What if you wanted to filter such that you keep values less than some element that happens to be positive zero; might that keep around any negative zeros? Seems problematic.
> On Jul 22, 2016, at 7:53 PM, Dave Abrahams <dabrah...@apple.com> wrote: > > >> on Fri Jul 22 2016, Xiaodi Wu <xiaodi.wu-AT-gmail.com> wrote: >> >>> On Fri, Jul 22, 2016 at 9:38 PM, <jaden.gel...@gmail.com> wrote: >>> >>> This seems reasonable to me. I don't see why `===` has to do a total order >>> comparison when we already have another operator, `<=>`, that does that. >> >> I take it back. It wouldn't solve the issue that generic `<` would >> still behave in surprising ways, where two equal floating point values >> represented differently might be less than each other or greater than >> each other. > > I wonder if that's really a problem. What generic algorithm are you > going to run on a collection of floats where it *would* be problematic? > Hmm, stableSort would not necessarily preserve the order of zeros in the > original collection if it contained both positive and negative zeros. > >> I think what we really want is all identity and comparison divorced >> from IEEE totalOrder. > > That might work. Thanks for thinking this problem through; keep it up! > >>> On Jul 22, 2016, at 7:35 PM, Xiaodi Wu <xiaodi...@gmail.com> wrote: >>> >>> On Fri, Jul 22, 2016 at 9:28 PM, Dave Abrahams <dabrah...@apple.com> >>> wrote: >>> >>>> >>>>> on Fri Jul 22 2016, Xiaodi Wu <xiaodi.wu-AT-gmail.com> wrote: >>>>> >>>>> On Fri, Jul 22, 2016 at 9:13 PM, Matthew Johnson < >>>> matt...@anandabits.com> >>>>> wrote: >>>>> >>>>>> >>>>>> On Jul 22, 2016, at 9:10 PM, Xiaodi Wu <xiaodi...@gmail.com> wrote: >>>>>> >>>>>> On Fri, Jul 22, 2016 at 9:08 PM, Matthew Johnson < >>>> matt...@anandabits.com> >>>>>> wrote: >>>>>> >>>>>>> >>>>>>> On Jul 22, 2016, at 9:04 PM, Xiaodi Wu <xiaodi...@gmail.com> wrote: >>>>>>> >>>>>>> On Fri, Jul 22, 2016 at 8:57 PM, Matthew Johnson < >>>> matt...@anandabits.com> >>>>>>> wrote: >>>>>>> >>>>>>>> >>>>>>>> On Jul 22, 2016, at 8:54 PM, Xiaodi Wu via swift-evolution < >>>>>>>> swift-evolution@swift.org> wrote: >>>>>>>> >>>>>>>> On Fri, Jul 22, 2016 at 8:52 PM, Jaden Geller via swift-evolution < >>>>>>>> swift-evolution@swift.org> wrote: >>>>>>>> >>>>>>>>> "The totalOrder predicate will order these cases, and it also >>>>>>>>> distinguishes between different representations of NaNs and between >>>> the >>>>>>>>> same decimal floating point number encoded in different ways." >>>>>>>>> - [Wikipedia]( >>>> https://en.wikipedia.org/wiki/IEEE_floating_point#Total-ordering_predicate >>>>>>>>> ) >>>>>>>>> >>>>>>>>> Sounds like `===` should not return `true` for zeros of different >>>>>>>>> signs, then. >>>>>>>> >>>>>>>> Fair enough; the result of that will be, as Pyry noted above, that: >>>>>>>> >>>>>>>> ``` >>>>>>>> [-0.0, 1.0, .nan, 0.0].firstIndex(of: 0.0) //=> 3, not 0 >>>>>>>> ``` >>>>>>>> >>>>>>>> >>>>>>>> Maybe we need floating point specific implementations of some >>>> algorithms >>>>>>>> to resolve this problem? >>>>>>>> >>>>>>>> It doesn’t seem like there is a way to provide the semantics >>>> required by >>>>>>>> generic algorithms and still provide the expected behavior for >>>> floating >>>>>>>> point values. >>>>>>> >>>>>>> Well, what I'm trying to say is that generic algorithms such as >>>>>>> `index(of:)` require only an equivalence relation. For floating point >>>>>>> types, there are three ways to slice it: >>>>>>> >>>>>>> 1. NaN != NaN and +0 == -0 [what the traditional comparison operators >>>> are >>>>>>> constrained to do] >>>>>>> 2. NaN == NaN, +0 == -0, and the same number encoded different ways >>>>>>> compare equal >>>>>>> 3. NaN == NaN, +0 != -0, and the same number encoded different ways >>>>>>> compare not equal >>>>>>> >>>>>>> Both #2 and #3 can fall out of valid equivalence relations; if `===` >>>>>>> behaved like #2 for FloatingPoint types, then generic algorithms work >>>> just >>>>>>> fine. If we insist on using a total ordering defined by `<=>` all the >>>> time, >>>>>>> then we've got problems. >>>>>>> >>>>>>> >>>>>>> And if we don’t then we’re back to 3 different concepts of equality. >>>>>>> There is definitely a tradeoff no matter what we choose. >>>>>> >>>>>> If some types have three concepts of equality, each with their >>>> particular >>>>>> use, why must we eliminate one of them? >>>>>> >>>>>> >>>>>> This isn’t about eliminating concepts of equality for a type. They can >>>>>> have 42 if they want. >>>>>> >>>>>> This is about the right way to define the semantics of specific >>>>>> protocols. It says nothing about additional notions of equality a >>>> type may >>>>>> have available. >>>>>> >>>>>> The difficulty is finding a design for the protocols that makes sense >>>> with >>>>>> floating point types because we want them to be able to conform to the >>>>>> protocols. >>>>> >>>>> Agreed. My argument is that if a Comparable can define its own `===`, >>>> still >>>>> supplying a valid equivalence relation but not being constrained by a >>>>> contract that `(a <=> b) == .same` iff `a === b`, then we are good to go >>>>> with floating point types. >>>> >>>> How would that work? Can you spell out the implications, show how <=> >>>> and === would be implemented, and describe what it would mean for >>>> algorithms? >>> >>> Right. I'm not married to this solution anymore, but I do think it could >>> work. There would still be a relationship required between `===` and `<=>`. >>> Namely: >>> >>> `a === b` if `(a <=> b) == .same` >>> >>> But for some values a and b, it is permitted that `a === b && (a <=> b) != >>> .same`. That is, two identical values may be ordered in a total ordering >>> based on *inessential* qualities. >>> Generic algorithms that need to produce a stable ordering of elements will >>> use `<=>`. Those such as `index(of:)` will use `===` to test for identity. >>> Wouldn't that work? >>> >>>> >>>>> On Jul 22, 2016, at 6:48 PM, Dave Abrahams via swift-evolution < >>>>>>>>> swift-evolution@swift.org> wrote: >>>>>>>>> >>>>>>>>> >>>>>>>>> on Fri Jul 22 2016, Jaden Geller <swift-evolution@swift.org> wrote: >>>>>>>>> >>>>>>>>> For floating point, I'd hope that `a === b` if `(a <=> b) == .same` >>>>>>>>> *but not iff*. This is to satisfy IEEE 754: "Comparisons