+
+ // Partial_iterator is an iterator rather than an engraver,
+ // so the active context it is getting called in does not
+ // depend on which context definition the engraver might be
+ // defined.
+ //
+ // Using where_defined to find the context where
+ // measurePosition should be overwritten does not actually
+ // work since the Timing_translator does not set
+ // measurePosition when initializing.
+
+ Context *timing = unsmob<Context>
+ (Lily::ly_context_find (get_outlet ()->self_scm (),
+ ly_symbol2scm ("Timing")));
+
+ if (!timing)
+ programming_error ("missing Timing in \\partial");
+ else if (get_outlet ()->now_mom () > 0)
+ {
+ timing->set_property ("partialBusy", ly_bool2scm (true));
+ Global_context *tg = get_outlet ()->get_global_context ();
+ tg->add_finalization (scm_list_3 (finalization_proc,
+ get_outlet ()->self_scm (),
+ length.smobbed_copy ()));
+ }
+ else
+ {
+ Moment mp = robust_scm2moment
+ (timing->get_property ("measurePosition"),
+ Rational (0));
+ mp.main_part_ = 0;
+ timing->set_property
+ ("measurePosition", (mp - length).smobbed_copy ());
+ }