[Boost-users] Re: boost::iterator_facade problem with postfix increment proxy

From: David Abrahams (dave_at_[hidden])
Date: 2005-03-21 22:57:38

Thomas Witt <witt_at_[hidden]> writes:

> David Abrahams wrote:
>> If that's the case, the iterator_facade is choosing
>> postfix_increment_proxy instead of writable_postfix_increment_proxy,
>> on the basis of the fact that you haven't given the iterator a proxy
>> reference type.  I'm not sure I understand the logic behind it, but
>> iterator_facade assumes that if your readable iterator doesn't support
>> forward traversal, it must have a proxy reference in order to also be
>> writable.  If you have a counterexample, it would be good to see it.
>> [Jeremy, Thomas: Can you shed any light on this assumption?
>
> Sorry, but no.
>
>>  Also, it
>> looks like we left out the requirement that a single-pass iterator is
>> also an incrementable iterator.  Am I mistaken?  If not, I'd like to
>> fix the docs: http://tinyurl.com/2dm3h]
>
> Hmm, the requirements table header says:
>
> 'Single Pass Iterator Requirements (in addition to Incrementable 
> Iterator and Equality Comparable)'
>
> Isn't that sufficient?

Yup, I'm blind.

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