'Default' implementation in protocol extension is used as fail safe. You should
not consider it like something super class does. If you want it that way, use
class inheritance instead.
Zhaoxin
Get Outlook for iOS
_____________________________
From: Rick Mann via swift-users <[email protected]>
Sent: 星期三, 十一月 16, 2016 07:51
Subject: Re: [swift-users] Attempting to call default protocol implementation
crashes Playground
To: Dan Loewenherz <[email protected]>
Cc: swift-users <[email protected]>
Well, this is a standard protocol default implementation. I was experimenting
to see if it was possible to call the default implementation after providing a
concrete implementation.
> On Nov 15, 2016, at 14:47 , Dan Loewenherz <[email protected]> wrote:
>
> What are you trying to accomplish here, more concretely?
>
> My first thought is that you shouldn't implement the same function in both a
> protocol extension and a conforming class. Why not just give them different
> names and call the function from within the extension instead of from the
> class? E.g.
>
> protocol FooPro {
> func _fooFunc()
> }
>
> extension FooPro {
> func fooFunc() {
> print("fooFunc default")
> _fooFunc()
> }
> }
>
> class FooClass: FooPro {
> func _fooFunc() {
> print("fooFunc FooClass")
> }
> }
>
> let fc = FooClass()
> fc.fooFunc()
>
> Dan
>
> On Tue, Nov 15, 2016 at 4:28 PM, Rick Mann via swift-users
> <[email protected]> wrote:
> The following gives Xcode 8.1 a very hard time. Eventually I get a Bad Access
> on the last line. I'm guessing it's a recursive call. Is there any way to
> call the default implementation from a "real" implementation?
>
> protocol FooPro
> {
> func fooFunc()
> }
>
> extension FooPro
> {
> func
> fooFunc()
> {
> print("fooFunc default")
> }
> }
>
> class FooClass : FooPro
> {
> func
> fooFunc()
> {
> (self as FooPro).fooFunc()
> print("fooFunc FooClass")
> }
> }
>
> let fc: FooPro = FooClass()
> fc.fooFunc()
>
>
> Thanks!
>
>
> --
> Rick Mann
> [email protected]
>
>
> _______________________________________________
> swift-users mailing list
> [email protected]
> https://lists.swift.org/mailman/listinfo/swift-users
>
--
Rick Mann
[email protected]
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