+ if (handle != SCM_BOOL_F)
+ {
+ bool same_bar = (bn == robust_scm2int (scm_caddr (handle), 0));
+ bool same_alt
+ = (p->get_alteration () == robust_scm2rational (scm_cadr (handle), 0));
+
+ if (!same_bar || (same_bar && !same_alt))
+ handle = SCM_BOOL_F;
+ }
+