This new maintainer of Spirit has bumped up the language requirements to C++23, for what is in my opinion a gratuitous reason. To serve the widest audience I think it is best when libraries use the lowest version of C++ which is practical, and only adopt new language features when doing so improves the public API or offers a significant benefit to the user experience. While it is true that newer language features can make it easier for the maintainer to express the implementation, we make sacrifices (like writing `typename...type` instead of using the newer type trait aliases) for the convenience of users. This bump to C++23, which came without warning, has affected Boost.MQTT5 which must now scramble to fix itself before the next release. There should have been a warning for a version first. The Spirit author's rationale can be seen in this GitHub issue: https://github.com/boostorg/mqtt5/issues/36 Quoted here for convenience:
There's one political reason that I didn't mention: young people. Why would a high school student who likes to experiment with C++ consider some obsolete (C++17) library as attractive? Boost is dying and we're doomed if we don't use bleeding edge features to attract young people. You might think this is some kind of joke but I believe this is the right way to proceed.
Young people will avoid contribution to the existing library if it sticks to the C++ standard that is now obsolete for 2 versions. That was my feeling when I saw a C++03 library when I was a high school student. I'm 30 years old now and still think the same.
My goal is to revitalize C++. It is impossible without gathering contributions from the young people. Some people write C++ for business, while some people write C++ because it's genuinely fun to hack. That's the difference. It's the same reason that Rust is getting wider audience than C++.
Many Japanese University students think otherwise. I have active connections to the young community and they actually empathize with me. Thanks for the video anyways, that is a good evidence that western, agitated-by-businessman young people are very different than my colleagues.
Thanks