clara_rules_external_facts.clj

(ns example
  (:require [clara.rules :refer :all]))

(def view-counts
  {123 1000})

(def view-event
  {:type :view-event
   :video 123})

(defquery get-counts
  []
  [?count <- :view-count])

(defrule view-count-rule
  [:view-event [view-event] (= ?count (get view-counts (:video view-event)))]
  =>
  (insert! {:type :view-count
            :count ?count}))

(defn example []
  (-> (mk-session 'example :fact-type-fn :type)
      (insert view-event)
      (fire-rules)
      (query get-counts)))