Implement 'as' operator.

corelib/src/exceptions.dart

Index: corelib/src/exceptions.dart
diff --git a/corelib/src/exceptions.dart b/corelib/src/exceptions.dart
index 3e95797999cb3a90cce1e2ea8a3e4cd1c8b00e35..ddb3042e9e8423311c2cff8cf967a9f520e26435 100644
--- a/corelib/src/exceptions.dart
+++ b/corelib/src/exceptions.dart
@@ -38,7 +38,7 @@ class NoSuchMethodException implements Exception {
   const NoSuchMethodException(Object this._receiver,
                               String this._functionName,
                               List this._arguments,
-                              [List existingArgumentNames = null]) : 
+                              [List existingArgumentNames = null]) :
                                 this._existingArgumentNames = existingArgumentNames;

[floitsch, 2012/06/25 18:21:09]

not your code, but 80chars.

[Lasse Reichstein Nielsen, 2012/06/26 08:26:03]

Done.

 
   String toString() {
@@ -140,6 +140,22 @@ class NullPointerException implements Exception {
 }
 
 
+class CastException implements Exception {
+  // TODO(lrn): Change actualType and expectedType to "Type" when reified
+  // types are available.
+  final Object actualType;
+  final Object expectedType;
+
+  CastException(this.actualType, this.expectedType);
+  String toString() {
+    return "$exceptionName: Casting value of type $actualType to"
+           " incompatible type $expectedType";
+  }
+
+  String get exceptionName() => "CastException";
+}
+
+
 class NoMoreElementsException implements Exception {
   const NoMoreElementsException();
   String toString() => "NoMoreElementsException";