else
val = do_break_substitution (val);
- *tail = scm_cons (scm_cons (sym, val), SCM_EOL);
- tail = SCM_CDRLOC (*tail);
- }
+ if (val != SCM_UNDEFINED)
+ {
+ /*
+ for ly:grob? properties, SCM_UNDEFINED could leak out
+ through ly:grob-property
+ */
+ *tail = scm_cons (scm_cons (sym, val), SCM_EOL);
+ tail = SCM_CDRLOC (*tail);
+ }
+ }
return l;
}