Handle parsing errors

bot.ml

@@ -17,6 +17,7 @@ let write iobuf command args text =
     Iobuf.write iobuf cmd
 
 let scheme_eval str =
+  try
     let thread = Ocs_top.make_thread () in
     let env = Ocs_top.make_env () in
     let inport = Ocs_port.open_input_string str in
@@ -24,11 +25,12 @@ let scheme_eval str =
     let lexer = Ocs_lex.make_lexer inport "interactive" in
     let v = Ocs_read.read_expr lexer in
     let c = Ocs_compile.compile env v in
-    try
       Ocs_eval.eval thread (Ocs_print.print outport false) c;
       Ocs_port.get_output_string outport
-    with Ocs_error.Error msg ->
-      msg
+  with 
+    | Ocs_error.Error msg 
+    | Ocs_error.ErrorL (_, msg) ->
+        "Error: " ^ msg
 
 
 let handle_privmsg iobuf sender target text =