array<Rational> span_stop_moments_;
-
- /// The spanners. Array order is synced with time_scaled_musics_
- Link_array<Spanner> started_spanners_;