Wouldn't it be easier (syntax wise) to extend the meta type directly? :
protocol P {}
extension P.Type {
static func a() {}
}
Kind regards
- Maximilian
> Am 28.02.2016 um 02:05 schrieb Joe Groff via swift-evolution
> <[email protected]>:
>
> Rasmus Kjeldsen via swift-evolution
> <[email protected]> wrote:
>>
>> I propose to allow static protocol extension methods to be used directly on
>> the protocol.
>> This would enable the Factory-pattern to be elegantly implemented as in the
>> example below:
>>
>> protocol P {}
>>
>> class A : P {}
>> class B : P {}
>>
>> extension P {
>> static func factory(type: Bool) -> P { return type ? A() : B()}
>> }
>>
>> let a = P.factory(false) // <- Not possible in Swift 2, factory() can
>> only be used on either A or B
>>
>> Regards
>>
>> Rasmus Friis Kjeldsen
>
> 'extension P' extends all types that conform to P. We could introduce a new
> syntax for extending the protocol type, maybe:
>
> extension protocol<P> { ... }
>
> This might be an important part of fleshing out our support for protocol
> existential types. It would offer a way for protocol types to conform to
> their own protocols even when Self or associated types make that normally
> impossible.
>
> -Joe
>
>
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