[swift-users] Initializer accessing self
I am at a loss:
Why does this not work:
class Test {
let timer: Timer!
init() {
timer = Timer.scheduledTimer(timeInterval: 20, target: self, selector:
#selector(test(_:)), userInfo: nil, repeats: true)
}
@objc func test(_ timer: Timer) {
}
}
error: constant 'self.timer' used before being initialized
timer = Timer.scheduledTimer(timeInterval: 20, target: self, selector:
#selector(test(_:)), userInfo: nil, repeats: true)
But this does:
class TestTwo {
var timer: Timer!
init() {
timer = Timer.scheduledTimer(timeInterval: 20, target: self, selector:
#selector(test(_:)), userInfo: nil, repeats: true)
}
@objc func test(_ timer: Timer) {
}
}___
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Re: [swift-users] Using 'SomeProtocol' as a concrete type conforming to protocol 'SomeProtocol' is not supported
Aren’t I losing the ability to enforce what is going into this enum’s
associated value then?
Brandon
> On Dec 28, 2016, at 7:05 PM, Nevin Brackett-Rozinsky
> <nevin.brackettrozin...@gmail.com> wrote:
>
> It will work if you change the enum declaration to:
>
> enum ElementNode
>
> In other words, let the enum hold arbitrary unconstrained associated types,
> and then make your APIs utilize instances of the enum with the associated
> type constrained to a protocol.
>
> The specific example you provide is essentially equivalent to:
>
> var childElements = [Element?]()
>
> Nevin
>
>
> On Wed, Dec 28, 2016 at 6:41 PM, Brandon Knope via swift-users
> <swift-users@swift.org <mailto:swift-users@swift.org>> wrote:
> I don’t understand why this is a problem
>
> protocol Element {
>
> }
>
> enum ElementNode {
> case element(T)
> case empty
> }
>
> var childElements = [ElementNode]()
>
> I need to represent an array of my nodes that could be multiple kinds of
> elements
>
> Is there a workaround?
>
> Brandon
>
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>
>
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[swift-users] Using 'SomeProtocol' as a concrete type conforming to protocol 'SomeProtocol' is not supported
I don’t understand why this is a problem
protocol Element {
}
enum ElementNode {
case element(T)
case empty
}
var childElements = [ElementNode]()
I need to represent an array of my nodes that could be multiple kinds of
elements
Is there a workaround?
Brandon___
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[swift-users] swift-commits notifications mailing list no longer working
The swift-commits archive is empty and I am no longer receiving email updates when a commit is made. Where is the best place to report or address this? Thanks, Brandon ___ swift-users mailing list swift-users@swift.org https://lists.swift.org/mailman/listinfo/swift-users
Re: [swift-users] super.init() called automatically?
I did not know of this behavior, but it looks like if the superclasses
designated initializer is just a plain init() then it will automatically call
super.init() from your subclass.
There is no way to avoid not calling your superclasses’s designated initializer
and I guess the compiler ensures this by implicitly placing a call to super?
For example, if you change your Foo init to init(test:Int) { } then your
subclass will complain that it’s not calling super’s designated initializer.
I have no idea why super can be implicitly called and I see no reference to
this in the language guide.
I am not sure I like this behavior. It should either be documented (maybe I am
missing it?) or requiring calling super explicitly.
Brandon
> On May 16, 2016, at 10:09 AM, tuuranton--- via swift-users
> wrote:
>
> Why does the following code compile?
> Why does Bar's init(x: Int) automatically call Foo's init()?
> Why don't I have to manually call super.init() myself?
>
> What passage of
> https://developer.apple.com/library/ios/documentation/Swift/Conceptual/Swift_Programming_Language/Initialization.html#//apple_ref/doc/uid/TP40014097-CH18-ID203
>
>
> tells me that this should be the case?
>
>
> class Foo {
> init() {
> print("foo init")
> }
> }
> class Bar: Foo {
> init(x: Int) {
> print("bar init")
> }
> }
> let b = Bar(x: 0)
> //prints:
> //bar init
> //foo init
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