From: Chris Pine <nemo@...>
Date: 2003-02-12T01:55:08+09:00
Subject: Re: inheriting from base classes

----- Original Message -----
From: <dblack@candle.superlink.net>

But a further question is: how fundamental is the inheritance hierarchy
to designing programs in Ruby, given the non-kind_of? underpinnings of
Ruby objects (i.e., their dynanism and "in-the-moment" behavior)?
----------------------------

I'm not sure I understand what you mean.  `kind_of?' determines what methods
an object has, even if those methods are dynamically added, or singleton
methods, or whatever.  Without `kind_of?' (meaning the inheritance heirarchy
it represents), Ruby objects would become C structures!

In that quote, matz seemed to be against over-using inheritance.  And I
think that's similar to my original point:  don't subclass from a class
(base class or not) unless you want to use the subclass in place of the
class.  Don't inherit from Array unless you are making a new kind_of? Array;
a class where you *will* want to use every method Array has, and (perhaps)
then some.

Removing methods from a subclass is generally a sign that it should not be a
subclass, IMHO.  (That's one of the reasons why I think Method should be a
subclass of UnboundMethod, and not the other way around.)

Chris