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From: donh@syd.csa.com.au (Don Harrison)
Subject: Re: Real OO
Date: 1996/04/24
Message-ID: <DqCLD4.In3@assip.csasyd.oz>#1/1
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sender: news@assip.csasyd.oz
references: <DqAyLG.D47@assip.csasyd.oz>
organization: CSC Australia
reply-to: donh@syd.csa.com.au
newsgroups: comp.lang.eiffel,comp.lang.ada,comp.object
Date: 1996-04-24T00:00:00+00:00
List-Id: <comp.lang.ada>

I wrote:

:Jon S Anthony writes:
:
::In article <Dq3EtF.8vC@assip.csasyd.oz> donh@syd.csa.com.au (Don Harrison) writes:

[...]

::> :  And the reason it is a problem
::> :is that Eiffel source does not have as much semantic information in it
::> :in this area.
::> 
::> What might that be?
::
::Specifically, the distinction and use of the difference between class
::and type.  The funny thing is, all this brouhaha about system validity
::concerns this distinction and an attempt to try to separate them
::again.
:
:No. This is not why. It's due to the distinction between static and dynamic
:types.

Correction. In the case of catcalls resulting from a change of routine 
signature, the problem arises when calls are attempted using a combination 
of objects which have incompatible dynamic types wrt the call.

eg. surgeon.cut (carving_knife), when you really want
    surgeon.cut (scalpel)

Most patients would prefer that the former is excluded :-).

Don.