Inline Rust for Python.

inline-rust.py

"""inline-rust.

Based on https://gist.github.com/adamnew123456/12546e6e36607a63e254

Works with integers out-of-the-box. Other types not so much without work.
"""

import ctypes
import tempfile
import os
import atexit


class InlineRust:
    compiler: str = "rustc"

    def __init__(self, code: str) -> None:
        self.code = code

    def compile(self) -> ctypes.CDLL:
        with tempfile.NamedTemporaryFile(
            mode="w", prefix="PYC", suffix=".rs", delete=False
        ) as temp_c_file:
            temp_c_file_name = temp_c_file.name
            temp_c_file.write(self.code)
            temp_c_file.flush()

        obj_file_name = tempfile.mktemp(prefix="PYC", suffix=".dylib")
        cmd = (
            f"{self.compiler} {temp_c_file_name} --crate-type cdylib -o {obj_file_name}"
        )
        os.system(cmd)
        os.remove(temp_c_file_name)
        atexit.register(lambda: os.remove(obj_file_name))

        return ctypes.cdll.LoadLibrary(obj_file_name)


def main() -> None:
    code = """
    #[no_mangle]
    pub extern "C" fn factorial(number: i64) -> i64 {
        if number <= 1 {
            return 1;
        }

        return number * factorial(number - 1);
    }
    """
    compiled = InlineRust(code).compile()
    factorial = compiled["factorial"]

    for i in range(10):
        res = factorial(i)
        print(res)


if __name__ == "__main__":
    main()