Dartdoc comments retrieved as metadata through dart2js mirrors.

sdk/lib/_internal/compiler/implementation/compiler.dart

 // Copyright (c) 2012, 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.
 
 part of dart2js;
 
 /**
  * If true, print a warning for each method that was resolved, but not
  * compiled.
  */
@@ skipping 85 matching lines @@
   void dumpInferredTypes() {}
 
   ItemCompilationContext createItemCompilationContext() {
     return new ItemCompilationContext();
   }
 
   SourceString getCheckedModeHelper(DartType type) => null;
   void registerInstantiatedClass(ClassElement cls, Enqueuer enqueuer) {}
 }
 
+class CommentTokenMapEntry {

[ahe, 2013/01/03 13:04:09]

Document class please. How about:

/// An entry in [CommentTokenMap].

+  final key;

[ahe, 2013/01/03 13:04:09]

Add types one these two fields please.

+  final value;
+
+  CommentTokenMapEntry(this.key, this.value);
+}
+
+/**
+ * Map of tokens and the first associated comment.

[ahe, 2013/01/03 13:04:09]

One line comment?

+ */
+class CommentTokenMap  {
+  Link<CommentTokenMapEntry> entries = const Link<CommentTokenMapEntry>();
+
+  Token operator[] (Token key) {
+    for (CommentTokenMapEntry entry in entries) {

[ahe, 2013/01/03 13:04:09]

This seems like a sub-optimal implementation. I would like to understand why
this is doesn't cause quadratic runtime before approving this change.

+      if (entry.key == key) {
+        return entry.value;
+      }
+    }
+  }
+
+  void operator[]= (Token key, Token value) {
+    entries = entries.prepend(new CommentTokenMapEntry(key, value));
+  }
+}
+
 abstract class Compiler implements DiagnosticListener {
   final Map<String, LibraryElement> libraries;
   final Stopwatch totalCompileTime = new Stopwatch();
   int nextFreeClassId = 0;
   World world;
   String assembledCode;
   Types types;
 
+  /**
+   * Map from token to the first preceeding comment token.
+   */
+  final CommentTokenMap commentMap = new CommentTokenMap();
+
   final bool enableMinification;
   final bool enableTypeAssertions;
   final bool enableUserAssertions;
   final bool enableConcreteTypeInference;
   /**
    * The maximum size of a concrete type before it widens to dynamic during
    * concrete type inference.
    */
   final int maxConcreteTypeSize;
   final bool analyzeAll;
   final bool enableNativeLiveTypeAnalysis;
   final bool rejectDeprecatedFeatures;
   final bool checkDeprecationInSdk;
 
+  /**
+   * If [:true:], comment tokens are collected in [commentMap] during scanning.
+   */
+  final bool preserveComments;
+
   bool disableInlining = false;
 
   final Tracer tracer;
 
   CompilerTask measuredTask;
   Element _currentElement;
   LibraryElement coreLibrary;
   LibraryElement isolateLibrary;
   LibraryElement isolateHelperLibrary;
   LibraryElement jsHelperLibrary;
@@ skipping 102 matching lines @@
             this.enableConcreteTypeInference: false,
             this.maxConcreteTypeSize: 5,
             this.enableMinification: false,
             this.enableNativeLiveTypeAnalysis: false,
             bool emitJavaScript: true,
             bool generateSourceMap: true,
             bool disallowUnsafeEval: false,
             this.analyzeAll: false,
             this.rejectDeprecatedFeatures: false,
             this.checkDeprecationInSdk: false,
+            this.preserveComments: false,
             List<String> strips: const []})
       : libraries = new Map<String, LibraryElement>(),
         progress = new Stopwatch() {
     progress.start();
     world = new World(this);
 
     closureMapping.ClosureNamer closureNamer;
     if (emitJavaScript) {
       js_backend.JavaScriptBackend jsBackend =
           new js_backend.JavaScriptBackend(this, generateSourceMap,
@@ skipping 631 matching lines @@
   }
 
   // TODO(karlklose): split into findHelperFunction and findHelperClass and
   // add a check that the element has the expected kind.
   Element findHelper(SourceString name)
       => jsHelperLibrary.findLocal(name);
   Element findInterceptor(SourceString name)
       => interceptorsLibrary.findLocal(name);
 
   bool get isMockCompilation => false;
+
+  Token processAndStripComments(Token currentToken) {
+    Token firstToken = currentToken;
+    Token prevToken;
+    while (currentToken.kind != EOF_TOKEN) {
+      if (identical(currentToken.kind, COMMENT_TOKEN)) {
+        Token firstCommentToken = currentToken;
+        while (identical(currentToken.kind, COMMENT_TOKEN)) {
+          currentToken = currentToken.next;
+        }
+        commentMap[currentToken] = firstCommentToken;
+        if (prevToken == null) {
+          firstToken = currentToken;
+        } else {
+          prevToken.next = currentToken;
+        }
+      }
+      prevToken = currentToken;
+      currentToken = currentToken.next;
+    }
+    return firstToken;
+  }
 }
 
 class CompilerTask {
   final Compiler compiler;
   final Stopwatch watch;
 
   CompilerTask(this.compiler) : watch = new Stopwatch();
 
   String get name => 'Unknown task';
   int get timing => watch.elapsedMilliseconds;
@@ skipping 76 matching lines @@
   // TODO(johnniwinther): Use [spannable] and [message] to provide better
   // information on assertion errors.
   if (condition is Function){
     condition = condition();
   }
   if (spannable == null || !condition) {
     throw new SpannableAssertionFailure(spannable, message);
   }
   return true;
 }