Template function as a template argument

Question

I\'ve just got confused how to implement something in a generic way in C++. It\'s a bit convoluted, so let me explain step by step.

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Consider such code:

Answer 1

In order to solve this problem with templates, you have to use a template template parameter. Unfortunately, you cannot pass template template function as a type, because it has to be instantiated first. But there is a workaround with dummy structures. Here is an example:

template 
struct a {

    static void foo (T = T ())
    {
    }

};

template 
struct b {

    static void foo (T = T ())
    {
    }

};

struct SomeObj {};
struct SomeOtherObj {};

template