如何在STL容器中存储模板对象和成员函数调用 [英] How to store templated objects in an STL container and member function call

问题描述

假设您有一个类

template<class T>
struct A {
  void foo() {
    // Need access to "T" here
    typedef typename someTrait<T>::someType T2;
  }
};

，并且你想注册（或存储）类的实例它）与一个容器（可能是STL），以便稍后调用所有注册实例的 foo（）方法。

and you would like to "register" (or store) instances of the class (or a pointers to it) with a container (probably STL) for later calling the foo() method of all registered instances.

因为要存储用不同模板参数实例化的实例（ A ， A ，.. 。）显然，不能使用 std :: vector 并存储实例或指针。我可以想象的是使方法 static 并存储函数指针 void foo（），如：

Since instances instantiated with different template parameters are to be stored (A<int>, A<float>, ...) obviously one can't use a std::vector and store the instances or pointers to it. What I can imagine is making the method static and storing function pointers to void foo(), like:

 void static foo();

 typedef void (* fooPtr)(void);
 std::vector<fooPtr>

但是不知怎的，我觉得这不是很C ++ 11-ish。是否有一个很好的解决方案，引入一个包装类或者什么？

But somehow I have the feeling this is not very C++11-ish. Is there a nice solution which introduces a wrapper class or something?

引入基类并使用动态转换将引入依赖关系 RTTI ，对不对？我想避免对 RTTI 的依赖。

Introducing a base class and using dynamic cast would introduce dependencies on RTTI, right? I would like to avoid dependencies on RTTI.

在C ++ 11中如何做？ （我不想引入其他依赖关系，如链接到Boost或依赖于 RTTI 。）

How would one do this in C++11? (I would not like to introduce additional dependencies like linking to Boost or depending on RTTI.)

意见！

推荐答案

可能你只能使用虚拟方法？这也适用于C ++ 03。

Probably you could just use virtual methods? This works with C++03 too.

struct ABase {
    virtual void foo() = 0;
};

template<class T>
struct A : ABase {
    virtual void foo() override {
        // Access to "T" here
    }
};

...

std::vector<std::unique_ptr<ABase>> vec;
vec.emplace_back(new A<int>());
vec.emplace_back(new A<float>());

for (auto& p_a : vec)
    p_a->foo();

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