on Fri Apr 01 2016, Maximilian Hünenberger <[email protected]> wrote:
> See inline > >> Am 31.03.2016 um 20:14 schrieb Dave Abrahams via swift-evolution >> <[email protected]>: >> >> >>> on Tue Mar 29 2016, Jason Sadler <[email protected]> wrote: >>> >>> Hi folks, >>> >>> I have an issue with using a heterogeneous array of objects conforming >>> to a protocol - I want to write an extension on Array (or >>> CollectionType) that applies only when Element : MyProtocol, but I >>> can’t call methods in that extension from an instance of [MyProtocol] >>> because "Using ‘MyProtocol' as a concrete type conforming to protocol >>> ‘MyProtocol' is not supported” >> >> Hint: write your extension so it applies when Element == MyProtocol instead. >> > > Why don't we also imply `Element == MyProtocol` when using `Element: > MyProtocol` ? Because Element == MyProtocol is more restrictive; it doesn't allow arbitrary types that conform to—but are not—MyProtocol. > > Both extensions can have the exact same functions/implementation. > Am I missing something? > I currently don't see why we are forced to distinguish between homogeneous > and heterogeneous Collections. > > Kind regards > - Maximilian > >>> (For more background, my full use case can be seen in this gist: >>> https://gist.github.com/sadlerjw/2cc16b4375b02fe7f400) >>> >>> I’ve asked about this on swift-users >>> (https://lists.swift.org/pipermail/swift-users/Week-of-Mon-20160321/001560.html) >>> and got some good workarounds but no one was able to provide me with >>> information on any future plans in swift to address this issue - >>> whether that’s making protocols conform to themselves, or some other >>> improved approach to heterogeneous collections. I wonder if anyone >>> here can shed some light on this? (I’m new to the mailing lists, >>> sorry!) >> >> -- >> Dave >> >> _______________________________________________ >> swift-evolution mailing list >> [email protected] >> https://lists.swift.org/mailman/listinfo/swift-evolution > _______________________________________________ > swift-evolution mailing list > [email protected] > https://lists.swift.org/mailman/listinfo/swift-evolution -- Dave _______________________________________________ swift-evolution mailing list [email protected] https://lists.swift.org/mailman/listinfo/swift-evolution
