[swift-evolution] Getting rid of willSet/didSet

Charles Srstka cocoadev at charlessoft.com
Tue Dec 15 10:45:24 CST 2015

> On Dec 15, 2015, at 1:23 AM, Tino Heth via swift-evolution <swift-evolution at swift.org> 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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-1 on this. As others have mentioned, willSet and didSet are extremely useful, and the above is a misuse of “super”, misleading the reader to suppose that UIView implements “foo”, when it does not.


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