Re: [boost] [Hana] Formal review

Subject: Re: [boost] [Hana] Formal review
From: Joel de Guzman (djowel_at_[hidden])
Date: 2015-06-17 20:38:23

On 6/18/15 3:55 AM, David Sankel wrote:
>> You are strongly encouraged to also provide additional information:
>> >- What is your evaluation of the library's:
>> >   * Design
>> >
> The core technique of combining value and type expressions is solid and
> makes metaprogramming easier and, as a bonus, improves compilation speeds.
>
> My one question, as I read though the implementation, is "can the core
> benefits of this library be achived with a simpler 'light' version of this
> implementation?". While I appreciate the attempt to encode a Haskell-style
> typeclass hierarchy, I feel like that is not the core competency of hana
> and should be a separate library and discussion. As it is, this is a 32k
> header mega library. I'd prefer several small, highly-targeted,
> highly-composable libraries.

I still need to find time to make a formal review, but allow me to concur
with this sentiment. Hana is a nice library, well implemented and executed.
I'd vote yes for its acceptance into boost. But will I use it? That's a
negative. I share the same opinion as Peter Dimov, and Eric Niebler that
C++11 makes it very (extremely!) easy to do TMP. I'd prefer to use a very
small TMP library like Peter's or Eric's with a very small (close to zero)
conceptual overhead, or none at all. My current inclination is to use Eric's
Tiny Metaprogramming Library. In my opinion, less is more in modern post
c++11 TMP.

Regards,
-- 
Joel de Guzman
http://www.ciere.com
http://boost-spirit.com
http://www.cycfi.com/