Tagging the minimum C++ standard level for Boost libs

From: Edward Diener (eldiener_at_[hidden])
Date: 2020-12-15 17:12:42

I had previously proposed that we tag the minimum C++ standard level for 
Boost libs by adding information to the json meta information in 
libraries.json for each library. I would like to revisit that proposal, 
which involved more elaborate suggestions, with this simpler overall 
proposal: for each Boost C++ library whose minimum C++ standard level is 
C++11 or above we add a json field called 'cxxstd' whose value 
corresponds to one of the same values as currently exists in Boost.Build 
for the 'cxxstd' feature, ie. 11,14,17,20, to the libraries.json file 
for that library. This json value can then be used in Boost 
documentation of each library to specify the minimum C++ standard level 
needed by an end-user in order to use that library. Obviously we can 
also add "cxxstd": "03" for the many Boost libraries which can still be 
used at the C++98/C++03 compilation level also, even though I would 
argue that not having a "cxxstd" json field should mean C++98/C++03 by 
default. I would be willing to create the necessary PRs for each 
library, as I have a pretty good internal list of this information.

The gist of this proposal is to make it much easier for end-users 
wishing to use a Boost library to immediately know whether the library 
they wish to use is usable at the C++ standard compilation level they 
are using for compilation, without having to spend time searching for 
such information, which is often not readily available, in the 
documentation of the library they are considering.

I can go ahead and start doing this now, but of course I am willing to 
listen to what others think about this. But let's not let another round 
of inertia stop doing at all what should be a simple means of telling 
end-user's whether a Boost library is at least minimally usable by them 
in their C++ projects.