Re: Interest for C++20 modules support of boost officially

From: Dominique Devienne (ddevienne_at_[hidden])
Date: 2024-12-19 11:51:10

On Thu, Dec 19, 2024 at 10:27 AM Peter Dimov via Boost
<boost_at_[hidden]> wrote:
> Chuanqi Xu wrote:
> > But another concern is, given boost (or any other library) should be accepted
> > by other compilers and older clang. Then how could we put `export` in the
> > sources directly? Didn’t we have to use yet another macro to handle this?
>
> That's a good point, yes. Since in pre-20 mode we have to remove the `export`
> anyway, there's perhaps not much point in having ignorable `export`.
>
> Or... maybe there still is, because we could at least use a single Config macro
> BOOST_CXX20_EXPORT, instead of separate ones per library.

Just a thought from the peanut gallery here...

Was it ever discussed to partially preprocess the sources to generate
a modules-only distribution without #includes and with only imports?
Still single-source, with macros and such (which is a burden for
maintainers), but generating a "cleaned-up" modules-only source
package for those who want to opt in to modules. Kind of like a
module-based Boost 2.0 but without it being a fork. And pushing it a
little further, preprocess out pre-C++20 compiler workarounds too—why
not? If this was discussed, I missed it on the mailing list. But
perhaps it's too preposterous to even be discussed. :)

--DD