Generate TOC for a markdown file

mdown_toc.py

#!/usr/bin/python3
# -*- coding: utf-8 -*-
# @author: Jean-Gabriel Young <jean.gabriel.young@gmail.com>
"""Generate TOC for a markdown file."""
import re

# Match between 1 and 4 #
section = re.compile('^\s*(#){1,4}\s?')
strip_url = re.compile('[\W_]+', re.UNICODE)


def gen_toc(markdown_file):
    """Generate TOC for a markdown file."""
    toc_content = []
    for l in markdown_file:
        match = section.match(l)
        if match is not None:
            level = match.group().count('#') - 1
            title = strip_url.sub(' ', section.sub('', l)).strip()
            url = title.replace(' ', '-').lower()
            toc_content.append((level, title, url))
    toc = []
    numerotation = [1, 1, 1, 1]
    for item in toc_content:
        toc.append('  ' * (item[0]) + str(numerotation[item[0]]) +
                   ". " + "[" + item[1] + "](#" + item[2] + ")")
        numerotation[item[0]] += 1
        numerotation[item[0] + 1:] = [1] * (3 - item[0])
    return toc

if __name__ == "__main__":
    # Options parser.
    import argparse as ap
    import sys
    prs = ap.ArgumentParser(description="Generate TOC for a markdown file.")
    prs.add_argument('markdown_file', type=str,
                     help='Markdown file')
    if len(sys.argv) == 1:
        prs.print_help()
        sys.exit(1)
    args = prs.parse_args()

    with open(args.markdown_file, 'r') as f:
        toc = gen_toc(f)
        for item in toc:
            print(item)

mdown_toc_example.md

Top level

Sub-section A

Sub-section B

Sub-sub-section B.1

Sub-section C

Sub-sub-section C.1

Sub-sub-section C.2

mdown_toc_example.sh

> python mdown_toc.py mdown_toc_example.md
1. [Top level](#top-level)
  1. [Sub section A](#sub-section-a)
  2. [Sub section B](#sub-section-b)
    1. [Sub sub section B 1](#sub-sub-section-b-1)
  3. [Sub section C](#sub-section-c)
    1. [Sub sub section C 1](#sub-sub-section-c-1)
    2. [Sub sub section C 2](#sub-sub-section-c-2)

Many thanks, that worked.

In my case, running ./mdown_toc.py does not work, but python mdown_toc.py does.
Thanks also for your patience.