I've seen this before; I considered it something to be resolved in AppKit. Strings in Swift are values, and the framework expects it to be a reference. Since NSTextStorage is itself a reference-type and informs its delegate of changes, those frameworks should probably retain the NSTS itself and pull Strings out as-needed.
Once the new String model is done (long time yet), I would love it if Apple's CoreText team created a truly Swift (i.e. Protocol-based) NSTextStorage API. You wouldn't necessarily have to provide a stdlib String; any UTF16-encoded Unicode/StringProtocol instance could possibly suffice, allowing you to optimise storage through buffer-gaps and whatnot (doable today with NSMutableString subclass, but you can't subclass a struct). - Karl > > On Feb 10, 2017 at 10:51 pm, <Jacob Bandes-Storch via swift-users > (mailto:swift-users@swift.org)> wrote: > > > > Got some clarity on this from Apple folks on Twitter: > https://twitter.com/jtbandes/status/830159670559993856 > > > On Fri, Feb 10, 2017 at 12:54 PM, Michel Fortin <michel.for...@michelf.ca > (mailto:michel.for...@michelf.ca)> wrote: > > > > > I did file one (30314719). I might not have explained the problem clearly > > enough, I suppose, because at the time I was misinterpreting the API > > contract thinking it was the new AppKit Touch Bar stuff that was violating > > it instead. That bug now sits closed and I hesitate opening a new bug for > > the same problem just to ask it to be fixed in another way. Meanwhile I > > found an acceptable workaround that I attached to the existing bug report > > in addition and I posted all this to the list. Hopefully someone at the > > right place will notice. > > > > > > But yeah... maybe I should file another bug, against Foundation's Swift > > interface this time, since NSTextStorage's string property comes from > > NSAttributedString. I'll think about it. > > > > > > > > > > > > > > > > > > Le 10 févr. 2017 à 11:36, Jacob Bandes-Storch <jtban...@gmail.com > > > (mailto:jtban...@gmail.com)> a écrit : > > > > > > > > > > > > This seems like a bug (missing feature?) in how the API is imported for > > > Swift. You might consider filing a Radar. > > > > > > > > > > > > > > > On Thu, Feb 9, 2017 at 3:12 PM Michel Fortin via swift-users > > > <swift-users@swift.org (mailto:swift-users@swift.org)> wrote: > > > > > > > The `string` property of `NSTextStorage` is of type `String`, but the > > > > contract it must implement is that it should return the backing store > > > > of the attributed string (the underlying `NSMutableString` used as the > > > > backing store). It seems to me that this makes it impossible to > > > > implement correctly a subclass of `NSTextStorage` in Swift, because > > > > Swift automatically wraps the `NSString` into a `String` and the > > > > underlying mutable storage is not passed around. > > > > > > > > Here's the documentation for that method: > > > > > > > > https://developer.apple.com/reference/foundation/nsattributedstring/1412616-string > > > > > > > > In case the contract isn't clear from the documentation (it wasn't for > > > > me), I got a confirmation as a response in radar 30314719: > > > > > It’s returning a copy of the backing store, but the contract is > > > > actually returning the backing store string. The copy storage > > > > declaration in the property spec is only used for setter implementation. > > > > > > > > So looks like this is impossible to model correctly in Swift due to > > > > the automatic bridging to `String`. Some APIs in AppKit expect the > > > > `NSString` they receive to mutate when mutating the text storage (touch > > > > bar suggestions in `NSTextView`) and will do bad things this isn't the > > > > case. > > > > > > > > Obviously, I can work around this by writing some Objective-C code, > > > > but it'd be better if I could avoid splitting the class implementation > > > > between two languages. There's another way using swizzling to map the > > > > Objective-C method to a Swift implementation of the same method that > > > > has the correct signature, and that's probably what I'll end up doing > > > > unless a better solution can be pointed out to me. > > > > > > > > > > > > -- > > > > Michel Fortin > > > > https://michelf.ca (https://michelf.ca/) > > > > > > > > _______________________________________________ > > > > swift-users mailing list > > > > swift-users@swift.org (mailto:swift-users@swift.org) > > > > https://lists.swift.org/mailman/listinfo/swift-users > > > > > > > > > > > > > > > > > > > > > > -- > > Michel Fortin > > https://michelf.ca > > > > > > > > > > > > > > > > > > > _______________________________________________ swift-users mailing
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