On Thu, 8 Sep 2011, Christopher Jefferson wrote: > This might be totally insane, but I believe that: > > tuple_cat(tuple_cat(A,B), C) always equivalent to tuple_cat(A,B,C); That's a fine way to find the return type, but for code, doesn't it generate many copies? I think I'd forward_as_tuple and use some magic indices to extract everything at once. -- Marc Glisse