def clean_asciidoc(text):
    r""" Transform asciidoc text into ASCII text that NL parsers can handle

    TODO:
      Tag lines and words with meta data like italics, underlined, bold, title, heading 1, etc

    >>> clean_asciidoc('**Hello** _world_!')
    '"Hello" "world"!'
    """
    text = re.sub(r'(\b|^)[\[_*]{1,2}([a-zA-Z0-9])', r'"\2', text)
    text = re.sub(r'([a-zA-Z0-9])[\]_*]{1,2}', r'\1"', text)
    return text
r""" Transform asciidoc text into ASCII text that NL parsers can handle

    TODO:
      Tag lines and words with meta data like italics, underlined, bold, title, heading 1, etc

    >>> clean_asciidoc('**Hello** _world_!')
    '"Hello" "world"!'