Polymorphism over python classes in rust

[jayphur]

Hello,

I was wondering: Is it possible to:

Define a parent in class in my rust api:

#[pyclass(subclass)
pub struct ParentClass{
     // stuff
}
#[pymethods]
impl ParentClass{
     fn do_stuff(&self) { 
            // default implementation
      }
     fn get_two(&self) -> u8{ 
            2
      }
}

Then, have python define children of this class:

from rust_api import ParentClass
class Child(ParentClass):
        def do_stuff(self):
                # python version

...and have this new child class be usable at runtime by rust code (possibly loaded from something like PyModule::from_code()).

I've seen something like this in the user guide with both the parent class/struct and child class/struct defined in rust.

The implementation of a system like (how it relates to the GIL, lifetimes, safety, etc) this does not matter to me. I am just wondering if something like this was possible.

Thanks :)

[birkenfeld]

You can do that, you just need to call methods via the Python API, not directly on the Rust level.

[jayphur]

Do you mean with something like call_method(...)?

[davidhewitt]

Yep exactly, see for example the older discussion #1875 (comment)