George Sakkis a écrit : > John Machin wrote: > > >>Peter Wang wrote: >> >>>Bruno Desthuilliers wrote: >>> >>>><my humble opinion> >>>>Python is dynamic, and fighting against the language is IMHO a really >>>>bad idea. The only places where theres a real need for this kind of >>>>stuff are when dealing with the "outside world" (IOW : inputs and >>>>outputs). And then packages like formencode can do much more than mere >>>>type-checking >>>></my humble opinion> >>> (snip) > I have also a very recent real-world example to share, from the other > side of the fence this time. It's even worse because it's an error that > passes silently. Cut-down version follows: > > @cherrypy.expose > def retrieve(self, **kwds): > queries = kwds['q'] > rows = self._selectRows(*queries) > # more stuff > > 'q' here is a multiselect field that is binded to a list of selected > strings. Or so I thought, until someone noticed bizarre results in some > cases. Turns out that if you select a single item from the select box, > 'q' is binded to a string instead of a list of length 1, so instead of > retrieving 'apple', she got back the results for 'a', 'p', 'p', > 'l','e'.
This is a typical case of converting/validating data from the "outside world" - something well covered by formencode. > Bottom line, type checking is a tricky business. Indeed. In fact, proper "type checking" would first require some agreement on what's a "type"... -- http://mail.python.org/mailman/listinfo/python-list
