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From: doylep@ecf.toronto.edu (Patrick Doyle)
Subject: Re: Which wastes more time? (Was Re: Software landmines (loops))
Date: 1998/09/08
Message-ID: <EyzFwJ.IIn@ecf.toronto.edu>#1/1
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References: <l5HC1.6840$wN.1856764@news.giganews.com>
 <35F4F454.542516E4@s054.aone.net.au> <Eyyw3u.5AF@ecf.toronto.edu>
 <35F56290.AB5491D9@s054.aone.net.au>
Organization: University of Toronto, Engineering Computing Facility
Newsgroups: comp.lang.eiffel,comp.object,comp.software-eng,comp.lang.ada
Date: 1998-09-08T00:00:00+00:00
List-Id: <comp.lang.ada>

In article <35F56290.AB5491D9@s054.aone.net.au>,
Loryn Jenkins  <loryn@acm.org> wrote:
>Patrick Doyle wrote:
>> 
>> I gave an example earlier of a reporting program which generates
>> a report based on a moment in time.  If a person sells his car,
>> he will either do so before or after this program is run;
>> in either case, if he is a CAR_OWNER at the start, he will
>> be a CAR_OWNER for the duration of the program.
>
>That's what I thought. And my response to that is: Why do you need class
>PERSON at all, in this situation? 

Sorry for the duplication.  It seems I didn't understand your
point, so I did the only rational thing and proceeded to
ignore it.  :-)

>You're not intending to use it
>polymorphically with CAR_OWNER. In fact, the only reason for having it
>is that it existed before, and now you simply want to extend it to cover
>this CAR_OWNERship situation.

How do you know that?

class PERSON
feature
	name: STRING
	age: INTEGER
end

class CAR_OWNER inherit PERSON
feature
	cars: ARRAY [CAR]
end


CAR_OWNER is a subtype of PERSON.  In the portion of the report
that lists everyone's age, this polymorphism is important.

 -PD
-- 
--
Patrick Doyle
doylep@ecf.toronto.edu