[swift-evolution] [Proposal Draft] automatic protocol forwarding

[Matthew Johnson]

Sent from my iPad

> On Dec 30, 2015, at 12:52 AM, Thorsten Seitz <tseitz42 at icloud.com> wrote:
> 
> Thanks for proposing this, Matthew!
> 
> Am 30. Dezember 2015 um 03:05 schrieb Matthew Johnson via swift-evolution <swift-evolution at swift.org>:
> 
>>>>> * Why the method-based conversion syntax for return values, rather than something a little more like a property declaration?
>>>>> 
>>>>>  var number: Int
>>>>>  forward IntegerType to number {
>>>>>   static return(newValue: Int) {
>>>>>    return NumberWrapper(newValue)
>>>>>   }
>>>>>   return(newValue: Int) {
>>>>>    return NumberWrapper(newValue)
>>>>>   }
>>>>>  }
>>>> 
>>>> This is actually a really good idea to consider!  I didn’t consider something like this mostly because I didn’t think of it.  I’m going to seriously consider adopting an approach along these lines.
>>> 
>>> Great.
>>> 
>>>> One possible advantage of the approach I used is that the initializer may already exist for other reasons and you would not need to do any extra work.
>>> 
>>> True. But it may also exist and *not* do what you want in the forwarding case. It's easier to explicitly use the right initializer than it is to work around the forwarding system implicitly using the wrong one.
>> 
>> Right, I am generally leaning pretty strongly towards changing the proposal to use a solution similar to what you suggest.
> 
> 
> That's great. I was about to suggest something similar (like having to name the conversion functions used in the forward clause) when I read Brent's proposal which is much more elegant, so I'd like to support that. Making this explicit without some "implicit magic" is truely important.

Yes, I am definitely going in this direction.  I want to think it over a bit more and will update the proposal soon.

> 
> The one thing I'm missing is some real-life examples which would be really helpful to consider this proposal properly (Dave Abrahams already pointed this out).

I'm working on this right now.  I was really looking forward to feedback on the solution so I decided to share a draft before the motivation was fully written.  Maybe that was a mistake, or at least should have been called out more clearly.

> 
> -Thorsten
> 
>