+ extract_grob_set (me, "ties", ties);
+ Direction d = LEFT;
+ for (vsize i = 0; i < ties.size (); i++)
+ {
+ Direction this_d = to_dir (ties[i]->get_property ("head-direction"));
+ if (i > 0 && d != this_d)
+ {
+ programming_error ("all semi-ties in a semi-tie-column should have the same head-direction");
+ return scm_from_int (d);
+ }
+ d = this_d;
+ }
+ return scm_from_int (d);
+}