[swift-evolution] [Proposal]: support disable to trailing closure syntax

[Jérôme Duquennoy]

Hi everybody,

I do agree with Kevin : trailing closures is only a possibility offered by the language, you are not forced to use it.
In the case you show, I agree that the second syntax is more readable than the first one. Good news is : it does compile :-).

I think adding a specific keyword or annotation to locally forbid trailing closure would add complexity to the language for no real advantage.

-1 for me thus.

Jerome


> On 04 Jan 2016, at 19:52, Kevin Ballard via swift-evolution <swift-evolution at swift.org> wrote:
> 
> What's the point of this? What problem does it solve? If you don't want a trailing closure, just don't use trailing closure syntax. I don't see what benefit there is in explicitly annotating the function to disallow trailing closure syntax with it; just because you don't want to use trailing closure syntax doesn't mean nobody should be able to use it. And other people using it shouldn't affect you.
>  
> -Kevin Ballard
>  
> On Mon, Jan 4, 2016, at 04:45 AM, QQ Mail via swift-evolution wrote:
>> Hi, All: 
>> trailing closure is good for most cases, but sometimes it is also make code unclear, for example: 
>>  
>> UIView.animateWithDuration(0.3, animations: { () -> Void in
>> // animation code here
>>     }) { (Bool) -> Void in
>> // completion code here
>> }
>>  
>> the label been removed and the code also not aligned well. 
>> I would like to write like this: 
>>  
>> UIView.animateWithDuration(0.3,
>> 
>>     animations: { () -> Void in
>> // animation code here
>>     },
>>     completion: { Bool -> Void in
>> // completion code here
>>     }
>> )
>>  
>> It is possible, just every time you have to write it manually. It’s a little wast.
>> So I have a thought, since we already know this function is not well suit for trailing 
>> closure, can we add a attribute to disable it, for example: 
>>  
>> extensionUIView {
>>  
>> @disable_trailing_closure
>>     public static func animateWithDuration(duration:NSTimeInterval, animations:()->Void, completion:()->Void) {
>> // implementations ...
>>     }
>> }
>>  
>> I also found another one have issue for this too. link: http://www.natashatherobot.com/swift-trailing-closure-syntax/ <http://www.natashatherobot.com/swift-trailing-closure-syntax/>
>> what do you think?
>>  
>> Best Regards
>>  
>> ChenYungui
>> 
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>  
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