SCM ci = get_music ()->get_property ("context-id");
if (scm_is_string (ci))
c_id = ly_scm2string (ci);
SCM ops = get_music ()->get_property ("property-operations");
SCM ci = get_music ()->get_property ("context-id");
if (scm_is_string (ci))
c_id = ly_scm2string (ci);
SCM ops = get_music ()->get_property ("property-operations");