Well it depends on a runtime/compile-time distinction. A nominal type is a structural type with a compile-time constraint. If you have compile-time only consta

Well it depends on a runtime/compile-time distinction. A nominal type is a structural type with a compile-time constraint. If you have compile-time only constants you can model nominals with structural, type Square static const IsSquare = true var length = 10 You can kinda hack-in subtyping, type Shape static const Shape = true type Square import static from Shape static const IsSquare = true var length = 10