shall >>>>>>>>> ignore the sign of zero (so +0 = −0)". >>>>>>>>> >>>>>>>>> >>>>>>>>> I don't see why both `(+0) === (-0)` and `(+0) <=> (-0)` can't >>>> return >>>>>>>>> `true` and `.same`, respectively. This doesn't break the total >>>>>>>>> ordering of values. `===` doesn't do raw memory comparison. They're >>>>>>>>> "identical", so it ought to return `true`. >>>>>>>>> >>>>>>>>> >>>>>>>>> It ought to do whatever IEEE-754 specifies that its total ordering >>>> test >>>>>>>>> does. That is, IEEE-754 gets to decide whether the difference >>>> between >>>>>>>>> +0 and -0 is “essential” to IEEE-754 floating point types, or not. >>>>>>>>> >>>>>>>>> >>>>>>>>> On Jul 22, 2016, at 6:37 PM, Xiaodi Wu via swift-evolution >>>>>>>>> <swift-evolution@swift.org> wrote: >>>>>>>>> >>>>>>>>> On Fri, Jul 22, 2016 at 8:20 PM, Dave Abrahams via swift-evolution >>>>>>>>> <swift-evolution@swift.org >>>>>>>>> <mailto:swift-evolution@swift.org <swift-evolution@swift.org>>> >>>>>>>>> wrote: >>>>>>>>> >>>>>>>>> on Fri Jul 22 2016, Daniel Duan <daniel-AT-duan.org >>>> <http://daniel-at-duan.org> >>>>>>>>> <http://daniel-at-duan.org/>> wrote: >>>>>>>>> >>>>>>>>> On Jul 22, 2016, at 3:00 PM, Dave Abrahams via swift-evolution >>>>>>>>> <swift-evolution@swift.org >>>>>>>>> <mailto:swift-evolution@swift.org <swift-evolution@swift.org>>> >>>>>>>>> wrote: >>>>>>>>> >>>>>>>>> >>>>>>>>> on Fri Jul 22 2016, Daniel Duan >>>>>>>>> <swift-evolution@swift.org >>>>>>>>> <mailto:swift-evolution@swift.org <swift-evolution@swift.org>> >>>>>>>>> <mailto:swift-evolution@swift.org <swift-evolution@swift.org> >>>>>>>>> <mailto:swift-evolution@swift.org <swift-evolution@swift.org>>>> >>>>>>>>> wrote: >>>>>>>>> >>>>>>>>> >>>>>>>>> On Jul 22, 2016, at 11:05 AM, Dave Abrahams via swift-evolution >>>>>>>>> <swift-evolution@swift.org >>>>>>>>> <mailto:swift-evolution@swift.org <swift-evolution@swift.org>> >>>>>>>>> <mailto:swift-evolution@swift.org <swift-evolution@swift.org> >>>>>>>>> <mailto:swift-evolution@swift.org <swift-evolution@swift.org>>>> >>>>>>>>> wrote: >>>>>>>>> >>>>>>>>> >>>>>>>>> on Thu Jul 21 2016, Duan >>>>>>>>> >>>>>>>>> >>>>>>>>> <swift-evolution@swift.org >>>>>>>>> <mailto:swift-evolution@swift.org <swift-evolution@swift.org>> >>>>>>>>> <mailto:swift-evolution@swift.org <swift-evolution@swift.org> >>>>>>>>> <mailto:swift-evolution@swift.org <swift-evolution@swift.org>>> >>>>>>>>> <mailto:swift-evolution@swift.org <swift-evolution@swift.org> >>>>>>>>> <mailto:swift-evolution@swift.org <swift-evolution@swift.org>> >>>>>>>>> <mailto:swift-evolution@swift.org <swift-evolution@swift.org> >>>>>>>>> <mailto:swift-evolution@swift.org <swift-evolution@swift.org>>>>> >>>>>>>>> wrote: >>>>>>>>> >>>>>>>>> Great proposal. I want to second that areSame may mislead user to >>>>>>>>> think this is about identity. >>>>>>>>> >>>>>>>>> I like areEquivalent() but there may be better names. >>>>>>>>> >>>>>>>>> >>>>>>>>> It really *is* about identity as I posted in a previous message. >>>> But >>>>>>>>> that doesn't change the fact that areEquivalent might be a better >>>> name. >>>>>>>>> It's one of the things we considered; it just seemed