extension Array where Element == Int {
    func fizzBuzz() -> [String] {
        return self.map(evalBuilder(pickers: [fibui(3, "Fizz"), fibui(5, "Buzz"), fibui(7, "Humm")]))
    }
    
    private func fibui(_ mult: Int, _ out: String) -> ((Int)->String?) {
        return { (number: Int) in number.isMultiple(of: mult) ? out : nil }
    }
    
    private func evalBuilder(pickers:[(Int)->String?]) -> ((Int)->String) {
        return { (number: Int) in
            let output = pickers.compactMap { f in return f(number) }
            return output.isEmpty ? "\(number)" : output.joined()
        }
    }
}


let array = Array(1...20)
print(array.fizzBuzz())