for (; scm_is_pair (i); i = scm_cdr (i), j++)
{
Music *mus = unsmob_music (scm_car (i));
SCM scm_iter = get_static_get_iterator (mus);
for (; scm_is_pair (i); i = scm_cdr (i), j++)
{
Music *mus = unsmob_music (scm_car (i));
SCM scm_iter = get_static_get_iterator (mus);