From: Robert Klemme <shortcutter@...>
Date: 2006-12-26T04:40:05+09:00
Subject: Re: dynamic changes!

On 25.12.2006 19:37, Spitfire wrote:
> These are the sequence of actions I performed in irb.
> 
>     class Dumber
>         def sayHello
>             puts "Hello!"
>         end
>     end
>     
>     db = Dumber.new()
> 
>     db.sayHello
>     ## executes sayHello method!
> 
>     Class Dumber
>         def sayHi
>             puts "Hi"
>         end
>     end
> 
>     db.sayHi
>     ## executes the newly added method sayHi!
> 
>   how does the object already created aware of the newly added method?

The method is added to it's *class* - and that relationship does not 
change, only the class changes.

$ irb
irb(main):001:0> class Dumber
irb(main):002:1> def say_hello() puts "hello" end
irb(main):003:1> end
=> nil
irb(main):004:0> Dumber.instance_methods.grep /^say_/
=> ["say_hello"]
irb(main):005:0> Dumber.object_id
=> 1913790
irb(main):006:0> class Dumber
irb(main):007:1> def say_hi() puts "hi" end
irb(main):008:1> end
=> nil
irb(main):009:0> Dumber.instance_methods.grep /^say_/
=> ["say_hi", "say_hello"]
irb(main):010:0> Dumber.object_id
=> 1913790

As you see, Dumber stays the same instance, there are no multiple 
versions of it.

Kind regards

	robert