sS asciiTable(LS headers, LL<S> data) {
  new L<LS> buffers;
  for i over headers:
    addAll(listGetOrCreate(buffers, i, L), headers.get(i), " ");

  for unnull (LS line : data)
    for i over line:
      listGetOrCreate(buffers, i, L).add(line.get(i));
      
  LS out = lines(asciiSideBySideWithBarsAllAround(map lines(buffers)));
  if (l(lines) > 2)
    lines.set(2, lines.get(2).replace(" ", "-"));
  ret lines(out);
}