Is mixin considered a design pattern?

Question

Are mixins considered a design pattern? Structural?

Answer 1

They're a language feature. A "pattern" is different from a feature, in that it resolves a set of forces that may influence a situation in contradictory ways. Features, by their presence or absence, tend to create the forces that patterns resolve. Many design patterns (Double Dispatch is a good example) came about to work around language limitations (in this case method dispatching on a single argument).