Playing with GameplayKit rule system 1.

RuleSystem.swift

//: Check divisible by 3 and 5 with GameplayKit Rule System

import GameplayKit

let divisibleBy3Rule = GKRule(blockPredicate: { system in
    (system.state["value"] as! Int) % 3 == 0
    }, action: { system in
        system.assertFact("divisibleBy3and5", grade: 0.5)
        system.assertFact("divisibleBy3", grade: 1)
})

let divisibleBy5rule = GKRule(blockPredicate: { system in
    return (system.state["value"] as! Int) % 5 == 0
    }, action: { system in
        system.assertFact("divisibleBy3and5", grade: 0.5)
        system.assertFact("divisibleBy5", grade: 1)
})

let ruleSystem = GKRuleSystem()
ruleSystem.addRule(divisibleBy3Rule)
ruleSystem.addRule(divisibleBy5rule)

for i in 1...100 {
    ruleSystem.state["value"] = Int(i)
    ruleSystem.evaluate()
    
    print("\(i), divisible by 3 and 5 (grade of fact) is \(ruleSystem.gradeForFact("divisibleBy3and5") * 100)% ")
    ruleSystem.reset()
}