I never said a RangeReplaceableCollection shouldn’t be empty. I just think it’s strange that it requires an empty initialiser (while the Collection protocol doesn’t).
> On 6 Jul 2016, at 16:33, Zhao Xin <owe...@gmail.com> wrote: > > No. You didn't catch what I meant. I meant it should be like an equation. > If foo is a RangeReplaceableCollection, foo minus foo equates zero, zero > means an empty collection. Both side of the equation should be with the same > unit, the unit is RangeReplaceableCollection. Below code also shows init() > is useful in RangeReplaceableCollection. > > var foo = Array<Int>() > foo.append(contentsOf: [2,4,6,8]) > > Zhaoxin > > On Wed, Jul 6, 2016 at 10:07 PM, Tim Vermeulen <tvermeu...@me.com > <mailto:tvermeu...@me.com>> wrote: > You wouldn’t need an empty initialiser to remove all elements from a > collection, right? You could just use `replaceRange` instead. > > > Now I understood you concerns. Have you ever thought of if a non-empty > > RangeReplaceableCollection being removed all of its elements, which makes > > the collection to be an empty collection. That shouldn't change > > theRangeReplaceableCollection to be a non-RangeReplaceableCollection. Sothe > > empty collection must also be aRangeReplaceableCollection. > > > > > init() > > (file:///Users/zhaoxin/Library/Application%20Support/Dash/DocSets/Apple_API_Reference/Apple_API_Reference.docset/Contents/Resources/Documents/developer.apple.com/reference/swift/rangereplaceablecollection/1641467-init.html > > > > <http://developer.apple.com/reference/swift/rangereplaceablecollection/1641467-init.html>)> > > Creates a new, empty collection. > > > > Zhaoxin > > > > On Wed, Jul 6, 2016 at 9:09 PM, Tim Vermeulen<tvermeu...@me.com > > <mailto:tvermeu...@me.com>(mailto:tvermeu...@me.com > > <mailto:tvermeu...@me.com>)>wrote: > > > I’m not allowing generic subscripts. The collection is declared as > > > `AnyIndexArray<Index: Strideable, Element where Index.Stride == Int>` and > > > it can be subscripted with type `Index`. > > > > > > Either way, it’s not really important. I’m mostly wondering why > > > RangeReplaceableCollection needs an empty initialiser. > > > > > > >Then how you defined the index to conform toStrideable? Below code does > > > >work as it seams that you can't use generics in subscripts. > > > > > > > > > > > >subscript<T:Strideable>(index:T) ->Element > > > > > > > > > > > > > > > > > > > > > > > > > > > >Zhaoxin > > > > > > > > > > > > > > > > > > > >On Wed, Jul 6, 2016 at 8:32 PM, Tim Vermeulen<tvermeu...@me.com > > > ><mailto:tvermeu...@me.com>(mailto:tvermeu...@me.com > > > ><mailto:tvermeu...@me.com>)(mailto:tvermeu...@me.com > > > ><mailto:tvermeu...@me.com>)>wrote: > > > >> > > > >>>On 6 Jul 2016, at 14:03, Zhao Xin<owe...@gmail.com > > > >>><mailto:owe...@gmail.com>(mailto:owe...@gmail.com > > > >>><mailto:owe...@gmail.com>)(mailto:owe...@gmail.com > > > >>><mailto:owe...@gmail.com>)>wrote: > > > >>>According to the document of Swift 3, Array has already conformed > > > >>>protocolRangeReplaceableCollection. > > > >> > > > >>That’s exactly why I also want to conform my wrapper to that protocol? > > > >>I think there’s a misunderstanding. I’m making a collection that can be > > > >>subscripted with any index (that conforms to Strideable), but behaves > > > >>like an array otherwise. > > > >> > > > >>> > > > >>>Zhaoxin > > > >>> > > > >>>On Wed, Jul 6, 2016 at 7:09 PM, Tim Vermeulen via > > > >>>swift-users<swift-users@swift.org > > > >>><mailto:swift-users@swift.org>(mailto:swift-users@swift.org > > > >>><mailto:swift-users@swift.org>)(mailto:swift-users@swift.org > > > >>><mailto:swift-users@swift.org>)>wrote: > > > >>>>RangeReplaceableCollection has three initialisers: init(), init(_:) > > > >>>>and init(repeating:count:). The latter two are implemented using the > > > >>>>empty initialiser. But why are these initialisers part of this > > > >>>>particular protocol? As far as I can tell, no other methods of this > > > >>>>protocol depend on these initialisers. The requirement of the empty > > > >>>>initialiser makes it impossible to have a collection conform to this > > > >>>>protocol that needs additional data for its initialisation. > > > >>>> > > > >>>>For instance, I was making an array that works with any Strideable > > > >>>>indices, not just integers. A startIndex is needed for its > > > >>>>initialisation, so I can’t really conform it to > > > >>>>RangeReplaceableCollection. If I do it anyways (with a fatalError() > > > >>>>in the required empty initialiser) everything seems to work just > > > >>>>fine, except for the protocol’s three initialisers. > > > >>>> > > > >>>>Perhaps these initialisers should be moved to a (possible new) > > > >>>>different protocol? > > > >>>>_______________________________________________ > > > >>>>swift-users mailing list > > > >>>>swift-users@swift.org > > > >>>><mailto:swift-users@swift.org>(mailto:swift-users@swift.org > > > >>>><mailto:swift-users@swift.org>)(mailto:swift-users@swift.org > > > >>>><mailto:swift-users@swift.org>) > > > >>>>https://lists.swift.org/mailman/listinfo/swift-users > > > >>>><https://lists.swift.org/mailman/listinfo/swift-users> > > > >>> > > > >> > > > > > > > > > > > > > > > > > > >
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