I wrote a little library for building DSLs in JavaScript [0] because of this very issue—JSON is not good for this kind of stuff. I want to be able to create small DSLs to solve problems rather than squeezing the language into a JSON format. I want the full power of a language AND the ability to serialize the semantics to send over the wire. Maybe we'll move toward that one day.
[0] https://github.com/smizell/treebranch