Drools forward chaining example knowledge base with roots from wikipedia definition example / published by https://github.com/dacr/code-examples-manager #d0bf6eb4-acb7-49b9-bb54-edd6d63f3572/29adce8710cd38b0e5e1fe67e682888ed64cc5e

drools-kb-reasoning-forward-chaining.sc

// summary : Drools forward chaining example knowledge base with roots from wikipedia definition example
// keywords : scala, drools, mvel, scalatest, ai, knowledgebase, @testable
// publish : gist
// authors : David Crosson
// license : Apache NON-AI License Version 2.0 (https://raw.githubusercontent.com/non-ai-licenses/non-ai-licenses/main/NON-AI-APACHE2)
// id : d0bf6eb4-acb7-49b9-bb54-edd6d63f3572
// created-on : 2019-10-04T16:36:54+02:00
// managed-by : https://github.com/dacr/code-examples-manager
// run-with : scala-cli $file

// ---------------------
//> using scala  "3.3.0"
//> using dep "fr.janalyse::drools-scripting:1.1.0"
//> using dep "org.scalatest::scalatest:3.2.16"
// ---------------------

import fr.janalyse.droolscripting._, org.scalatest._, flatspec._, matchers._, OptionValues._
object KbTest extends AnyFlatSpec with should.Matchers {
  override def suiteName: String = "KBTest"
  /*  https://en.wikipedia.org/wiki/Forward_chaining
    If X croaks and X eats flies - Then X is a frog
    If X chirps and X sings - Then X is a canary
    If X is a frog - Then X is green
    If X is a canary - Then X is yellow
   */
  val drl =
    """package test
      |dialect "mvel"
      |
      |declare ItCroaks    end
      |declare ItEatsFlies end
      |declare ItChirps    end
      |declare ItSings     end
      |
      |declare IsGreen     end
      |declare IsYellow    end
      |
      |declare IsFrog      end
      |declare IsCanary    end
      |
      |rule "frog"   when ItCroaks() ItEatsFlies() then insert(new IsFrog()) end
      |rule "canary" when ItChirps() ItSings()     then insert(new IsCanary()) end
      |
      |rule "all frogs are green"     when IsFrog()   then insert(new IsGreen()) end
      |rule "all canaries are yellow" when IsCanary() then insert(new IsYellow()) end
      |""".stripMargin

  "Forward chaining KB" should "work" in {
    val engine = DroolsEngine(drl)
    val facts = List( ("{}", "test.ItCroaks"), ("{}", "test.ItEatsFlies") )
    //facts.foreach{case (kind, json) => engine.insertJson(json, kind)}
    for { (json, declareType) <- facts } {
      engine.insertJson(json, declareType)
    }
    engine.getModelInstances("test.IsFrog").size shouldBe 0
    engine.fireAllRules()
    engine.getModelInstances("test.IsFrog").size shouldBe 1
  }
}
KbTest.execute()