Re: Possible RFC: UniqueInterface that throws exception at refcount > 1

Thanks for your answers! Yes, it would be a dynamic uniqueness system, kind of. Another more flexible alternative would be to add magic methods at refcount = 1 and refcount > 1, possibly __owned() and __shared(int $refcount), for classes that implement a TrackReferencesInterface or similar. But this would need to do ~0 performance hit if not used, don't know if possible. Olle 2020-07-11 14:29 GMT, Chuck Adams <cja987@gmail.com>: > On Sat, Jul 11, 2020 at 8:06 AM Olle Härstedt <olleharstedt@gmail.com> > wrote: >> >> Dear internals, >> >> I'd like to discuss the concept of ownership in PHP, from the point of >> view of a new interface UniqueInterface (or SplUniqueInterface or >> something), which will throw a UniqueException if refcount > 1. >> >> Use-case: Mutable objects that cannot be shared (without (deep) cloning).. > > I don't think you want to do this on refcount, since that would > prevent even passing it to another function or using it in any number > of expressions. What would make more sense to me would be hooking > into copy-on-write, which would also be a slightly less hot code path > than reference counting (but still a pretty critical one). > > It almost sounds like a uniqueness type, something well beyond the > capabilities of PHP's type system (and most others). > > --c >