sS combineToNLPattern(S a, S b) {
  if (a == null || b == null) null;
  L<S> tok1 = codeTokens(dropPunctuation(javaTok(a)));
  L<S> tok2 = codeTokens(dropPunctuation(javaTok(b)));
  if (l(tok1) != l(tok2)) null;
  new L<S> out;
  for i over tok1: {
    S t = tok1.get(i);
    out.add(eqic(t, tok2.get(i)) ? t : "*");
  }
  ret joinWithSpace(out);
}

sS combineToNLPattern(Iterable<S> l) {
  ret foldl_noSeed(func(S a, S b) -> S { combineToNLPattern(a, b) }, l);
}