Is there any way of detecting whether a class is a normal type or is a template type which may include non-type parameters? I came up with this solution:
#include <iostream>
template <template<class...> class>
constexpr bool is_template()
{
return true;
}
template <class>
constexpr bool is_template()
{
return false;
}
struct Foo{};
template<class> struct TemplateFoo{};
template<class, int> struct MixedFoo{};
int main()
{
std::cout << std::boolalpha;
std::cout << is_template<Foo>() << std::endl;
std::cout << is_template<TemplateFoo>() << std::endl;
// std::cout << is_template<MixedFoo>() << std::endl; // fails here
}
however it will fail for templates that mix non-types and types, like
template<class, int> struct MixedFoo{};
I am not able to come up with any solution, except the one in which I must explicitly specify the types in the overloads. Of course this is un-reasonable due to combinatorial explosion.
Related question (not a dupe): Is it possible to check for existence of member template just by identifier?
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