+MAKE_SCHEME_CALLBACK (Property_iterator, once_finalization, 3);
+SCM
+Property_iterator::once_finalization (SCM ctx, SCM music, SCM previous_value)
+{
+ Music *m = unsmob_music (music);
+ Context *c = unsmob_context (ctx);
+
+ // Do not use UnsetProperty, which sets the default, but rather
+ // cache the value before the \once \set command and restore it now
+ send_stream_event (c, "SetProperty", m->origin (),
+ ly_symbol2scm ("symbol"), m->get_property ("symbol"),
+ ly_symbol2scm ("value"), previous_value);
+
+ return SCM_UNSPECIFIED;
+}
+
+void
+Property_iterator::do_quit ()
+{
+}
+
+bool
+check_grob (Music *mus, SCM sym)
+{
+ bool g = to_boolean (scm_object_property (sym, ly_symbol2scm ("is-grob?")));
+
+ if (!g)
+ mus->origin ()->warning (_f ("not a grob name, `%s'",
+ ly_symbol2string (sym)));
+
+ return g;
+}
+
+SCM
+get_property_path (Music *m)
+{
+ SCM grob_property_path = m->get_property ("grob-property-path");
+
+ SCM eprop = m->get_property ("grob-property");
+ if (scm_is_symbol (eprop))
+ {
+ grob_property_path = scm_list_1 (eprop);
+ }
+
+ return grob_property_path;
+}
+