Swiftでkotlin風if式

gistfile1.swift

enum elseer<T> {
    case `true`(T)
    case `false`
    
    func `else` (falseClosure: ()->(T)) -> T {
        switch self {
        case .true(let result):
            return result
        
        case .false:
            return falseClosure()
        }
    }
}

func letif<T>(_ cond: Bool, trueClosure: ()->(T)) -> elseer<T> {
    if cond {
        return elseer.true(trueClosure())
    } else {
        return elseer.false
    }
}

let boolean = false
let text: String = letif (boolean) {
    return "true!"
}.else {
    return "false!"
}

print(text)