Grant Edwards wrote:
On 2009-04-07, Grant Edwards <inva...@invalid> wrote:
On 2009-04-07, Scott David Daniels <scott.dani...@acm.org> wrote:
Grant Edwards wrote:
I realize that technically all methods are added to classes at
"run-time", but what I'm talking about is this:
...
ClientForm.Control.__eq__ = controlEqual
ClientForm.Control.__ne__ = controlNotEqual
...
Well, a more standard approach would be:
class FancyControl(ClientForm.Control):
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)
I like that, except it doesn't work. Objects instantiated from
sub-classes of ClientForm.Control break. I get errors like
this:
Traceback (most recent call last):
File "./testit.py", line 141, in <module>
f1 = getSocketForm(0)
File "./testit.py", line 99, in getSocketForm
return getForm("Socket",n)
File "./testit.py", line 88, in getForm
forms = ClientForm.ParseResponse(response,backwards_compat=False)
File "/usr/lib/python2.5/site-packages/ClientForm.py", line 1057, in
ParseResponse
return _ParseFileEx(response, response.geturl(), *args, **kwds)[1:]
File "/usr/lib/python2.5/site-packages/ClientForm.py", line 1128, in
_ParseFileEx
type, name, attrs, select_default=select_default, index=ii*10)
File "/usr/lib/python2.5/site-packages/ClientForm.py", line 2843, in
new_control
control.add_to_form(self)
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. 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.
--Scott David Daniels
scott.dani...@acm.org
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