Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10 UW 5/3/83; site uw-june Path: utzoo!watmath!clyde!burl!ulysses!mhuxj!houxm!vax135!cornell!uw-beaver!uw-june!trow From: trow@uw-june (Jay Trow) Newsgroups: net.lang.st80 Subject: Re: instance variable question Message-ID: <1847@uw-june> Date: Mon, 8-Oct-84 20:40:13 EDT Article-I.D.: uw-june.1847 Posted: Mon Oct 8 20:40:13 1984 Date-Received: Tue, 9-Oct-84 04:09:59 EDT References: <15992@arizona.UUCP> Reply-To: Krasner@Xerox.arpa, Smalltalk80Interest^@Xerox.arpa Organization: U of Washington Computer Science Lines: 28 Forwarded from Smalltalk80Interest^@Xerox.arpa ---------------------------------------------------------------- Date: Mon, 8 Oct 84 8:52:48 PDT From: krasner@xerox.arpa Subject: Re: instance variable question Restricting classes to use only the instance variables defined in them and not in their superclass will result in making inheritance almost useless. Inheritance for us has proven to be significantly more powerful than the ability to change class definitions. So given the trade-off between restricting the power of inheritance and longer execution time for re-defining classes, I would recommend that you opt for the latter, as described in Kim McCall's message. The entire Smalltalk-80 system source code is part of the ($400 for universities) license package. Reading the sources would help you answer some of these types of questions. You do not necessarily have to have a running system to browse the code--at least one of our licensees, for example, was able in about a week to write a reasonably powerful Unix tool to browse the code before their system was widely available. I recommend you try to get a license for U. of Arizona; let me know if you need more details on how. Glenn Krasner ----------------------------------------------------------------