anchor.diff:  %% Internal API
   
   test_to_html() ->
  -    Expect = <<"<html><head><title>hey!</title></head><body><p class=\"foo\">what's up<br /></p><div>sucka</div></body></html>">>,
  +    Expect = <<"<html><head><title>hey!</title></head><body><p class=\"foo\">what's up<br /></p><div>sucka</div><!-- comment! --></body></html>">>,
       Expect = iolist_to_binary(
                  to_html({html, [],
  -                        [{"head",
  +                        [{"head", [],
                             [{title, "hey!"}]},
                            {body, [],
                             [{p, [{class, foo}], ["what's", <<" up">>, {br}]},
  -                           {'div', <<"sucka">>}]}]})),
  +                           {'div', <<"sucka">>},
  +                           {comment, " comment! "}]}]})),
  +    Expect1 = <<"<!DOCTYPE html PUBLIC \"-//W3C//DTD XHTML 1.0 Transitional//EN\" \"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd\">">>,
  +    Expect1 = iolist_to_binary(
  +                to_html({doctype,
  +                         ["html", "PUBLIC",
  +                          "-//W3C//DTD XHTML 1.0 Transitional//EN",
  +                          "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"]})),
       ok.
   to_html([], Acc) ->
       lists:reverse(Acc);
  +to_html([{'=', Content} | Rest], Acc) ->
  +    to_html(Rest, [Content | Acc]);
  +to_html([{comment, Comment} | Rest], Acc) ->
  +    to_html(Rest, [["<!--" ++ Comment, "-->"] | Acc]);
  +to_html([{doctype, Parts} | Rest], Acc) ->
  +    Inside = doctype_to_html(Parts, Acc),
  +    to_html(Rest, [["<!DOCTYPE" ++ Inside, ">"] | Acc]);
   to_html([{data, Data, _Whitespace} | Rest], Acc) ->
       to_html(Rest, [escape(Data) | Acc]);
   to_html([{start_tag, Tag, Attrs, Singleton} | Rest], Acc) ->
  
positive.code:                       [{start_tag, T1, A1, false} | Acc])
      end;
  to_tokens([{Tag0, [L | R1]} | Rest], Acc) when is_list(L) ->
      Tag = to_tag(Tag0),
      to_tokens([{Tag, R1} | Rest], [{data, L, false} | Acc]);
  to_tokens([{Tag0, [B | R1]} | Rest], Acc) when is_binary(B) ->
      Tag = to_tag(Tag0),
      to_tokens([{Tag, R1} | Rest], [{data, binary_to_list(B), false} | Acc]).
  
  
negative.code:         end).
  
  -define(IS_WHITESPACE(C),
   	(C =:= $\s orelse C =:= $\t orelse C =:= $\r orelse C =:= $\n)).
  -define(IS_LITERAL_SAFE(C),
          ((C >= $A andalso C =< $Z) orelse (C >= $a andalso C =< $z)
           orelse (C >= $0 andalso C =< $9))).
                                  
  -record(decoder, {line=1,
  		  column=1}).
  
  %% @type html_node() = {string(), [html_attr()], [html_node() | string()]}
  %% @type html_attr() = {string(), string()}
  %% @type html_token() = html_data() | start_tag() | end_tag() | inline_html() | html_comment() | html_doctype()
  %% @type html_data() = {data, string(), Whitespace::boolean()}
  %% @type start_tag() = {start_tag, Name, [html_attr()], Singleton::boolean()}
  %% @type end_tag() = {end_tag, Name}
  %% @type html_comment() = {comment, Comment}
  %% @type html_doctype() = {doctype, [Doctype]}
  %% @type inline_html() = {'=', iolist()}
  
  %% External API.
  
  