Convert code snippets in Markdown to use fences

markdown_code_snippet_converter.py

import fileinput
import os
import sys

# WARNING: This is Work-In-Progress!!!

def convert(inp):
    code_snippet = False
    for line in inp:
        if code_snippet and line == "\n":
            code_snippet = False
            print("```\n")
        elif line.startswith(" " * 4) and line.strip().startswith(":::"):
            code_snippet = True
            converted_line = line.replace(":", "").strip()
            converted_line = "```" + converted_line
            print(converted_line)
        elif code_snippet:
            print(line.replace(" " * 4, "", 1).rstrip())
        else:
            print(line, end='')


if __name__ == '__main__':
    for root, dirs, files in os.walk(sys.argv[1]):
        for file in files:
            md_file = os.path.join(root, file)
            if md_file.endswith(".md"):
                print(f"Processing {md_file}", file=sys.stderr)
                with fileinput.input(files=(md_file), inplace=True) as f:
                    convert(f)