Oh, yeah, good point about "final".
Would there be a performance difference between "override var x: Int {return
7}" and "override let x = 7"?
Sent from my iPhone
> On Apr 23, 2016, at 16:06, Haravikk via swift-evolution
> <swift-evolution@swift.org> wrote:
>
> I don’t think using a let constant should prevent a further sub-class from
> overriding again, that’s what the final keyword should be for.
>
> It would still need to be implemented like this behind the scenes though:
>
> override var x:Int { return 7 }
>
> By the same token you could also allow var to implicitly create something
> like the following:
>
> private var _x = 7
> override private(set) var x:Int {
> get { return _x }
> set { _x = newValue }
> }
>
> I’m not sure what my preference is though; while being able to do overrides
> with stored property-like syntax might be convenient and tidy in some cases,
> it’s probably better to force developers to use explicitly computed
> properties to be clear what’s really going on to make it actually work.
>
>> On 23 Apr 2016, at 20:30, Adrian Zubarev via swift-evolution
>> <swift-evolution@swift.org> wrote:
>>
>> I already see the problem here:
>>
>> class A { var x: Int { return 42 } }
>> class B: A { override let x = 7 } // assume that will work
>> class C: B { override var x: Int { /* wait this wont work anymore */ } }
>>
>> You won’t be able to override an immutable constant.
>>
>> I don’t like such a change.
>>
>> --
>> Adrian Zubarev
>> Sent with Airmail
>>
>> Am 23. April 2016 bei 21:19:27, Roman Zhikharevich via swift-evolution
>> (swift-evolution@swift.org) schrieb:
>>
>>> I think, it could be a good idea to make computed properties overridable
>>> with let constants.
>>>
>>> Something like this:
>>>
>>> class Parent {
>>> var x: Int {
>>> let x = 42
>>> /*
>>> * Compute x...
>>> */
>>> return x
>>> }
>>> }
>>>
>>> class Child: Parent {
>>> /*
>>> * Sometimes you need to override computed properties with simple
>>> constants.
>>> * This is currently done like this.
>>> */
>>> //override var x: Int {return 7}
>>>
>>> /*
>>> * But this looks neater.
>>> * Currently this gives "error: cannot override with a stored property
>>> 'x'".
>>> */
>>> override let x = 7
>>> }
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