Well, I considered encapsulation as syntactical sugar. And even prolog knows polymorphism, but I wouldn't call it OOP. (Yes, I know in a typless context polymorphism doesn't mean too much. And btw, if Python is a multi-paradigm language why doesn't support polygamy? :) ) Or maybe I'm wrong ...
Alan Gauld wrote: >I just found this message (because Mike posted the tinyurl....) >and couldn't resist responding... > >"Zsiros Levente" <[EMAIL PROTECTED]> wrote > > >>If we're talking about data hiding, let me ask: why Python doesn't >>implement data hiding (I mean 'private' and 'protected')? I consider >>it >>a very important OOP feature, because that makes OOP different from >>structural programming. >> >> > >This is a hot-button of mine... > >Why do you think data hiding is important for OOP? >And in particular why do you think it differentiates >OOP from structural techniques? > >Data Hiding was not part of the early OOP languages >(Simula, Lisp and the first Smalltalks) it was introduced >first by Smalltalk in (Smalltalk 74 I think) and it was only >when C++ came out that all the public/private nonsense >appeared, followed by protected in C++ v2.0 > >Many OOP languages do not support data hiding, it is >not necessary for OOP. Data hiding is supported in many >structual languages like the Modula family and ADA., >but they are not OOP. (The concept was introduced by >David Parnas in 1972 - long before OOP became popular) > >The point being that Data hiding is an orthogonal issue >to OOP which relies on encapsulation and polymorphism. >- Encapsulation(*) is the ability to treat the data and methods > as a single entity - an object. >- Polymorphism is the ability for different objects supporting > the same protocol to react in different ways to the same > message. > >Inheritance is an optional extra but is usually required to >implement polymorphism... > >(*)Some texts get data hiding and encapsulation confused. >Encapsulation as originally applied to OOP is about joining >the data and function together - so fundamental to OOP that >some folks forget its even there as a feature! > >Data hiding is about making data available through an API. >That API could be an object's protocol or it could be a >module interface. It's usually a good thing to do, but not >a requirement of OOP. > >Rant over, > >If anyone wants a more academic review oif the differences >between data hiding (or more correctly, information hiding), >encapsulation and abstraction see this white paper: > >http://www.itmweb.com/essay550.htm > >by Ed Berard. > > > _______________________________________________ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
