"Gavin Sinclair" <gsinclair / soyabean.com.au> writes: > - the cost of checking the class of the object to be compared, > after considering all of the above, is ... what? My main objection is that you remove flexibility from the future users of your class. Insisting that classes you write will only work with each other makes them closed. Promoting type checking based on #kind_of? in the FAQ runs counter to the style of Ruby (in my opinion). Cheers Dave