hello.ml - discussion about using open in OCaml

hello.ml

  
let rec join = function
    | []      -> ""
    | [x]     -> x
    | [x;y]   -> x^" and "^y
    | x::xs   -> x ^ ", " ^ join xs


let main () =
    let argv = Array.to_list Sys.argv in
    let args = List.tl argv in
        match args with
        | []        -> Printf.printf "Hello, world!\n"
        | names     -> Printf.printf "Hello, %s!\n" (join names)

let () = main ()