As you’ve correctly guessed, NSObject‘s default isEqual: behaviour is comparing the memory address of the object. Strangely, this is not presently documented in the NSObject Class Reference, but it is documented in the Introspection documentation, which states: The default NSObject implementation of isEqual: simply checks for pointer equality. Of course, as you are doubtless aware, … Read more
Technical Note TN2124 Note: print-object actually calls the debugDescription method of the specified object. NSObject implements this method by calling through to the description method. Thus, by default, an object’s debug description is the same as its description. However, you can override debugDescription if you want to decouple these; many Cocoa objects do this. If … Read more
__NSArrayI is a code-word for an immutable array – that is, a “regular” NSArray which you cannot change. __NSArrayM is a code-word for a mutable array – that is, NSMutableArray. In NSMutableArray, you can add and remove items.
I’m not Swift ninja but I would write MyClass as: class MyClass: NSObject { var someProperty: NSString // no need (!). It will be initialised from controller init(fromString string: NSString) { self.someProperty = string super.init() // can actually be omitted in this example because will happen automatically. } convenience override init() { self.init(fromString:”John”) // calls … Read more
NSObject already conforms to the Hashable protocol: extension NSObject : Equatable, Hashable { /// The hash value. /// /// **Axiom:** `x == y` implies `x.hashValue == y.hashValue` /// /// – Note: the hash value is not guaranteed to be stable across /// different invocations of the same program. Do not persist the /// hash value … Read more
Use NSValue’s +valueWithRange:. To retrieve the range structure back, use the property rangeValue. [a addObject:[NSValue valueWithRange:r]]; … NSRange r = a[4].rangeValue;
The load message The runtime sends the load message to each class object, very soon after the class object is loaded in the process’s address space. For classes that are part of the program’s executable file, the runtime sends the load message very early in the process’s lifetime. For classes that are in a shared … Read more