anchor.diff:  }
   
   class markdown_blockquote extends markdown_node {
  -    String content;
       markdown_blockquote(String _content) : super() {
  -        content = _content;
  +        for (markdown_node cur in generate_markdown_nodes(_content)) {
  +            children.add(cur);
  +        }
       }
   
       String generate_html() {
           String ret = "<blockquote>";
           for (markdown_node cur in children) {
  -            ret = "${ret}${cur.generate_html();}";
  +            ret = "${ret}${cur.generate_html()}";
           }
           ret = "${ret}</blockquote>";
           return ret;
  
positive.code:     }
  
      String generate_html() {
          String ret = "<p>";
          for (markdown_node cur in children) {
              ret = "${ret}${cur.generate_html();}";
          }
          ret = "${ret}</p>";
          return ret;
  
negative.code: import 'dart:json';
  import 'dart:uri';
  import 'dart:core';
  
  class markdown_regex {
      RegExp regex;
      Function callback;
      int start;
      int end;
      String before;
      String after;
      Match found;
      bool has_match;
      markdown_regex(RegExp _regex, Function _callback) {
          regex = _regex;
          callback = _callback;
          start = -1;
          end = -1;
          has_match = false;
      }
  
      void populate_variables(String inp) {
          if (regex.hasMatch(inp)) {
              has_match = true;
          } else {
              return;
          }
          found = regex.firstMatch(inp);
          start = found.start;
          end = found.end;
          before = inp.substring(0, start);
          after = inp.substring(end);
      }
  
      List<markdown_node> execute() {
          List<markdown_node> ret = new List<markdown_node>();
          if (!has_match)
              return ret;
          
          for (markdown_node cur in generate_markdown_nodes(before)) {
              ret.add(cur);
          }
          // call the callback
          ret.add(callback(found));
  
          for (markdown_node cur in generate_markdown_nodes(after)) {
              ret.add(cur);
          }
          return ret;
      }
  }
  
  class markdown_node {
      List<markdown_node> children;
  