Yes I know what you are saying and I am suggesting changing that so that: (0 ... -9) and (0 ..< -10)
Are both empty ranges rather than errors because they implicitly have a 'by' of 1. On Wednesday, 6 April 2016, Xiaodi Wu <xiaodi...@gmail.com> wrote: > Howard, the point I am raising is that `0...(-9)` is not valid Swift > because the first, "lower" bound is enforced to be less than the second, > "upper" bound. > > The problem is that with that restriction certain types of half-open > intervals, namely those where the lower bound is the one being excluded, > cannot be represented as a Range either currently or in Dave A's branch. > On Tue, Apr 5, 2016 at 3:30 PM Howard Lovatt <howard.lov...@gmail.com > <javascript:_e(%7B%7D,'cvml','howard.lov...@gmail.com');>> wrote: > >> I much prefer (0 ... -9).by(-1) and (0 ..< -10).by(-1) >> >> On Wednesday, 6 April 2016, Dave Abrahams via swift-evolution < >> swift-evolution@swift.org >> <javascript:_e(%7B%7D,'cvml','swift-evolution@swift.org');>> wrote: >> >>> >>> on Tue Apr 05 2016, Xiaodi Wu <xiaodi.wu-AT-gmail.com> wrote: >>> >>> > On Mon, Apr 4, 2016 at 1:22 PM, Dave Abrahams <dabrah...@apple.com> >>> wrote: >>> >> >>> >> on Sat Apr 02 2016, Xiaodi Wu <xiaodi.wu-AT-gmail.com> wrote: >>> >> >>> >>> [snip] >>> >>> >>> >>> Not included: >>> >>> 1. I know Ranges are in flux, so I've held off on extending Range >>> with >>> >>> a striding(by:) method in this proof-of-concept. >>> >> >>> >> They're not in flux, except for not having been reviewed yet; they are >>> >> settled in the swift-3-indexing-model branch. >>> > >>> > Did not know that. Will have to study what's there in more detail. >>> > >>> >>> 2. No attempt at the suggested stride(from:to:steps:) quite yet. >>> >> >>> >> #1 and #2 are mutually exclusive; we prefer #1 as it removes questions >>> >> about the meaning of "to" or "through." >>> > >>> > I wasn't aware that was the thinking. Limiting strides to >>> > `striding(by:)` removes the ability to express `stride(from: 0, to: >>> > -10, by: -1)` >>> >>> IMO this: >>> >>> (-9...0).reverse() >>> >>> is better than >>> >>> stride(from: 0, to: -10, by: -1) >>> >>> What do you think? >>> >>> -- >>> Dave >>> >> _______________________________________________ >>> swift-evolution mailing list >>> swift-evolution@swift.org >>> https://lists.swift.org/mailman/listinfo/swift-evolution >>> >> >> >> -- >> -- Howard. >> > -- -- Howard.
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