How to catch if the object is assigned None

[iqrf 3]

Hi,
Let's take Demo08 as an example where a myPoint object is created in Delphi. I need to detect on the Delphi side if the assignment spam.myPoint = None is made in Python. Cyclic polling using PythonModule1.GetVar('myPoint') is inappropriate for me. I would need something like OnChange in TPythonDelphiVar. I've studied PythonEngine.pas and can't think of anything.
Thank you for your opinion.

[pyscripter 694]

function  TPyPoint.SetAttr(key : PAnsiChar; value : PPyObject) : Integer

is called whenever a property is set (e.g. spam.myPoint.x = 10).     So you can take an action when the object is modified.  

 

However you are not notified when  spam.myPoint is assigned a value.

 

To do what you would have to override the __setattr__ on the module, but this is too complicated.

Edited June 6, 2023 by pyscripter

[iqrf 3]

Couldn't this be done at the Python level using a decorator above the module?

import types

class MyModule(types.ModuleType):
    def __setattr__(self, name, value):
        print(f"Setting attribute {name} to value {value}")
        super().__setattr__(name, value)

mymodule = MyModule('mymodule')
mymodule.my_attribute = 42
print(mymodule.my_attribute)

 

[pyscripter 694]

Not so simple: python - Overriding __setattr__ at runtime - Stack Overflow

[iqrf 3]

It's really not easy, so I'll accept the imperfection and try to solve it sometime in the future. Thanks