[swift-evolution] Selector for current method

[Rudolf Adamkovič]

> What I’m wondering is what you’re actually using this all for.


For example, when testing with Quick (popular testing framework), one can describe a function:

describe(“player.play()”) {
    ...
}

If #function worked like #selector, we could do:

describe(#function(Player.play())) {
    ...
}

This would be safe and refactoring friendly.

P.S. I could do this with #selector but that would require @objc/dynamic which is not ideal.

R+

> On 15 Nov 2016, at 18:02, Jordan Rose <jordan_rose at apple.com> wrote:
> 
> Sorry, I see that #function doesn’t work as a drop-in replacement for #selector. What I’m wondering is what you’re actually using this all for. It seems rare to have a dictionary keyed by the name of a function (but not its arguments) and rarer still to need to prepopulate that dictionary. The only use case I can think of is some generalized mock object, but even then I wonder how useful it is in practice.
> 
> (Per the original request, remember too that many Swift methods do not have selectors, since they are not exposed to Objective-C.)
> 
> Jordan
> 
> 
>> On Nov 15, 2016, at 03:47, Rudolf Adamkovič <salutis at me.com <mailto:salutis at me.com>> wrote:
>> 
>> Hi Jordan,
>> 
>>> The stripped-down code seems like it could use any unique key, including #function.
>> 
>> 
>> That would work only if #function could be used with an argument just like #selector:
>> 
>> class DirectoryListingStub: DirectoryListing {
>> 
>>   var cannedOutput: [Selector: Any?] = [
>>       #function(contentsOfDirectory(at:includingPropertiesForKeys:options:)): nil
>>   ]
>> 
>>   func contentsOfDirectory(at url: URL, includingPropertiesForKeys keys: [URLResourceKey]?, options: FileManager.DirectoryEnumerationOptions) throws -> [URL] {
>>       return cannedOutput[#function] as! [URL]
>>   }
>> 
>> }
>> 
>> Obviously, this doesn’t work as #function takes no arguments.
>> 
>> There's no way to get #selector for the current method. And there’s no way to get #function for arbitrary method.
>> 
>> R+
>> 
>>> On 14 Nov 2016, at 20:07, Jordan Rose <jordan_rose at apple.com <mailto:jordan_rose at apple.com>> wrote:
>>> 
>>> This doesn’t seem unreasonable, but I’m not sure if that makes it reasonable. :-) What’s your use case? The stripped-down code seems like it could use any unique key, including #function.
>>> 
>>> Jordan
>>> 
>>> 
>>>> On Nov 13, 2016, at 15:50, Rudolf Adamkovič via swift-evolution <swift-evolution at swift.org <mailto:swift-evolution at swift.org>> wrote:
>>>> 
>>>> Hi there!
>>>> 
>>>> in Swift 3, we now have #selector and #keyPath yet there’s still no _cmd like we have in Objective-C.
>>>> 
>>>> Example:
>>>> 
>>>> class DirectoryListingStub: DirectoryListing {
>>>> 
>>>>  var cannedOutput: [Selector: Any?] = [
>>>>      #selector(contentsOfDirectory(at:includingPropertiesForKeys:options:)): nil
>>>>  ]
>>>> 
>>>>  dynamic func contentsOfDirectory(at url: URL, includingPropertiesForKeys keys: [URLResourceKey]?, options: FileManager.DirectoryEnumerationOptions) throws -> [URL] {
>>>>      let selector = #selector(contentsOfDirectory(at:includingPropertiesForKeys:options:))
>>>>      return cannedOutput[selector] as!  [URL]
>>>>  }
>>>> 
>>>> }
>>>> 
>>>> Problem: I had to specify #selector twice.
>>>> 
>>>> I though I’d be able to use #function but:
>>>> 
>>>> #selector = contentsOfDirectoryAt:includingPropertiesForKeys:options:error:
>>>> #function = contentsOfDirectory(at:includingPropertiesForKeys:options:)
>>>> 
>>>> It’d be great if #selector (without arguments) returned the current selector.
>>>> 
>>>> Or am I missing something?
>>>> 
>>>> R+
>>>> _______________________________________________
>>>> swift-evolution mailing list
>>>> swift-evolution at swift.org <mailto:swift-evolution at swift.org>
>>>> https://lists.swift.org/mailman/listinfo/swift-evolution
>>> 
>> 
> 

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.swift.org/pipermail/swift-evolution/attachments/20161116/a53036fb/attachment.html>