[swift-evolution] [Discussion] Enforcing Calling Super

[Jean-Daniel Dupas]

> Le 25 févr. 2016 à 20:19, Matthew Johnson via swift-evolution <swift-evolution at swift.org> a écrit :
> 
> 
> 
> Sent from my iPad
> 
>> On Feb 25, 2016, at 1:17 PM, Jean-Daniel Dupas via swift-evolution <swift-evolution at swift.org> wrote:
>> 
>> 
>>> Le 25 févr. 2016 à 16:47, Jeremy Pereira via swift-evolution <swift-evolution at swift.org> a écrit :
>>> 
>>> 
>>>> On 17 Feb 2016, at 22:26, Kyle Sherman via swift-evolution <swift-evolution at swift.org> wrote:
>>>> 
>>>> Thanks for the replies.
>>>> 
>>>> Kenny: After thinking about it more, discussing with Peter, and looking Haravikk’s comments, I think the best thing would be for this to be a warning as suggested. I respectfully disagree that as a library creator you would not be able to know that a call to super should be required.
>>> 
>>> I disagree. You can’t possibly know all the use-cases in which your class might be subclassed. 
>>> 
>>> In particular, it is absurd to enforce having the call to super as the first or last line of the method. That would stop me doing things like this:
>>> 
>>>  override func viewDidLoad()
>>>  {
>>>      print(“About to run super.viewDidLoad()”)
>>>      super.viewDidLoad()
>>>      print(“Finished super.viewDidLoad()”)
>>>  }
>>> 
>>> Then there’s the perfectly reasonable case like this:
>>> 
>>>  override func viewDidLoad()
>>>  {
>>>      functionThatCallsSuperViewDidLoad()
>>>  }
>>> 
>>> Why shouldn’t I be allowed to do that?
>> 
>> +1 with your concern. I’d be curious to see a single real world use case where enforcing first or last is required.
> 
> I posted several examples from Apple frameworks in an old thread about this.  You might want to look for that message in the archives.

And not a single one has a strong requirement about prohibiting code to be call before or after the super class implementation.