From: Bob Hutchison <hutch@...>
Date: 2006-10-30T00:52:56+09:00
Subject: Re: Interesting trival example of why open classes are good?

Hi,

On 29-Oct-06, at 3:10 AM, Peter Michaux wrote:

>> Examples abound where this open-class business comes in handy.
>
> Do you know of a nice little example that doesn't modify a built in
> Ruby class? I didn't realize I wasn't specific enough in my request.

It isn't little, but xampl in Ruby makes heavy use of this capability  
(see my sig for links). I'd think that most code-generators could  
take advantage of open-classes.

It also allows you to organise your source code, at least partially,  
on a functional basis rather than a class basis.

It is also kind of central to the implementation of Ruby's definition  
of methods on objects, usually class objects, but not necessarily,  
allowing you to do stuff like:


class Basics
   def initialize(name)
     @name = name
   end
   def tag
     return "#{@name} says"
   end
   def hello
     puts "#{tag}: hello"
   end
   def method_missing(s, *a, &b)
     puts "#{tag}: pardon?"
   end
end

a = Basics.new('a')
b = Basics.new('b')

a.hello
b.hello

a.bye
b.bye

def b.bye
     puts "#{tag}: bye"
end

a.bye
b.bye



Cheers,
Bob

>
> Thanks again,
> Peter
>
>

----
Bob Hutchison                  -- blogs at <http://www.recursive.ca/ 
hutch/>
Recursive Design Inc.          -- <http://www.recursive.ca/>
Raconteur                      -- <http://www.raconteur.info/>
xampl for Ruby                 -- <http://rubyforge.org/projects/xampl/>