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From: lerman@stpstn.UUCP (Ken Lerman)
Newsgroups: comp.lang.c++
Subject: Re: typeof() and virtuals and overloading, oh my!
Message-ID: <6754@stpstn.UUCP>
Date: 5 Apr 91 15:10:41 GMT
References: <27F77834.16D6@tct.com> <27EF838D.4115@tct.uucp> <19093@milton.u.washington.edu> <157@devnull.mpd.tandem.com> <162@devnull.mpd.tandem.com>
Reply-To: lerman@stpstn.UUCP (Ken Lerman)
Organization: The Stepstone Corporation, Sandy Hook, CT 06482
Lines: 32

I've been sitting on the sidelines listening to the fracas, but now I
think it might be useful for me to comment based on my experience with
Objective-C.

1 -- It is possible to save and restore arbitrarily complex graphs of
objects without explicit cooperation from each class.  This is done in
Objective-C.

2 -- It IS necessary (IMHO) that each object be able to identify
itself.  In Objective-C, this is done by having an instance variable
(called isa) which points to a class structure which contains the
name, the types of instance variables, ... , for that class.

The construction of that structure requires compiler support.

3 -- It is NOT necessary that each class in Objective-C have the same
root class, but it IS necessary that each have a first instance
variable which is the "isa" pointer.

4 -- I don't understand the aversion to having a single root class for
those objects which we wish to make persistent.  It seems to me that
multiple inheritence might be good for this.  (If it is not good for
this, what is it good for?)

If you believe our customers, the ability to save and restore object
graphs is valuable.  At least for applications written in Objective-C.

This is NOT intended to tell you to change your language to match
mine.  But if you want to add this functionality, experience with
Objective-C might be valuable.

Ken