> On Feb 22, 2017, at 8:25 PM, Derrick Ho via swift-evolution
> <swift-evolution@swift.org> wrote:
>
> Did you know you can use a static variable as a default parameter?
>
> class poncho {
> static var color= "yellow"
>
> func foo(color: String = poncho.color){}
> }
>
> I think instance members should not be allowed as default members though. It
> may lead to unexpected behavior.
Could you explain or give an example of how the behavior would be unexpected?
> On Wed, Feb 22, 2017 at 11:06 PM T.J. Usiyan via swift-evolution
> <swift-evolution@swift.org <mailto:swift-evolution@swift.org>> wrote:
> +1 if this doesn't have terrible implications.
>
> The downside to making it IUO or Optional is that that changes the type
> signature of `index(i:offsetBy:)` for no reason other than a default value.
> If you decide to change to or away from providing a default value it probably
> shouldn't change the type accepted in that spot.
>
> On Wed, Feb 22, 2017 at 7:32 PM, Ben Cohen via swift-evolution
> <swift-evolution@swift.org <mailto:swift-evolution@swift.org>> wrote:
>
>> On Feb 22, 2017, at 10:42 AM, Nate Cook via swift-evolution
>> <swift-evolution@swift.org <mailto:swift-evolution@swift.org>> wrote:
>>
>> Oops, left out that there's this horrifying way of writing it right now:
>>
>> extension Collection {
>> func index(_ i: Index! = nil, offsetBy n: IndexDistance) -> Index {
>> let i = i ?? startIndex
>> // ...
>> }
>> }
>>
>> Nobody wants that.
>>
>
> Oh I don’t think it’s all that bad! It also doesn’t need to be an IUO, since
> you’re unwrapping it immediately into another variable no matter what.
>
> This also gives you the flexibility to write this:
>
> extension Collection {
> func index(_ i: Index? = nil, offsetBy n: IndexDistance) -> Index {
> let i = i ?? (n < 0 ? endIndex : startIndex)
> // ...
> }
> }
>
>> _______________________________________________
>> swift-evolution mailing list
>> swift-evolution@swift.org <mailto:swift-evolution@swift.org>
>> https://lists.swift.org/mailman/listinfo/swift-evolution
>> <https://lists.swift.org/mailman/listinfo/swift-evolution>
>
>
> _______________________________________________
> swift-evolution mailing list
> swift-evolution@swift.org <mailto:swift-evolution@swift.org>
> https://lists.swift.org/mailman/listinfo/swift-evolution
> <https://lists.swift.org/mailman/listinfo/swift-evolution>
>
>
> _______________________________________________
> swift-evolution mailing list
> swift-evolution@swift.org <mailto:swift-evolution@swift.org>
> https://lists.swift.org/mailman/listinfo/swift-evolution
> <https://lists.swift.org/mailman/listinfo/swift-evolution>
> _______________________________________________
> swift-evolution mailing list
> swift-evolution@swift.org
> https://lists.swift.org/mailman/listinfo/swift-evolution
_______________________________________________
swift-evolution mailing list
swift-evolution@swift.org
https://lists.swift.org/mailman/listinfo/swift-evolution
