Re: Clean Object Class Design -- Circle/Ellipse
Date: Fri, 20 Jul 2001 10:36:04 +0100
Message-ID: <9j8tnn$mdgo0$1_at_ID-75294.news.dfncis.de>
<D_at_B.A> wrote in message news:QLG57.872$Y47.13304_at_www.newsranger.com...
> In article <9TF57.167$%16.43276332_at_radon.golden.net>, Bob Badour says...
> 1. Is the case Square/Rectangle really similar to Circle/Ellipse?
> [...]
It is not similar. It is the *same* .
The problem that occurs when taking the spec into a solution, and therefore
coming to
grief with the Liskov Substitution Principle (LSP) , was called by Peter
Wegner
"subset subtyping" .
Go to Google etc to search comp.object for the full name of the paper by
Wegner
BTW, not sure why comp.theory is on the list.
But be warned, once you get those guys involved, what you'll get as "theory"
will
Regards,
that discusses the problem. Follow the thread to see what potential impl
solutions can
be used to alleviate the problem
make the comp.object debates look like Janet and John book 2 ... :-)
Steven Perryman
Received on Fri Jul 20 2001 - 11:36:04 CEST