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From: drw@culdev1.UUCP
Newsgroups: comp.lang.misc,comp.software-eng
Subject: software ICs vs. libraries
Message-ID: <1716@culdev1.UUCP>
Date: Wed, 28-Oct-87 13:16:11 EST
Article-I.D.: culdev1.1716
Posted: Wed Oct 28 13:16:11 1987
Date-Received: Sat, 31-Oct-87 08:39:47 EST
Organization: Cullinet Software, Westwood, MA, USA
Lines: 18
Xref: utgpu comp.lang.misc:772 comp.software-eng:16

chip@ateng.UUCP (Chip Salzenberg) writes:
| Objective-C supports _heterogoneous_ collections.  For example, a
| single Set can hold another Set, a Dictionary, an Array, and any number of
| other types -- _simultaneously_.

The other important feature that object-oriented systems need
(Objective-C has it, I don't know of C++ does) is that one can build
two objects that present the same external interface, but for which
the method-routines are different.  I.e., I can have two different
sorts of "dictionary", implemented differently, and the code that uses
them can't tell the difference between them.  (This is why you need
run-time mapping from method-names to routines.)

Dale
-- 
Dale Worley    Cullinet Software      ARPA: culdev1!drw@eddie.mit.edu
UUCP: ...!seismo!harvard!mit-eddie!culdev1!drw
If you get fed twice a day, how bad can life be?