通过模板参数号重载模板类 [英] Overloading template classes by template parameter number

问题描述

是否可以有多个版本的同一类，只有在他们采取的模板参数的数量不同？

Is it possible to have multiple versions of the same class which differ only in the number of template arguments they take?

例如：

template<typename T>
class Blah {
public:
    void operator()(T);
};

template<typename T, typename T2>
class Blah {
public:
    void operator()(T, T2);
};

我试图模仿functor类型的东西，可以接受可变数量的参数

I'm trying to model functor type things which can take a variable number of arguments (up to the number of different templates that were written out).

推荐答案

最简单的答案是只有一个模板，您要支持并使用void作为默认类型，除了第一种类型。然后你可以根据需要使用部分特化：

The simplest answer would be to have just one template, with the maximum number you want to support and use void for a default type on all but the first type. Then you can use a partial specialization as needed:

template<typename T1, typename T2=void>
struct foo {
    void operator()(T1, T2);
};

template <typename T1>
struct foo<T1, void> {
     void operator()(T1);
};

int main() {
   foo<int> test1;
   foo<int,int> test2;
   test1(0);
   test2(1,1);
}

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