return this == &other

|| ( size() == other.size()

&& std::equal(begin(), end(), other.begin(), detail::full_eq));

std::string result = "@<>";

for (size_t i = 0; i < tup.size(); ++i) {

auto uti = tup.type_at(i);

result += "+";

result += uti->name();

}

return result;