InvocationMirror implemented in dart2js.

lib/compiler/implementation/lib/js_helper.dart

Index: lib/compiler/implementation/lib/js_helper.dart
diff --git a/lib/compiler/implementation/lib/js_helper.dart b/lib/compiler/implementation/lib/js_helper.dart
index 5a180261b0950696b593ad5977f178849fb3a358..d2218327ea079906d215be09315fb473dc1a6d39 100644
--- a/lib/compiler/implementation/lib/js_helper.dart
+++ b/lib/compiler/implementation/lib/js_helper.dart
@@ -352,6 +352,78 @@ class ListIterator<T> implements Iterator<T> {
   }
 }
 
+createInvocationMirror(name, internalName, type, arguments, argumentNames) =>
+    new JSInvocationMirror(name, internalName, type, arguments, argumentNames);
+
+class JSInvocationMirror implements InvocationMirror {

[ahe, 2012/10/29 12:14:05]

Please move this to its own file, like string_helper.dart and
regexp_helper.dart.

+  static const METHOD = 0;

[ahe, 2012/10/29 12:14:05]

FYI: It is possible to read these constants from the source code using the
constant evaluator. For an example of how to do this, see
ResolverTask.resolveMetadataAnnotation.

+  static const GETTER = 1;
+  static const SETTER = 2;
+
+  final String memberName;
+  final String _internalName;
+  final int _kind;

[ahe, 2012/10/29 12:14:05]

This field could use some documentation.

+  final List _arguments;
+  final List _namedArgumentNames;
+  /** Map from argument name to index in _arguments. */
+  Map<String,dynamic> _namedIndices = null;
+
+  JSInvocationMirror(this.memberName,
+                     this._internalName,
+                     this._kind,
+                     this._arguments,
+                     this._namedArgumentNames) {
+    if (_kind == METHOD) {
+      if (_namedArgumentNames != null && _namedArgumentNames.length > 0) {

[ahe, 2012/10/29 12:14:05]

I think you need to compute this lazily.

+        _namedIndices = <String,int>{};
+        int namedArgumentCount = _namedArgumentNames.length;
+        int namedArgumentsStartIndex =
+            _arguments.length - _namedArgumentNames.length;
+        for (int i = 0; i < namedArgumentCount; i++) {
+          _namedIndices[_namedArgumentNames[i]] = i + namedArgumentsStartIndex;
+        }
+      } else {
+        _namedIndices = const <String,int>{};
+      }
+    }
+  }
+
+  bool get isMethod => _kind == METHOD;
+  bool get isGetter => _kind == GETTER;
+  bool get isSetter => _kind == SETTER;
+  bool get isAccessor => _kind != METHOD;
+
+  List get positionalArguments {
+    if (isAccessor) return null;
+    var list = [];

[ahe, 2012/10/29 12:14:05]

You should be able to preallocate the correct size of this list.

+    var argumentCount =
+        _arguments.length - _namedArgumentNames.length;

[ahe, 2012/10/29 12:14:05]

I think this fits on one line.

+    for (var index = 0 ; index < argumentCount ; index++) {

[ahe, 2012/10/29 12:14:05]

Please use the common pattern:

for (int i = 0;

+      list.add(_arguments[index]);
+    }
+    return list;
+  }
+
+  Map<String,dynamic> get namedArguments {
+    if (isAccessor) return null;
+    var map = <String,dynamic>{};
+    _namedIndices.forEach((String name, int index) {

[ahe, 2012/10/29 12:14:05]

I'm having a really hard time seeing why you would compute _namedIndices in the
constructor when you must iterate through the values after all.

+      map[name] = _arguments[index];
+    });
+    return map;
+  }
+
+  // TODO(lrn): Hide subtype when class literals are implemented.
+  // Type get runtimeType => InvocationMirror;
+
+  invokeOn(Object object) {
+    List arguments = _arguments;
+    if (!isJsArray(arguments)) arguments = new List.from(arguments);
+    return JS("var", "#[#].apply(#, #)",
+              object, _internalName, object, arguments);
+  }
+}
+
 class Primitives {
   static int hashCodeSeed = 0;