Add a generic main function.

bin/day2402.ml

@@ -22,15 +22,5 @@ let day2402a lsts = List.filter is_safe lsts |> List.length
 let day2402b lsts = List.filter is_safe_dampened lsts |> List.length
 
 let _ =
-  try
-    match Sys.argv with
-    | [| _; fname |] ->
-        let lines = nums_from_file fname in
-        Printf.printf "Part 1 = %d\n" (day2402a lines);
-        Printf.printf "Part 2 = %d\n" (day2402b lines)
-    | _ ->
-        Printf.printf "Usage: day2402 <fname>\n";
-        exit 1
-  with e ->
-    Printf.printf "An error occured: %s\n" (Printexc.to_string e);
-    exit 1
+  Aoc.main nums_from_file
+    [ (string_of_int, day2402a); (string_of_int, day2402b) ]