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Subject: Re: [boost] [fusion] is there an adapter for C-arrays?
From: Eric Niebler (eric_at_[hidden])
Date: 2010-02-07 17:30:51


On 2/8/2010 6:45 AM, Christopher Schmidt wrote:
>>> Check the (undocumented) code in the ext_-directories.
>>>
>>> https://svn.boost.org/trac/boost/browser/trunk/boost/fusion/container/ext_/tree.hpp
>>> https://svn.boost.org/trac/boost/browser/trunk/boost/fusion/algorithm/iteration/ext_/for_each_s.hpp
>>>
>>> Unfortunately the code is pretty much broken at the moment.
>>>
>>> https://svn.boost.org/trac/boost/ticket/3858
<snip>
>
> The segmented extension is pretty much proto specific in its current
> form. From my limited point of view, it still needs some work in order
> to be a useful component aside of Spirit/Proto-alike use-cases.
> Unfortunately Eric Niebler, the original author, has not continued
> development on this extension.
<snip>

Here's the deal: the code needs a complete rewrite. The original idea
was to make it vastly simpler to adapt a segmented data structure to
Fusion and greatly lower the burden Fusion algorithms place on
compilers. The problem is that -- for decent compile times -- it
requires a separate segmented version of every Fusion algorithm, which I
never got around to. Also, the segmented view is forward, and had I done
it right, it would be bidirectional. Then the Fusion code base shifted
and broke the extension.

In all my days of writing code, 2 coding problems stand out as
particularly difficult: reference tracking of xpressive::basic_regex,
and Fusion's segmented extension. To rewrite Fusion's segmented
extension, I'll need several weeks of free time, which I just haven't
had. I've always meant to get back to it, and still hope to.

-- 
Eric Niebler
BoostPro Computing
http://www.boostpro.com

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