I'm writing some serialization/deserialization code in Python that will read/write an inheritance hierarchy from some JSON. The exact composition will not be known until the request is sent in.
So, I deem the elegant solution to recursively introspect the Python class hierarchy to be emitted and then, on the way back up through the tree, install the correct values in a Python basic type.
E.g.,
A
|
|\
| \
B C
If I call my "introspect" routine on B, it should return a dict that contains a mapping from all of A's variables to their values, as well as B's variables and their values.
As it now stands, I can look through B.__slots__ or B.__dict__, but I only can pull out B's variable names from there.
How do I get the __slots__/__dict__ of A, given only B? (or C).
I know that python doesn't directly support casting like C++ & its descendants do-
You might try using the type.mro() method to find the method resolution order.
class A(object):
pass
class B(A):
pass
class C(A):
pass
a = A()
b = B()
c = C()
>>> type.mro(type(b))
[<class '__main__.B'>, <class '__main__.A'>, <type 'object'>]
>>> type.mro(type(c))
[<class '__main__.C'>, <class '__main__.A'>, <type 'object'>]
or
>>> type(b).mro()
Edit: I was thinking you wanted to do something like this...
>>> A = type("A", (object,), {'a':'A var'}) # create class A
>>> B = type("B", (A,), {'b':'B var'}) # create class B
>>> myvar = B()
def getvars(obj):
''' return dict where key/value is attribute-name/class-name '''
retval = dict()
for i in type(obj).mro():
for k in i.__dict__:
if not k.startswith('_'):
retval[k] = i.__name__
return retval
>>> getvars(myvar)
{'a': 'A', 'b': 'B'}
>>> for i in getvars(myvar):
print getattr(myvar, i) # or use setattr to modify the attribute value
A Var
B Var