On Wed, Dec 2, 2020 at 6:21 AM Edward Diener via Boost < boost@lists.boost.org> wrote:
Feel free to offer PRs to those C++98/C++03 libraries to transition them from MPL to mp11 and from Boost type traits to standard type traits so that they can become C++11 libraries. I do have the greatest admiration for mp11 so I am not being facetious. But "banning" MPL and Boost type traits is going to currently remove a great number of libraries from Boost. I do agree that a bottom up approach is necessary to transition Boost libraries to C++11 since a given Boost C++98/C++03 library has dependencies on other Boost C++98/C++03 which themselves use the Boost rather than the equivalent standard library.
This is the best approach, but it won't go anywhere because it requires a lot of work and not enough upside (or else it would have been done already). People who want to ban MPL or any other library are effectively admitting they have no skin in the game (they don't use it). We should hear from actual users, but we won't; they don't have a problem to complain about, because we have not broken their code yet. We should keep it that way.