Implement literal maps.

dart/frog/leg/lib/js_helper.dart

Index: dart/frog/leg/lib/js_helper.dart
diff --git a/dart/frog/leg/lib/js_helper.dart b/dart/frog/leg/lib/js_helper.dart
index a23ae9ba2ec725cc2a5302adc08698dfa47216d1..8fa910ec0c7b5bf82d575b974a717e5c82c0ba5f 100644
--- a/dart/frog/leg/lib/js_helper.dart
+++ b/dart/frog/leg/lib/js_helper.dart
@@ -314,9 +314,10 @@ checkGrowable(list, reason) {
 builtin$toString$0(var value) {
   if (JS('bool', @'typeof $0 == "object"', value)) {
     if (isJsArray(value)) {
-      return "Instance of 'List'";
+      return Collections.collectionToString(value);
+    } else {
+      return UNINTERCEPTED(value.toString());
     }
-    return UNINTERCEPTED(value.toString());
   }
   if (JS('bool', @'$0 === 0 && (1 / $0) < 0', value)) {
     return '-0.0';
@@ -1296,3 +1297,19 @@ unwrapException(ex) {
   }
   return ex;
 }
+
+/**
+ * Called by generated code to build a map literal. [keyValuePairs] is
+ * a list of key, value, key, value, ..., etc.
+ */
+makeLiteralMap(List keyValuePairs) {
+  var iterator = keyValuePairs.iterator();

[ngeoffray, 2012/03/01 08:36:09]

var -> Iterator ?

[ahe, 2012/03/06 15:34:12]

Done.

+  Map result = new LinkedHashMap();
+  while (iterator.hasNext()) {
+    var key = iterator.next();

[ngeoffray, 2012/03/01 08:36:09]

var key -> String key?

[ahe, 2012/03/06 15:34:12]

Done.

+    var value = iterator.next();
+    // TODO(ahe): Don't use UNINTERCEPTED when optimizer is smarter.

[floitsch, 2012/03/01 10:24:07]

Is this necessary or just a premature optimization?

[ahe, 2012/03/06 15:34:12]

Premature optimization to make the code readable. I'll try to do without it.

+    UNINTERCEPTED(result[key] = value);
+  }
+  return result;
+}