为什么swift是面向协议的编程--对面向对象机制的改进
主要目标是提供抽象能力和解决值类型的多态问题
Actually, Abrahams says, those are all attributes of types, and classes are just one way of implementing a type. Yet, they exact a heavy toll on programmers in that they may cause:
- Implicit sharing, such that if two objects refer a third object, then both can modify it without the other knowing about it. This leads to worarounds such as duplicating the referred object to avoid sharing, which in turn leads to inefficiencies; alternatively, sharing may require using locks to avoid race conditions and this can cause more inefficiency and even lead to deadlocks. What this entails is more complexity, which means more bugs.
- Inheritance issues: in many OOP language, there can be one just superclass, and it has to be chosen at the very start. Changing it later can be extremely hard. A superclass, furthermore, forces any stored property on derived classes and this can make it complex to handle initialization and not to break any invariants that the superclass require. Finally, there are usually limitations to what can be overridden, and how, or when it should not be, and those constraints are usually left to the docs.
- Lost type relationship, which ensues from the conflation of interface and implementation. This usually manifests itself through some base class’ methods where no implementation is possible and thus the necessity to downcast to the concrete derived class in that method’s implementation.
According to Abrahams, protocol-oriented programming is a better abstraction mechanism in that it allows:
- value types (besides classes)
- static type releationships (besides dynamic dispatch)
- retroactive modeling
- no forcing of data on models
- no initialization burden
- clarity as to what shall be implemented.
解决的问题:
1、面向对象的问题
2、值类型多态的支持
3、泛型与接口的结合 typeclass类型
一、面向对象的机制不支持值类型
In Swift, we use structs, enums, and tuples rather than working only with classes since, Value Semantics are preferred over Reference Types.
Also, there could be various cases where OOP is not the best solution to implement. Let’s check and figure out the drawbacks in Object-Oriented concept. We know that Inheritance is one of the most important concepts in OOP but, inheritance doesn’t work for value types and modern languages like Swift prohibits to support the feature of multiple inheritances due to complexities and value types is the first citizen of Swift. So, POP does a great job by providing the ability to add multiple abilities to the class, struct, and enum with protocols and extensions that supports multiple implementations while we code.
二、协议提供了抽象和多态机制
虚函数表和存在容器的多态支持;
接口函数+泛型编程的多态
三、协议支持值类型和引用类型;
- Classes use reference i.e if you set something to other it is not a copy instead it is a reference.
- Whereas, in value type such as structures, passes things as a copy, not as a reference.
四、协议本身支持类型的组织
五、模拟多重继承
Simply put and without quibbling over inanities, OOP and POP share most of these attributes, with one major exception: Classes can only inherit from one other class while protocols can inherit from multiple protocols.
参考文献:
https://www.technotification.com/2018/08/protocol-oriented-programming-swift.html
https://www.appcoda.com/pop-vs-oop/
https://www.infoq.com/news/2015/06/protocol-oriented-swift
为什么swift是面向协议的编程--对面向对象机制的改进的更多相关文章
- Swift中面向协议的编程
什么是面向协议的编程? 面向协议的编程,是一种编程范式. 编程范式,是一个计算机科学用语.维基百科中的解释是,计算机编程的基本风格或典型模式.通俗来说,就是解决某一个问题的方法不同方法和思路. 像大家 ...
- 为什么说swift是面向协议编程--草稿
为什么说swift是面向协议编程 public protocol ReactiveCompatible { /// Extended type associatedtype CompatibleTyp ...
- Swift -POP( 面向协议编程)与OOP(面向对象编程)
面向协议编程(Protocol Oriented Programming,简称POP),是Swift的一种编程范式,Apple于2015年WWDC提出的,如果大家看Swift的标准库,就会看到大量PO ...
- 用 Swift 编写面向协议的网络请求
和我一起参加9 月 1 日 - 9月 2 日在纽约举办的 Swift 社区庆典
- Swift 学习笔记(面向协议编程)
在Swift中协议不仅可以定义方法和属性,而且协议是可以扩展的,最关键的是,在协议的扩展中可以添加一些方法的默认实现,就是在协议的方法中可以实现一些逻辑,由于这个特性,Swift是可以面向协议进行编程 ...
- fir.im Weekly - 揭秘 iOS 面向协议编程
本期 fir.im Weekly 重点推荐关于 iOS 面向协议编程相关文章,还有 iOS 多线程安全.Swift 进阶.Android MVVM 应用框架.Android 蓝牙实践等技术文章分享和工 ...
- 【C++系列小结】面向过程的编程风格
前言 编程语言有面向过程和面向对象之分,因此编程风格也有所谓的面向过程的编程和面向对象的编程,并且语言的性质不会限制编程的风格. 这里主要说一以下向过程的编程. "面向过程"(Pr ...
- 编程范式 --- 面向协议编程(Protocol Oriented Programming,简称POP)
面向协议编程(Protocol Oriented Programming,简称POP) 是Swift的一种编程范式,Apple于2015年WWDC踢出 在Swift的标准库中,能见到大量POP的影子 ...
- Android 面向协议编程 体会优雅编程之旅
Android中面向协议编程的深入浅出 http://blog.csdn.net/sk719887916/article/details skay编写 说起协议,现实生活中大家第一感觉会想到规则或者约 ...
随机推荐
- Oracle高效分页查询(转)
page --没有order by的查询 -- 嵌套子查询,两次筛选(推荐使用) --SELECT * -- FROM (SELECT ROWNUM AS rowno, t.* -- FROM DON ...
- 46.Linux-分析rc红外遥控平台驱动框架,修改内核的NEC解码函数BUG(1)
内核版本 : Linux 3.10.14 rc红外接收类型: GPIO 类型的NEC红外编码 本章内容 1) rc体系结构分析 2) 分析红外platform_driver平台驱 ...
- python多任务-线程
目录 多任务的概念 线程基础 单线程执行 多线程执行 主线程会等待所有子线程结束后才结束 查看线程数量 线程-注意点 线程执行代码的封装 线程的执行顺序 总结 多任务的概念 什么叫"多任务& ...
- Java8 方法引用
概述 方法引用是用来直接访问类或实例阴茎存在的方法或者构造方法.它需要由兼容的函数式接口(lambda表达式中用到的接口)构成的目标类型上下文. 有时候, 当我们想要实现一个函数式接口的方法, 但是已 ...
- Java中单例实现
1:.经典懒汉: 代码如下: package org.pine.test; public class Person { private String name; private int age; pu ...
- laravel框架详解
一.基础篇 1.概念 Laravel是一个有着美好前景的年轻框架,它的社区充满着活力,同时提供了完整而清晰的文档,而且为快速.安全地开发现代应用提供了必要的功能.2011年,Taylor Otwell ...
- DEM山体阴影原理以及算法具体解释
山体阴影原理以及算法具体解释 山体阴影基本原理: 山体阴影是假想一个光源在某个方向和某个太阳高度的模拟下.用过临近像元的计算来生成一副0-255的灰度图. 一.山体阴影的主要參数: 1. 太阳光线的 ...
- 微信小程序 text属性设置 WXSS样式
>微信小程序的布局css样式 参考自 珺L 文字 width: fit-content;font-size:20px; /*设置文字字号*/color:red; ...
- (网页)jQuery判断checkbox是否选中的方法
if($('#checkbox-id').is(':checked')) { // do something} if ($('#checkbox-id').attr('checked')) { ...
- c++趣味之返回void
void a(){} void b(){return a();} int main() { b(); ; } 这个是能编译的(vs,gcc),void函数是能返回,一般不会这么写,但是这样确实可以.你 ...