Xref: utzoo comp.sys.next:8622 comp.lang.objective-c:36
Path: utzoo!attcan!uunet!wuarchive!usc!ucsd!network.ucsd.edu!weber.ucsd.edu!pbiron
From: pbiron@weber.ucsd.edu (Paul Biron)
Newsgroups: comp.sys.next,comp.lang.objective-c
Subject: probate
Summary: how to keep a sub-class from inheriting from its super-class?
Message-ID: <3861@network.ucsd.edu>
Date: 15 Oct 90 17:19:25 GMT
Sender: news@network.ucsd.edu
Reply-To: pbiron@weber.ucsd.edu (Paul Biron)
Followup-To: comp.sys.next
Organization: Division of Social Sciences, UCSD
Lines: 27
Nntp-Posting-Host: weber.ucsd.edu


I'm trying to figure out an "elegent" way to keep a sub-class
from inheriting methods from its super-class.  In this case,
I'm making a Stack class out of the List class.  Since a
Stack should specifically deny "random" access to its elements,
I need a way to keep it from inheriting ObjectAt:, etc.

So far, all I've done is defined these kinds of methods like:

- ObjectAt:(int)num
{
	fputs ("Stack does not recognize selector ObjectAt:\n", stderr) ;
	kill (getpid (), SIGIO) ;
}

In other words, just give the same kind of message that the
Obj-C runtime mechanism gives when you send an unknown message
to an object.

Is there a "better" way?  Is there anything in the specs for
Obj-C which say how this should be handled (I couldn't find
it, if it is there).

Paul Biron      pbiron@ucsd.edu        (619) 534-5758
Central University Library, Mail Code C-075-R
Social Sciences DataBase Project
University of California, San Diego, La Jolla, Ca. 92093