Re: Swift enums and NSNotificationCenter
Re: Swift enums and NSNotificationCenter
- Subject: Re: Swift enums and NSNotificationCenter
- From: Charles Srstka <email@hidden>
- Date: Wed, 05 Aug 2015 18:57:48 -0500
On Aug 5, 2015, at 6:45 PM, Rick Mann <email@hidden> wrote:
>
>>
>> On Aug 5, 2015, at 16:38 , Charles Srstka <email@hidden <mailto:email@hidden>> wrote:
>>
>> On Aug 5, 2015, at 6:22 PM, Rick Mann <email@hidden> wrote:
>>>
>>> I'd like to be able to write code like this:
>>>
>>> enum MyNotifications : String {
>>> case Note1 = "note1"
>>> case Note2 = "note2"
>>> }
>>>
>>> let nc = NSNotificationCenter.defaultCenter()
>>> nc.postNotificationName(MyNotifications.Note1, nil)
>>>
>>> But Swift (2.0) doesn't let me do that. Is it possible to write an extension method to NSNotificationCenter that accepts "any enum derived from String" (or that's convertible to String, or something like that)? e.g.:
>>>
>>> func postNotification(inName : enum:String)
>>>
>>> I tried doing this: http://pastebin.com/kXLEHu8f
>>>
>>> But it gets multiple errors, as you can see.
>>>
>>> Is there an elegant way to do this? Seems counter-intuitive that I can't pass a derived enum in place of an ancestral type.
>>
>> AFAIK there’s no way to do exactly what you’re asking for, but you could put a post() method on the enum itself.
>
> Well, that kinda works, for a single enum, but I can't derive an enum from that because I run into this when I subclass an enum.
>
> playground28.swift:26:16: error: raw type 'Notes' is not convertible from any literal
> enum MyNotes : Notes
> ^
> playground28.swift:26:6: error: type 'MyNotes' does not conform to protocol 'RawRepresentable'
> enum MyNotes : Notes
> ^
> Swift.RawRepresentable:11:13: note: protocol requires nested type 'RawValue'
> typealias RawValue
I get that error any time I try to subclass *any* enum. I don’t think enums are supposed to be subclassable.
Charles
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