あの日本語非対応で有名な JapaneseTraditionalDiceGame を Swift で書いてみた（ https://ja.wikipedia.org/wiki/NKODICE ）

JapaneseTraditionalDiceGame.swift

import Foundation

struct Dice {
    private let characters = ["う", "お", "こ", "ち", "ま", "ん"].sorted()
    
    func roll() -> String? {
        return Int.random(in: 0..<5) == 0 ? nil : characters.shuffled().first
    }
}

enum Hand: CaseIterable {
    case unchi
    case unko
    case manko
    case omanko
    case chinko
    case chinchin
    case ochinchin

    var effect: String {
        String(reflecting: self).components(separatedBy: ".").last!.uppercased()
    }

    var score: Int {
        switch self {
        case .unchi, .unko, .manko, .chinko:
            return 1000
        case .chinchin:
            return 3000
        case .omanko:
            return 5000
        case .ochinchin:
            return 10000
        }
    }

    private func condition(by rolls: [String]) -> Bool {
        let effectHiragana = effect.applyingTransform(.latinToHiragana, reverse: false)!
        switch self {
        case .unchi, .unko, .manko, .omanko, .chinko:
            return effectHiragana.reduce(true) { $0 && rolls.contains(String($1)) }
        case .chinchin:
            return Set(effectHiragana).reduce(true) { partialResult, element in
                partialResult && rolls.filter { $0 == String(element) }.count == 2
            }
        case .ochinchin:
            var effectHiragana = Set(effectHiragana)
            effectHiragana.remove("お")
            return rolls.contains("お") && effectHiragana.reduce(true) { partialResult, element in
                partialResult && rolls.filter { $0 == String(element) }.count == 2
            }
        }
    }

    static func check(from result: [String]) -> [Self] {
        return Hand.allCases.compactMap { $0.condition(by: result) ? $0 : nil }
    }
}

func play() {
    let dices = (0..<5).map { _ in Dice() }
    let rollResults = dices.compactMap { $0.roll() }
    let hands = Hand.check(from: rollResults)
    let effects = hands.map { $0.effect }
    let totalScore = hands.map { $0.score }.reduce(0, +)

    print(rollResults)
    if !effects.isEmpty {
        print("🎉  ", terminator: "")
        effects.forEach { print("\($0) ", terminator: "") }
        print()
    }
    print("SCORE:", totalScore)
}

for round in 1...3 {
    print("ROUND", round, "------------------------------")
    play()
    print()
}