OOP: class based and prototype based, are there other alternatives?

I know of class-based and protype based object orie开发者_JS百科nted programming languages, are there any other alternatives? What are they?

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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

• Traits: Composable Units of Behavior
• Expanders: Statically Scoped Object Adaptation for Java
• JavaGI: Generalized Interfaces for Java

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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.

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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.

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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.

http://en.wikipedia.org/wiki/Programming_paradigm