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

Subject: Re: [Boost-users] large variant performance compared (50 elements)
From: Dave Abrahams (dave_at_[hidden])
Date: 2011-01-08 17:38:26

At Sat, 08 Jan 2011 22:29:33 +0100,
Paul wrote:
> 
> 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 

Yes.  That's essentially the same problem as extracting an object from
a variant.  However, yes, if you want typesafe visitation you'd need
to build that on top, which essentially replicates logic in visitor.
In that case I would consider the shared_ptr<void> approach as a
possible future optimization but not a game changer.

-- 
Dave Abrahams
BoostPro Computing
http://www.boostpro.com