[nahname]

Multiple Inheritance is one of those things I really just cannot understand. From my experience, inheritance is almost always the wrong solution. Composition being the correct tool.

Mixins are based on the concept of composition. In my opinion, more instances of inheritance should be composition than not. I strongly suspect that many cases for multiple inheritance are actually confusion around when to use composition.

Admittedly I have little experience with languages that support multiple inheritance. Do you have an example where multiple inheritance is a clear solution to a problem that you faced?

[arxanas]

I wouldn't say mix-ins are based on the concept of composition. The mix-in is not a discrete object that's part of the composition of the class.

[nahname]

Their effect of adding a mixin is similar to macros, but they provide the same abilities as composition. I wouldn't be surprised to find that mixins were based off of macros. They work really well in places where I would compose behaviour into an object.