Re: [boost] [GSoC][MPL11] Post C++Now update

Subject: Re: [boost] [GSoC][MPL11] Post C++Now update
From: Larry Evans (cppljevans_at_[hidden])
Date: 2014-05-20 14:59:24

On 05/18/14 15:41, Louis Dionne wrote:
> Dear Boost,
>
> A lot happened during the past week in Aspen; the goal of this message
> is to summarize insights, changes and feedback received wrt MPL11.
>
> The slides of the presentation are available at [1]. The second part of
> the presentation is especially relevant to get an overview of the designs
> considered so far.
>
>
> Merging the MPL and Fusion
> --------------------------
> After discussing the issue several times during the week, I (and others)
> think it might be possible to merge Fusion and the MPL into a single
> library. I am currently trying to write a library that does that. Since
> this constitutes a large reorientation, I created a new repository which
> is available at [2]. Those with interest should consider subscribing to
> the repository to be updated as I make progress.
>
>
> Iterator-free design
> --------------------
> I was a bit anxious that people would complain about this, but the contrary
> happened. Nobody complained and some people expressed support. This design
> aspect will stay as-is.
>
>
> Request for guinea pigs
> -----------------------
> I am looking for people with hardcore C++1y metaprogramming needs who will
> be willing to test the library I come up with (MPL11 or MPL + Fusion merge).
> I also need to see use cases for the library, so please reply even if you
> are not willing to test.
>

As mentioned in this post:

https://groups.google.com/forum/?hl=en#!msg/comp.std.c++/_-6X_xZlKlA/-HhvKh5ccEAJ

One use case is:

 > 3) A guaranteed non-recursive way to access elements of parameter
 > packs

and Doug Gregor (quoting from above post) says:

   This is probably the most-requested feature for variadic templates,
   and it never it made it because we never found a good, unambiguous
   syntax.

The attached seems to do that.  What about adding something
like this to the library?

-regards,
Larry