From: Robert Klemme <shortcutter@...>
Date: 2007-10-18T04:45:06+09:00
Subject: Re: abstract superclasses

On 17.10.2007 21:22, Giles Bowkett wrote:
> I sometimes use the Java thing of an abstract superclass in Ruby. I
> usually just set up the abstract parent so that it'll break if used
> directly. Is it better to just use Modules? Have other people run into
> this?

Why bother?  If your "abstract" class requires a method to be present 
then just not defining it works pretty well - in modules as well as in 
classes:

irb(main):001:0> o=Object.new.extend Enumerable
=> #<Object:0x1001a92c>
irb(main):002:0> o.map {|y| y.to_i}
NoMethodError: undefined method `each' for #<Object:0x1001a92c>
         from (irb):3:in `map'
         from (irb):3
         from :0
irb(main):003:0>

Of course you need some documentation about the missing method - that 
would probably be the only reason why I'd add a dysfunctional definition 
of that method...

Kind regards
	
	robert