Re: [boost] [variant] Basic rvalue and C++11 features support

Subject: Re: [boost] [variant] Basic rvalue and C++11 features support
From: Andrey Semashev (andrey.semashev_at_[hidden])
Date: 2013-01-11 09:55:29

On Friday 11 January 2013 08:47:42 Larry Evans wrote:
> On 01/11/13 08:18, Peter Dimov wrote:
> 
> I was thinking that after the move to the target variant, the source
> variant has its tag reset to something to indicate the current type is
> this default constructable type and that type would be empty.  IOW,
> a default contructable something like:
> 
>   special_type<nothing_id>
> 
> found here:
> 
> 
> http://svn.boost.org/svn/boost/sandbox/variadic_templates/boost/composite_st
> orage/special_components.hpp

I vaugly remember that variant had a special support for type boost::blank 
that could be used as a fallback type for some operations. So if the variant 
has this type in the list of possible types the move operation could leave the 
source with boost::blank value. But that would only work if boost::blank was 
in the list.