Markdown to Slack

markdown-to-slack.py

# Translates Markdown syntax to Slack, replaces:
#
# - hyphened lists with bullet symbols
# - double bold marker asterisks `**` with single asterisk `*`
# - headers `#` with bold marker asterisks `*`
#
# Run with
#
#  python markdown-to-slack.py filename.md
#
# Result will be in filename.md.slack.
# Assumes that lists are indented with two spaces and underscore '_'
# is used for italic, which is already compatible with Slack.

import re
import sys

REGEX_REPLACE = (
  (re.compile('^- ', flags=re.M), '• '),
  (re.compile('^  - ', flags=re.M), '  ◦ '),
  (re.compile('^    - ', flags=re.M), '    ⬩ '), # ◆
  (re.compile('^      - ', flags=re.M), '    ◽ '),
  (re.compile('^#+ (.+)$', flags=re.M), r'*\1*'),
  (re.compile('\*\*'), '*'),
)

def main(i, o):
  s = i.read()
  for regex, replacement in REGEX_REPLACE:
    s = regex.sub(replacement, s)
  o.write(s)

if __name__ == '__main__':
  with open(sys.argv[1], encoding='utf-8') as i, \
       open(sys.argv[1] + '.slack', 'w', encoding='utf-8') as o:
    main(i, o)