+ send_stream_event (o, "UnsetProperty", m->origin (),
+ ly_symbol2scm ("symbol"), symbol);
+
+ /* For \once \unset install a finalization hook to reset the property to the
+ * previous value after the timestep */
+ if (once && !SCM_UNBNDP (previous_value))
+ {
+ Global_context *tg = get_outlet ()->get_global_context ();
+ tg->add_finalization (scm_list_4 (Property_iterator::once_finalization_proc,
+ o->self_scm (), m->self_scm (),
+ previous_value));
+ }
+
+ Simple_music_iterator::process (mom);