Deferred (aka lazy) loading of static functions.

dart/sdk/lib/_internal/compiler/implementation/tree/nodes.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 tree;
 
 abstract class Visitor<R> {
   const Visitor();
 
   R visitNode(Node node);
@@ skipping 1697 matching lines @@
       return new LibraryName(tag.token, argument);
     } else if (isSource()) {
       return new Part(tag.token, argument);
     } else {
       throw 'Unknown script tag ${tag.token.slowToString()}';
     }
   }
 }
 
 abstract class LibraryTag extends Node {
+  final Link<MetadataAnnotation> metadata;
+
+  LibraryTag(this.metadata);
+
   bool get isLibraryName => false;
   bool get isImport => false;
   bool get isExport => false;
   bool get isPart => false;
   bool get isPartOf => false;
 }
 
 class LibraryName extends LibraryTag {
   final Expression name;
 
   final Token libraryKeyword;
 
-  LibraryName(this.libraryKeyword, this.name);
+  LibraryName(this.libraryKeyword,
+              this.name,
+              Link<MetadataAnnotation> metadata)
+    : super(metadata);
 
   bool get isLibraryName => true;
 
   LibraryName asLibraryName() => this;
 
   accept(Visitor visitor) => visitor.visitLibraryName(this);
 
   visitChildren(Visitor visitor) => name.accept(visitor);
 
   Token getBeginToken() => libraryKeyword;
 
   Token getEndToken() => name.getEndToken().next;
 }
 
 /**
  * This tag describes a dependency between one library and the exported
  * identifiers of another library. The other library is specified by the [uri].
  * Combinators filter away some identifiers from the other library.
  */
 abstract class LibraryDependency extends LibraryTag {
   final StringNode uri;
   final NodeList combinators;
 
-  LibraryDependency(this.uri, this.combinators);
+  LibraryDependency(this.uri,
+                    this.combinators,
+                    Link<MetadataAnnotation> metadata)
+    : super(metadata);
 }
 
 /**
  * An [:import:] library tag.
  *
  * An import tag is dependency on another library where the exported identifiers
  * are put into the import scope of the importing library. The import scope is
  * only visible inside the library.
  */
 class Import extends LibraryDependency {
   final Identifier prefix;
   final Token importKeyword;
 
   Import(this.importKeyword, StringNode uri,
-         this.prefix, NodeList combinators)
-      : super(uri, combinators);
+         this.prefix, NodeList combinators,
+         Link<MetadataAnnotation> metadata)
+      : super(uri, combinators, metadata);
 
   bool get isImport => true;
 
   Import asImport() => this;
 
   Token get asKeyword => prefix == null ? null : uri.getEndToken().next;
 
   accept(Visitor visitor) => visitor.visitImport(this);
 
   visitChildren(Visitor visitor) {
@@ skipping 41 matching lines @@
     if (combinators != null) return combinators.getEndToken().next;
     return uri.getEndToken().next;
   }
 }
 
 class Part extends LibraryTag {
   final StringNode uri;
 
   final Token partKeyword;
 
-  Part(this.partKeyword, this.uri);
+  Part(this.partKeyword, this.uri, Link<MetadataAnnotation> metadata)
+    : super(metadata);
 
   bool get isPart => true;
 
   Part asPart() => this;
 
   accept(Visitor visitor) => visitor.visitPart(this);
 
   visitChildren(Visitor visitor) => uri.accept(visitor);
 
   Token getBeginToken() => partKeyword;
 
   Token getEndToken() => uri.getEndToken().next;
 }
 
 class PartOf extends Node {
   final Expression name;
 
   final Token partKeyword;
 
-  PartOf(this.partKeyword, this.name);
+  final Link<MetadataAnnotation> metadata;
+
+  PartOf(this.partKeyword, this.name, this.metadata);
 
   Token get ofKeyword => partKeyword.next;
 
   bool get isPartOf => true;
 
   PartOf asPartOf() => this;
 
   accept(Visitor visitor) => visitor.visitPartOf(this);
 
   visitChildren(Visitor visitor) => name.accept(visitor);
@@ skipping 199 matching lines @@
  * argument).
  *
  * TODO(ahe): This method is controversial, the team needs to discuss
  * if top-level methods are acceptable and what naming conventions to
  * use.
  */
 initializerDo(Node node, f(Node node)) {
   SendSet send = node.asSendSet();
   if (send != null) return f(send.arguments.head);
 }