Re: [boost] [fusion] segmented sequences [ was Re: [fusion] ftag ]

From: Joel de Guzman (joel_at_[hidden])
Date: 2006-09-26 01:04:19

David Abrahams wrote:
> Joel de Guzman <joel_at_[hidden]> writes:
> 
>> joint_view is a prime example of a segmented sequence. The resulting
>> iterators from it will have some overhead. That is inevitable.  See
>> joint_view_iterator so you'll know what I mean.
> 
> I don't get it.  Fusion iterators know their position at
> compile-time.  Why should there be any overhead?

joint_view_iterator needs to store these info:

a) an iterator from the first sequence (left)
b) an iterator from the second sequence (right)

then, if you have a stacked joint_view_iterators, the outermost
joint_view_iterator will be quite hefty.

I wonder if there's a better formulation other than segmented
iterators. Hmmm... yeah, there might be room for optimization.

Regards,
-- 
Joel de Guzman
http://www.boost-consulting.com
http://spirit.sf.net