Python and Rust may seem like an odd couple at first glance, but when utilized together, they form a powerful duo. Let's explore why combining these two languages can be a game-changer, and how you can seamlessly integrate them to harness their respective strengths.

Getting to Know Rust

Before diving into the synergy between Python and Rust, let's take a moment to appreciate what Rust brings to the table. Rust is a low-level language, designed to provide high-performance code with a strong emphasis on memory safety. It originated from the need to create a language that excels in both speed and security, particularly in scenarios like parsing protocols in web browsers, as seen in the case of the Firefox browser.

Why Rust?

Rust stands out for its ability to deliver zero-cost abstraction, where many language-level abstractions are optimized away during compilation. Memory safety in Rust is a key feature, minimizing the chances of memory violations to either bugs in the compiler or explicitly marked "unsafe" code. This makes Rust ideal for tasks requiring fast and secure processing of data from untrusted sources.

The Rust Challenge: Counting Characters

To illustrate the collaboration between Python and Rust, let's tackle a problem: counting the occurrences of a character in a string. We'll explore a Rust solution that resets the count on newlines or spaces, adding a touch of realism to our example.

Enum and Struct Support in Rust

Rust introduces enums to handle character resets and structs to encapsulate our counting logic.

enum Reset {
    NewlinesReset,
    SpacesReset,
    NoReset,
}

struct Counter {
    what: char,
    min_number: u64,
    reset: Reset,
}

Implementation Blocks in Rust

In Rust, we organize code in implementation blocks. Our counting method is defined here, calling external functions to maintain readability.

impl Counter {
    fn has_count(&self, data: &str) -> bool {
        has_count(self, data.chars())
    }
}

Rust Functionality: Counting Characters

The counting logic in Rust involves mutable variables, loops, and functions to reset and increment counts.

fn has_count(cntr: &Counter, chars: std::str::Chars) -> bool {
    let mut current_count: u64 = 0;
    for c in chars {
        if got_count(cntr, c, &mut current_count) {
            return true;
        }
    }
    false
}

Rust Matching and Increment Support

Rust showcases matching capabilities and efficient character increment checks.

fn maybe_reset(cntr: &Counter, c: char, current_count: &mut u64) {
    match (c, cntr.reset) {
        ('\\n', Reset::NewlinesReset) | (' ', Reset::SpacesReset) => {
            *current_count = 0;
        }
        _ => {}
    };
}

fn maybe_incr(cntr: &Counter, c: char, current_count: &mut u64) {
    if c == cntr.what {
        *current_count += 1;
    };
}

Bridging the Gap: Python Meets Rust

Now, the exciting part – connecting our Rust solution to Python! We'll use the PyO3 Rust crate to seamlessly integrate Rust into Python.

Wrapping Rust Code for Python with PyO3

First, we need to wrap Rust components using PyO3. Enums, structs, and implementations are annotated to generate the necessary interface.

use pyo3::prelude::*;

#[pyclass]
#[derive(Clone)]
#[derive(Copy)]
enum Reset {
    /* ... */
}

#[pyclass]
struct Counter {
    /* ... */
}

#[pymethods]
impl Counter {
    #[new]
    fn new(what: char, min_number: u64, reset: Reset) -> Self {
        Counter {
            what,
            min_number,
            reset,
        }
    }

    fn has_count(&self, data: &str) -> bool {
        has_count(self, data.chars())
    }
}

#[pymodule]
fn counter(_py: Python, m: &PyModule) -> PyResult<()> {
    m.add_class::<Counter>()?;
    m.add_class::<Reset>()?;
    Ok(())
}

Python Embraces Rust: A Seamless Experience

Utilizing the Rust solution in Python is a breeze. The integration is smooth, and you can leverage existing Python tests for your Rust library.

Importing the Rust Library into Python

Whether you use maturin develop or pip install to install the library, importing it into Python is straightforward.

import counter

Constructing and Using the Rust Object in Python

Constructing objects in Python mirrors the Rust constructor, allowing for a seamless experience.

cntr = counter.Counter(
    'c',
    3,
    counter.Reset.NewlinesReset,
)

Unleashing the Power: Python Calling Rust Code

Finally, the moment of truth arrives. Python effortlessly calls Rust to check for at least three "c" characters in a string.

>>> cntr.has_count("hello-c-c-c-goodbye")
True

Adding a newline triggers the reset logic, ensuring that three "c" characters without an intervening newline return False.

>>> cntr.has_count("hello-c-c-\\nc-goodbye")
False

The Perfect Pair: Python and Rust

In conclusion, the marriage of Python and Rust proves to be a harmonious blend of strengths. Rust excels in high-performance, secure coding, while Python offers a quick and easy prototyping experience. By combining them, you can prototype in Python and seamlessly transition performance-critical components to Rust. With tools like maturin, the development and deployment pipelines become a joy to navigate. Embrace the synergy of Python and Rust for a coding experience that balances efficiency and ease of use!