These are two Rails helpers that could be very useful when injecting new instance methods in a class.

underscore

Converts from a class name to a underscore attribute.

‘MyClassName’.underscore => my_class_name

classify

Inverse method from underscore.

>> “cool_articles”.classify
=> “CoolArticles”

>> “comment”.classify
=> “Comment”

Both, combined with singularize and pluralize, allows us to handle parent/child methods in a very handy way. For example:

elements_in_ = self.send(parent).send(self.class.to_s.pluralize.underscore)

or things like

Kernel.const_get(table_model.to_s.classify).find(:all) #Kernel.const_get gets an string and retrieves the class.

source: http://yarorb.wordpress.com/2008/05/06/underscore-and-classify/