For personal reasons I will not be able to participate in Boost as I have in the past, which means I will no longer be able to be part of CMT. I will continue to maintain the libraries I created for Boost, tti and VMD, as well as maintaining the preprocessor library created by Paul Mensonides. This means that I will not have the time or the will to be involved with other libraries any more, except on the most general level of discussion. For what it is worth I think that Cromwell Enage should become the maintainer of the Parameter library. I have not, and still do not understand, why when talented C++ programmers are willing to contribute heavily to Boost they are not encouraged and supported more. But this is not my problem. For those who are interested, the experimental C++ standard preprocessor which had been added for VC++ in VS2017 via the '/experimental:preprocessor' switch is still supported in VS2019, although not documented anywhere in the official VS2019 docs. Ths VC++ experimental preprocessor is fully supported in Boost PP and Boost VMD. Unfortunately this preprocessor can not pass all the Boost PP tests, although it has gotten a little better in VS2019 from VS2017. I posted bug reports in Microsoft's bug reporting system regarding its bugs. I have not bothered to test it with the VMD tests, since if it can not pass all the PP tests it is not going to pass the VMD tests. Also while clang on Windows, whether targeting gcc or VC++, passes all the Boost PP tests it fails to pass the VMD tests with lots of errors, seemingly because it is running out of memory ( ? ). I have not bothered reporting this to clang, since my previous experience has shown me that they are clearly not that interested in their Windows implementation. Both gcc on both Linux and Windows, and clang on Linux, pass all the Boost PP and VMD tests. Of course you can try all this out for yourself if you are interested. Edward Diener