def pandoc_author(authors_and_institutions, auth2index,
                 inst2index, index2inst, auth2email):
    # List authors on multiple lines
    authors = []
    for author, i, e in authors_and_institutions:
        author = '**%s**' % author  # set in boldface
        if i is None:
            authors.append(author)
        else:
            authors.append(author + ' at ' + ' and '.join(i))

    plain_text = '### Author'
    if len(authors) > 1:
        plain_text += 's'
    plain_text += '\n\n' + '\n\n'.join(authors) + '\n\n'

    if option('strapdown'):
        return plain_text
    elif option('strict_markdown_output'):
        return plain_text
    elif option('multimarkdown_output'):
        return 'Author: ' + ', '.join(authors) + '\n'
    else:
        # pandoc-extended markdown syntax
        return '% ' + ';  '.join(authors) + '\n'

    def __init__(self):
        self.tracks = os.listdir(option("music-dir"))
        if option("music-shuffle"):
            random.shuffle(self.tracks)
        self.track = 0

        pygame.mixer.music.set_endevent(Music.MUSIC_FINISHED)

def pandoc_date(m):
    date = m.group("subst")
    if option("strapdown"):
        return "#### Date: " + date
    elif option("strict_markdown_output"):
        return "#### Date: " + date
    elif option("multimarkdown_output"):
        return "Date: " + date + "\n"
    else:
        # pandoc-extended markdown syntax
        return "% " + date + "\n"

def pandoc_title(m):
    title = m.group('subst')
    if option('strapdown'):
        # title is in <title> tag in INTRO for the header of the HTML output
        return ''
    elif option('strict_markdown_output'):
        return '# ' + title
    elif option('multimarkdown_output'):
        return 'Title: ' + title
    else:
        return '% ' + title

def pandoc_title(m):
    title = m.group("subst")
    if option("strapdown"):
        # title is in <title> tag in INTRO for the header of the HTML output
        return ""
    elif option("strict_markdown_output"):
        return "# " + title
    elif option("multimarkdown_output"):
        return "Title: " + title
    else:
        # pandoc-extended markdown syntax
        return "% " + title

def pandoc_linebreak(m):
    # orig: r'\g<text>\\n',
    text = m.group("text")
    if option("github_md"):
        return text + "<br />"
    else:
        return text + r"\n"

def rst_abstract(m):
    # r'\n*\g<type>.* \g<text>\n\g<rest>'
    name = m.group('type').strip()
    text = m.group('text').strip()
    rest = m.group('rest').strip()

    if option('rst_uio'):
        s = """

.. uio-introduction::
%s

.. contents::

.. section-numbering::


%s
""" % (indent_lines(text, 'rst'), rest)
        return s
    else:
        if name.lower() == 'preface':
            # Drop heading (short abstract for books)
            return '\n%(text)s\n\n%(rest)s' % vars()
        else:
            return '\n*%(name)s.* %(text)s\n\n%(rest)s' % vars()

def rst_author(authors_and_institutions, auth2index,
               inst2index, index2inst, auth2email):
    if option('rst_uio'):
        if authors_and_institutions:
            # Use first author and email
            responsible = authors_and_institutions[0][0]
            email = authors_and_institutions[0][2]
            text = """
.. uio-meta::
   :responsible-name: %s
""" % responsible
            if email:
                text += '   :responsible-email: %s\n\n' % email
        else:
            errwarn('*** error: with --rst_uio there must be an AUTHOR:')
            errwarn('    field with (at least) one author w/email who will be')
            errwarn('    listed as the resposible under uio-meta::')
            _abort()
    else:
        authors = []
        for author, i, email in authors_and_institutions:
            if email:
                email = email.replace('@', ' at ')
                authors.append(author + ' (%s)' % email)
            else:
                authors.append(author)

        text = ':Authors: ' + ', '.join(authors)  # (text is already r-stripped in typeset_authors)
        # we skip institutions in rst
    return text

def sphinx_movie(m):
    filename = m.group("filename")
    special_movie = (
        "*" in filename
        or "->" in filename
        or "youtu.be" in filename
        or "youtube.com" in filename
        or "vimeo.com" in filename
    )
    if option("runestone") and not special_movie:
        # Use RunestoneInteractive video environment
        global video_counter
        video_counter += 1
        text = """
.. video:: video_%d
   :controls:

