From: Daniel Schierbeck <daniel.schierbeck@...>
Date: 2006-05-18T22:11:29+09:00
Subject: Re: instance variables for Fixnum?

Pascal Hurni wrote:
> irb(main):001:0> 1.instance_variable_set(:@foo, 123)
> => 123
> irb(main):002:0> 2.instance_variable_get(:@foo)
> => nil
> irb(main):003:0> 1.instance_variable_get(:@foo)
> => 123
> 
> How is this possible? I thought Fixnum were 'value' type not real objects.
> (in C they are VALUE which holds the value of the fixnum)

Almost everything in Ruby is an object -- even Fixnums. There is only 
one `3' object -- it's not like a string, where two strings with the 
same content can very well be different objects.

   "foo".instance_variable_set(:@bar, "baz")
   "foo".instance_variable_get(:@bar)  => ArgumentError

   3.instance_variable_set(:@bar, "baz")
   3.instance_variable_get(:@bar)  => "baz"

This is because Fixnums are immediates; so are symbols, btw.


Daniel