Re: [boost] Another variant type (was: [peer review queue tardiness] [was Cleaning out the Boost review queue] Review Queue member requirements)

Subject: Re: [boost] Another variant type (was: [peer review queue tardiness] [was Cleaning out the Boost review queue] Review Queue member requirements)
From: Antony Polukhin (antoshkka_at_[hidden])
Date: 2015-04-03 16:33:57

2015-04-02 18:38 GMT+03:00 Nevin Liber <nevin_at_[hidden]>:

> On 2 April 2015 at 08:13, Niall Douglas <s_sourceforge_at_[hidden]> wrote:
>
> > I
> > was recently working with eggs.variant for example, and that is Boost
> > quality written to Boost guidelines and yet I understand there is
> > zero interest in it entering Boost, despite it being superior to
> > Boost.Variant in almost every way.
>
>
> I don't remember anyone asking if they'd like to see this in Boost.  Could
> you point to a thread?
>
> Even though you claim it is superior in almost every way, if I'm reading it
> correctly it has one fundamental difference in that it models
> "at-most-one-of" vs. Boost.Variant which models "exactly-one-of".
>
> And yes, I would like to see it in Boost, because as variant gets proposed
> for the standard, it would be better to have a lot more user experience to
> help us decide that fundamental question.
>
> That certainly fits the current mission in that "We aim to establish
> 'existing practice' and provide reference implementations so that Boost
> libraries are suitable for eventual standardization."
>

I've been slowly improving Boost.Variant for two last years to achieve
result close to egg.variant. It is good that egg.variant exist and I'd like
to see it in Boost. Two things disturb me:
* egg.variant it requires a modern C++11 compiler in C+11 mode (Boost tries
to stick to C++98)
* egg.variant has some doubtfull places (all the comparisons of variant
with T, by index inplace constructors). This will be probably fixed during
review!

-- 
Best regards,
Antony Polukhin