I’m overall +1, but I’m curious: would you be able to conform an enum from another module to ValueEnumerable via an extension, and still have the compiler generate the protocol requirements for you? I can imagine that the client of a framework with an enum may have a valid use for iterating over all values that the author didn’t foresee, and I would very much like the client to be able to opt-in to the compiler code generation.
(Personally, I’d prefer that all simple enums automatically conform to the protocol and have automatic implementations, since I don’t really see a downside to this that exists for some other compiler-magic protocols like Codable) > On Jan 9, 2018, at 8:45 AM, Tony Allevato via swift-evolution > <swift-evolution@swift.org> wrote: > >> On Mon, Jan 8, 2018 at 11:02 AM Douglas Gregor via swift-evolution >> <swift-evolution@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: >> >> https://github.com/apple/swift-evolution/blob/master/proposals/0194-derived-collection-of-enum-cases.md >> Reviews are an important part of the Swift evolution process. All reviews >> should be sent to the swift-evolution mailing list at >> >> https://lists.swift.org/mailman/listinfo/swift-evolution >> 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: >> >> https://github.com/apple/swift-evolution/blob/master/proposals/0194-derived-collection-of-enum-cases.md >> Reply text >> Other replies >> What 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 as > expected. > > 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 protocols. > > >> 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 languages. > > >> 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 discussion > threads. > > >> More information about the Swift evolution process is available at >> >> https://github.com/apple/swift-evolution/blob/master/process.md >> Thank you, >> >> -Doug Gregor >> >> Review Manager >> >> _______________________________________________ >> swift-evolution mailing list >> swift-evolution@swift.org >> https://lists.swift.org/mailman/listinfo/swift-evolution > _______________________________________________ > swift-evolution mailing list > swift-evolution@swift.org > https://lists.swift.org/mailman/listinfo/swift-evolution
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