Implement script tags.

dart/frog/leg/resolver.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.
 
 interface TreeElements {
   Element operator[](Node node);
   Selector getSelector(Send send);
 }
 
 class TreeElementMapping implements TreeElements {
@@ skipping 559 matching lines @@
             // TODO(ngeoffray): The lookup should continue on super
             // classes.
             target = superElement.lookupLocalMember(name);
           }
           if (target === null) {
             error(node,
                   MessageKind.METHOD_NOT_FOUND,
                   [superElement.name, name]);
           }
         }
-      } else if (resolvedReceiver !== null
-                 && resolvedReceiver.kind === ElementKind.CLASS) {
+      } else if (resolvedReceiver === null) {
+        return null;
+      } else if (resolvedReceiver.kind === ElementKind.CLASS) {
         ClassElement receiverClass = resolvedReceiver;
         target = receiverClass.resolve(compiler).lookupLocalMember(name);
         if (target === null) {
           error(node, MessageKind.METHOD_NOT_FOUND, [receiverClass.name, name]);
         } else if (target.isInstanceMember()) {
           error(node, MessageKind.MEMBER_NOT_STATIC,
                 [receiverClass.name, name]);
         }
+      } else if (resolvedReceiver.kind === ElementKind.PREFIX) {
+        PrefixElement prefix = resolvedReceiver;
+        target = prefix.library.lookupLocalMember(name);
+        if (target == null) {
+          error(node, MessageKind.NO_SUCH_LIBRARY_MEMBER,
+                [resolvedReceiver.name, name]);
+        }
       }
     }
     return target;
   }
 
   resolveTypeTest(TypeAnnotation node) {
     ClassElement cls = resolveTypeRequired(node);
     if (cls.name == const SourceString('String') ||
         cls.name == const SourceString('List') ||
         cls.name == const SourceString('int') ||
@@ skipping 560 matching lines @@
 class TopScope extends Scope {
   LibraryElement library;
 
   TopScope(LibraryElement this.library) : super(null, null);
   Element lookup(SourceString name) => library.find(name);
 
   Element add(Element element) {
     throw "Cannot add an element in the top scope";
   }
 }