Naively and very handwavely, if I dont want users of my types to be able to
reflect arbitrarily over it, what i want is a way to overload ^^ operator
for my type and either assert(false) there to lock everything, or shape up
some kind of bespoke meta::info to be returned that fit my needs.

Sent from Gmail Mobile


On Wed, Nov 13, 2024 at 5:28 Peter Dimov via SG7 <sg7_at_[hidden]>
wrote:

> Corentin Jabot wrote:
> > code is code.
> > if a developer relies on the names, presence, order, or shape of private
> > members of a third party library, it is not robust over time.
> >
> > The long term ability to maintain large projects at scale trumps the
> very mild
> > inconvenience of more robust defaults.
> >
> > If someone wants to reflect on private members, it should be explicit.
> it has
> > nothing to do with usage or usefulness, it has to do with ensuring a
> healthy
> > ecosystem in the presence of Hyrum's law, to the extent that we can.
>
> Code can already rely on a lot of things it isn't supposed to rely on.
>
> It can rely on the size or alignment of library types. It can rely on the
> order
> and placement of the fields of `struct timespec`, even though that's
> explicitly unspecified.
>
> More to the point, it can rely on the result of every type query in
> <type_traits>
> even when no such results are guaranteed by the documentation of a library
> type.
>
> Even though all this complicates our (standardization) work because it
> makes
> it effectively impossible for a change to be "unobservable to a correct
> program", we consider the tradeoff acceptable, because the reflection
> functionality in <type_traits> is useful enough to outweigh the costs.
>
> It's the same with <meta>. Every query there makes things more observable
> than before. And that's exactly what <meta> is for.
>
>
> --
> SG7 mailing list
> SG7_at_[hidden]
> https://lists.isocpp.org/mailman/listinfo.cgi/sg7
>