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From: "Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de>
Subject: Re: tagged type as generic parameter
Newsgroups: comp.lang.ada
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Date: Thu, 3 Jan 2008 20:20:41 +0100
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Date: 2008-01-03T20:20:44+01:00
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On Thu, 03 Jan 2008 18:47:12 +0100, Jean-Pierre Rosen wrote:

> To be honnest, some languages offer 
> inheritance as the only way, so there is no choice.

There is nothing automatically wrong in doing aggregation per inheritance
if one can hide undesired side effects in public interfaces:

   type Container is private;
private
   type Container is new Contained...;

I can imagine Ada without built-in record types, but with record interfaces
implemented via privately made multiple inheritance. One can always escape
the base type class in Ada by deriving privately. Unfortunately "type X is
new Y" does not work for tagged types. Otherwise it would be even better.

Important to me is consistency of the language design preventing suspicious
code from being compiled. It did not compile because in Ada:

1. Generics are contracted;
2. Primitive operations are ones in all arguments and the result;
3. Private does not leak.

-- 
Regards,
Dmitry A. Kazakov
http://www.dmitry-kazakov.de