From: Anurag Priyam Date: 2011-01-05T02:14:19+09:00 Subject: Re: Is singleton class of an object already created? > I would like to know is there any ways to check is singleton class of an > object already created? Perhaps you need a method to determine the presence of singleton methods. In Ruby 1.9.2 you have the Object#singleton_methods that returns an array of singleton methods defined on the object. Flanagan, and Matz's book always talks about "opening" the eigenclass, and not defining one. I guess that a singleton class always exists for an object, whether a singleton method for that object exists or not. You can always get a reference to the eigenclass of the object with "class << object; self; end", where object can be any object (that allows singleton methods to be defined on them). -- Anurag Priyam