[boost] Re: Variant (aka Discriminated Union) implementation

From: Itay Maman (itay_maman_at_[hidden])
Date: 2002-07-04 18:14:11

"Eric Friedman" wrote:[snip]> 
> * Generic visitation by any functionable object.
> 
>   This is *very* powerful; nearly all of variant's internal features
>   are implemented in terms of generic (templated) visitation.
> 
(1) A short comment regarding proper credits: The technique of using the type index for selecting the correct 'variant-to-visitor bridge' functionwas first introduced in my post: http://lists.boost.org/MailArchives/boost/msg30415.php. At the same discussion, Doug Gregor made the suggestion, that operator() will be used as the visitor's 'visit_me()' function.  The initial inspiration came from the vtable idiom described at Andrei
Alexandrescu's paper: "An implementation of discriminated unions in C++".  (2) I'd like to repeat my view: given the fact that the two varaint implementations are getting more and more identical, the two implementations should be integrated into single library. I still believe that the most effective approach, would be for us to co-develop this (unified) variant library. -Itay 

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