Is there a way to enable tracking of a variable belong to a class in python using pyo3?

[jymchng]

class A:

    def __init__(self, a):
         self._a = a
    
    @decorator 
    def a(self):
        return self._a

The decorator can call the wrapped a and get the value of self._a.

What if I don't want the value of self._a but I want the pointer to self._a, such that whatever value self._a changed to, the pointer to self._a will always return me the newly updated value of self._a.

Thank you.

[adamreichold]

What if I don't want the value of self._a but I want the pointer to self._a, such that whatever value self._a changed to, the pointer to self._a will always return me the newly updated value of self._a.

Then you need to pass around self and access its _a field via getattr. Because e.g. setting to _a to different string will make it point to a different object, was stays the same but is modified is the enclosing object referenced by self in your example.

Alternatively, can store you can store a reference to the a method (also obtain via getattr) and invoke call0 on it to retrieve the value which would make the Rust code generic over whether an attribute or something else is accessed.

[jymchng]

Thank you, in that case, would that mean that for any method of any class that the decorator may wrap, there is a method in pyo3 to get that name of the variable assigned to the class?

[jymchng]

e.g. in my example, can a decorator get the name of the returned variable, i.e. _a?

[adamreichold]

e.g. in my example, can a decorator get the name of the returned variable, i.e. _a?

I have no idea. (But I don't think it is specific to PyO3.)

You could probably try to parse the methods byte count in the decorator implementation, but that does not really sound viable to me as a method could implement an arbitrarily complex method to produce its return value.

[jymchng]

Thank you for replying, if that's the case then I shall give up on persuing this line and do other things then! lol