[swift-evolution] [Review] SE-0036: Requiring Leading Dot Prefixes for Enum Instance Member Implementations

Dave Abrahams dabrahams at apple.com
Sat Apr 2 12:13:06 CDT 2016

Matthew Johnson via swift-evolution
<swift-evolution at swift.org> wrote:
>> On Apr 1, 2016, at 4:07 PM, Dave Abrahams via swift-evolution
>> <swift-evolution at swift.org> wrote:
>> Douglas Gregor via swift-evolution
>> <swift-evolution at swift.org> wrote:
>>> Hello Swift community,
>>> The review of SE-0036 "Requiring Leading Dot Prefixes for Enum Instance
>>> Member Implementations" begins now and runs throughApril 5, 2016. The
>>> proposal is available here:
>>> https://github.com/apple/swift-evolution/blob/master/proposals/0036-enum-dot.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
>>> <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/0036-enum-dot.md
>>> Reply text
>>> Other replies
>>> <https://github.com/apple/swift-evolution#what-goes-into-a-review-1>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?
>>> Is the problem being addressed significant enough to warrant a change to Swift?
>>> Does this proposal fit well with the feel and direction of Swift?
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>>> How much effort did you put into your review? A glance, a quick reading,
>>> or an in-depth study?
>>> More information about the Swift evolution process is available at
>>> https://github.com/apple/swift-evolution/blob/master/process.md
>>> <https://github.com/apple/swift-evolution/blob/master/process.md>
>>> Thank you,
>>> Doug Gregor
>>> Review Manager
>> This proposal seems to me like it's failing to fix the underlying problem,
>> which is that people don't understand the leading dot rules, and papering
>> over the problem by making the rule less consisten, with different behavior
>> for enums and other type-scoped (static/class) entities. It doesn't seem
>> like a principled solution to me. 
> This proposal doesn’t change the leading dot rules at all.  What it does
> is make the rules for referencing static members *more* consistent than
> they are now, removing the special case for enum cases.
> "Enumeration cases are essentially static not instance type members.
> Unlike static members in structures and classes, enumeration cases can be
> mentioned in initializers and instance methods without referencing a
> fully qualified type. This makes little sense. In no other case can an
> instance implementation directly access a static member."
> I believe at one point in Swift’s history all static members could be
> referenced directly.  This proposal seems like it is cleaning up a case
> that was missed when that changed. 

I believe I misread the proposal and you are right.

I do have reservations about leading dot syntax that are highlighted by
this sentence in the proposal:

A leading dot has become a conventional shorthand for "enumeration case"
across the language.

That isn't in fact what it means, and if we have to play into that
misperception I think it indicates a bigger problem. But we can handle that
outside of this review. 

>> -- 
>> -Dave
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