From: hipster <hipster@...4all.nl>
Date: 2001-08-16T20:57:36+09:00
Subject: [ruby-talk:19888] Re: Why not?: Assigning to self

On Thu, 16 Aug 2001  17:40:48 +0900, Pit Capitain wrote:
[snip]
> Take the famous Shape class hierarchy:
> 
> class Shape; ...; end
> class Rectangle < Shape; ...; end
> class Square < Rectangle; ...; end
> 
> Suppose you have a Rectangle instance and use one of its resizing 
> methods so that the new height equals the new width. After that it 
> would be nice if the Object had become a Square instance.
> 

FYI:

The C++ FAQ discusses an identical inheritance problem: circle
vs. ellipse -- and provides some valuable insights along the way.

http://www.parashift.com/c++-faq-lite/proper-inheritance.html#[21.6]

        Michel