From: Sam Sungshik Kong <ssk@...>
Date: 2004-06-22T06:33:14+09:00
Subject: Re: Ruby OO (Re: About top-level method)

James, thanks you so much for your elaborate answer.
Yes, there's a lot to learn yet...:-)
Ruby is a new world and a pleansant challenge to me.
Paradigm shifting is always difficult but eventually worthwhile.

I'll check out the links.

Thanks again.

kong

"James Britt" <jamesUNDERBARb@neurogami.com> wrote in message
news:40D741E9.2000903@neurogami.com...
> Sam Sungshik Kong wrote:
> > I'm getting more and more confused...
> > Before I started Ruby, I thought I understood OOP concepts very clearly
> > (with Java, C#, even Python).
> > But Ruby puts me in a deep confusion with singleton methods, somewhat
> > different concept of private/protected accessibility, metaclass, etc...
>
>
> Java and (to the best of my knowledge) C# have a particular philosophy
> of OO that differs from Ruby (and probably Python).
>
> My understanding of OO tends to center on the notion of sending messages
> to receivers; the receiver may or may not know how to handle the
> message.  The receiver may have originated from  a class derived from
> one or more other classes, but, once created, may have acquire new or
> altered behavior not found in any of the base class(es).  Messages sent,
> and methods implemented in the receiver, should not have to map to one
> another; how an object responds to a message is up to that particular
> object.  The default behavior for handling unknown messages tends to be
> an exception, but that should be left to the object (i.e., the
> developer), not hard-coded into the language.
>
> By analogy, think of a web site.  Pages generally map to specific URLs.
>   Many web sites simply toss back a 500 or 404 when given an unknown
> request, but the smarter sites know how to map all URLs to something
> useful.  Now imagine if a web site was operationally prevented from
> handling unknown URLs.  Or if a user could not even *try* to request a
> page without knowing the full, correct URL in advance.  (The
> statically-typed Web?)
>
> This view of OO runs counter to statically typed languages such as Java
> and C#, where behavior tends to be set in stone early on, and object
> behavior is defined by method invocation rather than message handling.
>
> The idea that one object may be able to respond to messages that another
> object of the same class cannot is alien in Java, but normal in Ruby.
>
> Likewise, the idea that classes and objects are malleable during runtime
> is largely foreign in Java, but an essential fact of Ruby.
>
> I'm not sure how much any of this helps you with your actual problem :);
> I'm not even sure how accurate it is*.   Getting your head around Ruby
> is may be an adventure if you're coming from Java/C#.
>
> There's also a good take on what constitutes various flavors of OO on
> Paul Graham's site [0].  (There's lot's of other good stuff on his site,
> BTW.  I particularly like his comments on Arc and OO [1])
>
>
>
> James
>
> * I'm trusting somebody here will promptly correct me where I'm wrong.
> But no flamewars, please.
>
> [0] http://www.paulgraham.com/reesoo.html
> [1] http://www.paulgraham.com/noop.html
>
>
>