[boost] Re: cycle_iterator update

From: David Abrahams (dave_at_[hidden])
Date: 2004-04-30 14:57:23

Roland Richter <roland_at_[hidden]> writes:

> Neal Becker wrote:
>
>> I like your suggestion, Roland.  Here is my adaptation (I will have to add
>> credits and copyright later).
>> It counts wraps as you suggest.  I found it easier to implement and
>> understand by basing it on an integral offset from a base.  It all becomes
>> pretty simple by calculating a "realposition" which is
>> wraps*size+position. This is like a virtual index into an infinitely
>> long sequence.
>> 
>
>   Definitely, this solution is elegant and better readable. Plus, it
>   passes the test I use for cyclic_iterator (in the sandbox) after
>   a minor modification:
>
>   For unknown reason, MSVC chokes on
>
>     typename std::iterator_traits<BaseIterator>::value_type
>
>   twice ('iterator_category' : is not a member of 'operator``global amespace'''),
>   but accepts
>
>     typename boost::iterator_value<BaseIterator>::type

Right.  iterator_value uses boost::iterator_traits, which contains
bajillions of workarounds for vc6/7 inadequacies.

>
>   I suggest to add your implementation to Boost.Iterator! Does this
>   require a review, or mini review, if there is something like that?

A review would help, but isn't strictly neccessary.  It requires at
least some extra confidence on my part.  If cycle_iterator is
thoroughly tested, including concept checks, and the documentation is
readable and complete, that will go a long way.  I don't know the
current status of these things...

-- 
Dave Abrahams
Boost Consulting
http://www.boost-consulting.com