成员函数中的显式`this->` [英] Explicit `this->` in member functions

问题描述

我已经看到推荐成员函数使用 this-> 显式地引用成员变量，以避免忘记声明成员变量和意外引用全局变量。任何人都可以评论，如果他们认为这是一个合理的预防措施或不必要的冗长，将不必要地使代码的阅读复杂化？

解决方案

由于我经常实现类模板，我习惯总是用 this-> 限定成员变量和成员函数。在类模板的上下文中还有另一个原因，为什么用 this-> 限定名称是有用的：不依赖于模板参数的名称只在阶段I查找，即，基类中的名称根据模板参数不会在基本中查找。通过用 this-> 限定成员名称，它们变得依赖。例如：

  #include< iostream> 
 
 void f（）{std :: cout<< :: f（）\\\
; } 
 
 template< typename T> 
 class base 
 {
 public：
 void f（）{std :: cout< base :: f（）\\\
; } 
}; 
 
 template< typename T> 
 class derived 
：public base< T> 
 {
 public：
 void g（）{
 f（）; 
 this-> f（）; 
} 
}; 
 
 int main（）
 {
 derived< int>（）。 
} 
  

我使用 this-> 在所有我的代码，除非一些编码指南禁止这样做（我会考虑这方面的编码指南愚蠢和错误）。当然，在我自己的代码中，我限定所有可以限定的名称，并且不是自定义点（例如，我不会限定 swap（））。 / p>

I have seen recommended that member functions refer to member variables using this-> explicitly, to avoid forgetting to declare the member variable and accidentally referring to a global variable. Can anyone comment if they think this is a reasonable precaution or unnecessary verbosity that will needlessly complicate the reading of the code? Does anybody actually do this in day-to-day real-life programming?

解决方案

Since I'm frequently implementing class templates, I'm used to always qualify member variables and member functions with this->. In the context of class templates there is another reason why it is useful to qualify names with this->: Names not depending on template arguments are looked up only in phase I look-up, i.e., names in base classes depending on template arguments are never looked up in the base. By qualifying member names with this-> they become dependent. For example:

#include <iostream>

void f() { std::cout << "::f()\n"; }

template <typename T>
class base
{
public:
    void f() { std::cout << "base::f()\n"; }
};

template <typename T>
class derived
    : public base<T>
{
public:
    void g() {
        f();
        this->f();
    }
};

int main()
{
    derived<int>().g();
}

I'm using qualification with this-> in all my code unless some coding guidelines prohibits me from doing so (and I'd consider this aspect of the coding guideline silly and wrong). Of course, in my own code I qualify all names which can be qualified and which aren't a customization point (e.g., I wouldn't qualify swap()).

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