Hello World

The most important project we'll be using for this component is PyO3. It does most of the heavy lifting for us so Python and Rust can talk to each other. That means we have more time to write actual code. Sweet!

Let's start by initializing a new package, sticking closely to PyO3's own guide.

cd paekli-rs
mkdir paekli-py
cd paekli-py
python -m venv .venv
source .venv/bin/activate

The PyO3 project has a build tool called maturin:

pip install maturin
maturin init --bindings pyo3

This will generate a Rust project with the necessary boilerplate to use it as a Python module. You might be interested to take a look at Cargo.toml, to see what kind of package configuration is needed.

Next, take some time to understand the generated src/lib.rs. You'll notice the annotations #[pyfunction] and #[pymodule] are used to make Rust code available to Python. There are also some Python-specific types like PyResult and PyModule.

Let's try to call the generated sum_as_string function from Python. The following command installs our Rust module into the virtual Python environment:

maturin develop

Now the module paekli_py should be available to import from Python:

> python
>>> import paekli_py
>>> paekli_py.sum_as_string(123, 678)
'801'