   %s
""" % (
            video_counter,
            filename,
        )
        return text
    else:
        # Use plain html code
        return rst_movie(m)

def xml_movie(m):
    filename = m.group('filename').srip()
    opts = m.group('options').strip()
    caption = m.group('caption').strip()

    if opts:
        opts = [s.split('=') for s in opts.split()]
        opts = ['%s="%s"' % (key, value) for key, value in opts]
        opts = ' ' + ' '.join(opts)
    else:
        opts = ''

    autoplay = option('html_video_autoplay=', 'False')
    if autoplay in ('on', 'off', 'True', 'true'):
        autoplay = True
    else:
        autoplay = False
    if opts:
        opts.append('autoplay="%s"' % str(autoplay))

    text = '<figure filename="%s%s>' % (filename, opts)
    if caption:
        text += '\n<caption>\n%s\n</caption>' % caption
    text += '\n</figure>\n'
    return text

def rst_abstract(m):
    # r'\n*\g<type>.* \g<text>\n\g<rest>'
    name = m.group("type").strip()
    text = m.group("text").strip()
    rest = m.group("rest").strip()

    if option("rst_uio"):
        s = """

.. uio-introduction::
%s

.. contents::

.. section-numbering::


%s
""" % (
            indent_lines(text, "rst"),
            rest,
        )
        return s
    else:
        return "\n*%(name)s.* %(text)s\n\n%(rest)s" % vars()

def rst_author(authors_and_institutions, auth2index, inst2index, index2inst, auth2email):
    if option("rst_uio"):
        if authors_and_institutions:
            # Use first author and email
            responsible = authors_and_institutions[0][0]
            email = authors_and_institutions[0][2]
            text = (
                """
.. uio-meta::
   :responsible-name: %s
"""
                % responsible
            )
            if email:
                text += "   :responsible-email: %s\n\n" % email
        else:
            print "*** error: with --rst_uio there must be an AUTHOR:"
            print "    field with (at least) one author w/email who will be"
            print "    listed as the resposible under uio-meta::"
            _abort()
    else:
        authors = []
        for author, i, email in authors_and_institutions:
            if email:
                email = email.replace("@", " at ")
                authors.append(author + " (%s)" % email)
            else:
                authors.append(author)

        text = ":Authors: " + ", ".join(authors)  # (text is already r-stripped in typeset_authors)
        # we skip institutions in rst
    return text

def plain_quiz(quiz):
    # Simple typesetting of a quiz
    import string

    question_prefix = quiz.get("question prefix", option("quiz_question_prefix=", "Question:"))
    common_choice_prefix = option("quiz_choice_prefix=", "Choice")
    quiz_expl = option("quiz_explanations=", "on")

    text = "\n\n"
    if "new page" in quiz:
        text += "======= %s =======\n\n" % (quiz["new page"])

    # Don't write Question: ... if inside an exercise section
    if quiz.get("embedding", "None") in ["exercise"]:
        pass
    else:
        text += "\n"
        if question_prefix:
            text += "%s " % (question_prefix)

    text += quiz["question"] + "\n\n"

    # List choices as paragraphs
    for i, choice in enumerate(quiz["choices"]):
        # choice_no = i+1
        choice_no = string.ascii_uppercase[i]
        answer = choice[0].capitalize() + "!"
        choice_prefix = common_choice_prefix
        if "choice prefix" in quiz:
            if isinstance(quiz["choice prefix"][i], basestring):
                choice_prefix = quiz["choice prefix"][i]
        if choice_prefix == "" or choice_prefix[-1] in [".", ":", "?"]:
            pass  # don't add choice number/letter
        else:
            choice_prefix += " %s:" % choice_no
        # Let choice start with a newline if pure code starts the choice
        # (test for different code block types so this function can work
        # for other formats too...)
        choice = choice[1].lstrip()
        code_starters = "Code::", "~~~", "```", "{{{"
        for code_starter in code_starters:
            if choice.startswith(code_starter):
                choice = "\n" + choice

        # Cannot treat explanations
        text += "%s %s\n\n" % (choice_prefix, choice)
    return text

def plain_quiz(quiz):
    # Simple typesetting of a quiz
    import string
    question_prefix = quiz.get('question prefix',
                               option('quiz_question_prefix=', 'Question:'))
    common_choice_prefix = option('quiz_choice_prefix=', 'Choice')
    quiz_expl = option('quiz_explanations=', 'on')

    text = '\n\n'
    if 'new page' in quiz:
        text += '======= %s =======\n\n' % (quiz['new page'])

