How to load .ml file with its corresponding .mli file in utop?

Question

Simply put, let us say I have an implementation file called moduleExample.ml and an interface file in the same directory called moduleExample.mli.

How could I load them together in such a way that the functions not listed in the interface moduleExample.mli are hidden from moduleExample.ml's signature in utop? Additionally, how about type abstraction through the moduleExample.mli file?

Answer 1

I think the proper method to do that, or more generally load within a toplevel a whole project of several modules and interfaces, is to use a build system to compile all modules and link them within a toplevel.

Using dune, you can do that by doing dune utop directory as described here. For exhaustiveness here's an architecture example:

dune.ml

(library
  (name dummy)
  (wrapped false)
)

ex.ml

type t = int
let of_int x = x
let to_string = string_of_int
let add = (+)
let print x = print_string (to_string x)

ex.mli

type t
val of_int : int -> t
val print : t -> unit

Loading all that into utop by doing dune utop . and then using the #show directive on the module Ex, gives:

utop # #show Ex;;
module Ex : sig type t val of_int : int -> t val print : t -> unit end