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From: jww@sdcsvax.UUCP
Newsgroups: comp.sys.mac
Subject: Re: Coral Object Logo
Message-ID: <2767@sdcsvax.UCSD.EDU>
Date: Fri, 27-Feb-87 00:11:47 EST
Article-I.D.: sdcsvax.2767
Posted: Fri Feb 27 00:11:47 1987
Date-Received: Sat, 28-Feb-87 08:09:26 EST
References: <1725@PUCC.BITNET> <4794@mit-eddie.MIT.EDU> <690@bgsuvax.UUCP> <1341@Shasta.STANFORD.EDU>
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Organization: Western Software Technology, Vista, CA
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Object Logo is not screwy because of multiple inheritance.
Object Logo is screwy because it's an instance-based inheritance.

Most o-o languages define classes (types in Object Pascal) of objects with
similar variables, procedures ("behaviors"), etc.  A few languages
make each object unique.  I don't have Object Logo, but Kurt Schmucker 
in his book notes that Object Logo is this way (and he confirmed this
when I talked to him at Macworld about o-o languages in general.)

A good example of multiple inheritance I've heard used is the window.
A window is an object that's part of a list, and it's something visual
(like a QD grafport).  Or maybe you have bitmap objects, and you also
have displayed bitmap objects that inherit both the bitmap stuff and
the property of being in a display list.

Multiple inheritance is pretty rare, mostly for implementation reasons,
so there aren't a lot of good examples out there.