long for no >>>> real >>>>>>>>> benefit. >>>>>>>>> >>>>>>>>> >>>>>>>>> If the addresses of the arguments aren’t being used, then we don’t >>>>>>>>> consider >>>>>>>>> them part of their *identity*. I can follow this logic. My fear is >>>> most >>>>>>>>> users >>>>>>>>> won’t make this leap on their own and get the same initial >>>> impression >>>>>>>>> as I did. >>>>>>>>> It's entirely possible this fear is unfounded. Some educated >>>> bikesheding >>>>>>>>> wouldn't hurt here IMO :) >>>>>>>>> >>>>>>>>> >>>>>>>>> Well, it's still a very real question whether we ought to have the >>>>>>>>> additional API surface implied by areSame, or wether we should >>>> collapse >>>>>>>>> it with ===. >>>>>>>>> >>>>>>>>> >>>>>>>>> To spell this out (because I had to think about it for a second): >>>> === >>>>>>>>> will be derived from >>>>>>>>> <=>, >>>>>>>>> but also becomes default implementation for ==, which remains open >>>> for >>>>>>>>> customization. >>>>>>>>> >>>>>>>>> >>>>>>>>> I was imagining roughly this (untested): >>>>>>>>> >>>>>>>>> /// Two references are identical if they refer to the same >>>>>>>>> /// instance. >>>>>>>>> /// >>>>>>>>> /// - Note: Classes with a more-refined notion of “identical” >>>>>>>>> /// should conform to `Identifiable` and implement `===`. >>>>>>>>> func ===(lhs: AnyObject, rhs: AnyObject) -> Bool { >>>>>>>>> ObjectIdentifier(lhs) == ObjectIdentifier(rhs) >>>>>>>>> } >>>>>>>>> >>>>>>>>> /// Supports testing that two values of `Self` are identical >>>>>>>>> /// >>>>>>>>> /// If `a` and `b` are of type `Self`, `a === b` means that >>>>>>>>> /// `a` and `b` are interchangeable in most code. A conforming >>>>>>>>> /// type can document that specific observable characteristics >>>>>>>>> /// (such as the `capacity` of an `Array`) are inessential and >>>>>>>>> /// thus not to be considered as part of the interchangeability >>>>>>>>> /// guarantee. >>>>>>>>> /// >>>>>>>>> /// - Requires: `===` induces an equivalence relation over >>>>>>>>> /// instances. >>>>>>>>> /// - Note: conforming types will gain an `==` operator that >>>>>>>>> /// forwards to `===`. >>>>>>>>> /// - Note: Types that require domain-specific `==` >>>>>>>>> /// implementations with different semantics (e.g. floating >>>>>>>>> /// point) should define a more-specific overload of `==`, >>>>>>>>> /// which will be used in contexts where the static type is >>>>>>>>> /// known to the compiler. >>>>>>>>> /// - Note: Generic code should usually use `==` to compare >>>>>>>>> /// conforming instances; that will always dispatch to `===` >>>>>>>>> /// and will be unaffected by more specific overloads of >>>>>>>>> /// `==`. >>>>>>>>> protocol Identifiable { // née Equatable name is negotiable >>>>>>>>> func ===(_: Self, _: aSelf) -> Bool >>>>>>>>> } >>>>>>>>> >>>>>>>>> /// Default definition of `==` for Identifiable types. >>>>>>>>> func ==<T: Identifiable>(lhs: T, rhs: T) -> Bool { >>>>>>>>> return lhs === rhs >>>>>>>>> } >>>>>>>>> >>>>>>>>> /// Conforming types have a default total ordering. >>>>>>>>> /// >>>>>>>>> /// If `a` and `b` are of type `Self`, `a <=> b` means that >>>>>>>>> /// `a` and `b` are interchangeable