- Pitch *p = unsmob_pitch (inversion_event->get_property ("pitch"));
- int octavation = scm_to_int (oct);
- Pitch orig = p->transposed (Pitch (-octavation, 0, 0));
-
- pitches = scm_cons (orig.smobbed_copy (), pitches);
+ SCM oct = inversion_event->get_property ("octavation");
+ if (scm_is_number (oct))
+ {
+ Pitch *p = unsmob_pitch (inversion_event->get_property ("pitch"));
+ int octavation = scm_to_int (oct);
+ Pitch orig = p->transposed (Pitch (-octavation, 0, 0));
+
+ pitches = scm_cons (orig.smobbed_copy (), pitches);
+ }
+ else
+ programming_error ("inversion does not have original pitch");