Hello Swift community,
The review of "SE-0095: Replace `protocol<P1,P2>` syntax with
`Any<P1,P2>`" begins now and runs through June 27. The proposal is
Reviews are an important part of the Swift evolution process. All reviews
should be sent to the swift-evolution mailing list at
or, if you would like to keep your feedback private, directly to the
What goes into a review?
The goal of the review process is to improve the proposal under review
through constructive criticism and contribute to the direction of Swift.
When writing your review, here are some questions you might want to answer
in your review:
* What is your evaluation of the proposal?
+1. This syntax is clean and its meaning is very clear ("what is A & B? A
type that conforms to A and B").
* Is the problem being addressed significant enough to warrant a
change to Swift?
Yes, and it's important to address now. As the type system becomes richer
in the future with the completion of generics, combined with Swift's
protocol-driven design philosophies, this feature will get much heavier use
going forward. Having a clean, simple, terse syntax to express multiple
protocol conformances (and eventually concrete type relationships) will
make those features much easier to use without being cluttered by keywords
and potential nested-angle-bracket hell.
The previously proposed Any<...> syntax suffers from ambiguity of meaning:
does it mean "a type that conforms to any of these..." or "any type that
conforms to all of these..."? Turns out it's the latter. The use of "&"
removes that ambiguity completely.
* Does this proposal fit well with the feel and direction of Swift?
Yes. It will go a long way toward making protocol-driven designs and
generics great to use.
* If you have used other languages or libraries with a similar
feature, how do you feel that this proposal compares to those?
* How much effort did you put into your review? A glance, a quick
reading, or an in-depth study?
Read the proposal and participated a small amount in the earlier
On Wed, Jun 22, 2016 at 11:04 AM Chris Lattner via swift-evolution < firstname.lastname@example.org> wrote:
More information about the Swift evolution process is available at
swift-evolution mailing list