From their "technical overview" page http://www.dartlang.org/docs/technical-overview/ http://www.dartlang.org/docs/technical-overview/ : "Dart will include a r

From their "technical overview" page http://www.dartlang.org/docs/technical-overview/ http://www.dartlang.org/docs/technical-overview/ : "Dart will include a rich set of execution environments, libraries, and development tools built to support the language. These tools will enable productive and dynamic development, including edit-and-continue debugging and beyond—up to a style where you program an application outline, run it, and fill in the blanks as you run." Sounds like a Smalltalk-style debugger running in the browser. Though it seems these tools aren't actually ready yet: "This is a technology preview, not a product launch" -- http://dartinside.com/2011/live-from-dart-launch/#liveblog-entry-102 http://dartinside.com/2011/live-from-dart-launch/#liveblog-e...