[boost] Re: graph structure interface (proxies and forward iterators)

From: Herb Sutter (hsutter_at_[hidden])
Date: 1999-12-08 10:45:44

Gret wrote:
>From: Herb Sutter <hsutter_at_[hidden]>
>> Greg wrote:
>> >I'm not sure whether we have a library issue or not,
>>
>> Yes, but the issue is with vector<bool>, not with the iterator requirements.
>
>But vector<bool> can't be fixed, and can't be killed either.

Yeah. Bummer, eh? (This isn't a facetious comment: To harmonize the standard, we
must  fix the container/allocator/iterator requirements, fix vector<bool>, or
kill vector<bool>. Those options are presenting in decreasing order of
difficulty. The first is impossible and will never happen IMO; hence "bummer,
eh?" that the only other two options "can't" be done.)

>I don't mind breaking libraries if it will help users, and I suspect
>that such libraries will eventually cone afoul of their users, if not
>the standard.

Neither do I, and Howard has already posted an anecdotal existence proof for
this problem, respectively.

>Just because we relax requirements on the iterators doesn't mean
>we have to relax them on the containers.  I'm wanting to give more
>leeway to users of the algorithms, not to implementors of the
>standard.

If you can come up with a change proposal that won't break user code, I'm sure
the LWG will be interested. I'm not arguing against this, I'm merely trying to
point out and describe the problem.

Herb

---
Herb Sutter (mailto:hsutter_at_[hidden])
CTO, PeerDirect Inc.                       (http://www.peerdirect.com)
Head of Delegation (Canada), ISO SC22/WG21 (ISO C++ standards committee)
Editor-in-Chief, C++ Report                (http://www.creport.com)
Moderator, comp.lang.c++.moderated         (news:comp.lang.c++.moderated)