anchor.diff:  	language_a :: undefined | binary(),
   
   	%% Charset.
  -	charsets_p = [] :: [binary()],
  +	charsets_p = [] :: [{binary(), integer()}],
   	charset_a :: undefined | binary(),
   
   	%% Cached resource calls.
  
positive.code: 
  match_charset(Req, State, Accept, [], _Charset) ->
  	choose_charset(Req, State, Accept);
  match_charset(Req, State, _Accept, [Provided|_], {Provided, _}) ->
  	set_content_type(Req, State#state{charset_a=Provided});
  match_charset(Req, State, Accept, [_|Tail], Charset) ->
  	match_charset(Req, State, Accept, Tail, Charset).
  
negative.code: 			case AcceptCharset of
  				undefined ->
  					set_content_type(Req3, State2#state{
  						charset_a=element(1, hd(CP))});
  				AcceptCharset ->
  					AcceptCharset2 = prioritize_charsets(AcceptCharset),
  					choose_charset(Req3, State2, AcceptCharset2)
  