+ try self#set_phrase history#next with MatitaMisc.History_failure -> ()
+
+ method wrap_exn: 'a. (unit -> 'a) -> 'a option =
+ fun f ->
+ try
+ Some (f ())
+ with exn ->
+ (match exn with (* highlight parse errors in user input *)
+ | CicTextualParser2.Parse_error (floc, msg) ->
+ let buf = self#buffer in
+ let (x, y) = CicAst.loc_of_floc floc in
+ let red = buf#create_tag [`FOREGROUND "red"] in
+ let (start_error_pos, end_error_pos) =
+ buf#end_iter#backward_chars (String.length last_phrase - x),
+ buf#end_iter#backward_chars (String.length last_phrase - y)
+ in
+ if x - y = 0 then (* no region to highlight, let's add an hint
+ about where the error occured *)
+ buf#insert ~iter:end_error_pos ~tags:[red] bullet
+ else (* highlight the region where the error occured *)
+ buf#apply_tag red ~start:start_error_pos ~stop:end_error_pos;
+ | _ -> ());
+ self#echo_error (explain exn);
+ None