On 2009-04-07, Scott David Daniels <scott.dani...@acm.org> wrote: > Grant Edwards wrote: >> On 2009-04-07, Scott David Daniels <scott.dani...@acm.org> wrote: >> >>>> File "/usr/lib/python2.5/site-packages/ClientForm.py", line 2016, in >>>> add_to_form >>>> Control.add_to_form(self, form) >>>> TypeError: unbound method add_to_form() must be called with >>>> FancyControl instance as first argument (got CheckboxControl instance >>>> instead) >>> OK, that is one of the problems with monkey-patching. What happened >>> is ClientForm apparently defines subclasses of Control such as >>> CheckboxControl. >> >> Right. Control is just a base class, and changing it to a >> "different" class after sub-classes have been defined pulls the >> rug out from under things. Had I thought about it for a >> minute, I should have known that would happen. The working >> patch tweaks the class in-place, so it works OK. >> >>> The monkey-patching only happens after the ClientForm module >>> has been executed (first import), and the monkey-patching >>> happens after all of that. So now the "tack it into the >>> class" method looks a bit better if you cannot simply add your >>> requirement to the ClientForm source. >> >> That's obviously the "right thing", but it makes portability >> more of an issue (I would have to archive/distribute ClientForm >> source and users would have to install the customized version >> of ClientForm). >> >> Of course there's always the chance that my version of >> monkey-patching will stop working with a different version of >> ClientForm. We'll burn that bridge when we come to it. >> > > What you might use as a half-way measure: > > class Mixin: # or class Mixin(object) if new-style: > def __eq__(self, other): > return (self.type == other.type > and self.name == other.name > and self.value == other.value > and self.disabled == other.disabled > and self.readonly == self.readonly) > > def __ne__(self, other): > return not self.__eq__(other) > ...(including FancyHTMLForm) ... > class FancyControl(MixIn, ClientForm.Control): pass > class FancyCheckboxControl(MixIn, ClientForm.CheckboxControl): pass > ... > ClientForm.HTMLForm = FancyHTMLForm > ClientForm.Control = FancyControl > ClientForm.CheckboxControl = FancyCheckboxControl
That would work -- but there are probably 8 or 10 different Control subclasses. It's a bit tedious mixing them all one at a time, and you need more "inside" information (the names of all the different subclasses). -- Grant -- http://mail.python.org/mailman/listinfo/python-list
