[swift-evolution] RFC: Proposed rewrite of Unmanaged<T>

[T.J. Usiyan]

Would `consumeReleased` work at all? It captures the 'don't use this again'
aspect and 'release' without much extra.

On Sat, Dec 19, 2015 at 7:45 PM, Rainer Brockerhoff via swift-evolution <
swift-evolution at swift.org> wrote:

> On 18/12/15 16:46 , swift-evolution-request at swift.org wrote:
> > Date: Fri, 18 Dec 2015 11:38:31 -0800
> > From: Dave Abrahams <dabrahams at apple.com>
> > Subject: Re: [swift-evolution] RFC: Proposed rewrite of Unmanaged<T>
> > Message-ID: <E82AADA9-F4A4-4E4E-98C3-6E9A3CEC4D12 at apple.com>
> >
> >> > On Dec 17, 2015, at 6:23 PM, T.J. Usiyan <griotspeak at gmail.com>
> wrote:
> >
> >> > My main point of contention with `.release()` is that it has the
> *exact* same name as a method from the MRC strategy. Maybe this is a silly
> point, but this overlap could further complicate teaching how ARC works and
> in what ways it is based on MRC conventions.
> >> > I am not of the opinion that ARC is fundamentally more difficult to
> understand than MRC, but I do believe that it takes a very particular kind
> of faith now that we don't get to manually write the retains and releases.
> This is completely worth it, in my opinion, but  I want to avoid making it
> *more* confusing to explain what ARC doing at compile time.
> > Well, unsafeRef.release() is equivalent to
> >
> >   {
> >     let x = $0.object
> >     CFRelease($0) // if CFRelease() wasn't @unavailable
> >     return x
> > }(unsafeRef)
> >
> > If you let the return value drop on the floor, it ends up being
> > exactly equivalent to the method with the exact same name from the
> > MRC strategy.  So the correspondence is strong and shouldn’t be a
> > problem.  That’s just my opinion, though, and part of the reason
> > we’re asking for feedback here is so people steeped in MRC like you
> > can argue with me about that :-), so if you find this unconvincing
> > please explain why.
>
> OK, guess I qualify as "steeped" there - I still use MRC in all my
> shipping apps, although I've tentatively used ARC in small fry like
> build-time utilities. (Never got used to GC.)
>
> Anyway, much of my code looks like one of these patterns:
>
> // 1
> NSDictionary* dict = [(id)CFCreateSomeCFDictionary() autorelease];
> ... use dict for some lines, done
>
> // 2
> NSArray* array = (NSArray*)CFGetSomeCFArray();
> ... use array for some lines, done
>
> // 3
> NSString* str = (NSString*)CFCreateSomeCFString();
> ... use str for some lines
> [release str];
>
> One thing about my not migrating to ARC is that I find the bridging cast
> names opaque - can't memorize them! Same, sadly, was true for the
> Umanaged<T> methods.
>
> So I'd say, use `.release` or `.autorelease` if they'd be used in the
> same place as above...
>
> --
> Rainer Brockerhoff  <rainer at brockerhoff.net>
> Belo Horizonte, Brazil
> "In the affairs of others even fools are wise
> In their own business even sages err."
> http://brockerhoff.net/blog/
> _______________________________________________
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>
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