[squeak-dev] Re: Instance variable access in superclasses.

James Foster Smalltalk at JGFoster.net
Wed Nov 26 05:42:15 UTC 2008

On Nov 25, 2008, at 7:45 PM, Igor Stasenko wrote:
> My understanding of inheritance is different, in short:
> A subclass of particular class is a _specialization_ of base class,
> not  _expansion_.

In this context, I sometimes wonder if Square should inherit from  
Rectangle (a specialization in which width and height are equal), or  
Rectangle should inherit from Square (adding an instance variable). Am  
I right that you would have Square inherits from Rectangle (Square  
being more specialized)? But then it feels like we are wasting an  
instance variable (since Rectangle would have two).


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