I'm working on a port of BloomL for clojure which will include a semi-naive datalog interpreter (it will already support naive, monotonic datalog by tonight). It will likely never be as well optimised as the Datomic libs but it is LGPL.

Source:

https://github.com/jamii/droplet

Background:

http://www.bloom-lang.net/

http://boom.cs.berkeley.edu/

http://db.cs.berkeley.edu/papers/UCB-lattice-tr.pdf