[swift-evolution] [Pitch] Introducing role keywords to reduce hard-to-find bugs

[David Hart]

Okay, I undertand. I’m just worried that the proposal is a net negative if the keywords stay optional. I’ll mention it in more detail once we get to the review period.

Thanks for the work on the proposal!!

> On 16 Jun 2017, at 16:33, Erica Sadun <erica at ericasadun.com> wrote:
> 
> As we say in our introduction, we're pitching the most conservative approach. 
> 
> The proposal was designed for minimal language impact. It chooses a conservative approach that can be phased in first over time and language release over more succinct alternatives that would impact existing code bases.
> 
> We discuss the one keyword version (which most of us are a fan of) in the alternatives. The core team has to decide how much they're willing to allow existing code to warn and/or break, which is the consequence of the one keyword solution.
> 
> -- E
> 
>> On Jun 16, 2017, at 7:44 AM, David Hart <davidhart at fastmail.com <mailto:davidhart at fastmail.com>> wrote:
>> 
>> Erica, any thoughts on only having default and making it an error in a future version of Swift like was discussed on this thread? The idea seems to have a few supporters.
>> 
>>> On 16 Jun 2017, at 15:33, Erica Sadun via swift-evolution <swift-evolution at swift.org <mailto:swift-evolution at swift.org>> wrote:
>>> 
>>> 
>>>> On Jun 14, 2017, at 11:46 PM, Dave Abrahams via swift-evolution <swift-evolution at swift.org <mailto:swift-evolution at swift.org>> wrote:
>>>> 
>>>> 
>>>> on Wed Jun 14 2017, Chris Lattner <swift-evolution at swift.org <mailto:swift-evolution at swift.org>> wrote:
>>>> 
>>>>>> On Jun 14, 2017, at 10:11 AM, Erica Sadun via swift-evolution
>>>>>> <swift-evolution at swift.org <mailto:swift-evolution at swift.org>> wrote:
>>>>>> 
>>>>>> Some pals and I have been kicking an idea around about introducing
>>>>>> better ways to support the compiler in protocol extensions. We want
>>>>> 
>>>>>> to eliminate some hard-to-detect bugs. We've been brainstorming on
>>>>>> how to do this without affecting backward compatibility and
>>>>>> introducing a minimal impact on keywords.
>>>>>> 
>>>>>> We'd love to know what you think of our idea, which is to introduce
>>>>>> "role" keywords. Roles allow the compiler to automatically check the
>>>>>> intended use of a extension member definition against its protocol
>>>>>> declarations, and emit errors, warnings, and fixits as needed.  We
>>>>>> think it's a pretty straightforward approach that, if adopted,
>>>>>> eliminates an entire category of bugs.
>>>>>> 
>>>>>> The draft proposal is here:
>>>>>> https://gist.github.com/erica/14283fe18254489c1498a7069b7760c4 <https://gist.github.com/erica/14283fe18254489c1498a7069b7760c4>
>>>>>> <https://gist.github.com/erica/14283fe18254489c1498a7069b7760c4 <https://gist.github.com/erica/14283fe18254489c1498a7069b7760c4>>
>>>>>> 
>>>>>> Thanks in advance for your thoughtful feedback,
>>>>> 
>>>>> +1 on the idea of this.  
>>>> 
>>>> ditto.  IMO it also makes the protocol extension much more expressive
>>>> and easy to read.
>>>> 
>>>> -- 
>>>> -Dave
>>> 
>>> 
>>> Pull request: https://github.com/apple/swift-evolution/pull/724 <https://github.com/apple/swift-evolution/pull/724>
>>> 
>>> -- E
>>> 
>>> _______________________________________________
>>> swift-evolution mailing list
>>> swift-evolution at swift.org <mailto:swift-evolution at swift.org>
>>> https://lists.swift.org/mailman/listinfo/swift-evolution <https://lists.swift.org/mailman/listinfo/swift-evolution>
>> 
> 

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.swift.org/pipermail/swift-evolution/attachments/20170616/b5d1caad/attachment.html>