Sent from my iPhone
> On Jul 16, 2016, at 8:45 PM, Andrew Trick <atr...@apple.com> wrote:
>
>
>> On Jul 16, 2016, at 8:36 PM, Arnold <aschwaigho...@apple.com> wrote:
>>
>> Thank you for the feedback. Answers online.
>>
>> Sent from my iPhone
>>
>>> On Jul 16, 2016, at 7:38 PM, Andrew Trick <atr...@apple.com> wrote:
>>>
>>>
>>>> On Jul 16, 2016, at 6:46 PM, Arnold Schwaighofer via swift-evolution
>>>> <swift-evolution@swift.org> wrote:
>>>>
>>>> Replace isUniquelyReferenced<T : NonObjectiveCBase> by
>>>> isUniquelyReferencedUnsafe<T: AnyObject> and remove the NonObjectiveCBase
>>>> class from the standard library.
>>>>
>>>
>>> So we’ll have:
>>>
>>> - isUniquelyReferencedNonObjC(object): true iff object is uniquely
>>> referenced and NonObjC
>>>
>>> - isUniquelyReferencedUnsafe(object): true iff object is uniquely
>>> reference, assert NonObjC
>>>
>>> I’m going to be picky. The “Unsafe” suffix doesn’t make sense to me. If you
>>> think this is an unsafe API then it should be:
>>> “unsafeIsUniquelyReferenced”.
>>>
>>> But I don’t really see how it is unsafe in the usual sense. If you want to
>>> convey that the programmer needs to satisfy some precondition, which is not
>>> generally associated with unsafety, then it should be:
>>> “isUniquelyReferencedAssumingNonObjC”
>>
>> Makes sense to me. I think it is unsafe in the sense if you don't satisfy
>> the precondition the resulting behavior is undefined in modes other than
>> -Onone and not checked by a precondition predicate that traps.
>>
>>> unsafeIsUniquelyReferenced
>>
>> I find it kind of nice to recognize a predicate by the 'is' prefix. All
>> unsafe APIs start with the word unsafe though. I could not find an unsafe
>> freestanding predicate.
>>
>> [As the implementor of the underlying builtin you may remember that it is
>> not actually undefined and will return a implementation defined value
>> (false) for objc classes. But we might not want to guarantee this going
>> forward.]
>
>
> Oh yeah. I think I only kept the two versions for fear of breaking the API.
> Since you’re renaming the second one anyway, why not just delete it with a
> fixit that it's renamed to isUniquelyReferencedNonObjC?
>
> The “assuming” version of the API is extremely confusing in addition to being
> useless.
The unsafe version would allow us to emit more efficient code (in the future)
for a static unknown object type but we know it is a native type (but not which
so we can't just cast it, this is public API so we can't cast to
Builtin.NativeObject).
var self: AnyObject // really: AnyNativeObject
...
if (!unsafeIsUniquelyReferenced(&self))
self = self.copy()
}
I admit this is somewhat contrived and am happy to just nuke the API if we
agree there is no value in the use case above._______________________________________________
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