[swift-evolution] Getting rid of willSet/didSet

[Colin Cornaby]

I think the below proposal also tries to pave over the difference between will and didSet, which are both important. In addition to unclear use of super.foo.

> On Dec 15, 2015, at 12:57 AM, Adrian Kashivskyy via swift-evolution <swift-evolution at swift.org> wrote:
> 
> I'm -1 on that, willSet and didSet are great tools for performing side effects (such as locking, for example). It was a major problem in Objective-C, as no easy solution (except overriding accessors) existed and still you'd have to write a lot of boilerplate code.
> 
> Pozdrawiam – Regards,
> Adrian Kashivskyy
> 
>> Wiadomość napisana przez Nicky Gerritsen via swift-evolution <swift-evolution at swift.org <mailto:swift-evolution at swift.org>> w dniu 15.12.2015, o godz. 08:50:
>> 
>> But how does this work if `super` does not have `foo`, exactly like in this example? UIView does not have a member named `foo`, so it will not work.
>> Moreover, currently if creating a setter, you also need to supply a getter.
>> 
>> Regards,
>> 
>> Nicky
>> 
>> On 12/15/2015 08:23 AM, Tino Heth via swift-evolution wrote:
>>>> It *is* odd, and I do the described didSet trick *all* the time.
>>>> 
>>>> Stuff like:
>>> The alternative wouldn’t be that complicated:
>>> 
>>> public class MyView: UIView {
>>> 	public var foo: Int {
>>> 		set(value) {
>>> 			super.foo = value
>>> 			setNeedsDisplay()
>>> 		}
>>> 	}
>>> }
>>> 
>>> It’s just one line more, but three(!) keywords less that could be removed from the language; and I bet in the wild there are many thousand errors in subclasses of UIViewController that happen because the author didn’t remember wether he has to call super in viewDid…, loadView etc.
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>> 
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> 
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