Background
I wish to use a meta class in order to add helper methods based on the original class. If the method I wish to add uses self.__attributeName
I get an AttributeError
(because of name mangling) but for an existing identical method this isn't a problem.
Code example
Here is a simplified example
# Function to be added as a method of Test
def newfunction2(self):
"""Function identical to newfunction"""
print self.mouse
print self._dog
print self.__cat
class MetaTest(type):
"""Metaclass to process the original class and
add new methods based on the original class
"""
def __new__(meta, name, base, dct):
newclass = super(MetaTest, meta).__new__(
meta, name, base, dct
)
# Condition for adding newfunction2
if "newfunction" in dct:
print "Found newfunction!"
print "Add newfunction2!"
setattr(newclass, "newfunction2", newfunction2)
return newclass
# Class to be modified by MetaTest
class Test(object):
__metaclass__ = MetaTest
def __init__(self):
self.__cat = "cat"
self._dog = "dog"
self.mouse = "mouse"
def newfunction(self):
"""Function identical to newfunction2"""
print self.mouse
print self._dog
print self.__cat
T = Test()
T.newfunction()
T.newfunction2() # AttributeError: 'Test' object has no attribute '__cat'
Question
Is there a way of adding newfunction2
that could use self.__cat
?
(Without renaming self.__cat
to self._cat
.)
And maybe something more fundamental, why isn't self.__cat
being treated in the same way for both cases since newfunction2
is now part of Test
?
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