+ Context *o = get_outlet ();
+ Music *m = get_music ();
+ bool once = to_boolean (m->get_property ("once"));
+ SCM symbol = m->get_property ("symbol");
+ SCM previous_value = SCM_UNDEFINED;
+ if (once) {
+ Context *w = o->where_defined (symbol, &previous_value);
+ if (o != w)
+ previous_value = SCM_UNDEFINED;
+ }
+ send_stream_event (o, "SetProperty", m->origin (),
+ ly_symbol2scm ("symbol"), symbol,
+ ly_symbol2scm ("value"), m->get_property ("value"));
+
+ /* For \once \set install a finalization hook to reset the property to the
+ * previous value after the timestep */
+ if (once)