ios - 在 Swift 中为自定义类重载等价 (==) 运算符

Question

是否可以在自定义类中重载自定义类的等价 (==) 运算符。但是我知道可以让这个运算符在类范围之外重载。感谢任何示例代码。提前致谢。

Answer 1

添加全局函数。例如:

class CustomClass {
    var id = "my id"
}

func ==(lhs: CustomClass, rhs: CustomClass) -> Bool {
    return lhs == rhs
}
func !=(lhs: CustomClass, rhs: CustomClass) -> Bool {
    return !(lhs == rhs)
}

在 Swift 2 中遵循 Equatable 协议(protocol)

class CustomClass: Equatable {
    var id = "my id"
}

func ==(left: CustomClass, right: CustomClass) -> Bool {
    return left.id == right.id
}

在 Swift 3 中遵循 Equatable 协议(protocol)

class CustomClass {
    var id = "my id"
}

extension CustomClass: Equatable {
    static func ==(lhs: CustomClass, rhs: CustomClass) -> Bool {
        return lhs.id == rhs.id
    }
}