From: Robert Klemme <shortcutter@...>
Date: 2006-12-26T04:55:08+09:00
Subject: Re: dynamic changes!

On 25.12.2006 20:44, Spitfire wrote:
> Robert Klemme wrote:
>> 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.
> 
> It's class? I'm sorry I don't understand what you are saying. Can you 
> please clarify?

Sorry, should have read "its class".  Please look closely at the IRB 
session to understand what I mean:

irb(main):001:0> class Foo
irb(main):002:1> def m1() end
irb(main):003:1> end
=> nil
irb(main):004:0> Foo.object_id
=> 1917050
irb(main):005:0> Foo.instance_methods.grep /m\d/
=> ["m1"]
irb(main):006:0> f=Foo.new
=> #<Foo:0x381468>
irb(main):007:0> f.class
=> Foo
irb(main):008:0> f.class.object_id
=> 1917050
irb(main):009:0> f.m1
=> nil
irb(main):010:0> f.m2
NoMethodError: undefined method `m2' for #<Foo:0x381468>
         from (irb):10
         from :0
irb(main):011:0> class Foo
irb(main):012:1> def m2() end
irb(main):013:1> end
=> nil
irb(main):014:0> Foo.object_id
=> 1917050
irb(main):015:0> Foo.instance_methods.grep /m\d/
=> ["m2", "m1"]
irb(main):016:0> f.class
=> Foo
irb(main):017:0> f.class.object_id
=> 1917050
irb(main):018:0> f.m1
=> nil
irb(main):019:0> f.m2
=> nil

	robert