in most code. A conforming >>>>>>>>> /// type can document that specific observable characteristics >>>>>>>>> /// (such as the `capacity` of an `Array`) are inessential and >>>>>>>>> /// thus not to be considered as part of the interchangeability >>>>>>>>> /// guarantee. >>>>>>>>> /// >>>>>>>>> /// - Requires: `<=>` induces a total ordering over >>>>>>>>> /// instances. >>>>>>>>> /// - Requires: the semantics of `<=>` are consistent with >>>>>>>>> /// those of `===`. That is, `(a <=> b) == .equivalent` >>>>>>>>> /// iff `a === b`. >>>>>>>>> >>>>>>>>> For floating point, I'd hope that `a === b` if `(a <=> b) == .same` >>>>>>>>> *but not iff*. This is to satisfy IEEE 754: "Comparisons shall >>>> ignore the >>>>>>>>> sign of zero (so +0 = −0)". >>>>>>>>> >>>>>>>>> /// - Note: conforming types will gain `<`, `<=`, `>`, and `>=` >>>>>>>>> /// operators defined in terms of `<=>`. >>>>>>>>> /// - Note: Types that require domain-specific `<`, etc. >>>>>>>>> /// implementations with different semantics (e.g. floating >>>>>>>>> /// point) should define more-specific overloads of those >>>>>>>>> /// operators, which will be used in contexts where the >>>>>>>>> /// static type is known to the compiler. >>>>>>>>> /// - Note: Generic code can freely use `<=>` or the traditional >>>>>>>>> /// comparison operators to compare conforming instances; >>>>>>>>> /// the result will always be supplied by `<=>` >>>>>>>>> /// and will be unaffected by more specific overloads of >>>>>>>>> /// the other operators. >>>>>>>>> protocol Comparable : Identifiable { >>>>>>>>> func <=> (lhs: Self, rhs: Self) -> Ordering >>>>>>>>> } >>>>>>>>> >>>>>>>>> /// Default implementations of `<`, `<=`, `>`, and `>=`. >>>>>>>>> extension Comparable { >>>>>>>>> static func <(lhs: Self, rhs: Self) -> Bool { >>>>>>>>> return (lhs <=> rhs) == .ascending >>>>>>>>> } >>>>>>>>> static func <=(lhs: Self, rhs: Self) -> Bool { >>>>>>>>> return (rhs <=> lhs) != .ascending >>>>>>>>> } >>>>>>>>> static func >(lhs: Self, rhs: Self) -> Bool { >>>>>>>>> return (lhs <=> rhs) == .descending >>>>>>>>> } >>>>>>>>> static func >=(lhs: Self, rhs: Self) -> Bool { >>>>>>>>> return (rhs <=> lhs) != .descending >>>>>>>>> } >>>>>>>>> } >>>>>>>>> >>>>>>>>> I like this idea. If we keep === as a separate thing, now users >>>> have 3 >>>>>>>>> “opportunities” to define >>>>>>>>> equality. The must be few, if any, use cases for this. >>>>>>>>> >>>>>>>>> Would love to see if anyone on the list can give us an example. >>>>>>>>> Otherwise we should make >>>>>>>>> areSame === again™! >>>>>>>>> >>>>>>>>> >>>>>>>>> Daniel Duan >>>>>>>>> Sent from my iPhone >>>>>>>>> >>>>>>>>> On Jul 21, 2016, at 6:32 PM, Robert Widmann via swift-evolution >>>>>>>>> <swift-evolution@swift.org >>>>>>>>> <mailto:swift-evolution@swift.org <swift-evolution@swift.org>>> >>>>>>>>> wrote: >>>>>>>>> >>>>>>>>> >>>>>>>>> On Jul 21, 2016, at 6:19 PM, Xiaodi Wu >>>>>>>>> <xiaodi...@gmail.com >>>>>>>>> <mailto:xiaodi...@gmail.com <xiaodi...