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From: "Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de>
Subject: Re: Ada Interfaces and the Liskov Substitution Principle
Newsgroups: comp.lang.ada
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Date: Thu, 24 May 2007 15:41:41 +0200
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Date: 2007-05-24T15:39:35+02:00
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On Thu, 24 May 2007 12:42:16 +0200, Georg Bauhaus wrote:

> In fact, Eiffel has a relative, the assignment attempt
> (written "?="). And the Eiffel arguments versus Liskov/Wing
> are that the principles guiding program design should come
> from the solution to a problem, not from models when these
> cannot capture the solution. In a sense, it is argued that
> that L/W substitution (and also co/contra-variance) violate
> programming principles!

Actually [absolute] LSP violates common sense.

IF A were fully and unconditionally substitutable for B in all possible
contexts, then As and Bs would be equivalent in any thinkable sense.
Because then they would be indistinguishable without magic.

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