I was just building in some error handling into some UI code, and wanted to catch errors relating to duplicate ids. The problem is that just about every client-side error raises the same kind of Exception, a 'Bad Request'. A quick grep counted 41 different types of 'Bad Request' in my Zope source. Wouldn't it be *much* nicer to have a hierarchy of exception types, so that applications can deal with them at an arbitrarily granular level? e.g. ZopeException | `RequestException | | | `XMLException | `IdException | | | `ReservedWordException | `DuplicateException Has this discussion taken place before? Would it be useful? Would its effort:benfits ratio be too great to justify doing? seb