Definitions [dpm2] [djg17]

[Gary D. Duzan]

In Message <2bbcd9b1.davgar@davgar.arlington.va.us> ,
   David Garfield <david@davgar.arlington.va.us> wrote:

=>> [ Dennis ]
=>>
=>> I feel just calling something an object is sufficient unless we really need
=>> to differentiate between an object class and an instance of that class.  Is
=>> this acceptable to everyone else?
=>
=>I have always thought object was synonymous with instance, at least
=>when refering to something concrete.  I suppose others use of object
=>as a synonum for class may have confused me somewhat.  Maybe we should
=>stick with "class" and "instance", because these terms don't have
=>multiple possible meanings.

   A Class is basically a data type with methods defining the
semantics of its interface. An object is an instance of a class, with
code and address space. I believe these are fairly basic, standard
concepts, and I don't think it would do much good to redefine them.
For reference, I looked up an article in the September, 1990 issue
of Communications of the ACM, entitled "Understanding Object-Oriented:
A Unifying Paradigm". The whole issue is dedicated to Object-Oriented
design, and I would encourage everyone here to look it over, as I plan
to do. At least then we will have some solid definitions to start
with instead of the marketing drivel that the software industry has
been spewing out lately. On the other side, the November, 1992 issue
of CACM has in interesting article entitled "What Orientation should
Ada Objects Take?", which might help explain some of the realities of
the Object-Oriented Paradigm.

                                        Gary Duzan
                                        Time  Lord
                                    Third Regeneration
                         Humble Practitioner of the Computer Arts