Advanced C++ Programming Cookbook

Adding const support to our delegate

Our delegate currently cannot take a member function marked as const as we have not provided our delegate with a wrapper capable of doing so. For example, our heroes' attack() function currently looks like this:

class spiderman{public:    bool attack(int x, int)    {        return x == 0 ? true : false;    }};

We would, however, like our hero attack() functions to look like the following since they do not modify any private member variables:

class spiderman{public:    bool attack(int x, int) const    {        return x == 0 ? true : false;    }};

To support this change, we must create a wrapper that supports this, shown as follows:

template<    typename T,    typename RET,    typename... ARGS    >class wrapper_const :    public base<RET, ARGS...>{