C ++ 11中的可变参数模板和多重继承 [英] Variadic templates and multiple inheritance in c++11

问题描述

我正在尝试实现以下目标：

i'm trying to achieve something like this:

我有一个要动态继承的模板化基类

I have a templated base class which i want to inherit dynamically

template<typename A, typename B>
class fooBase
{
public:
    fooBase(){};
    ~fooBase(){};
};

所需方法：（类似这样，不确定如何做到）

desired method: (something like this, not really sure how to do it)

template <typename... Interfaces>
class foo : public Interfaces...
{
public:
    foo();
    ~foo();
}

我的目标是让foo类的行为如下：

and my goal is to have the foo class act like this:

第二种方法：

class foo()
    : public fooBase<uint8_t, float>
    , public fooBase<uint16_t, bool>
    , public fooBase<uint32_t, int>
    // and the list could go on
{
    foo();
    ~foo();
}

使用第二种方法的问题是，如果我实例化一个foo对象，它将将会一直继承这3个基类，我想使其更通用，并且在实例化foo对象时，使用可变参数模板为它提供基类的参数，以便我可以将foo类用于其他类型（也许继承仅一个基类，可能是五个）

with the second method the problem is that if i instantiate an foo object, it will inherit all the time those 3 base classes, i want to make it more generally and when instantiate a foo object, give it with variadic templates the parameters for the base classes, so that i can use the foo class for other types(maybe will inherit just one base class, maybe five)

谢谢

实例化foo的示例

foo<<uint8_t, float>, <uint16_t, bool>, <uint32_t, int>, /* and the list could go on and on */> instance

推荐答案

您可以尝试使用2个参数的递归可变参数模板

You could try recursive variadic templates, taking 2 arguments at a time to add a derivation from fooBase.

可能是这样的：

template<typename A, typename B>
class fooBase
{
public:
    fooBase(){};
    ~fooBase(){};
};

template<typename A, typename B, typename ... C>
class foo: public fooBase<A, B>, public foo<C ...> {
};

// termination version by partial specialization
template<typename A, typename B>
class foo<A, B>: public fooBase<A, B> {
};

然后可以声明：

foo<uint8_t, float, uint16_t, bool, uint32_t, int> bar;

，bar将是 fooBase< uint8_t，float> 的子对象code>， fooBase< uint16_t，bool> 和 fooBase< uint32_t，int>

and bar will be a subobject of fooBase<uint8_t, float>, fooBase<uint16_t, bool> and fooBase<uint32_t, int>

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