Sort Rust `#[derive(...)]` macros

sort_derives.py

#!/usr/bin/env python3

import re
import sys

ORDER = [
    "Clone",
    "Copy",
    "Debug",
    "Default",
    "PartialEq",
    "Eq",
    "PartialOrd",
    "Ord",
    "Hash",
    "Serialize",
    "Deserialize",
]


def main():
    derive_regex = re.compile(
        r"#[\s\n]*\[[\s\n]*derive[\s\n]*\((.*?)\)[\s\n]*\]", re.DOTALL
    )

    files = sys.argv[1:]
    for file in files:
        with open(file, "r") as f:
            s = f.read()
        s = derive_regex.sub(derive_replacer, s)
        with open(file, "w") as f:
            f.write(s)
    pass


def derive_replacer(match: re.Match[str]):
    args = match.group(1)
    derives = args.split(",")
    derives = map(lambda s: s.strip(), derives)
    derives = filter(lambda s: s != "", derives)
    derives = sorted(derives, key=derive_key)
    derives = ", ".join(derives)
    return f"#[derive({derives})]"


def derive_key(derive: str):
    try:
        return ORDER.index(derive)
    except ValueError:
        return float("inf")


if __name__ == "__main__":
    main()