[swift-evolution] [Pitch] Make the first parameter in a function declaration follow the same rules as the others

[Jordan Rose]

Thank you! I realized one other potential flaw in the data-gathering: your search for "func foo(_ bar" will match both Objective-C methods and C functions. I'm not sure CF should really be contributing to the scores. Unfortunately the main way I can think of to differentiate them is by indentation, which seems a little sketchy.

Still, the conclusions I would draw from this are that the vast majority of methods fall into one of the three following categories:

- No arguments.
- Empty first argument label.
- First argument label that does not match the parameter name.

This doesn't mean we shouldn't change the convention—"_ completionHandler" is much easier to type than "completionHandler completionHandler", and it's still removing complexity—but it does mean (to me) that the new API naming guidelines don't make the "matching" case more important; they only make the "no label" case less important.

Jordan


> On Mar 14, 2016, at 20:30 , Shawn Erickson <shawnce at gmail.com> wrote:
> 
> 
> 
> On Mon, Mar 14, 2016 at 8:05 PM Jordan Rose <jordan_rose at apple.com <mailto:jordan_rose at apple.com>> wrote:
> Ah, this doesn't distinguish
> 
> func foo(bar baz: Int)
> 
> from
> 
> func foo(bar bar: Int)
> 
> That's pretty important for this discussion.
> 
> (Thanks for actually doing this! I just let it drop last week.)
> 
> [shawnce:~/Downloads/swift-3-api-guidelines-review-swift-3]
> [0:574]> grep -R "func [A-Za-z0-9]*(\([A-Za-z0-9]*\) \1:" Platforms/ | wc -l
>      274
> 
> [shawnce:~/Downloads/swift-3-api-guidelines-review-swift-3]
> [0:579]> grep -R "func [A-Za-z0-9]*(\([A-Za-z0-9]*\) \1:" Platforms/ | head -5
> Platforms//iOS/AssetsLibrary/ALAssetRepresentation.swift:  func cgImage(options options: [NSObject : AnyObject]! = [:]) -> Unmanaged<CGImage>!
> Platforms//iOS/CloudKit/CKContainer.swift:  func accountStatus(completionHandler completionHandler: (CKAccountStatus, NSError?) -> Void)
> Platforms//iOS/CloudKit/CKContainer.swift:  func fetchUserRecordID(completionHandler completionHandler: (CKRecordID?, NSError?) -> Void)
> Platforms//iOS/CloudKit/CKContainer.swift:  func discoverAllContactUserInfos(completionHandler completionHandler: ([CKDiscoveredUserInfo]?, NSError?) -> Void)
> Platforms//iOS/CloudKit/CKDatabase.swift:  func fetchAllRecordZones(completionHandler completionHandler: ([CKRecordZone]?, NSError?) -> Void)
> 
> 
>> On Mar 14, 2016, at 16:01 , Shawn Erickson via swift-evolution <swift-evolution at swift.org <mailto:swift-evolution at swift.org>> wrote:
>> 
>> I could have easily screwed up my grep but doing spot checks on the resulting data sets I didn't spot an issue. I did make assumptions about how well formed the data set was.
>> 
>> [shawnce:~/Downloads/swift-3-api-guidelines-review-swift-3]
>> [0:554]> grep -R "func [A-Za-z0-9]*([A-Za-z0-9]* [A-Za-z0-9]*:" Platforms/ | wc -l
>>    10587
>> 
>> [shawnce:~/Downloads/swift-3-api-guidelines-review-swift-3]
>> [0:555]> grep -R "func [A-Za-z0-9]*(_ [A-Za-z0-9]*:" Platforms/ | wc -l
>>    21654
>> 
>> [shawnce:~/Downloads/swift-3-api-guidelines-review-swift-3]
>> [0:556]> grep -R "func [A-Za-z0-9]*([A-Za-z0-9]* _:" Platforms/ | wc -l
>>        0
>> 
>> [shawnce:~/Downloads/swift-3-api-guidelines-review-swift-3]
>> [0:557]> grep -R "func [A-Za-z0-9]*([A-Za-z0-9]*:" Platforms/ | wc -l
>>       14
>> 
>> [shawnce:~/Downloads/swift-3-api-guidelines-review-swift-3]
>> [0:558]> grep -R "func [A-Za-z0-9]*()" Platforms/ | wc -l
>>     7190
>> 
>> ----
>> 
>> [shawnce:~/Downloads/swift-3-api-guidelines-review-swift-3]
>> [0:559]> grep -R "func [A-Za-z0-9]*([A-Za-z0-9]* [A-Za-z0-9]*:" SampleCode/ | wc -l
>>       12
>> 
>> [shawnce:~/Downloads/swift-3-api-guidelines-review-swift-3]
>> [0:560]> grep -R "func [A-Za-z0-9]*(_ [A-Za-z0-9]*:" SampleCode/ | wc -l
>>        0
>> 
>> [shawnce:~/Downloads/swift-3-api-guidelines-review-swift-3]
>> [0:561]> grep -R "func [A-Za-z0-9]*([A-Za-z0-9]* _:" SampleCode/ | wc -l
>>        0
>> 
>> [shawnce:~/Downloads/swift-3-api-guidelines-review-swift-3]
>> [0:562]> grep -R "func [A-Za-z0-9]*([A-Za-z0-9]*:" SampleCode/ | wc -l
>>      512
>> 
>> [shawnce:~/Downloads/swift-3-api-guidelines-review-swift-3]
>> [0:563]> grep -R "func [A-Za-z0-9]*()" SampleCode/ | wc -l
>>      221
>> 
>> 
>> On Mon, Mar 14, 2016 at 3:28 PM Dave Abrahams via swift-evolution <swift-evolution at swift.org <mailto:swift-evolution at swift.org>> wrote:
>> 
>> on Sun Mar 13 2016, Shawn Erickson <swift-evolution at swift.org <mailto:swift-evolution at swift.org>> wrote:
>> 
>> > On Fri, Mar 11, 2016 at 1:30 PM Dave Abrahams via swift-evolution <
>> > swift-evolution at swift.org <mailto:swift-evolution at swift.org>> wrote:
>> >
>> >>
>> >> Anyone who wants to measure is free to do so: simple regexps and wc
>> >> generally work for this purpose.
>> >>
>> >>
>> >> https://github.com/apple/swift-3-api-guidelines-review/tree/swift-3/Platforms <https://github.com/apple/swift-3-api-guidelines-review/tree/swift-3/Platforms>
>> >>
>> >
>> > Not sure if anyone actually got around to this so doing a basic set of
>> > regex (includes class functions and overrides)...
>> >
>> > func foo(bar baz:Baz... ---> 10544
>> > func foo(baz:Baz... ---> 526
>> > func foo(_:Baz... ---> 92
>> > func foo() ---> 7392
>> 
>> Are you certain?  Last we checked it was about 50/50 between having and
>> not-having a distinct argument label.
>> 
>> --
>> -Dave
>> 
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