Clara Rules Save

Forward-chaining rules in Clojure(Script)

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Clara is a forward-chaining rules engine written in Clojure(Script) with Java interoperability. It aims to simplify code with a developer-centric approach to expert systems. See for more.


Here's a simple example. Complete documentation is at

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

(defrecord SupportRequest [client level])

(defrecord ClientRepresentative [name client])

(defrule is-important
  "Find important support requests."
  [SupportRequest (= :high level)]
  (println "High support requested!"))

(defrule notify-client-rep
  "Find the client representative and send a notification of a support request."
  [SupportRequest (= ?client client)]
  [ClientRepresentative (= ?client client) (= ?name name)] ; Join via the ?client binding.
  (println "Notify" ?name "that"  ?client "has a new support request!"))

;; Run the rules! We can just use Clojure's threading macro to wire things up.
(-> (mk-session)
    (insert (->ClientRepresentative "Alice" "Acme")
            (->SupportRequest "Acme" :high))

;;;; Prints this:

;; High support requested!
;; Notify Alice that Acme has a new support request!


Clara is built, tested, and deployed using Leiningen. ClojureScript tests are executed via puppeteer.

npm install -g puppeteer
npx puppeteer browsers install chrome


Clara releases are on Clojars. Simply add the following to your project:

Clojars Project


Questions can be posted to the Clara Rules Google Group or the Slack channel.




Copyright 2018 Cerner Innovation, Inc.

Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at

Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.

Open Source Agenda is not affiliated with "Clara Rules" Project. README Source: oracle-samples/clara-rules
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