You can argue the current status is a bug, but… Welcome to Apple Swift version 4.0.1 (swiftlang-900.0.67 clang-900.0.38). Type :help for assistance. 1> CountableRange<Int64>.IndexDistance.self $R0: Int.Type = Int 2> (Int64.min..<Int64.max).count Execution interrupted. Enter code to recover and continue.
> On Nov 29, 2017, at 4:04 AM, Xiaodi Wu <xiaodi...@gmail.com> wrote: > > So that we are all clear on the implications of this, if IndexDistance > becomes Int, ranges of integers will stop conforming to Collection, because > Int.min..<Int.max has Int.max * 2 elements, and Int64.min..<Int64.max has > potentially many more. > > This would entail nontrivial source breakage. > > > On Mon, Nov 27, 2017 at 22:02 Ben Cohen via swift-evolution > <swift-evolution@swift.org <mailto:swift-evolution@swift.org>> wrote: > My suggestion would be: don’t have your Collection-like type conform to > Collection. Give it collection-like methods if you want them, like an > indexing and slicing subscript that takes an Int64. It can still conform to > Sequence. > > In practice, these “huge” collections will be mostly used concretely, so > their Collection conformance doesn’t buy you much. The reality is that very > few generic uses on these types will succeed. You get a few things like > .first, .last etc. for free. But very few algorithms are written to handle > > Int.max lengths (several in the std lib don’t) – it just isn’t practical. And > meanwhile, this is a huge burden on many other use cases. > > The existence of the memory mapped file case is hypothetical. I canvassed a > bit on twitter for some use cases. The only one I got back was where someone > was using IndexDistance to stash other information: but this isn’t really a > legal use of IndexDistance, since it must be numerically castable to other > integer types when needed which would be a lossy operation so at best, it > would just be an optimization. > >> On Nov 27, 2017, at 19:29, Nevin Brackett-Rozinsky via swift-evolution >> <swift-evolution@swift.org <mailto:swift-evolution@swift.org>> wrote: >> >> The proposal mentions one reasonable situation where a larger-than-Int type >> would be useful, namely a Collection wrapping a memory-mapped file, being >> used on 32-bit systems. >> >> Is there a recommended migration strategy for this scenario? >> >> Nevin >> >> >> On Mon, Nov 27, 2017 at 8:34 PM, Douglas Gregor via swift-evolution >> <swift-evolution@swift.org <mailto:swift-evolution@swift.org>> wrote: >> Hello Swift community, >> >> The review of SE-0191 "Eliminate IndexDistance from Collection" begins now >> and runs through December 3, 2017. The proposal is available here: >> >> https://github.com/apple/swift-evolution/blob/master/proposals/0191-eliminate-indexdistance.md >> >> <https://github.com/apple/swift-evolution/blob/master/proposals/0191-eliminate-indexdistance.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/0191-eliminate-indexdistance.md >> >> <https://github.com/apple/swift-evolution/blob/master/proposals/0191-eliminate-indexdistance.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? >> If you have used other languages or libraries with a similar feature, how do >> you feel that this proposal compares to those? >> 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 >> >> Review Manager >> >> >> _______________________________________________ >> swift-evolution mailing list >> swift-evolution@swift.org <mailto: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> >> 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> > https://lists.swift.org/mailman/listinfo/swift-evolution > <https://lists.swift.org/mailman/listinfo/swift-evolution>
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