@arnetheduck, regarding run-time polymorphism, there is a planned feature called "VTable types". You can read the spec here:
[https://github.com/nim-lang/Nim/blob/5491f1f53b4011785b41b30897b73538d564fd55/doc/manual.rst#L4764](https://github.com/nim-lang/Nim/blob/5491f1f53b4011785b41b30897b73538d564fd55/doc/manual.rst#L4764)
