Fizz Buzz with Gameplay Kit in Swift

fizzbuzz.swift

import Cocoa
import GameplayKit

let fizzRule = GKRule(blockPredicate: { system in
    (system.state["value"] as! Int) % 3 == 0
}, action: { system in
    system.state["output"] = "fizz"
})
fizzRule.salience = 1;

let buzzRule = GKRule(blockPredicate: { system in
    return (system.state["value"] as! Int) % 5 == 0
}, action: { system in
    if let out = system.state["output"] as? String {
        system.state["output"] = "\(out) buzz"
    } else {
        system.state["output"] = "buzz"
    }
})
buzzRule.salience = 2;

let printRule = GKRule(blockPredicate: { system in
    let value = system.state["value"] as! Int
    return (value % 5 != 0) && (value % 3 != 0)
}, action: { system in
    let value = system.state["value"] as! Int
    system.state["output"] = "\(value)"
})
printRule.salience = 0

let ruleSystem = GKRuleSystem()
ruleSystem.addRule(fizzRule)
ruleSystem.addRule(buzzRule)
ruleSystem.addRule(printRule)

for i in 1...100 {
    ruleSystem.state["value"] = Int(i)
    ruleSystem.state["output"] = nil
    ruleSystem.evaluate()
    print(ruleSystem.state["output"]!)
    ruleSystem.reset()
}

Output

1
2
fizz
4
buzz
fizz
7
8
fizz
buzz
11
fizz
13
14
fizz buzz
16
17
fizz
19
buzz
fizz
22
23
fizz
buzz
26
fizz
28
29
fizz buzz
31
32
fizz
34
buzz
fizz
37
38
fizz
buzz
41
fizz
43
44
fizz buzz
46
47
fizz
49
buzz
fizz
52
53
fizz
buzz
56
fizz
58
59
fizz buzz
61
62
fizz
64
buzz
fizz
67
68
fizz
buzz
71
fizz
73
74
fizz buzz
76
77
fizz
79
buzz
fizz
82
83
fizz
buzz
86
fizz
88
89
fizz buzz
91
92
fizz
94
buzz
fizz
97
98
fizz
buzz