Also, only some things in OCaml are structurally typed (modules, objects, polymorphic vairants), others are not (records, variants). For example: # type me

Also, only some things in OCaml are structurally typed (modules, objects, polymorphic vairants), others are not (records, variants). For example: # type meters = I of int;; type meters = I of int # let meters i = I i;; val meters : int -> meters = <fun> # type newtons = I of int;; type newtons = I of int # let newtons i = I i;; val newtons : int -> newtons = <fun> # let f b = if b then newtons 12 else meters 12;; Characters 36-45: let f b = if b then newtons 12 else meters 12;; ^^^^^^^^^ Error: This expression has type meters but an expression was expected of type newtons