Rust Calculator

This is a simple calculator library implemented in Rust and exposed to Python using the PyO3 framework.

The purpose of this project is:

• To demonstrate how to create a Python module from Rust code using PyO3 and Maturin.
• To demonstrate how to propagate errors from Rust to Python.
• To demonstrate how to create custom error types in Rust.

Structure

rust_calculator
├── Cargo.lock
├── Cargo.toml
├── pyproject.toml
├── src
│   ├── calc_error.rs
│   ├── calculator.rs
│   ├── lib.rs
│   └── main.rs

Features

• Basic arithmetic operations: addition, subtraction, multiplication, and division.
• Error propagation from Rust to Python.
• Custom error types for division by zero and invalid operations.

Requirements

• Rust 1.41 or later
• Python 3.7 or later
• pyO3
• maturin

Usage

Rust

You can test the Rust side using the provided main.rs:

cargo run

Python

First, compile the Rust library into a Python module:

maturin develop

Then you can import and use the module in Python:

import rust_calculator

calc = rust_calculator.PyCalculator()

# Perform some calculations
print(calc.add(2, 3))  # 5
print(calc.subtract(5, 3))  # 2
print(calc.multiply(2, 3.7))  # 7.4

# Attempt division by zero
try:
    print(calc.divide(2, 0))
except Exception as e:
    if type(e).__name__ == 'PyCalculatorError':
        print(f'Error Code: {e.args[0].code}, Message: {e.args[0].message}')
    else:
        print(e)

Testing

Rust

You can run the Rust unit tests with:

cargo test

Python

You can also test the Python module (after compiling with Maturin) in your Python test suite as you would with any other Python module.

Contributing

Pull requests are welcome. For major changes, please open an issue first to discuss what you would like to change.

Please make sure to update tests as appropriate.

License

MIT