greg@cygnus.sce.carleton.ca (Greg Franks) (11/23/90)
Greetings. We have an evolving application that adds new classes, changes existing classes and disposes of old classes. Adding new classes is no problem. We have a solution to the dreaded 'change instance variable of a class and try to read in old versions problem' that works for us so changing classes is no problem. However, we have now tried to dispose of a class. No problem... Just link in 'Unknown' and the old references will be read in and blown away. Surprise surprise. The code for handling 'Unknown' in Filer.m has been commented out. Furthermore, the interface to Unknown has changed so even if we compiled it back in it would still bomb. Sooo, we have left the old class linked in. Question: Has anyone successfully used Unknown?? If so, can they share the method for getting it work. Enquiring minds want to know! We are running objc 4.0. Thanks -- Greg Franks, (613) 788-5726 | "The reason that God was able to Systems Engineering, Carleton University, | create the world in seven days is Ottawa, Ontario, Canada K1S 5B6. | that he didn't have to worry about greg@sce.carleton.ca uunet!mitel!sce!greg | the installed base" -- Enzo Torresi
ras@stpstn.UUCP (Richard A. Strilowich) (11/29/90)
Greg Franks@carleton posted: | Greetings. We have an evolving application that adds new classes, | changes existing classes and disposes of old classes. Adding new | classes is no problem. We have a solution to the dreaded 'change | instance variable of a class and try to read in old versions problem' | that works for us so changing classes is no problem. However, we have | now tried to dispose of a class. No problem... Just link in 'Unknown' | and the old references will be read in and blown away. Surprise | surprise. The code for handling 'Unknown' in Filer.m has been | commented out. Furthermore, the interface to Unknown has changed so | even if we compiled it back in it would still bomb. Sooo, we have | left the old class linked in. Question: Has anyone successfully used | Unknown?? If so, can they share the method for getting it work. | Enquiring minds want to know! | We are running objc 4.0. We are working on a solution but this will not make it into our new Objective-C 4.3 release. When we have a solution we will issue a posting on the net telling everyone how to get the fix. Sorry for any inconvenience this may have cause anyone. -- The Stepstone Corporation Richard Strilowich 75 Glen Rd. ras@stepstone.com Sandy Hook, CT 06482 uunet!stpstn!ras (203) 426-1875 fax (203)270-0106
gavin@praxis.co.uk (Gavin Finnie) (12/04/90)
In article <1990Nov22.215303.29686@ccs.carleton.ca> greg@cygnus.sce.carleton.ca (Greg Franks) writes: > >Greetings. We have an evolving application that adds new classes, >changes existing classes and disposes of old classes. Adding new >classes is no problem. We have a solution to the dreaded 'change >instance variable of a class and try to read in old versions problem' >that works for us so changing classes is no problem. I would be interested to see people's solutions to this general problem (not just the specific question about the Unknown class), since it is a potential headache when maintaining a large system written in Objective-C. Gavin Finnie email: gavin@praxis.co.uk Praxis Systems plc 20 Manvers Street phone: +44-225-444700 Bath BA1 1PX, England fax: +44-225-465205