I know of class-based and protype based object oriented programming languages, are there any other alternatives? What are they?
+2
A:
mixins allow you to extend a class with code that is defined elsewhere, such as in a module.
See Ruby Mixin Tutorial for an introduction.
Justin Ethier
2010-04-30 16:13:11
how is it different from class based OOP with multiple inheritance (implementation without diamond problem)?
Gabriel Ščerbák
2010-04-30 16:18:48
I agree it is very similar, however a mixin allows you to inject code from an "ancestor" without implying an *is a* relationship for the descendant. Or in other words you could think of it as an interface that may also contain code.
Justin Ethier
2010-04-30 16:22:45
ah, I understand, something like plicy based design in C++, where you would use traits to compose template class... if I understand it right, this violates Liskov Substitution principle right? Or is the "mixedIn" relationship explicitly different from inheritance?
Gabriel Ščerbák
2010-04-30 16:50:32
A:
You may want to check Wikipedia's article on programming paradigms. The one I've worked with is aspect-oriented programming, which is where the mixins come in.
bryanjonker
2010-04-30 16:24:01
I read it and there is no further information regarding my question.
Gabriel Ščerbák
2010-04-30 16:31:19
+1
A:
Go has a concept that is similar to classes, but without inheritance and with very flexible interfaces. You can read more about it in Effective Go.
Lukáš Lalinský
2010-04-30 16:24:49
Hmm, this remainds me of something I heard about OOP in functional languages. Are there any requirements for a function adding to types interface/bahaviour? Does it have to be in same package at least?
Gabriel Ščerbák
2010-04-30 17:02:55
+1
A:
These are indeed the two main approaches behind object-oriented languages, and I'm not aware of another completely different underlying principle.
But there exists a lot of variants of both approaches, as well as a lot of other programming language constructs that tackles reuse/extensibility in either class-based or prototype-based language. Examples: traits, mixin, extension methods, partial class, generics, first-class slots, split objects, etc. A lot of such constructions are first proposed in research papers (ECOOP, OOPSLA, POPL conferences), and a few of them become mainstream in popular languages. But I would qualify them as variations and not as groundbreaking new underlying principle.
Note though than you can mimic object-oriented programming in languages which are not object-oriented per-se. For instance, with Clojure multi-method. Object-oriented and functional programming are also slowly merging, for instance in Scala.
EDIT
It's actually hard to make a list of classic/seminal papers, and I don't pretend to have sufficient knowledge to do so. If there is one somewhere, I would be very interested to see it :) Still, here are a few ones that might interest you.
Inheritance, delegation, subtyping:
- Genericity vs inheritance
- Inheritance Is Not Subtyping
- On the notion of inheritance
- Split objects: a disciplined use of delegation within objects
Module, composition, adaptation
ewernli
2010-04-30 18:05:34
Hmm, I guess you are right, can you point me directly to some influential/good research papers? I will give you upvote straight for some links... I am aware of some of the functional stuff like in CLOS etc. I am interested in hearing more, therefore I asked this question:)
Gabriel Ščerbák
2010-04-30 18:27:49