[boost] Review Request: impl_ptr (pimpl)

Subject: [boost] Review Request: impl_ptr (pimpl)
From: Vladimir Batov (Vladimir.Batov_at_[hidden])
Date: 2017-08-15 00:51:15

After much procrastination I would like to request a formal review for 
the pimpl library... once and for all :-) (given it's been through a few 
almost-reviews and discussions)... to get some kind of a resolution one 
way or the other. :-)

On one hand it is embarrassingly simple and no match to a string of late 
TMP submissions. On the other hand it seems quite handy for ordinary s/w 
folk (like me) as it formalizes, streamlines and noticeably simplifies 
(IMO) pimpl-based deployments and makes code-review process quite simple 
and straightforward. Its benefits are more visible for pimpls with 
exclusive-ownership proxy-implementation relationships (value-semantics 
pimpls) as it uses internally an incomplete-type management smart 
pointer instead of std:unique_ptr.

Given that it is policy-based I am hoping others might get interested 
writing additional policies within that framework such as COW or 
stack-based.

The major oddity/peculiarity (that caused a stir before and Gavin 
mentioned about a year ago) is that the main class -- impl_ptr -- is 
declared in the global namespace. That might happen to be a deal breaker 
but that's the best I could come up with to get it to work. If anyone 
has a better working solution, I am all ears.

That "oddity" is an "implementation detail" and does not affect the user 
-- from the user side it appears inside boost. Like boost::impl_ptr... 
Internally to address that we might think of striking a compromise. For 
ex., instead of the traditional

namespace boost { template<> class impl_ptr }

have

template<> class _boost_impl_ptr_

Again, that is an implementation nit, wrinkle, niggle (IMO anyway). From 
the outside it all looks kosher -- boost::impl_ptr<...> and such.

The code and the docs are at https://github.com/yet-another-user/pimpl 
<https://github.com/yet-another-user/pimpl>.

Due to personal circumstances Glen -- Pimpl's original manager -- had to 
bail out. So, if anyone kindly steps forward to manage the review, 
that'd be immensely appreciated.

​Thank you,
Vladimir.​

P.S. Ron, I am only CCing you so that you'd put it to the schedule... Tnx.