In the current language, it probably is.
Variadic generics will likely improve how these things can be represented
Yes, I take it for granted that programming with the kinds of type structures in the structural generic programming proposal would be improved with variadic generics, and I look forward to the introduction of those features with antici… pation. The basic approach is still valid, and could subsume many one-off language extension proposals such as this one, and most ideas for general reflection.