static S xyzToNewIDs(S s, L<S> varCollector) {
  L<S> tok = javaTok(s);
  for (S var : ll("X", "Y", "Z", "AA", "AB", "AC")) // TODO
    if (tok.contains(var))
      replace(tok, var, addAndReturn(varCollector, aGlobalID()));
  ret join(tok);
}