Added check for multiple input files

main.ml

@@ -39,11 +39,9 @@ let parse_args () =
       raise (Failure ("missing argument value for \"" ^ arg ^ "\""))
     | ("-v" | "-o" | "-upto") as arg :: next :: _ when next.[0] = '-' ->
       raise (Failure ("missing argument value for \"" ^ arg ^ "\""))
-
     | "-h" :: _ ->
       prerr_string usage;
       exit 0
-
     | "-v" :: num :: tl ->
       begin
         try
@@ -66,6 +64,8 @@ let parse_args () =
       handle tl
     | arg :: tl when arg.[0] = '-' ->
       raise (Failure ("unknown option \"" ^ arg ^ "\""))
+    | filename :: _ when Globals.args.infile <> None ->
+      raise (Failure "cannot handle multiple input files")
     | filename :: tl ->
       Globals.args.infile <- Some filename;
       handle tl