I wonder if the only speed benefits that the Dart VM gives would be able to be beaten out by a smart compiler. I know this is early for the cross-compilation code (it doesn't trim out anything it doesn't need here), but I hope this isn't what is ultimately used in that comparison.
As I understand it, dart isn't trying to be a faster javascript. Its trying to be a better GWT.
Many googlers I've spoken to firmly believe that you need a strongly typed, OO language with good tooling to be able to develop any large application. They believe web apps are no exception.
Google has worked hard adding types to javascript with the closure compiler. But, there are limits to what you can achieve using javascript.
Comfortable programming in the large is the main value proposition of Dart. Expect to see good developer tools, debuggers, profilers and server-side runtime environments for Dart appearing over the next few years.
It isn't trying to be a javascript, but it's certainly trying to be faster. Performance features prominently in every statement of their design goals. Not only that, but performance in all modern browsers - i.e. including the ones they don't control and won't ship with a Dart VM. I don't see how they can possibly pull that off. Can anybody?
> Many googlers I've spoken to firmly believe that you need a strongly typed
Dart might be many things, none of them come remotely close to _strongly typed_.
Also, I never understood why Google ever started GWT, the idea itself is like a bad Apr 1st joke that got out of hand. I guess that the legions of Java programmers google has been hiring have started to take over sigh
The Dart VM buys you sane numeric semantics (integers and floats and bignums). Dart is also quite a bit less dynamic and introspective than JS, which should make it easier to optimize.
V8 does not use static type inference, as you seem to suggest. It uses dynamic type specialization based on observed types. Only recent builds of SpiderMonkey (not those that are shipping in current Firefoxes) do static type inference.
v8 is not crazy fast. It is a fast dynamic language VM -- beats php, ruby, python and other javascript VMs. In absolute terms, it executes code slowly compared to, for instance, the Java, Scala, C, C++, C# and others.
