You can not mutate a array itself in a
`var asScriptable`
you might be able to accomplish such with a function.
struct AllSubscriptable<E, Index> {
let setSubscriptee: (index: Index, element: E) -> Void
}
extension Array {
mutating func asScriptable() -> AllSubscriptable<Element, Int> {
func sub(key:Int, element: Element) {
self[key] = element
}
return AllSubscriptable<Element, Int>(
setSubscriptee: sub
)
}
}
Kyle
On Fri, Mar 25, 2016 at 2:50 PM zhigang <zhigang1...@gmail.com> wrote:
> It might have something to do with
>
> `setSubscriptee`
>
> with seems from the implementation is a `mutating` operation.
>
> If you comment it out, or just give it a empty callback, it will pass
> compile.
>
>
> Kyle
>
> On Tue, Mar 22, 2016 at 6:23 AM Howard Lovatt via swift-users <
> swift-users@swift.org> wrote:
>
>> Hi,
>>
>> I don't understand your comment, can you explain some more please?
>>
>> Thanks,
>>
>> -- Howard.
>>
>>
>> On Monday, 21 March 2016, zh ao <owe...@gmail.com> wrote:
>>
>>> You protocol is not defined properly.
>>>
>>> On Mon, Mar 21, 2016 at 7:08 AM, Howard Lovatt via swift-users <
>>> swift-users@swift.org> wrote:
>>>
>>>> HI,
>>>>
>>>> Does anyone know what is happening here:
>>>>
>>>> protocol Subscriptable {
>>>>
>>>> associatedtype Element
>>>>
>>>> associatedtype Index
>>>>
>>>> var firstIndex: Index { get }
>>>>
>>>> var lastIndex: Index { get }
>>>>
>>>> subscript(index: Index) -> Element { get set }
>>>>
>>>> }
>>>>
>>>>
>>>> struct AllSubscriptable<E, I>: Subscriptable {
>>>>
>>>> typealias Element = E
>>>>
>>>> typealias Index = I
>>>>
>>>> let firstIndexee: () -> I
>>>>
>>>> let lastIndexee: () -> I
>>>>
>>>> let subscriptee: (index: I) -> E
>>>>
>>>> let setSubscriptee: (index: I, element: E) -> Void
>>>>
>>>> var firstIndex: I { return firstIndexee() }
>>>>
>>>> var lastIndex: I { return lastIndexee() }
>>>>
>>>> subscript(index: I) -> E {
>>>>
>>>> get { return subscriptee(index: index) }
>>>>
>>>> set { setSubscriptee(index: index, element: newValue) }
>>>>
>>>> }
>>>>
>>>> }
>>>>
>>>>
>>>> extension Array {
>>>>
>>>> var asScriptable: AllSubscriptable<Element, Int> {
>>>>
>>>> return AllSubscriptable(
>>>>
>>>> firstIndexee: { return self.startIndex }, // Error: Cannot
>>>> convert `() -> Int` to expected `() -> _`
>>>>
>>>> lastIndexee: { return self.endIndex },
>>>>
>>>> subscriptee: { return self[$0] },
>>>>
>>>> setSubscriptee: { self[$0] = $1 }
>>>>
>>>> )
>>>>
>>>> }
>>>>
>>>> }
>>>>
>>>>
>>>> The error, "Cannot convert `() -> Int` to expected `() -> _`", on the
>>>> `firstIndexee` closure is very strange since the types are correct and the
>>>> same as `lastIndexee` which does not have an error.
>>>>
>>>> Also if the set subscript in Subscriptable and then all the other set
>>>> support in AnySubscriptabe and in the extension is removed, then no error.
>>>>
>>>> Any clues to why?
>>>>
>>>> -- Howard.
>>>>
>>>> _______________________________________________
>>>> swift-users mailing list
>>>> swift-users@swift.org
>>>> https://lists.swift.org/mailman/listinfo/swift-users
>>>>
>>>>
>>>
>>
>> --
>> -- Howard.
>> _______________________________________________
>> swift-users mailing list
>> swift-users@swift.org
>> https://lists.swift.org/mailman/listinfo/swift-users
>>
>
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