[swift-evolution] Selector for current method

[Jordan Rose]

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> 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> 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> 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+
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>>> swift-evolution mailing list
>>> swift-evolution at swift.org
>>> https://lists.swift.org/mailman/listinfo/swift-evolution
>> 
> 

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