Multiple inheritance (Was: OOP)

Wed, 28 May 1997 12:08:20 +0200 (MET DST)

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, but

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

  * 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.

  * Whether we want to use it or not, I would like to think about how
    to implement it due to academical curiousity.

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

Greetings,

    Peter

  Dipl.-Phys. Peter Gerwinski, Essen, Germany, free physicist and programmer
peter.gerwinski@uni-essen.de - http://home.pages.de/~peter.gerwinski/ [970201]
 maintainer GNU Pascal [970510] - http://home.pages.de/~gnu-pascal/ [970125]

Peter Gerwinski (peter@agnes.dida.physik.uni-essen.de)