> On Apr 4, 2016, at 11:44 AM, Dave Abrahams <dabrah...@apple.com> wrote: > > > on Mon Apr 04 2016, Joe Groff <jgroff-AT-apple.com> wrote: > >>> On Apr 4, 2016, at 11:05 AM, Dave Abrahams via swift-evolution >>> <swift-evolution@swift.org> wrote: >>> >>> >>> on Mon Apr 04 2016, Erica Sadun <swift-evolution@swift.org> asked: >>> >> >>>> Can you ping me off-list or in another thread and explain what the >>>> issues are? >>> >>> All of the following make me uncomfortable with our leading-dot thang: >>> >>> * The rules for lookup don't seem obvious to me. I admit this is very >>> personal/subjective. >>> >>> * There is some evidence that people think it means something it doesn't >>> (“enum case”), as mentioned in SE-0036. That suggests it is a >>> confusing feature. That confusion may be fairly harmless so far, but >>> still. >>> >>> * The dot doesn't seem to buy enough to be worth the complexity it adds >>> to the language; why not just let those names be looked up without the >>> dot? You can always disambiguate with full qualification if you have >>> to. >> >> Making every unqualified reference context-dependent would be >> impractical. `foo.bar(bas)` would become an exponential search to find >> a contextual type containing a `foo` which has a `bar` member that can >> accept an type containing a `bas` member. > > I don't think I'm talking about making every unqualified reference > context-dependent. When I have a context that demands an instance of a > particular enum type, I think it's reasonable to look up the names in > the enum without qualification, and I strongly question the value of > leading-dot syntax for general static member lookup.
Therein lies the rub—*any* context an unqualified name can appear in could potentially demand an instance of a particular enum type, until the type checker rules that out. Limiting the behavior to enums doesn't simplify the implementation. > I would normally > never think of using it that way—because, guess what? I think of > leading-dot as a notation for enums like everybody else does—and I don't > think there are any important idioms it supports, that couldn't be > equally well handled by something like `Self.x` if we were allowed to > use it. Enums are only the most common place where static members of Self type appear in numbers, but option sets also do. While this may be a matter of taste, being able to refer to `.max`, `.infinity`, `.nan`, or other abstract constants of numeric types in a concrete-type-agnostic way also seems like a win to me. -Joe _______________________________________________ swift-evolution mailing list swift-evolution@swift.org https://lists.swift.org/mailman/listinfo/swift-evolution
