Re: [boost] [variant] awkward recursion

Subject: Re: [boost] [variant] awkward recursion
From: Steven Watanabe (watanabesj_at_[hidden])
Date: 2012-10-29 18:45:20

AMDG

On 10/29/2012 02:59 PM, Mathias Gaunard wrote:
> On 29/10/12 22:33, Dave Abrahams wrote:
>>
>> 
>> As I had feared, and as
>> http://news.gmane.org/find-root.php?message_id=%3cm2objlggaw.fsf%40pluto.luannocracy.com%3e
>>
>> demonstrates, extra dynamic allocations will be used to store maps and
>> vectors (or anything at all?) in the variant.
> 
> Why not fix the implementation then instead of writing hacks?
> 

There's no automatic way around dynamic allocation.

a) vector<variant<...> > requires variant to be complete.
b) variant<std::vector<...> > requires vector to be
   complete because it needs to know the sizeof(std::vector<...>).

The only way to break the cyclic dependency is
to make the size of variant not depend on the
size of the vector.

> Of course, the code of variant is horrible enough to make it very
> difficult to do anything with it.
> 

In Christ,
Steven Watanabe