Re: [boost] [containers] Are there flat_map/set and stable_vector proposals at work?

Subject: Re: [boost] [containers] Are there flat_map/set and stable_vector proposals at work?
From: Rob Stewart (robertstewart_at_[hidden])
Date: 2013-10-24 05:16:55

On Oct 23, 2013, at 11:57 AM, Klaim - Joël Lamotte <mjklaim_at_[hidden]> wrote:

> On Wed, Oct 23, 2013 at 5:07 PM, TONGARI J <tongari95_at_[hidden]> wrote:
> 
>> I wonder if we can choose the underlying container for flat_xxx, for example, use deque instead of vector.
>> Or would it be better to make them as adaptors?
> 
> That would be a different question for the container implementor.

It can, and possibly should, be in the hands of the user. After all, one selects flat_map over map, for example, for performance reasons.

> Experience shows that having the implementation type as a parameter is rarely a good idea.
> Having a vector as implementation is far enough for me right now but I don't really care as long as the flat_* behaviour and performance are
> similar.

Is that general experience, or just yours?

> I'm not sure what a deque would enable in this case.

The same things deque offers over vector normally: VM-friendly allocations and growth at front and back without copying.

If one reserves enough space up front, there's benefit in vector. If allocating on demand, deque can be better.

___
Rob

(Sent from my portable computation engine)