This post originated from an RSS feed registered with Ruby Buzz by Matt Williams. Original Post: A Class is not always a Class Feed Title: Ruby Blender Feed URL: http://feeds2.feedburner.com/RubyBlender Feed Description: This blog contains short-ish ruby tips, hints, and techniques. Latest Ruby Buzz Posts Latest Ruby Buzz Posts by Matt Williams Latest Posts From Ruby Blender

While playing around in irb last night, I discovered something interesting Class does not always have the same superclass:

  
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>> Class.superclass
=> Module
>> Class.object_id
=> -605542778
>> class Fud
>>   end
=> nil
>> Fud.class
=> Class
>> Fud.object_id
=> -606747838
>> Fud.superclass
=> Object
>> Class.class
=> Class
>> Class.class.superclass
=> Module
>> Fud.class.superclass
=> Module
>> Fud.class.object_id
=> -605542778
>> Fud.class
=> Class
>> Fud.class
=> Class
>> Fud.class.object_id
=> -605542778
>> Fud.superclass
=> Object
>> Fud.instance_of? Class
=> true
>> Class.instance_of? Class
=> true
>> Class.class.object_id
=> -605542778
>> Class.object_id
=> -605542778

Curious, huh? So, despite Fud being an instance of Class, it's superclass is Object. And Class is an instance of itself.

I believe that this has to do with the mysterious "class" object which every class has. This class object allows one to get at the guts, if you will, of a class in order to do metaprogramming.

Still it's pretty interesting...