> On May 8, 2017, at 6:46 PM, Giacomo Leopizzi <gi...@icloud.com> wrote: > Our starting point was that in ObjC at the beginning of the execution, the > root meta-class (most of the time NSObject) instantiates all the other > meta-classes, that create the class as object for the software.
This is somewhat like how a Smalltalk VM is bootstrapped, but there isn't any real sense in which root classes control how classes are created or loaded in ObjC. > In Swift is it the same? If so, which is the name of the root meta-class? The root class of a Swift class is a private implementation detail; it's not guaranteed in any way. If you're just curious about the current implementation, you can look in stdlib/public/runtime/SwiftObject.mm, but again, nothing in there is something that you should rely on as a Swift programmer. John. > Thanks for the fast reply. > > Giacomo > >> On 9 May 2017, at 00:30, John McCall <rjmcc...@apple.com> wrote: >> >>> On May 8, 2017, at 6:21 PM, Giacomo Leopizzi via swift-dev >>> <swift-dev@swift.org> wrote: >>> Hello everyone! >>> I was discussing with a friend about metaclasses in Objective-C. In Obj-C >>> the root meta-class was the NSObject's one. >> >> ObjC does not have a single root class. Most ObjC classes inherit from >> NSObject, but that is not guaranteed, and in fact there are other common >> root classes including NSProxy. >> >>> When in a swift class you create a subclass of NSObject, the root metaclass >>> should be the same. What happen when you delcare a class without NSObject >>> dependence? There is an hidden root-class? Where can we read more about >>> this topic? >> >> When ObjC interop is enabled, Swift classes that do not inherit from >> NSObject use a private root class. However, that is a private >> implementation detail and we don't promise much about it. >> >> Do you have any specific questions? > >> >> John. > _______________________________________________ swift-dev mailing list swift-dev@swift.org https://lists.swift.org/mailman/listinfo/swift-dev
