anchor.diff:  import 'dart:io';
   import 'dart:mirrors';
   
  +import 'package:args/args.dart' show ArgParser;
   import 'package:collection/collection.dart';
   import 'package:html/parser.dart' show parseFragment;
   import 'package:markdown/markdown.dart';
  
positive.code:       var actual = parseFragment(output);
        nestedMap[e.example] = compareHtml(expected.children, actual.children);
        if (verbose && !nestedMap[e.example]) {
          print('FAIL');
          print('input:');
          print(indent(e.markdown));
          print('expected:');
  
negative.code:     .path);
  
  void main(List<String> args) {
    final parser = new ArgParser()
      ..addOption('section', help: 'Restrict tests to one section')
      ..addFlag('raw', defaultsTo: false, help: 'raw JSON format')
      ..addFlag('verbose', defaultsTo: false, help: 'verbose output');
    var options = parser.parse(args);
  
    var specifiedSection = options['section'];
    var raw = options['raw'];
    var verbose = options['verbose'];
  
    var sections = loadCommonMarkSections();
  
  