I have hit yet another wall. I am dynamically creating a class and then
creating instances of that class. The class relies on a second class to store a
list of objects. (This is simplified from the the original by a factor of about
20. The real program is trying to create a Python object around an XML
definition object.)
Here's the code:
## OPTION ONE for class: ElementList
### Not really a list, but a wrapper that behaves like a list
class ElementList(object):
def __init__(self, parent, name):
self._parent = parent
self._name = name
def MakeWrapper(checker, _addNameAsAttribute = False ):
## OPTION TWO for class: ElementList
class Wrap(object):
## OPTION THREE for class: Elementlist
def __init__(self, name):
self._name = name
setattr(Wrap, 'stuff', ElementList(self, 'test'))
Wrap.__name__= checker.title()
return Wrap
if __name__ == '__main__':
Dude = MakeWrapper('Dude')
print Dude
d1 = Dude('Josh')
print d1, d1.stuff
# creating the second instance changes the behavior of the subclass
d2 = Dude('Ben')
print d2, d2.stuff
print d1.stuff._parent
print d2.stuff._parent
#creating a third instance changes the behavior of all the subclasses
d3 = Dude('David')
print d3, d3.stuff
print d1.stuff._parent, d2.stuff._parent, d3.stuff._parent
## END CODE
And here is the output:
>>>
<class '__main__.Dude'>
<__main__.Dude object at 0x00DFB930> <__main__.ElementList object at 0x00DFB950>
<__main__.Dude object at 0x00DFB730> <__main__.ElementList object at 0x00DFB770>
<__main__.Dude object at 0x00DFB730>
<__main__.Dude object at 0x00DFB730>
<__main__.Dude object at 0x00DFB870> <__main__.ElementList object at 0x00DFB9B0>
<__main__.Dude object at 0x00DFB870> <__main__.Dude object at 0x00DFB870>
<__main__.Dude object at 0x00DFB870>
The 'stuff' attribute is an ElementList object linked back to the parent
instance, but every time I create an instance, every instance's 'stuff' links
back to the last instance created.
I'm not sure why this is happening, or how to prevent it.
Any suggestions?
--
http://mail.python.org/mailman/listinfo/python-list
