iOS nil

[grandM]

If I remember correctly nil in Objective-C meant the pointer was not set to any place in memory yet. Once you initialized the object you could set the pointer to the particular instance being the object.

But what is nil in Swift? Is it also a pointer not set?

 

[smirk]

Nil in Swift is used with optionals, to indicate that the variable has no value. It is not a reflection of the state of any pointer.

For more info, refer to https://developer.apple.com/library...html#//apple_ref/doc/uid/TP40014097-CH5-ID330

 

[grandM]

Nil in Swift is used with optionals, to indicate that the variable has no value. It is not a reflection of the state of any pointer.

For more info, refer to https://developer.apple.com/library...html#//apple_ref/doc/uid/TP40014097-CH5-ID330

Yes I know nil is used with Optionals. I also saw in the Stanford course that an optional actually is an enum. But I was wondering how nil got defined in Swift.

 

[smirk]

I'd be interested in learning that as well, but I don't know that you'll get the answer you're looking for, beyond what's written in the Swift guide:

Swift’s nil is not the same as nil in Objective-C. In Objective-C, nil is a pointer to a nonexistent object. In Swift, nil is not a pointer—it is the absence of a value of a certain type. Optionals of any type can be set to nil, not just object types.