anchor.diff:  zulu_zone(7) -> "G";
   zulu_zone(8) -> "H";
   zulu_zone(9) -> "I";
  +% no Juliet
   zulu_zone(10) -> "K";
   zulu_zone(11) -> "L";
   zulu_zone(12) -> "M";
  
positive.code:          {PresMods,[]};
        true ->
           Last = lists:last(PresMods),
           if Last == $a;
              Last == $t;
              Last == $c;
              Last == $o ->
                 First = lists:sublist(PresMods, Len - 1),
                 {First, [Last]};
              true ->
  
negative.code:    end.
  
  %% There must be at least one mandatory-digit-sign. 
  %% There may be zero or more optional-digit-signs, and (if present) 
  %%    these must precede all mandatory-digit-signs. 
  %% There may be zero or more grouping-separator-signs. 
  %% A grouping-separator-sign must not appear at the start or end of the 
  %%    decimal-digit-pattern, nor adjacent to another grouping-separator-sign.
  valid_decimal_digit_pattern(List) ->
     HasMand = lists:keyfind(digit, 1, List) =/= false, % true == good
     DropOpt = lists:dropwhile(fun({digit, _}) ->
  