format

#!/usr/bin/env python3
"""
usage: ./format <filepaths>...

Format script for lettering. Makes everything lowercase except pronoun 'I'.
"""

import os
import sys
import re

def main(argv: list) -> None:
    if not argv:
        print("usage: ./format <filepaths>...")

    for filename in argv:
        if os.path.exists(filename):
            with open(filename, mode="r+", encoding="utf-8") as f:
                lines = f.readlines()
                lines = [process(x) for x in lines]
                f.seek(0)
                f.writelines(lines)

        else:
            print(f"Couldn't find file {filename}")


def process(line: str) -> str:
    line = re.sub(r"[‘’']", r"'", line.lower())
    return re.sub(r"(^|\W)i(?:(')(ll|ve|d|m))?($|\W)", r"\1I\2\3\4", line)


if __name__ == "__main__":
    main(sys.argv[1:])