Function metafunction

example/tutorial/type.cpp:230–231

//! [metafunction1]
template <template <typename> class F, typename T>
constexpr auto metafunction(hana::basic_type<T> const&)
{ return hana::type_c<typename F<T>::type>; }

auto t = hana::type_c<int>;
BOOST_HANA_CONSTANT_CHECK(metafunction<std::add_pointer>(t) == hana::type_c<int*>);