From: Phrogz <phrogz@...>
Date: 2008-02-15T08:14:56+09:00
Subject: Re: object specific methods and id

On Feb 14, 3:59 pm, UpsNDowns <tnospamho...@povtal.org> wrote:
> If I create an object specifc method foo on my string instance obj, a
> new anonymous class (the singleton, I gather) is created and obj is
> considered an instance of that.
>
> Also, every thing is an object (event classes). So how come,
> obj.class.id
> and
> "someString".class.id
> is the same?

You should be using object_id; but that won't change what you see.


> According to the documentation on id: "The same number will be returned
> on all calls to id for a given object, and no two active objects will
> share an id."

Creating an eigenclass (singleton class) for an object does not change
the .class of that object.

irb(main):001:0> s1 = "hello"
=> "hello"
irb(main):002:0> s2 = "world"
=> "world"
irb(main):003:0> def s2.special_method; end
=> nil
irb(main):004:0> s1.class == s2.class
=> true
irb(main):005:0> s1.class
=> String
irb(main):006:0> s2.class
=> String

irb(main):008:0> s2eigenclass = class << s2; self; end
=> #<Class:#<String:0x2b813c8>>

irb(main):012:0> s2.class.instance_methods.grep /special/
=> []

irb(main):013:0> s2eigenclass.instance_methods.grep /special/
=> ["special_method"]