Re: [Boost-users] [Fusion] Views of Associative Sequences

Subject: Re: [Boost-users] [Fusion] Views of Associative Sequences
From: Joel de Guzman (joel_at_[hidden])
Date: 2009-10-15 19:23:46

Christopher Schmidt wrote:
> James Knight schrieb:
>> I'm trying to find a solution to the following problem.  If I have an 
>> associative sequence such as a fusion::set
>> and I make a filter view of it, the view is not a model of an 
>> associative sequence and does not support the
>> has_key and at_key functions.  I can use fusion::as_set on the view to 
>> get an associative sequence again, but
>> this doesn't really have the effect I want as it results in a set 
>> holding copies of the original data whereas the
>> view referenced the original data.  Example below.
>>
>> Would it be possible to create a view which supported the associative 
>> sequence interface?   Any suggested alternative approaches?
>>
>> Thanks
>> Nate
> 
> There is already a feature request for associative views (ticket 3473). 
> I will get down to it once I am granted write access to the trunk.
> For now you could use my c++0x port of fusion. It correctly preserves 
> the category of the underlying sequence's for all views.
> The port is fully backwards compatible, in terms of both features and 
> compiler (non-0x compiler are supported).
> You can find the code in the sandbox (/sandbox/SOC/2009/fusion/).

And in case you are wondering, Christopher Schmidt's wonderful
c++0x port will be the future of fusion.

Regards,
-- 
Joel de Guzman
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