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From: mikeb@coho.ee.ubc.ca (Mike Bolotski)
Newsgroups: comp.lang.misc
Subject: Re: Languages that allow extensions to classes
Message-ID: <1238@fs1.ee.ubc.ca>
Date: 12 Apr 90 01:09:05 GMT
References: <16560@estelle.udel.EDU>
Sender: root@fs1.ee.ubc.ca
Reply-To: mikeb@coho.ee.ubc.ca (Mike Bolotski)
Organization: Dept. of Electrical Engineering University of B.C.
Lines: 23

In article <16560@estelle.udel.EDU> new@ee.udel.edu (Darren New) writes:
>One feature of Smalltalk that I really like and use is the ability to
>put methods from one class into several files.  This allows, for example,
>for the extention of already-defined classes with new methods.

>In C++, I (think) I have to change the header file, thereby requiring me

Yes..

> [..]                                                    Does anybody know
>of other languages which allow the user to extend functionality of system
>classes/libraries/etc without changing files where the old stuff is
>defined? 

Well, CLOS (Common Lisp Object System) for one.  And I really dislike 
the above feature, actually.  In C++ the header file documents the entire
behaviour of the class.  In CLOS that information is spread out all over
the source files.   Not an example of proper software engineering, IMHO. 

Mike Bolotski, Department of Electrical Engineering,
               University of British Columbia, Vancouver, Canada 
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