Hi, I recently discovered (or maybe not) a neat trick to implement a tuple-like container. The technique has a couple of drawbacks which I will explain later. For a real example, you can see my list implementation in Boost.Hana at [1]. Here's the idea: auto list = [](auto ...xs) { return [=](auto access) { return access(xs...); }; }; auto head = [](auto xs) { return xs([](auto first, auto ...rest) { return first; }); }; auto tail = [](auto xs) { return xs([](auto first, auto ...rest) { return list(rest...); }); }; auto length = [](auto xs) { return xs([](auto ...z) { return sizeof...(z); }); }; // etc... // then use it like auto three = length(list(1, '2', "3")); The idea is to use the capture of the lambda as a fast compiler-generated struct with the desired members. By passing a function to that lambda, we get an access to the unpacked representation of those members and we can then apply any fast algorithm on parameter packs. Drawbacks --------- 1. The type of that tuple is completely opaque. Hence, it is harder to debug, but I'm working on other stuff that should make this a moot point. 2. Since lambdas can't be made constexpr, this tuple can't either. However, there was some discussion about proposing constexpr lambdas at C++Now and it looked like there was a lot of support for the idea, so this might change. Benchmarks ---------- I ran a couple of benchmarks testing the compilation time and the results are self explanatory. The benchmark suite is at [2]. ## Create a tuple of n elements The test code looks like: #include <boost/tuple/tuple.hpp> int main() { auto go = boost::make_tuple(1, ..., n); } <a href="http://imgur.com/rKqmvk3"><img src="http://i.imgur.com/rKqmvk3.png"/></a> ## Access the last element of a tuple of n elements The test code looks like: #include <boost/tuple/tuple.hpp> int main() { auto go = boost::make_tuple(1, ..., n); auto last = boost::get<n-1>(go); } <a href="http://imgur.com/b4rWR4y"><img src="http://i.imgur.com/b4rWR4y.png"/></a> Also, for those following the development of Boost.Hana, it is going well and I am preparing for a followup in the near future. Stay tuned! Regards, Louis Dionne [1]: http://github.com/ldionne/hana/blob/master/include/boost/hana/list.hpp [2]: http://github.com/ldionne/benchcc/tree/master/benchmarks