Evaluate compile-time constants of metadata.

dart/lib/compiler/implementation/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);
   Type getType(TypeAnnotation annotation);
 }
 
@@ skipping 381 matching lines @@
          !link.isEmpty();
          link = link.tail) {
        parameterTypes.addLast(link.head.computeType(compiler));
        // TODO(karlklose): optional parameters.
     }
     return new FunctionType(signature.returnType,
                             parameterTypes.toLink(),
                             element);
   }
 
+  void resolveMetadataAnnotation(MetadataAnnotation annotation) {
+    Node node = annotation.parseNode(compiler);
+    Element fakeElement = new Element(const SourceString(''),

[ngeoffray, 2012/08/22 14:28:56]

Should we have a metadata element instead? This sounds like a big hack around
the system.

[ahe, 2012/08/22 17:23:02]

Done.

+                                      ElementKind.FUNCTION,
+                                      annotation.enclosingElement);

[Johnni Winther, 2012/08/22 13:45:40]

The element kind should be something else. We cannot risk code wrongfully
relying on fakeElement to be a function.

[ahe, 2012/08/22 17:23:02]

Done.

+    ResolverVisitor visitor = new ResolverVisitor(compiler, fakeElement);
+    node.accept(visitor);
+    annotation.value = compiler.constantHandler.compileNodeWithDefinitions(
+        node, visitor.mapping);
+    print(annotation);

[Johnni Winther, 2012/08/22 13:45:40]

Debug output.

[ahe, 2012/08/22 17:23:02]

Done.

+  }
+
   error(Node node, MessageKind kind, [arguments = const []]) {
     ResolutionError message = new ResolutionError(kind, arguments);
     compiler.reportError(node, message);
   }
 }
 
 class InitializerResolver {
   final ResolverVisitor visitor;
   final Map<SourceString, Node> initialized;
   Link<Node> initializers;
@@ skipping 2114 matching lines @@
   TopScope(LibraryElement library) : super(null, library);
   Element lookup(SourceString name) {
     return library.find(name);
   }
 
   Element add(Element newElement) {
     throw "Cannot add an element in the top scope";
   }
   String toString() => '$element';
 }