[swift-evolution] [Review] SE-0194: Derived Collection of Enum Cases
tony.allevato at gmail.com
Tue Jan 9 10:45:02 CST 2018
On Mon, Jan 8, 2018 at 11:02 AM Douglas Gregor via swift-evolution <
swift-evolution at swift.org> wrote:
> Hello Swift community,
> The review of SE-0194 "Derived Collection of Enum Cases" begins now and
> runs through January 11, 2018. The proposal is available here:
> 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
> review manager. When replying, please try to keep the proposal link at the
> top of the message:
> Proposal link:
> Reply text
> Other replies
> goes into a review?
> The goal of the review process is to improve the proposal under review
> through constructive criticism and, eventually, determine 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?
> Big +1. I've been looking forward to something like this for a long time.
I'm extremely happy with the API chosen here. ValueEnumerable and allValues
are absolutely the correct names, because the protocol is not *restricted*
to enums, it is merely *synthesized automatically* for enums. That's a very
important distinction. Someone could provide their own conformance to
ValueEnumerable and use it in generic algorithms and have everything work
In a perfect world I would argue that the associated type of allValues
should be a Sequence instead of a Collection as this would allow it to be
extended to infinite sequences (i.e., cases with associated values that are
deeply ValueEnumerable), but I'll admit that I've never come up with a
compelling use case for this beyond obscure combinatorial algorithms. Since
getting the count of values is important to many users, Collection is a
reasonable compromise and I don't have any objections.
> - Is the problem being addressed significant enough to warrant a
> change to Swift?
> Yes. It's a frequently requested feature and has utility both in UI-driven
logic (table view sections based on an enum) and other algorithms.
> - Does this proposal fit well with the feel and direction of Swift?
> Yes. The API design fits right into other stdlib concepts, and the
conditions for synthesis align with the synthesis of other synthesized
> - If you have used other languages or libraries with a similar
> feature, how do you feel that this proposal compares to those?
> Just Java's values() function that is present on all enums. The
functionality provided here is what I would expect, similar to other
> - How much effort did you put into your review? A glance, a quick
> reading, or an in-depth study?
> An in-depth read and I was heavily involved in some of the earlier
> More information about the Swift evolution process is available at
> Thank you,
> -Doug Gregor
> Review Manager
> swift-evolution mailing list
> swift-evolution at swift.org
-------------- next part --------------
An HTML attachment was scrubbed...
More information about the swift-evolution