Programmer and project leader Lars Bak detailed the project in a talk today at the Goto conference in Denmark and in a blog post. Dart is geared for everything from small, unstructured projects to large, complicated efforts--Gmail and Google Docs, for example.
"If we want to focus on making the Web better over time, we have to innovate," including with new programming languages, Bak said in an interview today.
Google also unveiled a Dart language site that includes open-source tools for writing Dart programs, code samples, and tutorials; libraries of supporting software; the Dart language specification; and forums for discussion.
Bak bristled at some of the complaints about Google's approach to creating Dart in-house and not through a more collaborative approach.
"I don't buy the argument that before writing any line of code or designing any features, you put it in a standards committee, because that would just be a lot of screaming," Bak said. "You have to have coherent design before you start adopting Dart as a standard."
Making a standard is a goal, though. "It will be fairly lonely to create a standards committee when there's only us in it. We first have to get the backing of other partners before we can make a standard that's useful," he said.
Google is releasing Dart now for the next step in its maturation: outside feedback and participation. "We hope the other browser vendors will be excited," Bak said, adding that today is the first that Google has shared details about Dart with them or others.
Google is evaluating the best way to integrate Dart directly into its Chrome browser, something Bak is keen on. One reason: it will enable a "snapshotting" technology that dramatically improves a Web app's startup time. Snapshotting involves taking an application and "serializing" it into a single block of data.
Here is Bak's quick description of Dart's design goals:
Make Dart feel familiar and natural to programmers and thus easy to learn.
Ensure that Dart delivers high performance on all modern Web browsers and environments ranging from small handheld devices to server-side execution.
Dart targets a wide range of development scenarios: from a one-person project without much structure to a large-scale project needing formal types in the code to state programmer intent. To support this wide range of projects, Dart has optional types; this means you can start coding without types and add them later as needed. We believe Dart will be great for writing large web applications.
Building Dart into Chrome could let Google build Dart versions of its advanced Web apps that--if the language lives up to its billing--could be better than those Web apps today.
"Google has a lot fairly big Web applications. That includes Gmail and Docs. I hope many of these apps will be converted into Dart," Bak said. But he cautioned that this is his personal option, not an explicit plan.
Google also is trying to gain a foothold for Go, a programming language geared more for native software that today would most likely be written with C or C++.
Dart is designed to address several shortcomings Google sees with Web programming today, according to the Dart technical overview:
Scripting languages are popular because their lightweight nature makes it easy to write code quickly. Generally, the contracts with other parts of an application are conveyed in comments rather than in the language structure itself. As a result, it's difficult for someone other than the author to read and maintain a particular piece of code.
With existing languages, the developer is forced to make a choice between static and dynamic languages. Traditional static languages require heavyweight toolchains and a coding style that can feel inflexible and overly constrained.
Developers have not been able to create homogeneous systems that encompass both client and server, except for a few cases such as Node.js and Google Web Toolkit (GWT).
Different languages and formats entail context switches that are cumbersome and add complexity to the coding process.
The priority right now is to hear what the rest of the world thinks and to get them participating in Dart's development, Bak said.
"At this point it is mostly the language we are focused on," he said. "We hope to get positive feedback on the language."
Updated at 3:53 a.m. PT with comments from an interview with Bak.