It doesn't seem to be. Well perhaps it is intended to be, but there are bugs. Notably, the associations are not associative! If you take the example from the do

It doesn't seem to be. Well perhaps it is intended to be, but there are bugs. Notably, the associations are not associative! If you take the example from the docs and run (e= :two-door :vehicle) it evaluates to false. The implementation seems to be based on building up a hashmap (mutable, in the namespace) of pairs of facts, with some convenience functions and macros. If you are interested in a simple set of functions for relational type stuff I recommend checking out http://richhickey.github.io/clojure/clojure.set-api.html http://richhickey.github.io/clojure/clojure.set-api.html