[boost] Re: Re: Using variant library with Boost 1.30.0

From: Eric Friedman (ebf_at_[hidden])
Date: 2003-04-04 19:09:11

Allen Bierbaum wrote:
> Eric Friedman wrote:
> > Allen Bierbaum wrote:
> >
> >>I have been very impressed with the Variant library and started using it
> >>with Boost 1.29.
> >
> >
> > Good to hear. I'd be interested in your experience using the library in
a
> > real-world (?) application.
>
>
> I was able to get variant working with 1.30 by pulling some of the code
> out of the sandbox.

Good to hear.

> I have started using it in my application and have run into one major
> limitation: variant size  (in number of allowed types)
>
> I need to use a variant of about 15-20 allowed types.  By default
> variant only works with 10 types.
[snip: longer lists]
> What do you think, are either of these two options feasible (or is there
> already support for it that I missed)?

The support is present, but it was not publicized during the review (since
mpl::is_sequence from 1.30 is required, and 1.30 had not been released):

  variant< mpl::list27<T1, T2, ..., T27> >  // ...or mpl::vector27, etc.

Note, however, that such support, while present, is experimental, and it has
not been tested much. The feature will definitely appear when variant is
released though.

 - Eric