[swift-evolution] Proposal: weakStrong self in completion handler closures

[Jacob Bandes-Storch]

Another approach would be to simply allow

guard let self = self else { return }
On Sat, Dec 5, 2015 at 3:48 AM Robert Vojta <rvojta at me.com> wrote:

> Hi all,
>
> let’s say we have a completion handler closure for some function
> (networking, …) and we have [weak self] there. Example …
>
> doSomething() { [weak self] result in
>   …
> }
>
> … then we can use self?.whatever to access self properties, methods. Or we
> can try to check if self exists ...
>
> guard let strongSelf = self else { return }
>
> … and use strongSelf.
>
> Can we introduce [weakStrong self] with following behavior:
>
>  - self is a weak reference
>  - when the closure is going to be executed, all weakStrong weak
> references are checked if they do exist
>  - if they do exist, they’re strong referenced for the closure and the
> closure is executed
>  - if they don’t exist, closure is not executed
>
> doSomething() { [weakStrong self] result in
>   // Closure code is not executed if self no longer exists
>   // self is a strong reference now
> }
>
> What do you think? Does it make sense?
>
> My motivation is to get rid off of the repetitive code like this one:
>
> doSomething() { [weak self] result in
>   guard let strongSelf = self else { return }
>   strongSelf.doSomethingWithResult(result)
> }
>
> Robert
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