rem: if (k <= max_range_endpoint && printable_field[k]) { if (range_start) *range_start = (printable_field[k] == RANGE_START_SENTINEL); return 1; }
add: bool is_selected = k_selected ^ complement; if (range_start && is_selected) *range_start = is_range_start_index (k);
context: print_kth (unsigned int k, int *range_start){  if (0 < eol_range_start && eol_range_start <= k)    {      if (range_start)	*range_start = (k == eol_range_start);      return 1;    }  if (k <= max_range_endpoint && printable_field[k])    {      if (range_start)	*range_start = (printable_field[k] == RANGE_START_SENTINEL);      return 1;    }  return 0;}