[boost] Re: Variant size bug?

From: Eric Friedman (ebf_at_[hidden])
Date: 2003-11-03 20:57:04

David Abrahams wrote:

> Eric Friedman <ebf_at_[hidden]> writes:
> 
> 
>>I think the benefits of the variant< type-seq > syntax as equivalent
>>to variant< type-seq[0], type-seq[1], ... > far outweigh the benefits
>>of making variant directly store what should in my opinion be an empty
>>type.
>>
>>IMO, all templates with 'variadic' template parameter lists should
>>adopt this F< type-seq > == F< type-seq[0], type-seq[1], ... >
>>convention.
> 
> Interesting idea.  But in the end, types should be types should be
> types.  I don't want types with special properties having unique
> behavior when used as template parameters.  That would eventually
> break all generic metaprogramming.

I think that may be a bit extreme. Type sequences seem to me a rather 
unique exception...

> Consider the syntax currently being discussed by the committee for
> doing the same sort of thing with tuple types at runtime:
> 
>       f(some-tuple...)
>       == f(at<0>(some-tuple), at<1>(some-tuple), ... )
> 
> That would lead to:
> 
>      F<type-seq...>
>      == F< type-seq[0], type-seq[1], ... >
> 
> I rather like that symmetry.

Wait, so does this mean you agree or disagree with me? I'm confused.

Eric