Re: [boost] New Library Proposal: dual_state

From: Calum Grant (calum_at_[hidden])
Date: 2005-07-16 13:50:47

Andrey Melnikov wrote:
> Calum Grant wrote:
> > Andrey Melnikov wrote:
> >>
> >>I hate extra dynamic memory allocation even more than I hate extra
> >>copies, because the former cannot be optimized out and 
> usually takes 
> >>more time than 10 extra copies. Well, pool allocators help a lot 
> >>sometimes, but it's an optimization technology.
> >>
> >>I like Boost.Optional because it offers a good way to deal with
> >>optonality without any extra pointers, memory allocations, special 
> >>"NULL" values or construction or copy operations . I think it's way 
> >>different from the concept of smart pointers.
> > 
> > 
> > But we're talking about private implementation.  From a semantic 
> > perspective, Optional behaves like a smart pointer with a "copy on 
> > assign" policy.  Perhaps there would be fewer howls of 
> disapproval if 
> > I called it a smart container, not a smart pointer.
> 
> It's just a terminology question. Boost.Optional isn't a 
> "pointer". It 
> isn't an enhanced C pointer, it isn't used like a pointer, it doesn't 
> use pointers internally. It can be "dereferenced", but it's just a 
> syntactic feature.
> 
> Also it isn't a container in STL sense. It doesn't provides range 
> interface, iterators etc.
> 
> I would call Boost.Optional a proxy.

Perhaps a broker.

> > 
> > If an implementation improves a smart container/pointer in this 
> > circumstance then that's fanstastic.
> 
> I don't understand you here.

All I'm saying is that one could regard in-object storage as an
optimization over out-of-object storage, which is a "good thing".

Calum