My dream is a static-first (like with inmutable-first) language with a way to do dynamic. The thing is not available (as far I know) is to build a dynamic obje

My dream is a static-first (like with inmutable-first) language with a way to do dynamic. The thing is not available (as far I know) is to build a dynamic object and "close it" for further modification so the compiler can optimize well. Other, that requiere good metaprograming, is to build a dynamic object AT COMPILE TIME (macro?) and close it, then the type-system work after that (F# type provider is almost this) A use case is reflect a database/data storage like JSON or relational table. I wish, like with python, to do: class Customer = @build(table("Customer")) and after this line : c = Customer() print c.name to 'c' be a static type. If at compile time, it check the type, let say the field change to c.fullname, to mark as a type error. If in runtime, like a interpreter, to "close" Customer and be certain that it never will mutate. AKA: Inmutable types/clases, but the posibility to mutate it in some discret places. Make sense?