Refactor dartdoc into a class. Use method overriding to extend.

client/html/scripts/html_diff.dart

 // Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 /**
  * A script to assist in documenting the difference between the dart:html API
  * and the old DOM API.
  */
 #library('html_diff');
 
@@ skipping 65 matching lines @@
 
   /** A map from `dart:html` members to corresponding `dart:dom` members. */
   final Map<Member, Set<Member>> htmlToDom;
 
   /** A map from `dart:dom` types to corresponding `dart:html` types. */
   final Map<Type, Set<Type>> domTypesToHtml;
 
   /** A map from `dart:html` types to corresponding `dart:dom` types. */
   final Map<Type, Set<Type>> htmlTypesToDom;
 
+  final CommentMap comments;
+
   /**
    * Perform static initialization of [world]. This should be run before
    * calling [HtmlDiff.run].
    */
   static void initialize() {
     world.processDartScript('dart:htmlimpl');
     world.resolveAll();
   }
 
   HtmlDiff() :
     domToHtml = new Map<Member, Set<Member>>(),
     htmlToDom = new Map<Member, Set<Member>>(),
     domTypesToHtml = new Map<Type, Set<Type>>(),
-    htmlTypesToDom = new Map<Type, Set<Type>>();
+    htmlTypesToDom = new Map<Type, Set<Type>>(),
+    comments = new CommentMap();
 
   /**
    * Computes the `dart:dom` to `dart:html` mapping, and places it in
    * [domToHtml], [htmlToDom], [domTypesToHtml], and [htmlTypesToDom]. Before
    * this is run, Frog should be initialized (via [parseOptions] and
    * [initializeWorld]) and [HtmlDiff.initialize] should be called.
    */
   void run() {
     final htmlLib = world.libraries['dart:htmlimpl'];
     for (var implType in htmlLib.types.getValues()) {
@@ skipping 99 matching lines @@
       return htmlType.getMember(implMember.name);
     }
   }
 
   /**
    * Returns the `dart:dom` [Type]s that correspond to [htmlType] from
    * `dart:htmlimpl`. This can be the empty list if no correspondence is found.
    */
   List<Type> htmlToDomTypes(Type htmlType) {
     if (htmlType.name == null) return [];
-    final tags = _getTags(findComment(htmlType.span));
+    final tags = _getTags(comments.find(htmlType.span));
 
     if (tags.containsKey('domName')) {
       var domNames = map(tags['domName'].split(','), (s) => s.trim());
       if (domNames.length == 1 && domNames[0] == 'none') return [];
       return map(domNames, (domName) {
         // DOMWindow is Chrome-specific, so we don't use it in our annotations.
         if (domName == 'Window') domName = 'DOMWindow';
         final domType = world.dom.types[domName];
         if (domType == null) print('Warning: no dart:dom type named $domName');
         return domType;
@@ skipping 16 matching lines @@
   }
 
   /**
    * Returns the `dart:dom` [Member]s that correspond to [htmlMember] from
    * `dart:htmlimpl`. This can be the empty set if no correspondence is found.
    * [domTypes] are the `dart:dom` [Type]s that correspond to [implMember]'s
    * defining [Type].
    */
   Set<Member> htmlToDomMembers(Member htmlMember, List<Type> domTypes) {
     if (htmlMember.isPrivate || htmlMember is! MethodMember) return new Set();
-    final tags = _getTags(findComment(htmlMember.span));
+    final tags = _getTags(comments.find(htmlMember.span));
     if (tags.containsKey('domName')) {
       final domNames = map(tags['domName'].split(','), (s) => s.trim());
       if (domNames.length == 1 && domNames[0] == 'none') return new Set();
       final members = new Set();
       domNames.forEach((name) {
         var nameMembers = _membersFromName(name, domTypes);
         if (nameMembers.isEmpty()) {
           if (name.contains('.')) {
             print('Warning: no member $name');
           } else {
@@ skipping 155 matching lines @@
   Map<String, String> _getTags(String comment) {
     if (comment == null) return const <String>{};
     final re = new RegExp("@([a-zA-Z]+) ([^;]+)(?:;|\$)");
     final tags = <String>{};
     for (var m in re.allMatches(comment.trim())) {
       tags[m[1]] = m[2];
     }
     return tags;
   }
 }