Re: [boost] Re: Variant size bug?

From: Peter Dimov (pdimov_at_[hidden])
Date: 2003-11-04 08:26:41

David Abrahams wrote:
> "Peter Dimov" <pdimov_at_[hidden]> writes:
>
>> David Abrahams wrote:
>>>
>>> My feeling is that the most-principled (if not most-convenient)
>>> design for variant would change the current usage
>>>
>>>    variant<some-mpl-type-sequence>
>>>
>>> into
>>>
>>>    variant<variant_types<some-mpl-type-sequence> >
>>>
>>> and leave
>>>
>>>    variant<some-mpl-type-sequence>
>>>
>>> for the case where you actually want an instance of
>>> some-mpl-type-sequence in the variant.
>>
>> Or variant_from_sequence<mpl-seq>::type?
>
> OK, sure.

I take it back. The only correct interface is variant<mpl-seq>, without the
variable-length enhancement. The question is when will we bite the bullet
and adopt it since it does make life harder for many users.

While on the variant subject, why would anyone want to use the variant<>
special case (as it's not a variant)? I don't even see the usefulness of
variant< mpl::list<> > being special cased.