Multiple inheritance (Was: OOP)_(re)

Wed, 28 May 1997 12:02:42 +0100 (BST)

On Wed, 28 May 1997 12:08:20 +0200 (MET DST) Peter Gerwinski 
 wrote:
>According to Pierre Phaneuf:
>> 
>> I strongly advises *agains't* multiple inheritance. It is the OOP 'goto'
>> equivalent. Everything MI can do, you can do without MI if you design
>> well. C++ is the bloated monster we know today in part because of that
>> pseudo-feature. Neither Modula-3 or Oberon has multiple inheritance and
>> both have been used in programming operating systems and huges projects.
>
>I don't vote for or against multiple inheritance, 

If it can be done, then it should be done. However, I would advise
against using it in the RTS or in any UNIT supplied as part of the GPC
distribution. Let us make it's use completely optional (i.e., people can
use it in their own programs if they want, but GPC is itself free from it.

> but
>
>  * are there existing Pascal standards (ANSI Object Pascal, Delphi)
>    requiring it?  (I *really* don't know.)

Delphi does not do MI.

>  * There are few places in my planned object hierarchy (I am *also*
>    working on a completely new library;) where MI could be useful:
>    There are several independent branches of recursive objects, say
>    `VisibleObj' and `DataObj', which all have a `Child ( i: Integer )'
>    method returning the `i'th child.  It would be nice to implement
>    some stuff, say a `ForEach' method, in a common ancestor.  Without
>    MI, this common ancestor must be a *very* "low" object, `BaseObj'
>    itself, the parent of all objects.  I am not sure if it is wise to
>    make *every* object in the hierarchy potentially recursive.

I think this is better than using MI. BP seems to have set the trend to
have an almost useless ultimate ancestor for an object heirarchy. I
personally do not agree with that philosophy. 

> (* And: C++ has it, and we must demonstrate that GPC is not inferior. ;*)

Agreed :-)=

Best regards, The Chief 
Dr Abimbola A. Olowofoyeku (The African Chief, and the Great Elephant)
Author of:  Chief's Installer Pro v3.50 for Win16 and Win32.
Homepage:  http://ourworld.compuserve.com/homepages/African_Chief/
E-mail: laa12@cc.keele.ac.uk


The African Chief (laa12@cc.keele.ac.uk)