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Subject: Re: [boost] Review request for variant2, review manager wanted
From: Niall Douglas (s_sourceforge_at_[hidden])
Date: 2019-02-23 23:34:00


>> The main appeal for me is the well-designed avoidance of the valueless-
>> by-exception state.
>
> 2009: Boost library components often form the basis of new standard
> library components
>
> 2019: Standard library components often form the basis for new,
> improved Boost components

If I remember rightly, former senior Boost folk tried to stop
std::variant shipping with its valueless-by-exception design,
demonstrating that it could be easily avoided using a fallback to a
double buffer design.

WG21 were so keen to ship variant in C++ 17 that those concerns, amongst
others since defect remedied, were brushed off, and we are where we are
at. It could be worse.

I think it's entirely right and proper that Boost ought to ship fixed
standard library types where possible. In many ways, Boost always has -
std::deque is not useful in portable code, whereas Boost's containers
have the same behaviours everywhere. I'd just love if WG21 would
deprecate the current containers, and standardise new non-allocator
intrusive ones instead, perhaps with an inefficient convenience wrapper.

Niall


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