This gets us ever closer to the goals of the elusive (and presumably abandoned?) Grok project [1]. I'd love to see syntax highlighters (like Pygments), editors and IDEs, autocompletion providers, debuggers, and all other language-related tooling consume a standardized canonical "language description format". Making a new language? Bam! It's automatically supported by Visual Studio, Eclipse, Emacs, vim, Sublime Text,…
Steve spoke about Grok earlier this year: http://www.youtube.com/watch?v=uRO3dNJx5Dw (sadly the video is only worth listening to), and at the end of the talk guesses there would be more public information 1.5 years from then.