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From: "Matthew Heaney" <mheaney@on2.com>
Newsgroups: comp.lang.ada
Subject: Re: Sugestion to Multiple Inheritance
Date: Fri, 18 Jan 2002 14:03:26 -0500
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Date: 2002-01-18T14:03:26-05:00
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"Lutz Donnerhacke" <lutz@iks-jena.de> wrote in message
news:slrna48km8.ka.lutz@taranis.iks-jena.de...
> Exactly. Matthew showed also the impact of multiple inheritance by
> duplicating the multiple included structure A. I'm pretty sure to find a
way
> without MI. Simply by designing the whole type more carefully and use
> derivated packages.

It's not clear what you're trying to do here, using a type hierarchy.

Do you want a generic algorithm, that works for any kind of collection?  If
so, then what's wrong with the model that the C++ STL uses?  It doesn't use
tagged types, just generics.

You can do something very similar in Ada95:

generic

   type Iterator_Type is private;

   with function Is_Less (L, R : Iterator_Type) return Boolean is <>;

   with procedure Swap (L, R : Iterator_Type) is <>;

   with function "+" (L : Iterator_Type; R : Integer)
      return Iterator_Type is <>;

   with function "-" (L : Iterator_Type; R : Integer)
      return Iterator_Type is <>;

   with function "-" (L, R : Iterator_Type)
      return Integer is <>;

   with function "<" (L, R : Iterator_Type)
      return Boolean is <>;

   with function "=" (L, R : Iterator_Type)
      return Boolean is <>;

procedure Generic_Quicksort
  (First : in Iterator_Type;
   Back  : in Iterator_Type);

This will work for any collection that has an iterator.  It even works for
arrays.  The algorithm itself doesn't know anything about the collection
type or the item type.