OCaml : Unbound Module.function value

Question

I'm new to OCaml and I am a little confused about Modules.

I tried to implement a really simple test but I can't compile it...

Here are the files (I'm on Linux by the way) :

main.ml

let main () =
  if ((Array.length Sys.argv) > 2 && int_of_string Sys.argv.(1) > 1 && int_of_string Sys.argv.(2) > 1)
  then
    begin
      Printf.printf "Args = %d && %d\n" (int_of_string Sys.argv.(1)) (int_of_string Sys.argv.(2));
      Laby.initLaby (int_of_string Sys.argv.(1)) (int_of_string Sys.argv.(2))
    end
  else
    Printf.printf "Usage : ./test x y n"

let _ = main ()

Laby.ml

let initLaby (x : int) (y : int) =
  let testCell = Cell.initCell 0 1 in
  begin
    Printf.printf "Init Laby with X(%d) / Y(%d)\n" x y;
    Cell.printCell testCell;
  end

Cell.ml

module type CELL =
  sig
    type  t

    val initCell : int -> int -> t
    val printCell : t ->  unit
  end

module Cell : CELL =
  struct
    type t = (int * int)

    let initCell (x : int) (y : int) =
      (x, y)

    let printCell (x, y) =
      Printf.printf "Cell -> X(%d) / Y(%d)\n" x y

  end

Cell.mli

module type CELL =
  sig
    type  t

    val initCell : int -> int -> t
    val printCell : t ->  unit
  end

module Cell : CELL

And here is the Makefile :

NAME =  test


ML =    Cell.ml  \
    Laby.ml  \
    main.ml


MLI =   Cell.mli


CMI = $(MLI:.mli=.cmi)
CMO = $(ML:.ml=.cmo)
CMX = $(ML:.ml=.cmx)


OCAMLDPE = ocamldep
CAMLFLAGS = -w Aelz -warn-error A
OCAMLC = ocamlc $(CAMLFLAGS)
OCAMLOPT = ocamlopt $(CAMLFLAGS)
OCAMLDOC = ocamldoc -html -d $(ROOT)/doc


all:        .depend $(CMI) $(NAME)

byte:       .depend $(CMI) $(NAME).byte


$(NAME):    $(CMX)
        @$(OCAMLOPT) -o $@ $(CMX)
        @echo "[OK] $(NAME) linked"

$(NAME).byte:   $(CMO)
        @$(OCAMLC) -o $@ $(CMO)
        @echo "[OK] $(NAME).byte linked"

%.cmx:      %.ml
        @$(OCAMLOPT) -c $<
        @echo "[OK] [$<] builded"

%.cmo:      %.ml
        @$(OCAMLC) -c $<
        @echo "[OK] [$<] builded"

%.cmi:      %.mli
        @$(OCAMLC) -c $<
        @echo "[OK] [$<] builded"

documentation:  $(CMI)
        @$(OCAMLDOC) $(MLI)
        @echo "[OK] Documentation"


re:     fclean all


clean:
        @/bin/rm -f *.cm* *.o .depend *~
        @echo "[OK] clean"


fclean:     clean
        @/bin/rm -f $(NAME) $(NAME).byte
        @echo "[OK] fclean"


.depend:
        @/bin/rm -f .depend
        @$(OCAMLDPE) $(MLI) $(ML) > .depend
        @echo "[OK] dependencies"

Here is the output of the Makefile :

[OK] dependencies
[OK] [Cell.mli] builded
[OK] [Cell.ml] builded
File "Laby.ml", line 3, characters 17-30:
Error: Unbound value Cell.initCell
Makefile:47: recipe for target 'Laby.cmx' failed
make: *** [Laby.cmx] Error 2

I think it's a compilation error, since it seems to not found the Cell module, but I can't make it works... What am I doing wrong, and how can I fix it?

Answer 1

Each .ml file serves as its own module. You seem to have module Cell inside cell.ml which is double. You would have to address that function as Cell.Cell.initCell. Or open Cell in laby.ml. Also, I think .ml file names are conventionally lowercase? Aside: why does make output wrong english?