    # Don't write Question: ... if inside an exercise section
    if quiz.get('embedding', 'None') in ['exercise',]:
        pass
    else:
        text += '\n'
        if question_prefix:
            text += '%s ' % (question_prefix)

    text += quiz['question'] + '\n\n'

    # List choices as paragraphs
    for i, choice in enumerate(quiz['choices']):
        #choice_no = i+1
        choice_no = string.ascii_uppercase[i]
        answer = choice[0].capitalize() + '!'
        choice_prefix = common_choice_prefix
        if 'choice prefix' in quiz:
            if isinstance(quiz['choice prefix'][i], basestring):
                choice_prefix = quiz['choice prefix'][i]
        if choice_prefix == '' or choice_prefix[-1] in ['.', ':', '?']:
            pass  # don't add choice number/letter
        else:
            choice_prefix += ' %s:' % choice_no
        # Let choice start with a newline if pure code starts the choice
        # (test for different code block types so this function can work
        # for other formats too...)
        choice = choice[1].lstrip()
        code_starters = 'Code::', '~~~', '```', '{{{'
        for code_starter in code_starters:
            if choice.startswith(code_starter):
                choice = '\n' + choice

        # Cannot treat explanations
        text += '%s %s\n\n' % (choice_prefix, choice)
    return text

def sphinx_ref_and_label(section_label2title, format, filestr):
    # Special fix early in the process:
    # Deal with !split - by default we place splits before
    # the all the topmost sections
    # (This must be done before labels are put above section
    # headings)
    if '!split' in filestr and not option('sphinx_keep_splits'):
        print '*** warning: new !split inserted (override all existing !split)'
        # Note: the title is at this stage translated to a chapter heading!
        # This title/heading must be removed for the algorithm below to work
        # (remove it, then insert afterwards)
        pattern = r'^.. Document title:\n\n={3,9}.+?={3,9}'
        m = re.search(pattern, filestr, flags=re.MULTILINE)
        title_replacement = '<<<<<<<DOCUMENT TITLE>>>>>>>>>>>>' # "unlikely" str
        if m:
            title = m.group()
            filestr = filestr.replace(title, title_replacement)
        else:
            title = ''

        topmost_section = 0
        for i in [9, 7, 5]:
            if re.search(r'^%s' % ('='*i), filestr, flags=re.MULTILINE):
                topmost_section = i
                print '    before every %s heading %s' % \
                      ('='*topmost_section, '='*topmost_section)
                print '    because this strategy gives a well-functioning'
                print '    table of contents in Sphinx'
                print '    (use --sphinx_keep_splits to enforce your own !split commands)'
                break
        if topmost_section:
            # First remove all !split
            filestr = re.sub(r'^!split *\n', '', filestr, flags=re.MULTILINE)
            # Insert new splits before all topmost sections
            pattern = r'^%s (.+?) %s' % \
                      ('='*topmost_section, '='*topmost_section)
            lines = filestr.splitlines()
            for i in range(len(lines)):
                if re.search(pattern, lines[i]):
                    lines[i] = '!split\n' + lines[i]

            filestr = '\n'.join(lines)
        filestr = filestr.replace(title_replacement, title)

    filestr = ref_and_label_commoncode(section_label2title, format, filestr)

    # replace all references to sections:
    for label in section_label2title:
        filestr = filestr.replace('ref{%s}' % label, ':ref:`%s`' % label)

    # Not of interest after sphinx got equation references:
    #from common import ref2equations
    #filestr = ref2equations(filestr)

    # Replace remaining ref{x} as :ref:`x`
    filestr = re.sub(r'ref\{(.+?)\}', ':ref:`\g<1>`', filestr)

    return filestr

def pandoc_quiz(quiz):
    # Simple typesetting of a quiz
    import string
    question_prefix = quiz.get('question prefix',
                               option('quiz_question_prefix=', 'Question:'))
    common_choice_prefix = option('quiz_choice_prefix=', 'Choice')
    quiz_expl = option('quiz_explanations=', 'on')

    text = '\n\n'
    if 'new page' in quiz:
        text += '## %s\n\n' % (quiz['new page'])

