[swift-evolution] [swift-evolution-announce] [Review] SE-0125: Remove NonObjectiveCBase and isUniquelyReferenced

[Dmitri Gribenko]

On Tue, Jul 19, 2016 at 10:51 PM, Chris Lattner <clattner at apple.com> wrote:
> The review of "SE-0125: Remove NonObjectiveCBase and isUniquelyReferenced" begins now and runs through July 22. The proposal is available here:
>
>         https://github.com/apple/swift-evolution/blob/master/proposals/0125-remove-nonobjectivecbase.md

I like the API simplification.  A few thoughts that I have after
reading the proposal that could take the simplification it even
further:

- I find it a little strange to see a mention of Objective-C, and a
negation in `isUniquelyReferencedNonObjC`.  For example, if we get C++
import, would we need to rename it to
`isUniquelyReferencedNonObjCAndNonCXX`?  I think that is the issue
with negation.  If we want to emphasize that the API will work only
with Swift types, we can do something
`isUniquelyReferencedSwiftReference`.  But I would probably suggest
that we just go with just `isUniquelyReferenced` and mention the
Swift-only requirement in the documentation.

- I find the use of different names in `isUniquelyReferenced()` and
`ManagedBufferPointer.holdsUniqueReference()` to be strange.  Why not
call the latter `ManagedBufferPointer. isUniquelyReferenced()`?  It is
true that we are not checking that pointer is not uniquely referenced,
if we want to emphasize that, maybe something like
`ManagedBufferPointer.isBufferUniquelyReferenced()` or
`isPointeeUniquelyReferenced()` will work?

The reason why I'm suggesting this is that `isUniquelyReferenced` and
`holdsUniqueReference` don't immediately strike me as performing the
same operation, the immediate impression I get is that these
operations are related, but subtly different, and it is not obvious
what the difference is (but after reading the docs I figure out that
there is no difference... until I need to use these APIs again).

- We have `ManagedBufferPointer.holdsUniqueOrPinnedReference()`, but
don't have an equivalent free function `isUniquelyReferencedOrPinned`
(we actually have one, but it is internal).  Do we need a public one?
If we do, we could as well add it as a part of this proposal, while we
are cleaning up this library subsystem.

Dmitri

-- 
main(i,j){for(i=2;;i++){for(j=2;j<i;j++){if(!(i%j)){j=0;break;}}if
(j){printf("%d\n",i);}}} /*Dmitri Gribenko <gribozavr at gmail.com>*/