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> 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> 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. >
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