anchor.diff:  
       RegExp plain_header = new RegExp(r"^(#+) ([^#\n]+)#*\n?", multiLine: true);
       RegExp blockquote = new RegExp(r"(^> ?.*?$\n?)+", multiLine: true);
  +    RegExp multiline_code = new RegExp(r"(^    ?.*?$\n?)+", multiLine: true);
       RegExp underline_big_header = new RegExp(r"^(.+)\n=+\n?", multiLine: true);
       RegExp underline_little_header = new RegExp(r"^(.+)\n-+\n?", multiLine: true);
       
  
positive.code: }
  
  main_wrapped() {
      String inp = "A First Level Header\n====================\n\nA Second Level Header\n---------------------\n\nNow is the time for all good men to come to\nthe aid of their `country`. This is just a\nre_gu_lar paragraph.\n\nThe quick brown fox jumped over the lazy\ndog's back.\n\n### Header 3\n\n> This is a blockquote.\n> \n> This is the second paragraph in the blockquote.\n>\n> ## This is an H2 in a blockquote";
      RegExp single_asterix = new RegExp(r"(?! )\*(?! )[^*]+(?! )\*(?! )");
      print(markdown_to_html(inp));
  }
  
negative.code:                     });
                  return new markdown_blockquote(fixed);
      }));
      regular_expressions.add(new markdown_regex(multiline_code, (Match found) {
                  // Trim the '> ' at the start of the line
                  String fixed = found.group(0).splitMapJoin("\n", onNonMatch: (String match) {
                          if (match.length < 4)
                              return "";
                          else
                              return match.substring(4);
                      });
                  return new markdown_code(fixed);
      }));
      regular_expressions.add(new markdown_regex(underline_big_header, (Match found) {
                  return new markdown_headline(1, found.group(1));
      }));
  