clara-rules
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Cybozu Startups, Inc. has been developing web applications using Clojure and ClojureScript since May 2016, focusing on rule engines like Clara-rules. The document discusses the functionalities and advantages of Clara-rules, including code cleanliness, allowing non-developers to define domain logic, and efficient performance in complex scenarios. It also mentions various resources and examples for implementing rules and queries effectively.
![- http://www.clara-rules.org/
- [com.cerner/clara-rules "0.16.0"]
- Clojure(JVM)
- ClojureScript(Browser etc)](https://image.slidesharecdn.com/clara-rules-170922163937/85/clara-rules-5-320.jpg)
![- Anything
- Typically record or Java Class
;; Clojure
(defrecord Item [item-name id price])
//Java
public Class Item{
String itemName etc...
}](https://image.slidesharecdn.com/clara-rules-170922163937/85/clara-rules-11-320.jpg)
![- Match with fact(s) in session
- LFS => RHS
- Bind variables (LFS)
- Join with other facts (LFS)
- Create new facts (RHS)
(r/defrule tax-item
[Item (= ?n item-name) (= ?id id) (= ?p price)]
[Tax (= id ?id) (= ?t tax)]
=> (r/insert! (->TaxedItem ?n ?id (+ ?p (* ?p ?t)))))](https://image.slidesharecdn.com/clara-rules-170922163937/85/clara-rules-12-320.jpg)
![(require '[clara.rules.accumulators :as acc])
(r/defquery total
[] ;; Can accept parameter
[?total <- (acc/sum :taxed-price) :from [TaxedItem]])](https://image.slidesharecdn.com/clara-rules-170922163937/85/clara-rules-14-320.jpg)
clara-rules
- 2. - Cybozu Startups, inc - Write web apps with Clojure/ClojureScript - Since May 2016
- 3. - http://qiita.com/iku000888 - http://github.com/iku000888 - https://twitter.com/iku000888
- 4. - Rule Engines - About - Are good - Clara-rules - Facts - defrule & defquery - session - serialization - Use from Java - RETE - Application in UI dev
- 5. - http://www.clara-rules.org/ - [com.cerner/clara-rules "0.16.0"] - Clojure(JVM) - ClojureScript(Browser etc)
- 6. - Historical: - Shortage of devs - Let non devs code domain logic - Lisp! - Prolog! - Branch of AI! - Failed or not debate App Domain Logic Domain Logic
- 7. - ANA case - JBoss BRMS - https://japan.zdnet.com/article/35107193/ - ‘作業時間を20〜40%削減’!! - ‘スクラッチ開発と比較すると約3分の1の低コスト’!!
- 8. Layers of functions! - Responsibility of each layer? - Border line case? - Change in function params? - Brittle! - Spaghetti! Controller DB View External Service
- 11. - Anything - Typically record or Java Class ;; Clojure (defrecord Item [item-name id price]) //Java public Class Item{ String itemName etc... }
- 12. - Match with fact(s) in session - LFS => RHS - Bind variables (LFS) - Join with other facts (LFS) - Create new facts (RHS) (r/defrule tax-item [Item (= ?n item-name) (= ?id id) (= ?p price)] [Tax (= id ?id) (= ?t tax)] => (r/insert! (->TaxedItem ?n ?id (+ ?p (* ?p ?t)))))
- 13. - Can take parameter - Accumulators - Cator to result consumers
- 14. (require '[clara.rules.accumulators :as acc]) (r/defquery total [] ;; Can accept parameter [?total <- (acc/sum :taxed-price) :from [TaxedItem]])
- 15. - App interface - Immutable: ops return new sessions - Insert facts - Fire - Query Results
- 16. (-> (r/mk-session);;defsession also (r/insert (->Item "fish" "001" 200)) (r/insert (->Tax "001" 0.08)) (r/insert (->Item "milk" "002" 150)) (r/insert (->Tax "002" 0.28)) (r/fire-rules) (r/query total))
- 17. - Advanced - e.g. Hot load rules from a remote server - e.g. Store working session in DB - e.g. Validate rules with hash
- 18. Still write rules/queries in Clojure Official website:
- 19. - Used by many rule engines - Allows clara-rules to be fast - RETEII, RETEIII - ‘Dramatically faster’ for complex problems - Proprietary! - Bummer!
- 20. - Makes code clean - Query -> View(React) - Events -> Facts - Instances - Precept - Fact UI
- 21. clara-rules: 1. Helps keep your code clean 2. Can be used to build cool stuff 3. Compelling excuse to introduce Clojure for Java/Scala/etc users
- 23. Talks: Clarifying Rules Engines with Clara Rules - Mike Rodriguez - https://www.youtube.com/watch?v=Q_k5MkZmd-o "Retaking Rules for Developers" by Ryan Brush - https://www.youtube.com/watch?v=Z6oVuYmRgkk Midwest.io 2014 - Rules as a Control Structure - Ryan Brush - https://www.youtube.com/watch?v=zs5Rueo42TA