Trait PyModuleMethods

pub trait PyModuleMethods<'py>: Sealed {
    // Required methods
    fn dict(&self) -> Bound<'py, PyDict>;
    fn index(&self) -> PyResult<Bound<'py, PyList>>;
    fn name(&self) -> PyResult<Bound<'py, PyString>>;
    fn filename(&self) -> PyResult<Bound<'py, PyString>>;
    fn add<N, V>(&self, name: N, value: V) -> PyResult<()>
       where N: IntoPy<Py<PyString>>,
             V: IntoPy<PyObject>;
    fn add_class<T>(&self) -> PyResult<()>
       where T: PyClass;
    fn add_wrapped<T>(
        &self,
        wrapper: &impl Fn(Python<'py>) -> T,
    ) -> PyResult<()>
       where T: IntoPyCallbackOutput<PyObject>;
    fn add_submodule(&self, module: &Bound<'_, PyModule>) -> PyResult<()>;
    fn add_function(&self, fun: Bound<'_, PyCFunction>) -> PyResult<()>;
}

Implementation of functionality for PyModule.

These methods are defined for the Bound<'py, PyModule> smart pointer, so to use method call syntax these methods are separated into a trait, because stable Rust does not yet support arbitrary_self_types.

Required Methods

fn dict(&self) -> Bound<'py, PyDict>

Returns the module’s __dict__ attribute, which contains the module’s symbol table.

fn index(&self) -> PyResult<Bound<'py, PyList>>

Returns the index (the __all__ attribute) of the module, creating one if needed.

__all__ declares the items that will be imported with from my_module import *.

fn name(&self) -> PyResult<Bound<'py, PyString>>

Returns the name (the __name__ attribute) of the module.

May fail if the module does not have a __name__ attribute.

fn filename(&self) -> PyResult<Bound<'py, PyString>>

Returns the filename (the __file__ attribute) of the module.

May fail if the module does not have a __file__ attribute.

fn add<N, V>(&self, name: N, value: V) -> PyResult<()>

where N: IntoPy<Py<PyString>>, V: IntoPy<PyObject>,

Adds an attribute to the module.

For adding classes, functions or modules, prefer to use PyModuleMethods::add_class, PyModuleMethods::add_function or PyModuleMethods::add_submodule instead, respectively.

Examples

use pyo3::prelude::*;

#[pymodule]
fn my_module(module: &Bound<'_, PyModule>) -> PyResult<()> {
    module.add("c", 299_792_458)?;
    Ok(())
}

Python code can then do the following:

from my_module import c

print("c is", c)

This will result in the following output:

c is 299792458

fn add_class<T>(&self) -> PyResult<()>

where T: PyClass,

Adds a new class to the module.

Notice that this method does not take an argument. Instead, this method is generic, and requires us to use the “turbofish” syntax to specify the class we want to add.

Examples

use pyo3::prelude::*;

#[pyclass]
struct Foo { /* fields omitted */ }

#[pymodule]
fn my_module(module: &Bound<'_, PyModule>) -> PyResult<()> {
    module.add_class::<Foo>()?;
    Ok(())
}

Python code can see this class as such:

from my_module import Foo

print("Foo is", Foo)

This will result in the following output:

Foo is <class 'builtins.Foo'>

Note that as we haven’t defined a constructor, Python code can’t actually make an instance of Foo (or get one for that matter, as we haven’t exported anything that can return instances of Foo).

fn add_wrapped<T>(&self, wrapper: &impl Fn(Python<'py>) -> T) -> PyResult<()>

where T: IntoPyCallbackOutput<PyObject>,

Adds a function or a (sub)module to a module, using the functions name as name.

Prefer to use PyModuleMethods::add_function and/or PyModuleMethods::add_submodule instead.

fn add_submodule(&self, module: &Bound<'_, PyModule>) -> PyResult<()>

Adds a submodule to a module.

This is especially useful for creating module hierarchies.

Note that this doesn’t define a package, so this won’t allow Python code to directly import submodules by using from my_module import submodule. For more information, see #759 and #1517.

Examples

use pyo3::prelude::*;

#[pymodule]
fn my_module(py: Python<'_>, module: &Bound<'_, PyModule>) -> PyResult<()> {
    let submodule = PyModule::new_bound(py, "submodule")?;
    submodule.add("super_useful_constant", "important")?;

    module.add_submodule(&submodule)?;
    Ok(())
}

Python code can then do the following:

import my_module

print("super_useful_constant is", my_module.submodule.super_useful_constant)

This will result in the following output:

super_useful_constant is important

fn add_function(&self, fun: Bound<'_, PyCFunction>) -> PyResult<()>

Add a function to a module.

Note that this also requires the wrap_pyfunction! macro to wrap a function annotated with #[pyfunction].

use pyo3::prelude::*;

#[pyfunction]
fn say_hello() {
    println!("Hello world!")
}
#[pymodule]
fn my_module(module: &Bound<'_, PyModule>) -> PyResult<()> {
    module.add_function(wrap_pyfunction!(say_hello, module)?)
}

Python code can then do the following:

from my_module import say_hello

say_hello()

This will result in the following output:

Hello world!

Dyn Compatibility

This trait is not dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety", so this trait is not object safe.

Implementors

impl<'py> PyModuleMethods<'py> for Bound<'py, PyModule>