@gmail.com>>> >>>>>>>>> wrote: >>>>>>>>> >>>>>>>>> This is nice. Is `areSame()` being proposed because static `==` is >>>>>>>>> the status quo and you're trying to make the point that `==` in the >>>>>>>>> future need not guarantee the same semantics? >>>>>>>>> >>>>>>>>> >>>>>>>>> Yep! Equivalence and equality are strictly very different things. >>>>>>>>> >>>>>>>>> >>>>>>>>> Nit: I think the more common term in stdlib would be >>>>>>>>> `areEquivalent()`. Do you think `same` in that context (independent >>>>>>>>> of the word "ordering") might erroneously suggest identity? >>>>>>>>> >>>>>>>>> >>>>>>>>> There is room for improvement here. Keep ‘em coming. >>>>>>>>> >>>>>>>>> >>>>>>>>> >>>>>>>>> On Thu, Jul 21, 2016 at 8:11 PM, Robert Widmann via >>>>>>>>> swift-evolution >>>>>>>>> <swift-evolution@swift.org >>>>>>>>> <mailto:swift-evolution@swift.org <swift-evolution@swift.org>>> >>>>>>>>> wrote: >>>>>>>>> Hello Swift Community, >>>>>>>>> >>>>>>>>> Harlan Haskins, Jaden Geller, and I have been working on a >>>>>>>>> proposal to clean up the semantics of ordering relations in the >>>>>>>>> standard library. We have a draft that you can get as a gist. >>>>>>>>> Any feedback you might have about this proposal helps - though >>>>>>>>> please keeps your comments on Swift-Evolution and not on the gist. >>>>>>>>> >>>>>>>>> Cheers, >>>>>>>>> >>>>>>>>> ~Robert Widmann >>>>>>>>> >>>>>>>>> >>>>>>>>> >>>>>>>>> >>>>>>>>> >>>>>>>>> _______________________________________________ >>>>>>>>> swift-evolution mailing list >>>>>>>>> swift-evolution@swift.org >>>>>>>>> <mailto:swift-evolution@swift.org <swift-evolution@swift.org>> >>>>>>>>> https://lists.swift.org/mailman/listinfo/swift-evolution >>>>>>>>> <https://lists.swift.org/mailman/listinfo/swift-evolution> >>>>>>>>> >>>>>>>>> >>>>>>>>> >>>>>>>>> _______________________________________________ >>>>>>>>> swift-evolution mailing list >>>>>>>>> swift-evolution@swift.org >>>>>>>>> <mailto:swift-evolution@swift.org <swift-evolution@swift.org>> >>>>>>>>> https://lists.swift.org/mailman/listinfo/swift-evolution >>>>>>>>> <https://lists.swift.org/mailman/listinfo/swift-evolution> >>>>>>>>> >>>>>>>>> _______________________________________________ >>>>>>>>> swift-evolution mailing list >>>>>>>>> swift-evolution@swift.org >>>>>>>>> <mailto:swift-evolution@swift.org <swift-evolution@swift.org>> >>>>>>>>> https://lists.swift.org/mailman/listinfo/swift-evolution >>>>>>>>> <https://lists.swift.org/mailman/listinfo/swift-evolution> >>>>>>>>> >>>>>>>>> >>>>>>>>> -- >>>>>>>>> Dave >>>>>>>>> >>>>>>>>> _______________________________________________ >>>>>>>>> swift-evolution mailing list >>>>>>>>> swift-evolution@swift.org >>>>>>>>> <mailto:swift-evolution@swift.org <swift-evolution@swift.org>> >>>>>>>>> <mailto:swift-evolution@swift.org <swift-evolution@swift.org> >>>>>>>>> <mailto:swift-evolution@swift.org <swift-evolution@swift.org>> >>>>>>>>> <mailto:swift-evolution@swift.org <swift-evolution@swift.org> >>>>>>>>> <mailto:swift-evolution@swift.org <swift-evolution@swift.org>>>> >>>>>>>>> https://lists.swift.org/mailman/listinfo/swift-evolution >>>>>>>>> <https://lists.swift.org/mailman/listinfo/swift-evolution> >>>>>>>>> <https://lists.swift.org/mailman/listinfo/swift-evolution >>>>>>>>> <https://lists.swift.org/mailman/listinfo/swift-evolution>> >>>>>>>>> <https://lists.swift.org/mailman/listinfo/swift-evolution >>>>>>>>> <https://lists.swift.org/mailman/listinfo/swift-evolution> >>>>>>>>> <https://lists.swift.org/mailman/listinfo/swift-evolution >>>>>>>>> <https://lists.swift.org/mailman/listinfo/swift-evolution>>> >>>>>>>>> >>>>>>>>> _______________________________________________ >>>>>>>>> swift-evolution mailing list >>>>>>>>> swift-evolution@swift.org >>>>>>>>> <mailto:swift-evolution@swift.org <swift-evolution@swift.org>> >>>>>>>>> <mailto:swift-evolution@swift.org <swift-evolution@swift.org> >>>>>>>>> <mailto:swift-evolution@swift.org <swift-evolution@swift.org>>> >>>>>>>>> https://lists.swift.org/mailman/listinfo/swift-evolution >>>>>>>>> <https://lists.swift.org/mailman/listinfo/swift-evolution> >>>>>>>>> <https://lists.swift.org/mailman/listinfo/swift-evolution >>>>>>>>> <https://lists.swift.org/mailman/listinfo/swift-evolution>> >>>>>>>>> >>>>>>>>> >>>>>>>>> -- >>>>>>>>> Dave >>>>>>>>> >>>>>>>>> _______________________________________________ >>>>>>>>> swift-evolution mailing list >>>>>>>>> swift-evolution@swift.org >>>>>>>>> <mailto:swift-evolution@swift.org <swift-evolution@swift.org>> >>>>>>>>> <mailto:swift-evolution@swift.org <swift-evolution@swift.org> >>>>>>>>> <mailto:swift-evolution@swift.org <swift-evolution@swift.org>>> >>>>>>>>> https://lists.swift.org/mailman/listinfo/swift-evolution >>>>>>>>> <https://lists.swift.org/mailman/listinfo/swift-evolution> >>>>>>>>> <https://lists.swift.org/mailman/listinfo/swift-evolution >>>>>>>>> <https://lists.swift.org/mailman/listinfo/swift-evolution>> >>>>>>>>> >>>>>>>>> >>>>>>>>> -- >>>>>>>>> Dave >>>>>>>>> _______________________________________________ >>>>>>>>> swift-evolution mailing list >>>>>>>>> swift-evolution@swift.org >>>>>>>>> <mailto:swift-evolution@swift.org <swift-evolution@swift.org>> >>>>>>>>> https://lists.swift.org/mailman/listinfo/swift-evolution >>>>>>>>> <https://lists.swift.org/mailman/listinfo/swift-evolution> >>>>>>>>> >>>>>>>>> _______________________________________________ >>>>>>>>> swift-evolution mailing list >>>>>>>>> swift-evolution@swift.org >>>>>>>>> <mailto:swift-evolution@swift.org <swift-evolution@swift.org>> >>>>>>>>> https://lists.swift.org/mailman/listinfo/swift-evolution >>>>>>>>> <https://lists.swift.org/mailman/listinfo/swift-evolution> >>>>>>>>> >>>>>>>>> _______________________________________________ >>>>>>>>> swift-evolution mailing list >>>>>>>>> swift-evolution@swift.org >>>>>>>>> https://lists.swift.org/mailman/listinfo/swift-evolution >>>>>>>>> >>>>>>>>> >>>>>>>>> -- >>>>>>>>> Dave >>>>>>>>> >>>>>>>>> _______________________________________________ >>>>>>>>> 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 >>>>>>>> _______________________________________________ >>>>>>>> swift-evolution mailing list >>>>>>>> swift-evolution@swift.org >>>>>>>> https://lists.swift.org/mailman/listinfo/swift-evolution >>>> >>>> -- >>>> Dave > > -- > Dave _______________________________________________ swift-evolution mailing list swift-evolution@swift.org https://lists.swift.org/mailman/listinfo/swift-evolution
