Afair I was the first to argue against this plan, and I still think the problem in question is better solved with Default implementations in protocol declarations (combined with the func Protocol.method() idea) instead of adding a keyword.
But I think with a small yet significant change default func could become much more useful:
extension ExampleProtocol {
// Error 1
// Error: Does not satisfy any known protocol requirement
// Fixit: replace type with Float
public default func thud(with value: Double) { ... }
}
Instead of throwing an error, we could "simply" add thud to the official methods declared in ExampleProtocol.
Basically, this would solve the disadvantage of to much repetition from the other direction, because obviously, you wouldn't include that method in the declaration anymore.
That alone imho still doesn't justify a change -- but there's more:
protocol Foo {
var foo: String { get }
}
protocol Bar {
var bar: String { get }
}
extension Foo where Self: Bar {
default func foobar() {
print(foo, bar)
}
}
class Foobar: Foo, Bar {
var bar: String = "bar"
var foo: String = "foo"
}
Foobar().foobar()
If we could do this (it might be rather complicated, and nothing for the near future -- we might even have extension Foo & Bar by then ;-), we could define all kinds of functionality that is possible when some protocols are combined (maybe there's even a specific example where for that ;-)