+compress_music_list (SCM l, Moment m)
+{
+ for (SCM s = l; scm_is_pair (s); s = scm_cdr (s))
+ unsmob<Music> (scm_car (s))->compress (m);
+}
+
+Moment
+Music_sequence::minimum_start (SCM l)
+{
+ Moment m;
+
+ for (SCM s = l; scm_is_pair (s); s = scm_cdr (s))
+ m = min (m, unsmob<Music> (scm_car (s))->start_mom ());
+ return m;
+}
+
+Moment
+Music_sequence::first_start (SCM l)
+{
+
+ for (SCM s = l; scm_is_pair (s); s = scm_cdr (s))
+ {
+ Music *mus = unsmob<Music> (scm_car (s));
+ Moment start = mus->start_mom ();
+ if (mus->get_length ().to_bool () || start.to_bool ())
+ return start;
+ }
+ return Moment ();
+}
+
+MAKE_SCHEME_CALLBACK (Music_sequence, simultaneous_relative_callback, 2);
+SCM
+Music_sequence::simultaneous_relative_callback (SCM music, SCM pitch)
+{
+ Music *me = unsmob<Music> (music);
+ Pitch p = *unsmob<Pitch> (pitch);
+ return music_list_to_relative (me->get_property ("elements"),
+ p, false).smobbed_copy ();
+}
+
+MAKE_SCHEME_CALLBACK (Music_sequence, event_chord_relative_callback, 2);
+SCM
+Music_sequence::event_chord_relative_callback (SCM music, SCM pitch)