Dear Boost, As some may be aware of, I am currently working on a metaprogramming library called Hana, with the intention of proposing it for inclusion in Boost. The purpose of that library is to act as a toolbox for expressing computations on both types (like the MPL) and heterogeneous values (like Fusion). The library is built around C++14 idioms and implementation techniques to maximize expressiveness and performance. I am now requesting feedback from the community, with the intention of asking for a formal review in the next months. A similar review was asked for in last August. The library has undergone several modifications since then, both to address issues raised during the review and for general improvement. Here are some issues that were raised during the review and addressed: - Usage of names and terms unknown to C++ programmers: Efforts were made to make this better, and several functions were renamed (`fmap` is now `transform`). When possible, the documentation also uses terms more familiar to C++ programmers, like concept instead of "type class". - The order of the arguments to some algorithms was unfortunate for C++. It was consistent with Haskell, but it turned out to be cumbersome in C++. This is changed in most places. - Inability to easily implement individual algorithms: This is fixed, and algorithms are now standalone structures using tag-dispatching, almost exactly as in Fusion. - Lack of a good introductory tutorial: A lot of work has gone into improving both the tutorial and the reference documentation. - Lack of support for mainstream compilers: The library is now almost fully functional with Clang 3.5. A GCC 4.9 port with reduced functionality is also underway on the `redux` branch. The library is available at [1] and the documentation at [2]. Comments should be directed to this mailing list, while bugs and other similar problems should be directed to the GitHub issue tracker. Please participate, especially if you have interest and/or experience in metaprogramming; after all, you represent the target audience for Hana. Thank you, Louis Dionne [1]: https://github.com/ldionne/hana [2]: http://ldionne.github.io/hana/