On Jun 14, 2014, at 3:45 PM, Roland King <r...@rols.org> wrote: > I'm a little confused about implicitly unwrapped optionals. > > My current understanding is that you can access their value directly, without > using the 'if let' syntax or the explicit unwrap (!) operator, but you'll > crash if the optional doesn't have a value when you do. You can also treat > them like an optional and using 'if' on them tells you if they exist just > like an optional does. > > I'm watching the Swift Interoperability In Depth talk and that basically says > that all object types in ObjC look like implicitly unwrapped optionals in > swift. Ie NSDate* date turns up as > > var date : NSDate! > > First question is why use an implicitly unwrapped optional instead of just an > optional? You still have to test them so what do you gain? > > One slide says at 5:16 into the talk "Can be explicitly tested for nil". That > to me means you can do > > If xxx == nil > > I assume the slide is being a little sloppy and that really means use the > normal "if xxx" syntax for these which returns true if the value exists, as > xxx == nil would surely attempt an unwrap and throw if the value didn't > exist. > > Finally if you have an implicitly optional Bool, bbb, what does > > if bbb > > do? Does it return whether bbb has a value or does it return the unwrapped > value of the Bool used in the if? I assume the former in which case how do > you use an implicitly unwrapped optional bool in an if?
Is this really the place to discuss Swift? This question is not even remotely Cocoa related. > _______________________________________________ > > Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) > > Please do not post admin requests or moderator comments to the list. > Contact the moderators at cocoa-dev-admins(at)lists.apple.com > > Help/Unsubscribe/Update your Subscription: > https://lists.apple.com/mailman/options/cocoa-dev/sevenbitstech%40gmail.com > > This email sent to sevenbitst...@gmail.com
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