Re: [boost] [fusion] is there an adapter for C-arrays?

Subject: Re: [boost] [fusion] is there an adapter for C-arrays?
From: Christopher Schmidt (mr.chr.schmidt_at_[hidden])
Date: 2010-02-07 16:02:24

vicente.botet schrieb:
> 
> ----- Original Message ----- 
> From: "Christopher Schmidt" <mr.chr.schmidt_at_[hidden]>
> To: <boost_at_[hidden]>
> Sent: Sunday, February 07, 2010 8:45 PM
> Subject: Re: [boost] [fusion] is there an adapter for C-arrays?
> 
> 
>>
>> vicente.botet schrieb:
>>> ----- Original Message ----- 
>>> From: "Christopher Schmidt" <mr.chr.schmidt_at_[hidden]>
>>> To: <boost_at_[hidden]>
>>> Sent: Sunday, February 07, 2010 2:19 AM
>>> Subject: Re: [boost] [fusion] is there an adapter for C-arrays?
>>>> vicente.botet schrieb:
>>>>>> On 2/7/2010 3:34 AM, vicente.botet wrote:
>>>>>>> Hi,
>>>>>>>
>>>>>>> I need to visit the members of a C++ type using Fusion sequences. For structures I plan
>>>>>>> to use BOOST_FUSION_ADAPT_STRUCT. I need also to visit also c-arrays (with static
>>>>>>> size). I see that there is already an adapter for boost::array. Is there an adapter for
>>>>>>> C-arrays?
>>>>>>
>>>>>> Sorry, no. Would you want to contribute one? It's easy if you
>>>>>> take a look at the boost::array adapter.
>>>>>
>>>>> Hi, 
>>>>>
>>>>> Well if doesn't exists I will need to see how to do it :) I will inform you when I reach to get something.
>>>>
>>>> I just added an implementation for adapting plain arrays to the c++0x
>>>> branch of fusion. You can find the code here:
>>>>
>>>> https://svn.boost.org/trac/boost/browser/sandbox/SOC/2009/fusion/boost/fusion/adapted/array.hpp
>>>> https://svn.boost.org/trac/boost/browser/sandbox/SOC/2009/fusion/boost/fusion/adapted/detail/po_array
>>>>
>>>>>
>>>> [snip]
>>>>>
>>>>> Is there a simple way to implement this flat view? Or even better, is it already available?
>>>>
>>>> It is. 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
>>>>
>>>> -Christopher
>>>
>>> Hi,
>>>
>>> thanks for all these pointers. I was starting to implement it,when DING, your post appeared. I'm sure I would made  a lot of errors before reaching to run the test.
>>
>> I ported my code to the trunk. Update to the HEAD and include
>> <boost/fusion/adapted/array.hpp> in your code.
>>
>>> Do you know if it is planned to document the tree extension soon? Is there any post about this subject?
>>
>> 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. For more information, see the old posts
>> in the archives.
>>
>> http://lists.boost.org/Archives/boost/2006/09/110708.php
>>
>> As the code is broken, undocumented and may change in the future, I
>> suggest you to connect your fusion sequences recursively via
>> fusion::fold and fusion::join.
>>
>>> Just a remark most of the .hpp files on po_array are not self contained as the structure po_array_tag is not declared in th file.
>>
>> the *.hpp-files in the detail folder are not meant to be included by the
>> user. po_array_tag is defined in /detail/tag_of.hpp, which is always
>> included by array.hpp before any other /detail/*_impl.hpp-header.
>>
>> -Christopher
>>
> 
> Hi, 
> 
> I've the impression you have introduced a interface break as before the array directory was for boost_array, and now is for POD arrays?

I moved the functionality for boost::array to boost_array.hpp .
boost_array.hpp is included by array.hpp though.

https://svn.boost.org/trac/boost/browser/trunk/boost/fusion/adapted/array.hpp#L12

By the way, I did not document my changes. I would like to wait for an
approval by Dan or Joel before introducing this new feature.

> I would prefer a hierarchycal directory
> 
> fusion/adapted/boost/array.hpp
> fusion/adapted/boost/mpl.hpp
> fusion/adapted/boost/tuple.hpp
> fusion/adapted/boost/detail/array
> fusion/adapted/boost/detail/mpl
> fusion/adapted/boost/detail/tuple
> fusion/adapted/builtin/array.hpp 
> fusion/adapted/builtin/struct.hpp
> fusion/adapted/builtin/detail/array
> fusion/adapted/builtin/detail/struct
> fusion/adapted/std/pair.hpp
> fusion/adapted/std/detail/pair
> 
> The old files can be made deprecated includig the new ones.

I used file prefixes in the c++0x port (array.hpp, boost_array.hpp,
std_array.hpp) to distinguish between specific types and/or namespaces.
>From a plain technical point of view this is a more convenient as the
detail implementation of certain types may be shared across namespaces.

https://svn.boost.org/trac/boost/browser/sandbox/SOC/2009/fusion/boost/fusion/adapted

-Christopher