swift - 使用扩展在 Swift 中符合协议(protocol)

Question

我有一个 Swift 协议(protocol)定义如下:

protocol SmartContract {

    func apply(transaction :Transaction)
    func addBrokenRule(_ brokenRule: BrokenRule)
    var brokenRules :[BrokenRule] { get set }
} 

我在 SmartContract 上有一个扩展，定义如下:

extension SmartContract {

    mutating func addBrokenRule(_ brokenRule :BrokenRule) {

        if self.brokenRules == nil {
            self.brokenRules = [BrokenRule]()
        }

        self.brokenRules.append(brokenRule)
    }
}

我还有一个类 MoneyTransferContract，它符合协议(protocol)但未定义 brokenRules。这是因为我在扩展中定义了 brokenRules。

class MoneyTransferContract : SmartContract { 

     func apply(transaction :Transaction) { // do something here }
}

我的问题是如何确保 MoneyTransformContract 符合 SmartContract 协议(protocol)。无论如何，是否有 BrokenRule 可用于 MoneyTransformContract 而无需在不同的 SmartContracts 中一次又一次地定义它。

Answer 1

john doe 写道:

Is there anyway to have BrokenRule available to MoneyTransformContract without defining it again and again in different SmartContracts.

您想要的是该行为的父类(super class)/子类关系。

class SmartContract {
    func apply(transaction :Transaction) {
        //implemention
    }
    var brokenRules: [BrokenRule] = []
    func addBrokenRule(_ brokenRule :BrokenRule) {
        brokenRules.append(brokenRule)
    }
}

class MoneyTransferContract : SmartContract {
    // Gets `brokenRules` for free from superclass.
}

class BitCoinTransferContract : SmartContract { 
    // Gets `brokenRules` for free from superclass.
}