Should `PersistentDict` and `HAMT` be public from Base or not?

[jariji]

PersistentDict and HAMT were added to Base by @vchuravy in #51164 as part of the implementation of ScopedValues. I didn't see any discussion of whether they should be part of the public API. These days Julia is mostly moving things out of Base rather than in, so I'm bringing it up here.

What are the benefits and costs of putting these API in Base rather than

• using them privately without exporting, and/or
• having the types in a package that can be modified separately from Base?

#53980 reports PersistentDict's now-documented examples are using Base.delete which isn't a public function.

[nsajko]

Neither of those are currently marked public, although I'm not sure what was the intention with Base.PersistentDict, as it's documented even though it's not public.

[jariji]

I see, HAMT is exported from module Base.HashArrayMappedTries which isn't itself public.

[vchuravy]

HAMT is decidedly not public. PersistentDict should probably be, following ImmutableDict

[Tokazama]

If HAMT is not going to be public, should https://github.com/vchuravy/HashArrayMappedTries.jl be moved to JuliaCollections so the community can maintain a public facing version of it?

[vchuravy]

I am happy to move it if there is actual interest. Right now some of the implementation details are over-optimized for the base use-case.

[Tokazama]

I am happy to move it if there is actual interest. Right now some of the implementation details are over-optimized for the base use-case.

I'd be willing to help out with simple things but I'm not confident that I have the expertise to make it both efficient and generic.