    # Don't write Question: ... if inside an exercise section
    if quiz.get('embedding', 'None') in ['exercise',]:
        pass
    else:
        text += '\n'
        if question_prefix:
            text += '**%s** ' % (question_prefix)

    text += quiz['question'] + '\n\n'

    # List choices as paragraphs
    for i, choice in enumerate(quiz['choices']):
        #choice_no = i+1
        choice_no = string.ascii_uppercase[i]
        answer = choice[0].capitalize() + '!'
        choice_prefix = common_choice_prefix
        if 'choice prefix' in quiz:
            if isinstance(quiz['choice prefix'][i], basestring):
                choice_prefix = quiz['choice prefix'][i]
        if choice_prefix == '' or choice_prefix[-1] in ['.', ':', '?']:
            pass  # don't add choice number/letter
        else:
            choice_prefix += ' %s:' % choice_no
        if choice_prefix:
            choice_prefix = '**%s**' % choice_prefix
        # Always have a newline after choice in case code or tex
        # blocks appear first
        choice_prefix = choice_prefix + '\n'

        # Cannot treat explanations and answers
        text += '%s %s\n\n' % (choice_prefix, choice[1])
    return text

def pandoc_quiz(quiz):
    # Simple typesetting of a quiz
    import string

    question_prefix = quiz.get("question prefix", option("quiz_question_prefix=", "Question:"))
    common_choice_prefix = option("quiz_choice_prefix=", "Choice")
    quiz_expl = option("quiz_explanations=", "on")

    text = "\n\n"
    if "new page" in quiz:
        text += "## %s\n\n" % (quiz["new page"])

    # Don't write Question: ... if inside an exercise section
    if quiz.get("embedding", "None") in ["exercise"]:
        pass
    else:
        text += "\n"
        if question_prefix:
            text += "**%s** " % (question_prefix)

    text += quiz["question"] + "\n\n"

    # List choices as paragraphs
    for i, choice in enumerate(quiz["choices"]):
        # choice_no = i+1
        choice_no = string.ascii_uppercase[i]
        answer = choice[0].capitalize() + "!"
        choice_prefix = common_choice_prefix
        if "choice prefix" in quiz:
            if isinstance(quiz["choice prefix"][i], basestring):
                choice_prefix = quiz["choice prefix"][i]
        if choice_prefix == "" or choice_prefix[-1] in [".", ":", "?"]:
            pass  # don't add choice number/letter
        else:
            choice_prefix += " %s:" % choice_no
        if choice_prefix:
            choice_prefix = "**%s**" % choice_prefix
        # Always have a newline after choice in case code or tex
        # blocks appear first
        choice_prefix = choice_prefix + "\n"

        # Cannot treat explanations and answers
        text += "%s %s\n\n" % (choice_prefix, choice[1])
    return text

def sphinx_ref_and_label(section_label2title, format, filestr):
    # Special fix early in the process:
    # Deal with !split - by default we place splits before
    # the all the topmost sections
    # (This must be done before labels are put above section
    # headings)
    if "!split" in filestr and not option("sphinx_keep_splits"):
        errwarn("*** warning: new !split inserted (override all existing !split)")
        # Note: the title is at this stage translated to a chapter heading!
        # This title/heading must be removed for the algorithm below to work
        # (remove it, then insert afterwards)
        pattern = r"^.. Document title:\n\n={3,9}.+?={3,9}"
        m = re.search(pattern, filestr, flags=re.MULTILINE)
        title_replacement = "<<<<<<<DOCUMENT TITLE>>>>>>>>>>>>"  # "unlikely" str
        if m:
            title = m.group()
            filestr = filestr.replace(title, title_replacement)
        else:
            title = ""

        topmost_section = 0
        for i in [9, 7, 5]:
            if re.search(r"^%s" % ("=" * i), filestr, flags=re.MULTILINE):
                topmost_section = i
                errwarn("    before every %s heading %s" % ("=" * topmost_section, "=" * topmost_section))
                errwarn("    because this strategy gives a well-functioning")
                errwarn("    table of contents in Sphinx")
                errwarn("    (use --sphinx_keep_splits to enforce your own !split commands)")
                break
        if topmost_section:
            # First remove all !split
            filestr = re.sub(r"^!split *\n", "", filestr, flags=re.MULTILINE)
            # Insert new splits before all topmost sections
            pattern = r"^%s (.+?) %s" % ("=" * topmost_section, "=" * topmost_section)
            lines = filestr.splitlines()
            for i in range(len(lines)):
                if re.search(pattern, lines[i]):
                    lines[i] = "!split\n" + lines[i]

            filestr = "\n".join(lines)
        filestr = filestr.replace(title_replacement, title)

    filestr = ref_and_label_commoncode(section_label2title, format, filestr)

