[swift-evolution] [Draft Proposal] A simplified notation for avoiding the weak/strong dance with closure capture lists

[Erica Sadun]

I think it's important to defer to the programmer on how the weak self condition is handled, enabling any clean-up action to be taken as well as deciding whether to terminate the app, recover, etc.

-- E


> On Feb 12, 2016, at 3:20 PM, Jason Gregori <jasongregori at gmail.com> wrote:
> 
> Ah, I see. I think that totally makes sense but I would prefer to have just one bit to write and not have to do both the [weak self] and the guard statement. 
> 
> This is why I keep coming back to [guard weak self]. I want to to make self weak and I want to guard against it being nil.
> 
> On Fri, Feb 12, 2016 at 1:31 PM, Erica Sadun <erica at ericasadun.com <mailto:erica at ericasadun.com>> wrote:
> It would follow 
> 
> [weak self]
> 
> not replace it, e.g.
> 
> [weak self]
> guard reconstitute self else { return }
> 
> I thought it might be handy to control how the guard exits scope, enabling self == nil (as well as any other reconstitutions of a weak variable) failure cases to do reporting, fatalError-ing, etc.
> 
> -- E
> 
> 
>> On Feb 12, 2016, at 12:08 PM, Jason Gregori <jasongregori at gmail.com <mailto:jasongregori at gmail.com>> wrote:
>> 
>> 
>> 
>> On Fri, Feb 12, 2016 at 10:34 AM, Erica Sadun <erica at ericasadun.com <mailto:erica at ericasadun.com>> wrote:
>> How about 
>> 
>> guard reconstitute self else { return }
>> 
>> I like the idea behind this but I feel like a line inside the block can't really dictate whether self is captured weakly or not. Unless your saying put this in the bracket part?
>> 
>> [guard reconstitute self] ? That works for me.
>> 
>> 
>> PS: I got here from your blog post, thanks!
>>  
>> -- E
>> 
>>> On Feb 12, 2016, at 11:28 AM, Jason Gregori via swift-evolution <swift-evolution at swift.org <mailto:swift-evolution at swift.org>> wrote:
>>> 
>>> I like Kenny and Kurt's points about handling the majority case and keeping the syntax simpler.
>>> 
>>> I feel like most of the time I want to break a retain cycle is for a completion block which returns void. Can we just handle that case and get rid of the else?
>>> 
>>> Also, I don't think [guard self] is self explanatory enough. I think weak should be in there so it's much more obvious you are doing the weak/strong dance with self, otherwise it looks like you are guarding against a regular optional being nil.
>>> 
>>> So:
>>> 
>>> [guard weak self, other]
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>> 
>> 
> 
> 

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