anchor.diff:  		  end, A),
       lists:flatten(B).
   
  +
  +%%--------------------------------------------------------------------
  +%% Function: to_hex_string(Int)
  +%%           Int = integer()
  +%% Descrip.: convert Int into string() in hex encoding
  +%% Returns : string() containing $0-$F, upper case is used for $A-$F
  +%%--------------------------------------------------------------------
  +%% the basic idea of this function is to alway take the least 
  +%% significant (right) 4 bits (hex number) and add as a hex char to
  +%% the ones allready processed in HexString 
  +
  +%% this function is not defined for negative numbers 
  +to_hex_string(Int) when Int >= 0 ->
  +    Mask = 2#1111,
  +    to_hex_string(Int bsr 4, [to_hex_char(Int band Mask)] ).
  +
  +to_hex_string(0, HexString) ->
  +    HexString;
  +to_hex_string(IntRest, HexString) ->
  +    Mask = 2#1111,
  +    to_hex_string(IntRest bsr 4, [to_hex_char(IntRest band Mask) | HexString] ).
  +
  +%% - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
  +%% Function: to_hex_char(Int)
  +%%           Int = integer(), 0-15
  +%% Descrip.: convert Int into char() in hex encoding
  +%% Returns : integer(), $0-$F, upper case is used for $A-$F
  +%% - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
  +to_hex_char(Int) when (Int >= 0), (Int =< 9) -> 
  +    $0 + Int;
  +to_hex_char(Int) when (Int >= 10), (Int =< 15) -> 
  +    $A + Int -10.
  +
  +
  +%%--------------------------------------------------------------------
  +%% Function: from(String)
  +%%           to_int(String)
  +%%           String = string(), a numeric string of hex values (0-9, 
  +%%           A-F and a-f can be used)
  +%% Descrip.: convert hex string into a integer
  +%% Returns : integer()
  +%%--------------------------------------------------------------------
  +to_int(String) ->
  +    from(String, 0).
  +
  +from(String) ->
  +    from(String, 0).
  +
  +%% N keeps the current acumulated value, each new char encountered when
  +%% scaning to the right, is added and N is shifted 4 bits to the left
  +%% Note: "N * 16" could be replaced by "N bsl 4"
  +
   from([], N) ->
       N;
   
  
positive.code: -module(hex).
  -export([to/1, to/2, from/1]).
  
  to(_, 0) ->
      [];
  to(Number, N) when integer(Number), N > 0 ->
  
negative.code:     M = N * 16 + (C - $A + 10),
      from(String, M).
  
  
  