Why the claim that c# people don't get object-

Question

This caught my attention last night.

On the latest ALT.NET Podcast Scott Bellware discusses how as opposed to Ruby, languages like c#, java et al. are not truly object oriented rather opting for the phrase "class-oriented". They talk about this distinction in very vague terms without going into much detail or discussing the pros and cons much.

What is the real difference here and how much does it matter? What are other languages then are "object-oriented"? It sounded pretty interesting but I don't want to have to learn Ruby just to know what if anything I am missing.

Update: After reading some of the answers below it seems like people generally agree that the reference is to duck-typing. What I'm not sure I understand still though is the claim that this ultimately changes all that much. Especially if you are already doing proper tdd with loose coupling blah blah blah. Can someone show me an example of a wonderous thing I could do with ruby that I cannot do with c# and that exemplifies this different oop approach?

Answer 1

This is really probably getting down to what these people see others doing in c# and java as opposed to c# and java supporting OOP. Most languages cane be used in different programming paradigms. For example, you can write procedural code in c# and scheme, and you can do functional-style programming in java. It is more about what you are trying to do and what the language supports.

Answer 2

OO is sometimes defined as message oriented. The idea is that a method call (or property access) is really a message sent to another object. How the recieveing object handles the message is completely encapsulated. Often the message corresponds to a method which is then executed, but that is just an implementation detail. You can for example create a catch-all handler which is executed regardless of the method name in the message.

Static OO like in C# does not have this kind of encapsulation. A massage has to correspond to an existing method or property, otherwise the compiler will complain. Dynamic languages like Smalltalk, Ruby or Python does however support "message-based" OO.

So in this sense C# and other statically typed OO languages are not true OO, sine thay lack "true" encapsulation.