C++核心准则C.167:为具有约定俗成语义的操作使用运算符

C.167: Use an operator for an operation with its conventional meaning

C.167:为具有约定俗成语义的操作使用运算符

 

Reason(原因)

Readability. Convention. Reusability. Support for generic code。

可读性。遵守惯例。可复用性。支持泛化代码。

Example(示例)

void cout_my_class(const My_class& c) // confusing, not conventional,not generic
{
    std::cout << /* class members here */;
}

std::ostream& operator<<(std::ostream& os, const my_class& c) // OK
{
    return os << /* class members here */;
}

By itself, cout_my_class would be OK, but it is not usable/composable with code that rely on the << convention for output:

如果只考虑自己的话，cout_my_class还不错，但是它无法在通过<<运算符输出的代码中使用(或者和这样的代码一起使用)。

My_class var { /* ... */ };
// ...
cout << "var = " << var << '\n';

Note(注意)

There are strong and vigorous conventions for the meaning most operators, such as

很多操作符具有强烈而且活跃的约定含义，例如：

• comparisons (==, !=, <, <=, >, and >=),

• 比较运算符

• arithmetic operations (+, -, *, /, and %)

• 数学运算符

• access operations (., ->, unary *, and [])

• 访问运算符

• assignment (=)

• 赋值运算符

Don't define those unconventionally and don't invent your own names for them.

不要违反惯例定义这些运算符，也不要为它们发明新名称。

Enforcement(实施建议)

Tricky. Requires semantic insight.

不容易。需要语义方面的深入理解。

原文链接：

https://github.com/isocpp/CppCoreGuidelines/blob/master/CppCoreGuidelines.md#c167-use-an-operator-for-an-operation-with-its-conventional-meaning

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