Re: [boost] Re: Variant size bug?

From: Peter Dimov (pdimov_at_[hidden])
Date: 2003-11-15 10:45:25

David Abrahams wrote:
> "Peter Dimov" <pdimov_at_[hidden]> writes:
>
>>>> 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.
>
> I'm confused about what you mean.  Isn't that the one we already have?

We have

    variant<T1, T2, ..., Tn>

and

    variant<mpl-seq>

There are two problems with it. First, there is a collision when n == 1.
Second, if I write

    template<class Seq> void f( variant<Seq> const & v );

my function will not match all variants. I think that the correct but
painful thing to do is to just drop the convenience T1..Tn form.