> [Lisp macros] by their nature would be hard to implement properly in a language without turning it into a dialect of Lisp
Other candidates that come to mind (because I recently learned about them) are effect systems, like in Koka.
The main difference is: mixins are compile-time only, you can't add them to a running system like in Lisp.
In practice, it is a much smaller difference than it looks like.
The rest of lisp is pretty easy if you've done any sort of functional programming, and view the code through a lens that translates (foo ...) to foo(...)