[boost] Re: Re: generalization of types in variant

From: Fernando Cacciola (fernando_cacciola_at_[hidden])
Date: 2003-10-28 14:26:49

"E. Gladyshev" <egladysh_at_[hidden]> escribió en el mensaje
news:20031028185650.23854.qmail_at_web40811.mail.yahoo.com...
>
> --- Fernando Cacciola <fernando_cacciola_at_[hidden]> wrote:
>
> [...]
> > How about not requiring a visitor overload for boost::empty?
>
> Sorry, I am not sure I understand.
> Could you give some more details... piece of code?
>
What I meant is to change variant so as to treat boost::empty specially and,
for instance, never visit it.
>From the user POV, this amounts to loose the requirement that the visitor
must handle 'empty' as a visiting type.

Now, I do remember that this was originially a choice but it turned out that
instructing variant to have special knowldege of such a singular type was
very complex. I'm just suggesting that however complex it might be, seems to
solve some of this issues.

Fernando Cacciola