+1 for Scala's path dependent types. On Saturday, 16 April 2016, Thorsten Seitz via swift-evolution < swift-evolution@swift.org> wrote:
> > > Am 15.04.2016 um 23:19 schrieb Dmitri Gribenko via swift-evolution < > swift-evolution@swift.org <javascript:;>>: > > > > On Fri, Apr 15, 2016 at 1:30 PM, Stephan Tolksdorf <s...@quanttec.com > <javascript:;>> wrote: > >> On 2016-04-12 Dmitri Gribenko via swift-evolution wrote: > >>> > >>> Not even to mention that > >>> indices are valid only in context of a particular collection instance, > >>> so in this model you could validate an index against one collection > >>> and use it with another one. > >> > >> > >> The proposal requires Index values to be Comparable. Does that mean that > >> indices from different collection instances should be comparable i.e. > have a > >> strict total order? > > > > No, comparing indices from unrelated instances produces unspecified > > results (incl. traps). > > Path dependent types as used in Scala would allow making this distinction > type safe (see http://docs.scala-lang.org/tutorials/tour/inner-classes or > http://danielwestheide.com/blog/2013/02/13/the-neophytes-guide-to-scala-part-13-path-dependent-types.html) > by allowing the index type to be rooted at the instance. > > Are there any plans to adding path dependent types to Swift? > > -Thorsten > > _______________________________________________ > swift-evolution mailing list > swift-evolution@swift.org <javascript:;> > https://lists.swift.org/mailman/listinfo/swift-evolution > -- -- Howard.
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