Hello Louis, Mario Lang, a Spirit developer, played around with Hana and investigated on it's suitability for Spirit. His conclusion is that "Hana is really quite nice!". Then, he adds that: "However, Hana lacks a way to retrieve the members of a struct as references currently, which will pretty much kill a Hana based Spirit effort." So the question is: will Hana support references without resorting to using reference wrappers? I do appreciate the FP nature of Hana, but please be reminded that we're in C++. I also recall some discussion that Hana also does not support Fusion-like lightweight views. Is there a plan to support them? I haven't fully investigated yet what else Hana does not support that Fusion does, but at least these two important aspects of fusion come to mind. At the very least, I don't think Hana should advertize itself as a superset of Boost.Fusion. Faster runtime performance is also questionable, when lightweight views and reference members come into play. Regards, -- Joel de Guzman http://www.ciere.com http://boost-spirit.com http://www.cycfi.com/