Suppose you have a simple form like: <html> <form action="http://www.musi-cal.com/search" method="post"> City: <input name="performers" type="text"> Radius: <input name="radius:int" type="text"> <input type="submit" name="submit" value="Search"> </form> </html> and the user submits the form with an invalid input for the radius. Assuming ZServer was not run with -D, other than the standard boilerplate, all the user sees is exceptions.ValueError However, field2int raised ValueError with a string like ValueError: An integer was expected in the value 'wer' Making this available to the user, even in the non-debug case, seems like it would be useful feedback for the user that could help guide them to their mistake. -- Skip Montanaro (skip@mojam.com) http://www.mojam.com/ http://www.musi-cal.com/