Code vs. environment
Apps in JotSpot are collections of XML files with embedded code snippets written in standard scripting languages. Currently we support XPath and Ecmascript/Javascript; we have plans for Python, Groovy, and others. Making the environment as language-neutral as possible is more difficult than just binding everything to a single language, but I think the benefits are worth it: advanced users can extend Jot in the language that’s right for the job, and beginning users can opt for the language with the easiest learning curve.
Jon Udell recently made the case for separating code from environment. He observes that domain specific languages will “target fewer environments. The most obvious of these are the JVM and the .Net Common Language Runtime, along with their class frameworks.” I think that’s true, and I think the other side of that coin is that frameworks, particularly those written for the JVM and CLR, will provide better and better support for language-neutral extension.