anchor.diff:    static Parser<List<Block>> _hruleParser(String start) {
       if (_hruleParserCache[start] == null) {
         _hruleParserCache[start] = ((((count(2, skipSpaces > char(start)) >
  -                      (whitespaceChar | char(start)).skipMany) >
  +                      skipManySimple(whitespaceChar | char(start))) >
                     newline) >
                 blanklines.maybe) >
             success([new HorizontalRule()]));
  
positive.code:   Parser<String> get linkText {
      if (_linkTextCache == null) {
        _linkTextCache = (char('[') >
                (_linkTextChoice > _linkTextChoice.manyUntil(char(']'))).record) ^
            (String label) => label.substring(0, label.length - 1);
      }
      return _linkTextCache;
  
negative.code: 
    static final Parser<List<dynamic>> _setextHeaderParser =
        (((skipNonindentChars.notFollowedBy(char('>')) > anyLine) +
                (skipNonindentChars > many1Simple(oneOf2("=", "-")))).list <
            blankline);
    static final Parser<List<Block>> setextHeader =
        new Parser<List<Block>>((String s, Position pos) {
  