Better runtime type checks.

frog/frog.dart

Index: frog/frog.dart
diff --git a/frog/frog.dart b/frog/frog.dart
index 5fe2e679b2d95cd54ce9ca9d9f4f3cb987de0240..415948fd020c8aa54e3cb01d72665780df2bd6e5 100644
--- a/frog/frog.dart
+++ b/frog/frog.dart
@@ -9,10 +9,16 @@
 void main() {
   // Get the home directory from our executable.
   var homedir = path.dirname(fs.realpathSync(process.argv[1]));
-  if (compile(homedir, process.argv, new NodeFileSystem())) {
+
+  // Note: we create a copy of argv here because the one that is passed in is
+  // potentially a JS Array object from outside the sandbox. Hence it will have
+  // the wrong prototype.
+  var argv = new List.from(process.argv);

[jimhug, 2011/11/07 16:41:26]

TODO: This seems like a bug in the node interop that this would be needed here. 
I think any such shenanigans should be nicely encapsulated in whatever wrappers
we use to expose node.

[Jennifer Messerly, 2011/11/07 22:13:10]

It's a bug in our createSandbox. We pass certain objects (require, process,
console) to the child. These objects (by design of Node's sandbox) don't share
prototype with the parent. That part is good. The bad is that we are forcing the
child code to deal with the problem. The only fix I can think of is injecting
some code into the generate JS that patches the prototypes of those 3 objects,
as well as process.argv.

+
+  if (compile(homedir, argv, new NodeFileSystem())) {
     var code = world.getGeneratedCode();
     if (!options.compileOnly) {
-      process.argv = [process.argv[0], process.argv[1]];
+      process.argv = [argv[0], argv[1]];
       process.argv.addAll(options.childArgs);
       vm.runInNewContext(code, createSandbox());
     }