NSCopying
The NSCopying
protocol declares a method for providing functional copies of an object. The exact meaning of “copy” can vary from class to class, but a copy must be a functionally independent object with values identical to the original at the time the copy was made.
protocol NSCopying
Browse conforming typesNSCopying declares one method, copy(with:)
, but copying is commonly invoked with the convenience method copy
. The copy method is defined for all objects inheriting from NSObject and simply invokes copy(with:)
with the nil
zone.
If a subclass inherits NSCopying
from its superclass and declares additional instance variables, the subclass has to override copy(with:)
to properly handle its own instance variables, invoking the superclass’s implementation first.