[boost] Re: Proposal --- A type-safe union

From: Itay Maman (itay_maman_at_[hidden])
Date: 2002-06-13 07:57:45

Peter Dimov wrote:
> From: "Itay Maman" <itay_maman_at_[hidden]>
> 
>>The variant implementation relies on the ability to map concrete types 
>>to integers. My implementation uses the index_of TypeList algorithm, for 
>>instance.
>>
>>So, unless we'll come-up with some birlliant way to do this mapping 
>>differently, we will not be able to implement a variant whose list of 
>>legal (concrete) types is 'open'.
> 
> 
> It is possible to implement an 'open' list via inheritance.
> 

Sure, but this is intrusive (which is unacceptable for a variant class), 
isn't it?

-Itay