From: Rich Kilmer <rich@...>
Date: 2002-11-08T14:17:02+09:00
Subject: Re: Making Instace Variables Private/Local

Let's see: Dave Thomas gave a presentation on a 26kloc production
business system he wrote over the summer in Ruby.  I have a project
with about 10kloc's of Ruby controlling a distributed agent society
of 40+ machines in a highly dynamic environment...being used every
day.  I never had a need with what you are asking for, and obviously
Dave didn't.  

I think the main barrier to writing production systems in Ruby is 
people talking about why it cannot be done and not spending the 
time doing it.

-Rich

> -----Original Message-----
> From: Gavin Sinclair [mailto:gsinclair@soyabean.com.au] 
> Sent: Thursday, November 07, 2002 6:30 PM
> To: ruby-talk ML
> Subject: Re: Making Instace Variables Private/Local
> 
> 
> From: "William Djaja Tjokroaminata" <billtj@y.glue.umd.edu> [snipped]
> 
> 
> > (In
> > other words, whether you decide that it is perfectly fine 
> that a child 
> > class accesses its parent class data directly in terms of 
> '@var' and 
> > not
> > 'self.var'.)
> >
> >
> > Bill
> 
> The only other OO (rather, OI - Object Influenced) languages 
> I know are C++ and Java.  In both of these, derived classes 
> have access to parent classes' public
> (obviously) and protected instance variables.
> 
> It seems that the Ruby model is that all instance variables are a mix:
>  - protected, because children can access them; and
>  - private, because other objects of the same class *can't* 
> access them
> 
> If C++ and Java allow derived classes to access parent's 
> instance variables, then why not Ruby?  Granted, at least in 
> these languages, instance variables can be made genuinely 
> private, but I don't think it would make sense for Ruby to 
> make *all* instance variables private.
> 
> In my (limited) experience, there is less need for 
> inheritance in Ruby than in
> C++/Java, because dynamic binding takes place all the time, 
> and because 
> C++classes
> can be modified.  This is great, because in Ruby you only 
> inherit when it genuinely makes sense, rather than as a 
> convenience for modifying behaviour.  A corollary of this is 
> that you should be able to manage your inheritence trees 
> sufficiently to avoid trampling on parent's data.  Just my 2c.
> 
> Gavin
> 
> 
> 
>