static L<ParsedWithTokens<S>> pwt_fromTokenization(LS tok) {
  new L<ParsedWithTokens<S>> out;
  for i over tok: {
    S t = tok.get(i);
    // slightly abusing the spec of ParsedWithTokens by pointing to only 1 token (C or N)
    out.add(ParsedWithTokens(t, tok, i, i+1));
  }
  ret out;
}