    # replace all references to sections:
    for label in section_label2title:
        filestr = filestr.replace("ref{%s}" % label, ":ref:`%s`" % label)

    # Not of interest after sphinx got equation references:
    # from common import ref2equations
    # filestr = ref2equations(filestr)

    # Replace remaining ref{x} as :ref:`x`
    filestr = re.sub(r"ref\{(.+?)\}", ":ref:`\g<1>`", filestr)

    return filestr

def pandoc_table(table):
    if option('github_md'):
        text = html_table(table)
        # Fix the problem that `verbatim` inside the table is not
        # typeset as verbatim (according to the pandoc translator rules)
        # in the GitHub Issue Tracker
        text = re.sub(r'`([^`]+?)`', '<code>\g<1></code>', text)
        return text

    # else: Pandoc-extended Markdown syntax

        """

    Simple markdown tables look like this::

        Left         Right   Center     Default
        -------     ------ ----------   -------
        12              12     12            12
        123            123     123          123
        1                1      1             1

    """
    # Slight modification of rst_table

    column_width = table_analysis(table['rows'])
    ncolumns = len(column_width)
    column_spec = table.get('columns_align', 'c'*ncolumns).replace('|', '')
    heading_spec = table.get('headings_align', 'c'*ncolumns).replace('|', '')
    a2py = {'r': 'rjust', 'l': 'ljust', 'c': 'center'}
    s = ''  # '\n'
    for i, row in enumerate(table['rows']):
        #s += '    '  # indentation of tables
        if row == ['horizontal rule'] and i > 0 and i < len(table['rows'])-1:
            # No horizontal rule at the top and bottom, just after heading
            for w in column_width:
                s += '-'*w + '  '
        else:
            # check if this is a headline between two horizontal rules:
            if i == 1 and \
               table['rows'][i-1] == ['horizontal rule'] and \
               table['rows'][i+1] == ['horizontal rule']:
                headline = True
            else:
                headline = False

            for w, c, ha, ca in \
                    zip(column_width, row, heading_spec, column_spec):
                if headline:
                    s += getattr(c, a2py[ha])(w) + '  '
                elif row != ['horizontal rule']:
                    s += getattr(c, a2py[ca])(w) + '  '
        s += '\n'
    s += '\n'
    return s

def pandoc_table(table):
    if option("github_md"):
        text = html_table(table)
        # Fix the problem that `verbatim` inside the table is not
        # typeset as verbatim (according to the pandoc translator rules)
        # in the GitHub Issue Tracker
        text = re.sub(r"`([^`]+?)`", "<code>\g<1></code>", text)
        return text

        # else: Pandoc-extended Markdown syntax

        """

    Simple markdown tables look like this::

        Left         Right   Center     Default
        -------     ------ ----------   -------
        12              12     12            12
        123            123     123          123
        1                1      1             1

    """
    # Slight modification of rst_table

    column_width = table_analysis(table["rows"])
    ncolumns = len(column_width)
    column_spec = table.get("columns_align", "c" * ncolumns).replace("|", "")
    heading_spec = table.get("headings_align", "c" * ncolumns).replace("|", "")
    a2py = {"r": "rjust", "l": "ljust", "c": "center"}
    s = ""  # '\n'
    for i, row in enumerate(table["rows"]):
        # s += '    '  # indentation of tables
        if row == ["horizontal rule"] and i > 0 and i < len(table["rows"]) - 1:
            # No horizontal rule at the top and bottom, just after heading
            for w in column_width:
                s += "-" * w + "  "
        else:
            # check if this is a headline between two horizontal rules:
            if i == 1 and table["rows"][i - 1] == ["horizontal rule"] and table["rows"][i + 1] == ["horizontal rule"]:
                headline = True
            else:
                headline = False

            for w, c, ha, ca in zip(column_width, row, heading_spec, column_spec):
                if headline:
                    s += getattr(c, a2py[ha])(w) + "  "
                elif row != ["horizontal rule"]:
                    s += getattr(c, a2py[ca])(w) + "  "
        s += "\n"
    s += "\n"
    return s