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

From: David Abrahams (dave_at_[hidden])
Date: 2006-09-26 17:09:38

Joel de Guzman <joel_at_[hidden]> writes:

> 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.

OK, understood.

-- 
Dave Abrahams
Boost Consulting
www.boost-consulting.com