Func or field

funcorfield.h

// Tool to either invoke a method or read a field on a type.

class MyTypeName {
    using TSelf = MyTypeName;
    template<typename T> using func_or_field = std::variant<
        T(TSelf::*)(),
        T TSelf::*>;

    template<typename T> auto invoke_func_or_field(func_or_field<T> const& fof)
    {
        if (std::holds_alternative<T(TSelf::*)()>(fof))
        {
            return (this->*std::get<T(TSelf::*)()>(fof))();
        }
        else
        {
            return this->*std::get<T TSelf::*>(fof);
        }
    }
    
    int _f1;
    int _f2;
    int Func1();
    int Func2();
    
    void use(int);
    
    void calls() {
        constexpr static const func_or_field<int> c[] = { &TSelf::_f1, &TSelf::_f2, &TSelf::_f3, &TSelf::_f4 };
        for (auto&& i : c) {
            use(invoke_func_or_field(i));
        }
    }
}