At Friday 5/1/2007 11:01, Emin wrote:
Thank you for your reply. As you guessed, I want to be able to select
the method at runtime as in your final example, but when I tried your
suggestion I got the same error (see below). I think the problem is
that getattr is donig something different than in my example where I
explicitly get it from the dict (see the very end of the transcript
below):
I've modified it as follows:
- using new.instancemethod to create the dynamic method
- copy uses __getstate__ to determine what is needed to copy/save.
Assuming that self.x is derived from other attributes, it's not
actually needed in the saved state, and can be omited.
- __setstate__ does the inverse: after reconstructing the object
state, sets self.x to the right value
=== cut ===
import new
class A:
def foo(self, arg):
print "in foo, self=%r arg=%r" % (self, arg)
class B(A):
def __init__(self):
self.update_dynamic_methods()
def update_dynamic_methods(self):
"Should assign the dynamic methods based on other attributes"
self.x = new.instancemethod(getattr(A,"foo"),self,B)
def __getstate__(self):
state = self.__dict__.copy()
if 'x' in state: del state['x']
return state
def __setstate__(self, state):
self.__dict__.update(state)
self.update_dynamic_methods()
b=B()
b.something = 'something'
b.foo(123)
b.x(123)
import copy
b2 = copy.deepcopy(b)
assert b2.something=='something'
b2.foo(123)
b2.x(123)
=== cut ===
--
Gabriel Genellina
Softlab SRL
__________________________________________________
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