Function overload
本文讨论function overload。
What is function overload
在cppreference Functions中的介绍如下:
Multiple functions in the same scope may have the same name, as long as their parameter lists and, for non-static member functions, cv/ref (since C++11)-qualifications are different. This is known as function overloading. Function declarations that differ only in the return type and the noexcept specification (since C++17) cannot be overloaded.
关于non-static member functions，参见C++\Language-reference\Classes\Members\Non-static-member\Function-member。
需要注意的是: function overload是不考虑return type的，这和function type不同。
Overload is a kind of static polymorphism
参见C++\Guide\Plymorphism。
Overload is multiple dispatch
按照Theory\Programming-paradigm\Abstraction-and-polymorphism\Polymorphism\Implementation中的理论，我们可以认为: overload is multiple dispatch，因为: compiler overload resolution需要考虑所有的function argument，所以可以看做是multiple dispatch。