Re: Discriminated unions?

From: brianjparker (brianjparker_at_[hidden])
Date: 2002-02-19 09:58:31

--- In boost_at_y..., Eric Friedman <ebf_at_u...> wrote:
> Has there been any progress in bringing discriminated unions (aka
> variants) into Boost?
> 
> I know Andrei Alexandrescu's paper describes how to create a variant
> type at <http://www.oonumerics.org/tmpw01/alexandrescu.pdf>, but I 
have
> been unable to find an actual source implementation that can be used
> unchanged in a application today.
> 
> The project I am currently working on would benefit greatly from a
> stable, well-tested discriminated union implementation, and so I am 
very
> eager to get my hands on such an implementation.  I would also be
> willing to assist in bringing the implementation up to Boost 
standards
> so that it could be submitted for formal review.

I have submitted a very simple discriminated union class in the files 
section in "bjp_utilities*.zip". I have a slightly newer version on 
my local machine which I will upload soon, but there are only minor 
changes.

I must say, however, that I haven't personally found much use for 
this class and so I would be interested if you find it useful. 

Other discriminated union designs discussed on this list included 
additional features such as compile-time tags to essentially 
distinguish subtypes- these may be a better fit for your needs.

Cheers,
Brian Parker