In a programming language setting, this is usually called an AST (Abstract Syntax Tree), not a DOM. Though I see what you're getting at here with the AST query API. There are certainly parallels. (http://en.wikipedia.org/wiki/Abstract_syntax_tree)

This looks really great. On the topic of manipulating data structures in a funky way, see also specter (https://github.com/nathanmarz/specter).

Or instar: https://github.com/boxed/instar

Does jai have a meaning? It's also Jon Blow's programming language.

Not really... I just wanted to write (use 'jai.query) as a reference to the more famous library

Oh! I had so much need of this, if only it were ClojureScript.