rearrange some stuff

day1.ml

@@ -1,13 +1,4 @@
-module IntSet = struct
-  include Set.Make(Int)
-
-  let exists_opt (type a) (f: int -> a option) (set: t): a option =
-    let exception Found of a in
-    let f' x = Option.iter (fun x -> raise (Found x)) (f x) in
-    match iter f' set with
-    | exception Found x -> Some x
-    | _                 -> None
-end
+module IntSet = Set_ext.Make(Int)
 
 let read_ints =
   Bracket.infile_lines ~line:int_of_string ~of_seq:IntSet.of_seq
@@ -23,31 +14,18 @@ let rec find ?(target=2020) ~n set =
       Option.map (List.cons x) (find ~target:(target - x) ~n:(n - 1) set) in
     IntSet.exists_opt joined set
 
-let print_result xs =
-  let res = List.fold_left ( * ) 1 xs in
-  let rec print_prod fmt = function
-    | []    -> Format.pp_print_text fmt "{}"
-    | [x]   -> Format.fprintf fmt "%d" x
-    | x::xs -> Format.fprintf fmt "%d * %a" x print_prod xs in
-  Format.printf "%a = %d\n" print_prod xs res
-
-
 let main' n input =
   match find ~n (read_ints input) with
-  | Some xs -> print_result xs
+  | Some xs -> Misc.print_prod xs
   | None    -> raise Not_found
 
-let mains = [|main' 2; main' 3|]
-
-let main = function
-  | [part; input] -> mains.(int_of_string part - 1) input
-  | _             -> Usage.exit_default 1
+let main = Misc.main 1 [|main' 2; main' 3|]
 
 
 let%expect_test "part 1" =
-  mains.(0) "../../data/day1"; (* is this always the right path??? *)
+  main' 2 "../../data/day1"; (* is this always the right path??? *)
   [%expect{| 534 * 1486 = 793524 |}]
 
 let%expect_test "part 2" =
-  mains.(1) "../../data/day1";
+  main' 3 "../../data/day1";
   [%expect{| 71 * 686 * 1263 = 61515678 |}]