Grant Edwards wrote:
I realize that technically all methods are added to classes at
"run-time", but what I'm talking about is this:
import ClientForm
def controlEqual(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)
Note:
Here you are checking that self.readonly == self.readonly!
I also dislike the trailing backslashes and over-parenthesizing.
So, I'd do it like this (using the pare to avoid the backslash):
def controlEqual(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)
...
ClientForm.Control.__eq__ = controlEqual
ClientForm.Control.__ne__ = controlNotEqual
def formEqual(self,other):
if len(self.controls) != len(other.controls):
return False
for (c1,c2) in zip(self.controls,other.controls):
if c1 != c2:
return False
return True
def formNotEqual(self,other):
return not (self==other)
ClientForm.HTMLForm.__eq__ = formEqual
ClientForm.HTMLForm.__ne__ = formNotEqual
It works fine, but it seems like it might be dangerous (or just
bad form) to insert methods into existing classes like that.
Perhaps it would be safer to make sure that __eq__, __ne__,
and __cmp__ don't exist before adding my own?
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)
class FancyHTMLForm(ClientForm.HTMLForm):
def __eq__(self,other):
...
def __ne__(self, other):
return not self.__eq__(other)
You'd have to make sure FancyControl and FancyClientForm get used in
the app. The latter could be insured by monkey-patching:
...
ClientForm.Control = FancyControl
ClientForm.HTMLForm = FancyHTMLForm
But substituting monkey-patching for class method insertion seems like
you are going from one quick and dirty technique to a slightly nicer
quick and dirty technique.
--Scott David Daniels
scott.dani...@acm.org
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