在Swift中为自定义类重载等价(==)运算符

Question

是否可以为该自定义类中的自定义类重载等价(==)运算符.但是我知道可以让这个运算符重载在类范围之外.感谢任何示例代码.提前致谢.

Answer 1

添加全局功能.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中使用Equatable协议

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

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

符合Swift 3中的Equatable协议

class CustomClass {
    var id = "my id"
}

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

Answer 2

不,运算符使用全局函数重载.