It's not OOP, it's pattern matching, which is functional more than anything.
The other thing is generics (Option<EmacsDouble>) which is not necessarily OOP either and the option type itself which is functional (https://en.wikipedia.org/wiki/Option_type).
The other thing is generics (Option<EmacsDouble>) which is not necessarily OOP either and the option type itself which is functional (https://en.wikipedia.org/wiki/Option_type).