Re: [boost] Re: In-place construction for variant

From: E. Gladyshev (egladysh_at_[hidden])
Date: 2003-10-28 01:42:22

--- David Abrahams <dave_at_[hidden]> wrote:
[...]
> Umm.  OK, I guess that one works for the basic guarantee, though it's
> weird because the heterogeneous assignment only gives the basic
> guarantee when it could give the strong guarantee at similar cost.

A policy? :)

[...]
> 
> >
> > If the variant doesn't have any guarantees about 
> > the storage location of the controlled object,
> 
> ...like the stability of that location...

That's right.

> 
> > it seems that it is possible to create a heap
> > copy of the *lhs* not *rhs* and try to allocate
> > *rhs* in-place. If it is true, it seems that 
> > the current implementation is more efficient 
> > in terms of memory fragmentation (create a temp. *lhs* 
> > and if everything is fine, delete it).  
> 
> Oooh, now I understand.  Actually that's clever.  OK, sorry Eric; nice
> job!

Yeah, nice job!. I have been using variant 
a lot recently. I am quite happy with that.
variant has so many neat applications
that I think it will become the next most
widely used run-time class after shared_ptr. :)
It is important to get it right.
My guess is that we are almost there.

It seems that Eric has an interesting idea
about having const_variant at the variant's core.
Don't know the details but I hope it won't change 
the existing memory allocation/deallocation 
strategy to the "worse".

Eugene

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