From: Josh Cheek <josh.cheek@...>
Date: 2012-02-04T23:56:39+09:00
Subject: Re: Inheritance in other notation

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On Sat, Feb 4, 2012 at 7:03 AM, Robert Klemme <shortcutter@googlemail.com>wrote:

> On Sat, Feb 4, 2012 at 2:14 AM, Jeremy Bopp <jeremy@bopp.net> wrote:
>
> > The constant Square is a class effectively equivalent to conventionally
> created classes, so you don't have to do anything special to make Rectangle
> descend from it. Just do it as you originally expected:
> >
> > class Rectangle < Square
> >  ...
> > end
>
> Which leaves us with the "minor" issue that a rectangle _is not_ a
> square - it's the other way round.  Yeah, I know, implementation
> inheritance vs. conceptual inheritance.  But OP should be aware of
> this.
>
> Kind regards
>
> robert
>
>
> --
> remember.guy do |as, often| as.you_can - without end
> http://blog.rubybestpractices.com/
>
>
Probably neither should inherit from the other since they break Liskov
Substitution Principle.

rect.x = 2
rect.y = 4

Now what is the value of rect.x? When rectangle, this will be 2. When
square, will it be 4? Squares don't have setters/getters for individual
sides since their sides must change together.

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