问题 I'm taking a look to this programming language "Ocaml" and I have some troubles because I read the official ocaml documentation but I don't uderstand how to use : ";" and ";;" and "in" specially inside the definition of functions. This is my code : let abs_val value : int -> int = let abs_ret = ref 0 ; if value >= 0 then abs_ret := value else abs_ret := -value ; let return : int = abs_ret ;; print_int abs_val -12 Compiled with "ocamlc" it said : File "first_program.ml", line 7, characters 2-4