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Path: utzoo!watmath!clyde!burl!ulysses!mhuxj!ihnp4!arizona!budd
From: budd@arizona.UUCP (tim budd)
Newsgroups: net.lang.st80
Subject: instance variable question
Message-ID: <15992@arizona.UUCP>
Date: Sat, 29-Sep-84 17:31:04 EDT
Article-I.D.: arizona.15992
Posted: Sat Sep 29 17:31:04 1984
Date-Received: Sun, 30-Sep-84 05:02:07 EDT
Organization: Dept of CS, U of Arizona, Tucson
Lines: 17

Thanks for all of you who responded to my note on Little Smalltalk.

Here is a question that came up during the implementation of Little
Smalltalk.  Since my solution obviously differs from the Xerox solution, 
there must be something I am missing.

In st80, a subclass, say B, can manipulate instance variables in its
superclass, say A.  Suppose i is an instance variable name in the class A,
and a method in B uses i.  If we now edit the class description for A and
remove the instance variable i, what happens when we create a new
instance of B?

My solution in Little Smalltalk was to disallow methods for accessing
any but their own instance variables.  Obviously xerox has a different
solution, but I have not been able to discover, from reading the blue book,
what it is.