From: Reimer Behrends <behrends@...>
Date: 2002-09-06T21:50:47+09:00
Subject: Re: Ruby aesthetics

Christian Szegedy (szegedy@nospam.or.uni-bonn.de) wrote:
>  Reimer Behrends wrote:
> >
> > However, if we first factored out the functionality of the queue, we can
> > now subclass the implementation of the queue separately (the queue
> > having no private members), and substitute the new implementation for
> > the old one.
>  
>  But the queue should have private data since its implementation
>  is hidden from its interface. If you derive from this quese, then the
>  hidden data becames visible. If you instanciate it, you generate data,
>  you can't hide :(

If you have an instance of the queue, then it can only be accessed
through its public methods. The design decisions are hidden from the
class using the queue; yet the queue class itself can be subclassed
to be used elsewhere to enhance its functionality.

[...]
> > As I said, it is largely a religious issue, and this has become much
> > longer than I wanted it to be. But there is more to the problem
> > than you think.
>  
>  I disagree: It is a practical problem. If I can't guarantee name collision,
>  (and therefore working code), then it is a problem that disturbs me all the
>  time. It is far from a philosophical or theoretical issue.

It is a religious issue because it hinges on methodological assumptions
that cannot be validated objectively, but have to be taken on faith. By
your methodological assumptions, name collisions are the central
problem; by mine, lack of reuse and extensibility is. And there is no
way to decide the matter _objectively_. It's largely an article of
faith, not of right or wrong.

			Reimer Behrends