Deferred (aka lazy) loading of static functions.

dart/sdk/lib/_internal/compiler/implementation/scanner/listener.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 scanner;
 
 const bool VERBOSE = false;
 
 /**
  * A parser event listener that does nothing except throw exceptions
@@ skipping 330 matching lines @@
 
   void beginThrowStatement(Token token) {
   }
 
   void endThrowStatement(Token throwToken, Token endToken) {
   }
 
   void endRethrowStatement(Token throwToken, Token endToken) {
   }
 
+  void endTopLevelDeclaration(Token token) {
+  }
+
   void beginTopLevelMember(Token token) {
   }
 
   void endTopLevelFields(int count, Token beginToken, Token endToken) {
   }
 
   void endTopLevelMethod(Token beginToken, Token getOrSet, Token endToken) {
   }
 
   void beginTryStatement(Token token) {
@@ skipping 314 matching lines @@
   bool allowLibraryTags() {
     // Library tags are only allowed in the library file itself, not
     // in sourced files.
     LibraryElement library = compilationUnitElement.getLibrary();
     return !compilationUnitElement.hasMembers
       && library.entryCompilationUnit == compilationUnitElement;
   }
 
   void endLibraryName(Token libraryKeyword, Token semicolon) {
     Expression name = popNode();
-    addLibraryTag(new LibraryName(libraryKeyword, name));
+    addLibraryTag(new LibraryName(libraryKeyword, name, popMetadata(compilationUnitElement)));
   }
 
   void endImport(Token importKeyword, Token asKeyword, Token semicolon) {
     NodeList combinators = popNode();
     Identifier prefix;
     if (asKeyword != null) {
       prefix = popNode();
     }
     StringNode uri = popLiteralString();
-    addLibraryTag(new Import(importKeyword, uri, prefix, combinators));
+    addLibraryTag(new Import(importKeyword, uri, prefix, combinators,
+                             popMetadata(compilationUnitElement)));
   }
 
   void endExport(Token exportKeyword, Token semicolon) {
     NodeList combinators = popNode();
     StringNode uri = popNode();
     addLibraryTag(new Export(exportKeyword, uri, combinators));
   }
 
   void endCombinators(int count) {
     if (0 == count) {
@@ skipping 15 matching lines @@
   void endIdentifierList(int count) {
     pushNode(makeNodeList(count, null, null, ","));
   }
 
   void endTypeList(int count) {
     pushNode(makeNodeList(count, null, null, ","));
   }
 
   void endPart(Token partKeyword, Token semicolon) {
     StringNode uri = popLiteralString();
-    addLibraryTag(new Part(partKeyword, uri));
+    addLibraryTag(new Part(partKeyword, uri, popMetadata(compilationUnitElement)));
   }
 
   void endPartOf(Token partKeyword, Token semicolon) {
     Expression name = popNode();
-    addPartOfTag(new PartOf(partKeyword, name));
+    addPartOfTag(new PartOf(partKeyword, name, popMetadata(compilationUnitElement)));
   }
 
   void addPartOfTag(PartOf tag) {
     compilationUnitElement.setPartOf(tag, listener);
   }
 
   void endScriptTag(bool hasPrefix, Token beginToken, Token endToken) {
     LiteralString prefix = null;
     Identifier argumentName = null;
     if (hasPrefix) {
@@ skipping 14 matching lines @@
   }
 
   void endMetadata(Token beginToken, Token periodBeforeName, Token endToken) {
     if (periodBeforeName != null) {
       popNode(); // Discard name.
     }
     popNode(); // Discard node (Send or Identifier).
     pushMetadata(new PartialMetadataAnnotation(beginToken));
   }
 
+  void endTopLevelDeclaration(Token token) {
+    if (!metadata.isEmpty) {
+      recoverableError('Error: Metadata not supported here.',
+                       token: metadata.head.beginToken);
+      metadata = const Link<MetadataAnnotation>();
+    }
+  }
+
   void endClassDeclaration(int interfacesCount, Token beginToken,
                            Token extendsKeyword, Token implementsKeyword,
                            Token endToken) {
     SourceString nativeTagInfo = native.checkForNativeClass(this);
     NodeList interfaces =
         makeNodeList(interfacesCount, implementsKeyword, null, ",");
     Node supertype = popNode();
     NodeList typeParameters = popNode();
     Identifier name = popNode();
     int id = idGenerator();
@@ skipping 262 matching lines @@
   Token unmatched(Token token) {
     listener.cancel("unmatched '${token.slowToString()}'", token: token);
     return skipToEof(token);
   }
 
   void recoverableError(String message, {Token token, Node node}) {
     listener.cancel(message, token: token, node: node);
   }
 
   void pushElement(Element element) {
+    popMetadata(element);
+    compilationUnitElement.addMember(element, listener);
+  }
+
+  Link<MetadataAnnotation> popMetadata(Element element) {
+    var result = metadata;
     for (Link link = metadata; !link.isEmpty; link = link.tail) {
       element.addMetadata(link.head);
     }
     metadata = const Link<MetadataAnnotation>();
-    compilationUnitElement.addMember(element, listener);
+    return result;
   }
 
   void pushMetadata(MetadataAnnotation annotation) {
     metadata = metadata.prepend(annotation);
   }
 
   // TODO(ahe): Remove this method.
   void addScriptTag(ScriptTag tag) {
     listener.onDeprecatedFeature(tag, '# tags');
     addLibraryTag(tag.toLibraryTag());
@@ skipping 956 matching lines @@
 
 Node parse(DiagnosticListener diagnosticListener,
            CompilationUnitElement element,
            doParse(Parser parser)) {
   NodeListener listener = new NodeListener(diagnosticListener, element);
   doParse(new Parser(listener));
   Node node = listener.popNode();
   assert(listener.nodes.isEmpty);
   return node;
 }