class file_holder =
	object
		val mutable source_text = ""
		method get_source = source_text
		method load file_name =
			source_text <- IO.read_all file_name;       (* 6 *)
end;;

let main =
	let f = new file_holder;                                    (* 10 *)
	f#load Sys.argv.(1)
	print_string f#get_source;
	exit(0);;                                                   (* 13 *)

main;;

C:\dev>ocamlc test.ml
File "test.ml", line 13, characters 8-10:
Error: Syntax error

C:\dev>ocamlc test.ml
File "test.ml", line 6, characters 18-29:
Error: Unbound module IO

C:\dev>ocamlc -I C:\OCaml\lib\site-lib\extlib\ IO.cmo test.ml
File "test.ml", line 11, characters 8-20:
Error: This expression has type string but an expression was expected of type
         IO.input

class file_holder =
	object
		val mutable source_text = ""
		method get_source = source_text
		method load file_name =
			let chan_in = Pervasives.open_in file_name in
				source_text <- IO.read_all (IO.input_channel(chan_in));
				Pervasives.close_in chan_in;
end;;

let main =
	let f = new file_holder in
	f#load Sys.argv.(1);
	print_string f#get_source;
	exit(0);;

main;;

if ( a=b ) {
   foo();
   bar();
} elseif ( isFunction() ) {
  zap();
}

	Array.iter (fun parameter ->
		if Filename.check_suffix(parameter, ".txt") then
		begin
			print_string "Loading ";
			print_string parameter;
			holder#load parameter;  (* объект класса file_holder из предыдущих постов *)
			print_endline " ok";
		end 
		else if parameter.[0]='-' then
		begin
			print_endline ("option " ^parameter);
		end
	) Sys.argv;

File "main.ml", line 14, characters 26-44:
Error: This expression has type 'a * string
       but an expression was expected of type string