"Denis Gomes" <denisg...@gmail.com> wrote
I have a basic python question. I am writing an n dimensional vector class by inheriting from the builtin python list object. I want to be able to hide the parent object's methods in the derived class instances.
Doing so would break the Liskofff Substitution Principle which says you should be able to use your subclass anywhere that the parent class can be used. This is a very bad thing! If you want to expose a reduced set of operations, rather than an extended set, then inheritance is the wriong solution. You should consider using delegation instead. Create a list indside your class and forward any requests for the operations you do want to the list object. The only snag with delegation in this scenartio is that you have to write an awful lot of one-liner methods. To get round that you can use setattr() and getattr() combined with a list of allowed operation names. Check the operation is in the list and then forward the request by name. That can save a lot of coding! HTH, -- Alan Gauld Author of the Learn to Program web site http://www.alan-g.me.uk/ _______________________________________________ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
