Path: utzoo!attcan!uunet!cs.utexas.edu!usc!apple!netcom!cooper
From: cooper@netcom.UUCP (Ken Cooper)
Newsgroups: comp.lang.smalltalk
Subject: Re: ST V/286 a few questions...
Message-ID: <4431@netcom.UUCP>
Date: 21 Nov 89 07:45:06 GMT
References: <441@DB0TUI11.BITNET> <14621@well.UUCP>
Reply-To: cooper@netcom.UUCP (Ken Cooper)
Organization: NetCom- The Bay Area's Public Access Unix System {408 997-9175 guest}
Lines: 30

In article <14621@well.UUCP> mitsu@well.UUCP (Mitsuharu Hadeishi) writes:
>
>
>To add an instance variable to a class with a lot of distributed
>members, I've thought of doing this:

>	[ details of copying instances deleted ]

Although this approach seems reasonable, I'm pretty sure the method you've
described won't work.  The barrier that immediately stands out to me is
the use of "self become:".  Try, using Smalltalk V/286, to get an
integer to become anything other than itself.  Considering how many
instance variables there are in the system's classes, this might cause a
minor problem. 
 
Further, and perhaps more importantly, you're assuming a magical mapping
of instance variables with self become.  You'd have to depend on the order
of their declaration, which I'd feel a bit queasy about.

We've been working on a disk storage scheme for objects that deals a bit
with this issue of juggling object's instances variables, and one thing
we've learned: try not to assume too much about Digitalk's internals
(especially *across* platforms).

Ken Cooper

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Ken Cooper                                         USENET: cooper@netcom.uucp
Acumen Software                                Compu$erve: 71571,407
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