From: Ross Bamford <rosco@...>
Date: 2005-12-21T14:12:48+09:00
Subject: Re: When are attr_reader type  methods called?

On Wed, 21 Dec 2005 04:09:33 -0000, Vivek <krishna.vivek@gmail.com> wrote:

> I couldnt get a proper subject for the post but here is my question.
> Its regarding methods like
> attr_reader defined like below
> You can do this in ruby
>
> # file a.rb
> class A
>   call_this ("hello world")
>
>   def  call_this
>  ....
>   end
> end
>
>
> The A::call_this is called immediately after I run the script.Becuase I
> made the method print something and it printed it even though I hadnt
> instantiated an object of the class with new.
> What if the method uses some instance variables? wouldnt that be a
> problem because its called even before an object is created?My question
> is at what time during program execution are these methods called? If
> there are more than one classes in a file then whats the order ? is it
> defined by the language?

It's top to bottom, as you'd expect. Does the following surprise you?

   NewClass = Class.new(Array) do

     attr_accessor :myattr

     def this
       "that"
     end
   end

   puts (nc = NewClass.new).this
   nc.myattr = 16
   puts nc.myattr

   nc[3] = "Aha!"
   p nc

I just made a new nuby file trying out the attr_accessor and instance var  
stuff you asked about:

	http://roscopeco.co.uk/code/noob/class-def.html

-- 
Ross Bamford - rosco@roscopeco.remove.co.uk