static <A> L<Int> indicesOfCodeTokensContainedInMap(LS tok, Map<S, A> map) {
  new L<Int> l;
  if (nempty(map))
    for (int i = 1; i < l(tok); i += 2)
      if (map.containsKey(tok.get(i)))
        l.add(i);
  ret l;
}