How can I pass a member function pointer type to a template?-CodePudding

I am trying to delegate a method call using a nested std::invoke. Sample code:

class Executor
{
public:
    bool Execute(bool someFlag);
}

template <class TMemberFunction, class TInstance, typename TResponse>
class Invoker
{
public:
    TResponse Invoke(TMemberFunction* function, TInstance* instance, bool someFlag) {
        return std::invoke(function, instance, someFlag);
    }
}

void Main()
{
    // Create an executor
    Executor executor;
    bool someFlag = true;

    // How can I pass the member function type here?
    Invoker<???, Executor, bool> invoker;
    // Invoke member method
    bool response = invoker.Invoke(&Executor::Execute, &executor, someFlag);
}

What's the proper way to pass the member function's type to the Invoker template?

Edit: sample code corrections.

CodePudding user response：

You might write your Invoker class like:

template <typename TMemberFunction>
class Invoker;

template <class C, typename Ret, typename... Args>
class Invoker<Ret (C::*) (Args...)>
{
public:
    Ret Invoke(Ret (C::*method) (Args...), C* instance, Args... args) {
        return std::invoke(method, instance, std::forward<Args>(args)...);
    }
};

template <class C, typename Ret, typename... Args>
class Invoker<Ret (C::*) (Args...) const>
{
public:
    Ret Invoke(Ret (C::*method) (Args...) const, const C* instance, Args... args) {
        return std::invoke(method, instance, std::forward<Args>(args)...);
    }
};
// other specializations to handle combination of volatile, ref, c-ellipsis

and than use it:

int main()
{
    Executor executor;
    Invoker <bool (Executor::*)(bool)> invoker;
    bool response = invoker.Invoke(&Executor::Execute, &executor, true);
    // ..
}