From: David Naseby <david.naseby@...>
Date: 2003-09-03T09:33:02+09:00
Subject: Re: OOP flavours - was Python vs. Ruby

>From: james_b [mailto:james_b@neurogami.com]
>I've been doing this sort of thing in my code, and after a while it 
>struck me as common sense, not purist theory.   I find it goes a long 
>way towards cleaning up or avoiding procedural code where I 
>want OO, and 
>I find it easier to read.
>
I like this style too, and Ruby allows one to do it well via Mixin Oriented
Programming (MOP?). The best library based example I've seen is in Amrita,
where you extend your model class with Amrita::ExpandByMember, so amrita can
render the object correctly.

Similarly, you don't need to expand classes to predict there uses - for the
example of IO printing flying around, you can extend on the fly:
 module STDOUTPrinter
   def print
     STDOUT.print self.to_str
   end
 end
 
 str = "helloworld"
 str.extend STDOUTPrinter
 str.print

Its a fairly useless example in this case, but extend this to template based
GUIs along the amrita lines, and mixin oriented programming shows its real
strength.

Not that I do it much in practice right now, but this message captures a lot
about how I've been thinking in Ruby lately. Although I still don't
understand it, I really like the ideas of "side-inheritance" as used by
Matju:
http://www.ruby-talk.org/13827

David.