[swift-evolution] [Discussion] Modernizing Attribute Case and Attribute Argument Naming

[Erica Sadun]

How would you re-design the existing upper camel attributes then?

They are: @UIApplicationMain, @NSManaged, @NSCopying, @NSApplicationMain, @IBAction, @IBDesignable, @IBInspectable, and @IBOutlet

-- E


> On Feb 17, 2016, at 10:29 PM, Brent Royal-Gordon <brent at architechies.com> wrote:
> 
>> @Autoclosure // was @autoclosure
>> @Available // was @available
>> @ObjC // was @objc
>> @NoEscape // was @noescape
>> @NonObjC // was @nonobjc
>> @NoReturn // was @noreturn
>> @Testable // was @testable
>> @WarnUnusedResult // was @warn-unused-result
>> @Convention  // was @convention
>> @NoReturn // was @noreturn
>> 
>> In the revised design, the following example for Swift 2.2
>> 
>> @warn_unused_result(mutable_variant="sortInPlace")
>> public func sort() -> [Self.Generator.Element]
>> 
>> becomes
>> 
>> @WarnUnusedResult(mutableVariant: "sortInPlace")
>> public func sort() -> [Self.Generator.Element]
> 
> Wow, I'm surprised by how much I hate this. Currently, all Swift keywords are entirely lowercase (ignoring things like `Type`, `Protocol`, and `dynamicType` which come after a dot). I think I've learned to half-ignore things that look like that, but capitalizing suddenly pulls the spotlight onto these keywords. I'm just not a fan.
> 
> I think we're better off renaming or redesigning `warn_unused_result` so that it's readable when it's all-lowercase with no underscores. Some ideas:
> 
> 	@onlyreturns func sorted() -> [Self.Generator.Element]
> 	func sorted() -> @important [Self.Generator.Element]
> 
> Alternatively, we could reverse the semantic and make all all non-Void functions warn unless they have an attribute saying not to.
> 
> 	@ignoreresult mutating func updateValue(value: Value, forKey key: Key) -> Value?
> 	mutating func updateValue(value: Value, forKey key: Key) -> @ignorable Value?
> 	mutating func updateValue(value: Value, forKey key: Key) -> @convenience Value?
> 
> If we do that, we'll likely still want to be able to annotate non-mutating methods with their mutating variants (well, unless we think the compiler can guess based on the API Guidelines.)
> 
> 	@variant(mutating: "sort") func sorted() -> [Self.Generator.Element]
> 	@alternative(mutating: "sort") func sorted() -> [Self.Generator.Element]
> 
> That opens the possibility of using `@variant(nonmutating:)` on mutating functions, too.
> 
> -- 
> Brent Royal-Gordon
> Architechies
>