Path: utzoo!attcan!uunet!mcsun!sunic!nuug!ifi!skakke.uio.no!rmz
From: rmz@jamhog.uio.no (Bjoern Remseth)
Newsgroups: comp.object
Subject: Re: Evaluating "Object-Oriented" Programming Languages
Message-ID: <RMZ.90Jan12020729@jamhog.uio.no>
Date: 12 Jan 90 01:07:29 GMT
References: <638@ajpo.sei.cmu.edu> <706@cui.unige.ch> <644@ajpo.sei.cmu.edu>
	<753@cui.unige.ch> <649@ajpo.sei.cmu.edu>
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Organization: Institute of Informatics, University of Oslo
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In-reply-to: eberard@ajpo.sei.cmu.edu's message of 11 Jan 90 15:30:43 GMT


>  I too, would be interested in hearing from anyone with a different
>  viewpoint, i.e., that Simula is somehow not "truly object-oriented." 

I can think of two things:  

First of all there  are a number  of fundamental  things that  are not
"true" classes,  most   notably  all the  numbers and   texts.    This
basically means  that  even  if they  are  there,  and  have a clearly
defined protocol, a simula programmer can not make subclasses of them.

Secondly it is possible  to "INSPECT" any  class instance.  This means
that one can look into and modify the state of an object as if  it was
a part of the local execution environment.  Since identifiers local to
the inspected  object are used without  any form of  prefix it  is not
possible  only by looking at  a statement inside the inspect statement
to see if it sends a message to an object or not.

    BEGIN  
       CLASS foo;
       BEGIN
	  INTEGER bar;
       END;

       REF (foo) f;

       f :- NEW foo;
       INSPECT f do BEGIN
	! Note that "bar" is not declared on this block level,
	  it is  imported from the "f" object;
	 bar  := 200;
	 OutInt(bar,10);
	 OutImage
	end;
    END;

--
							(Rmz)

Bj\o rn Remseth				! Net:      rmz@ifi.uio.no
Institutt for Informatikk		! NeXTmail: rmz@neste.uio.no
Universitetet i Oslo, Norway		! Phone:    +472 453466