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From: bevan@cs.man.ac.uk (Stephen J Bevan)
Newsgroups: comp.lang.ada
Subject: Re: Classes vs Tagged Types - Terminology
Message-ID: <BEVAN.93Mar26110200@panda.cs.man.ac.uk>
Date: 26 Mar 93 11:02:00 GMT
References: <C4AGp4.1Fw@clw.cs.man.ac.uk> <17255@goanna.cs.rmit.oz.au>
	<1993Mar25.155650.16244@inmet.camb.inmet.com>
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Organization: Department of Computer Science, University of Manchester
In-reply-to: stt@spock.camb.inmet.com's message of 25 Mar 93 15:56:50 GMT
Date: 1993-03-26T11:02:00+00:00
List-Id: <comp.lang.ada>

In article <1993Mar25.155650.16244@inmet.camb.inmet.com> stt@spock.camb.inmet.com (Tucker Taft) writes:
   [ much that I agree with except for the following ]
   More important than inheritance (even with type extension), 
   in my view, is the ability to have multiple implementations of 
   a given abstraction.  This is what separates an "object-oriented"
   language (like Ada 9X or C++) from an "abstraction-oriented"
   language (like Ada 83 or CLU).  In an "abstraction-oriented"
   language, each abstraction interface has exactly one implementation,
   and hence all calls on operations of the interface can be
   statically bound.  

One of my favourite languages, ML, allows multiple implementations of
a single interface via parameterisation and to some extent so does
Ada83 via generics.  Can this be reconciled with the above statement?

bevan