[boost] Some statistics about the C++ 11/14 mandatory Boost libraries

Subject: [boost] Some statistics about the C++ 11/14 mandatory Boost libraries
From: Niall Douglas (s_sourceforge_at_[hidden])
Date: 2015-05-13 12:19:38

Tomorrow at 11am after Eric's talk I'll be presenting at C++ Now a 
review of the upcoming C++ 11/14 mandatory Boost libraries. I looked 
at fifteen libraries and decided ten were worth further 
investigation. I'm sure you all remember my colour coded ranking of 
those ten libraries by "nearness" to entering Boost:

https://goo.gl/6l1KiH

I sadly only have time to review four of those libraries during my 
talk, but one (APIBind) enables an alternative Boost 2.0 approach and 
I will spend 45 mins on that library alone. And here is my 
alternative Boost 2.0 vision:

Boost 2.0 is a alternative distro of modular standalone Boost 
libraries which can be each downloaded separately. Each has 
contemporary per commit CI testing and is nightly dashboarded by 
quality score by a web service under the 19 quality score headings 
listed at https://svn.boost.org/trac/boost/wiki/BestPracticeHandbook 
(still unfinished, but nearly there).

APIBind allows the library end user to dependency inject what 
dependencies that library uses. This allows a Boost library, in a 
single codebase, to be part of both the monolithic Boost 1.x distro 
and to be modular and standalone and part of the Boost 2.x distro. 
Motivated library maintainers port their Boost 1.x library to the 
APIBind platform, and therefore can be part of both 1.x and 2.x 
distros if they want.

Those libraries not ported to APIBind remain in the 1.x distro, which 
I would assume will gradually fade into obsolescence over time. This 
makes sense, as if a maintainer is not motivated to do the port then 
it seems proper that library should gracefully deprecate.

There is some empirical data supporting the inevitability of this 
alternative vision of Boost 2.0. Of the ten libraries I examined in 
any detail:

* Just 1.5 libraries have any dependencies on Boost headers at all 
(the 0.5 is because that library is currently removing its Boost 
dependencies).

* Just 3 libraries can use Boost.Test.

* Just 3 libraries use Boost Docs.

* Just 2 libraries require using Boost.Build. The rest are header 
only, or use cmake.

* Just 6 libraries use Travis/Appveyor for free CI testing on Linux, 
OS X and Windows.

* Just 3 libraries use valgrind as part of their unit testing (two 
are mine!).

* Just 3 libraries use coveralls for coverage reporting (two are 
mine!).

Personally speaking, I think the new library authors are 
overwhelmingly voting for a complete break with Boost 1.x. It makes 
no sense to bundle these new libraries into a 1.x monolithic distro 
when they have no dependencies on Boost.

I believe now is the time we start establishing the infrastructure to 
shape the new Boost 2.0 distro instead of wasting resources on trying 
to refactor the 1.x distro. APIBind is there for maintainers wanting 
to be part of both distros. Let's make a clean break.

Niall

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