Thanks for writing this up.
Some quick points.
Firstly, I think it is best if the `init(_ forwardeeReturnValue:
Forwardee)`-style initializer be replaced by something with a distinctly-named
argument, e.g. `init(forwardeeReturnValue value: Forwardee)`.
For use with actual wrapper types the “init(_ wrappedValue: Wrapped)`-style
init is too valuable to “claim” for this purpose (in particular b/c we may want
to “adjust" the forwarded result); it’s IMHO better if we use a distinct `init`
for the forwardee-return-value scenario so we know where the value is coming
from.
Secondly, I would prefer partial-forwarding be given more consideration, b/c it
seems somewhat common for me in practice at this time.
EG: I would do the following somewhat frequently:
struct FooIdentifier: Equatable, Comparable, Hashable
class Foo {
let identifier: FooIdentifier
let name: String
forward Hashable to identifier
}
func ==(lhs: Foo, rhs: Foo) -> Bool {
return lhs.identifier == rhs.identifier && lhs.name == rhs.name
}
…even though I agree that full-forwarding would the most-common scenario.
I have a few other similar cases involving non-standard-library types but they
all fit the same basic pattern as above for `Hashable`.
Finally, I’m actually at a bit of a loss for too many uses for the generic
forwarding mechanism; if it was added I’d use it to streamline some wrapper
types, but beyond that I’m not seeing all that many places where I’d do much
more than that with this feature if added.
Any chance at adding a few more-concrete motivating examples for the fancier
cases?
> On Dec 29, 2015, at 10:37 AM, Matthew Johnson via swift-evolution
> <[email protected]> wrote:
>
> I have completed a first draft of a proposal to introduce automatic protocol
> forwarding. I’m looking forward to feedback from everyone!
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