Improved the repl to return to evaluation upon error. Also added an exit command

bin/main.ml

@@ -8,12 +8,22 @@ let rec repl env c =
   let () = printf ">>> "; Out_channel.flush Out_channel.stdout; in
   match In_channel.input_line c with
   | None -> ()
+  | Some "exit" -> ()
   | Some l ->
+    try
       let vals = (parse_str l) in
       (* dbg_print_all vals; *)
       dbg_print_all (eval_all env vals);
       Out_channel.flush Out_channel.stdout;
-    repl env c;;
+      repl env c
+    with
+    | Invalid_argument s ->
+      printf "%s\nResuming repl\n" s;
+      repl env c
+    | Parser.Error ->
+      printf "Expression '%s' couldn't be parsed, try again\n" l;
+      repl env c
+;;
 
 
-let _ = repl (make_env ()) (In_channel.stdin)
+let () = repl (make_env ()) (In_channel.stdin)