Re: [Boost-users] large variant performance compared (50 elements)

Subject: Re: [Boost-users] large variant performance compared (50 elements)
From: Paul (peebor_at_[hidden])
Date: 2011-01-08 16:29:33

Dave,

Another alternative would be to pass shared/base-ptr's and use 
double-dispatching to provide functions on concrete types. This however 
bothers the model-objects with visitation code; which is fine for 1 or 2 
things but very disturbing on >10 functions. With the variant you can 
move the visitation logic completely to the client/caller code, 
Hopefully its not to vague...?

Your option requires dynacasting and it doesn't allow the goodies such 
as enable-if on subsets of the variant types; which is al optimized at 
compiletime. I however agree that it's much simpler and in-fact we might 
had to explore this option more back then... ;)

Thanks for thinking along.

Paul

Op 8-1-2011 21:53, Dave Abrahams schreef:
> At Sat, 08 Jan 2011 02:17:36 -0500,
> Dave Abrahams wrote:
>>
>> At Fri, 07 Jan 2011 23:45:04 +0100,
>> Paul wrote:
>>>
>>> In a project we are using variants holding shared_ptr's. These
>>> variants are typically 20 items large but are growing as the project
>>> progresses.
>>
>> If it's really just shared_ptr's in the variant, I would seriously
>> consider replacing it with shared_ptr<void>  (with a type tag if
>> necessary).  Just a thought.
>
> Seriously, could be a big simplification and speedup vs. using using
> variant.
>
> not-going-to-mention-it-again-ly y'rs,
> Dave
>