Generate tear-off closures dynamically.

dart/sdk/lib/_internal/compiler/implementation/js_emitter/class_builder.dart

Index: dart/sdk/lib/_internal/compiler/implementation/js_emitter/class_builder.dart
diff --git a/dart/sdk/lib/_internal/compiler/implementation/js_emitter/class_builder.dart b/dart/sdk/lib/_internal/compiler/implementation/js_emitter/class_builder.dart
index 627f359c8c7ffe6efeaa29eefc51e73bb45f20ad..7c09c68d5bf196eee516d3b083576a2119cf804e 100644
--- a/dart/sdk/lib/_internal/compiler/implementation/js_emitter/class_builder.dart
+++ b/dart/sdk/lib/_internal/compiler/implementation/js_emitter/class_builder.dart
@@ -11,6 +11,12 @@ class ClassBuilder {
   // TODO (sigurdm) this is just a bag of properties, rename this class

[kasperl, 2013/11/29 10:10:55]

Remove this TODO now?

[ahe, 2013/12/06 15:57:53]

Done.

 
   final List<jsAst.Property> properties = <jsAst.Property>[];
+  final List<String> fields = <String>[];
+
+  String superName;
+  String nativeName;
+  String functionType;
+  List<jsAst.Node> fieldMetadata;
 
   /// Set to true by user if class is indistinguishable from its superclass.
   bool isTrivial = false;
@@ -20,8 +26,32 @@ class ClassBuilder {
     properties.add(new jsAst.Property(js.string(name), value));
   }
 
-  jsAst.Expression toObjectInitializer() {
-    return new jsAst.ObjectInitializer(properties);
+  void addField(String field) {
+    fields.add(field);

[kasperl, 2013/11/29 10:10:55]

Should we be asserting that we aren't adding the same field multiple times? Too
expensive?

[ahe, 2013/12/06 15:57:53]

We could do that, but it does require an amount of programming that I'm too lazy
to do now.

+  }
+
+  jsAst.ObjectInitializer toObjectInitializer() {
+    StringBuffer buffer = new StringBuffer();
+    if (superName != null) {
+      if (nativeName != null) {
+        buffer.write('$nativeName/');
+      }
+      buffer.write('$superName');
+      if (functionType != null) {
+        buffer.write(':$functionType');
+      }
+      buffer.write(';');
+    }
+    buffer.writeAll(fields, ',');
+    var classData = js.string('$buffer');
+    if (fieldMetadata != null) {

[kasperl, 2013/11/29 10:10:55]

Maybe add a comment here that explains how metadata is in encoded in the class
data by turning it into an array?

[ahe, 2013/12/06 15:57:53]

Done.

+      classData =
+          new jsAst.ArrayInitializer.from([classData]..addAll(fieldMetadata));
+    }
+    var fieldsAndProperties =
+        [new jsAst.Property(js.string(''), classData)]
+        ..addAll(properties);
+    return new jsAst.ObjectInitializer(fieldsAndProperties);
   }
 
 }