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Identifying Template Specializations
In C , it is sometimes necessary to determine if a given class is a specialization of a particular class template. For instance, consider the following class template:
template <class T> struct A {};
Say we have a type CompareT. How can we verify if it is an A<> for some type ? Consider the following example:
template<class CompareT> void compare(){ // is this A ? cout << is_same< A<*> , CompareT >::value; // A<*> ???? } int main(){ compare< A<int> >(); }
In this example, we expect A
Solution:
One approach to address this problem is to utilize template metaprogramming. Here's a snippet that allows you to specify the desired template to be matched against:
template <class T, template <class...> class Template> struct is_specialization : std::false_type {}; template <template <class...> class Template, class... Args> struct is_specialization<Template<Args...>, Template> : std::true_type {}; static_assert(is_specialization<std::vector<int>, std::vector>{}, ""); static_assert(!is_specialization<std::vector<int>, std::list>{}, "");
This solution provides a convenient way to check if a given type is indeed a specialization of a specific class template.
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