on Fri Apr 29 2016, Erica Sadun <[email protected]> wrote:
> Gmane is down as far as my browser is concerned and I haven't found anything
> by
> Googling.
>
> Given the following:
>
> protocol A {func foo()}
> protocol B {} // empty protocol
>
> extension A where Self:B {
> func foo() {
> print("Self is B")
> }
> }
>
> // Works
> struct S1: A, B {}
> S1().foo()
>
> Is there a way to produce a similar extension that exempts any type that
> conforms to B?
Here's one horrible answer:
protocol A {
func foo()
}
protocol B {} // empty protocol
extension B {
func foo() {
fatalError("uncallable")
}
}
extension A {
func foo() {
print("Self is not B")
}
}
// Works
struct S0: A {
func foo() {
print("Self is S0")
}
}
S0().foo()
// Fails
struct S1: A, B {}
S1().foo()
I'm sure there are other awful things one could do, too. :-)
--
Dave
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