Dynamically adding methods

This is divine, ruby is too great to be true. no explanation needed.

1. class Object  
2.   def def(method_name, &block)  
3.     (class << self; self end).send(:define_method, method_name, block)  
4.   end  
5. end  
6.   
7. x = Object.new  
8.   
9. string = "This is a test"  
10. x.def(:elad_says) {puts "Elad says: " + string}  
11.   
12. x.elad_says  

get classes of a class

def get_all_subclasses_of(string)  
  raise ArgumentError.new("#{string} is not an AR Class") if eval(string).class.ancestors  
    .collect {|e| e.to_s.downcase}.include? ("ActiveRecord::Base")  
  
   return ObjectSpace.subclasses_of(eval(string))  
end