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From: Ehud Lamm <mslamm@mscc.huji.ac.il>
Subject: Re: OO puzzle
Date: 1999/12/25
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In article <83t2vt$arh$1@nnrp1.deja.com>,
  Ehud Lamm <mslamm@mscc.huji.ac.il> wrote:
> Suupose I have a routine that receives a class wide type. Inside I
> expicitly convert and treat it as some specific type.
> If I pass an actual paramter that is class-wide (access object'class)
> than, obviously, the valdity of the conversion can only be checked at
> run time.
> However if I pass a specific, and incompatible type - we can imagine a
> compiler flagging the conversion as raising an exception. whether we
> design a language to do this checking, and disallow such calls is,
> naturally, a deisgn choice. But as opposed to the first example - this
> checking seems possible to do (at least in limited cases like this).
>

Just ot clarify myeself. This issue, is conneted with the issue
of "seperate compilation" Indeed the "system validity" of Eiffel is
exactly the checks that are not (class) local.



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Ehud Lamm mslamm@mscc.huji.ac.il
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