>>>>> "P" == Paolino <paolo_veronelli / tiscali.it> writes: P> But why/how private messages are not accepting a receiver ? P> Is this their actual definition? yes, P> I suppose 'main' does some tricks when I define a method "there". no, not really. ruby has self and *internally* ruby_class which give it where the method must be defined. For example : * at top level it has : self = main, ruby_class = Object when you define a method at top level this will be an Object method * in the class A, it has : self = A, ruby_class = A when you define a method in A, this will be an instance method for A Guy Decoux