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authorS. Solomon Darnell2025-03-28 21:52:21 -0500
committerS. Solomon Darnell2025-03-28 21:52:21 -0500
commit4a52a71956a8d46fcb7294ac71734504bb09bcc2 (patch)
treeee3dc5af3b6313e921cd920906356f5d4febc4ed /.venv/lib/python3.12/site-packages/docutils/writers/latex2e
parentcc961e04ba734dd72309fb548a2f97d67d578813 (diff)
downloadgn-ai-master.tar.gz
two version of R2R are here HEAD master
Diffstat (limited to '.venv/lib/python3.12/site-packages/docutils/writers/latex2e')
-rw-r--r--.venv/lib/python3.12/site-packages/docutils/writers/latex2e/__init__.py3323
-rw-r--r--.venv/lib/python3.12/site-packages/docutils/writers/latex2e/default.tex14
-rw-r--r--.venv/lib/python3.12/site-packages/docutils/writers/latex2e/docutils.sty223
-rw-r--r--.venv/lib/python3.12/site-packages/docutils/writers/latex2e/titlepage.tex19
-rw-r--r--.venv/lib/python3.12/site-packages/docutils/writers/latex2e/titlingpage.tex18
-rw-r--r--.venv/lib/python3.12/site-packages/docutils/writers/latex2e/xelatex.tex21
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diff --git a/.venv/lib/python3.12/site-packages/docutils/writers/latex2e/__init__.py b/.venv/lib/python3.12/site-packages/docutils/writers/latex2e/__init__.py
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+# $Id: __init__.py 9581 2024-03-17 23:31:04Z milde $
+# Author: Engelbert Gruber, Günter Milde
+# Maintainer: docutils-develop@lists.sourceforge.net
+# Copyright: This module has been placed in the public domain.
+
+"""LaTeX2e document tree Writer."""
+
+__docformat__ = 'reStructuredText'
+
+# code contributions from several people included, thanks to all.
+# some named: David Abrahams, Julien Letessier, Lele Gaifax, and others.
+#
+# convention deactivate code by two # i.e. ##.
+
+from pathlib import Path
+import re
+import string
+from urllib.request import url2pathname
+import warnings
+try:
+    import roman
+except ImportError:
+    import docutils.utils.roman as roman
+
+from docutils import frontend, nodes, languages, writers, utils
+from docutils.transforms import writer_aux
+from docutils.utils.math import pick_math_environment, unichar2tex
+
+LATEX_WRITER_DIR = Path(__file__).parent
+
+
+class Writer(writers.Writer):
+
+    supported = ('latex', 'latex2e')
+    """Formats this writer supports."""
+
+    default_template = 'default.tex'
+    default_template_path = LATEX_WRITER_DIR
+    default_preamble = ('% PDF Standard Fonts\n'
+                        '\\usepackage{mathptmx} % Times\n'
+                        '\\usepackage[scaled=.90]{helvet}\n'
+                        '\\usepackage{courier}')
+    table_style_values = [  # TODO: align-left, align-center, align-right, ??
+                          'booktabs', 'borderless', 'colwidths-auto',
+                          'nolines', 'standard']
+
+    settings_spec = (
+        'LaTeX-Specific Options',
+        None,
+        (('Specify LaTeX documentclass.  Default: "article".',
+          ['--documentclass'],
+          {'default': 'article', }),
+         ('Specify document options.  Multiple options can be given, '
+          'separated by commas.  Default: "a4paper".',
+          ['--documentoptions'],
+          {'default': 'a4paper', }),
+         ('Format for footnote references: one of "superscript" or '
+          '"brackets".  Default: "superscript".',
+          ['--footnote-references'],
+          {'choices': ['superscript', 'brackets'], 'default': 'superscript',
+           'metavar': '<format>',
+           'overrides': 'trim_footnote_reference_space'}),
+         ('Use \\cite command for citations. (future default)',
+          ['--use-latex-citations'],
+          {'default': None, 'action': 'store_true',
+           'validator': frontend.validate_boolean}),
+         ('Use figure floats for citations '
+          '(might get mixed with real figures). (provisional default)',
+          ['--figure-citations'],
+          {'dest': 'use_latex_citations', 'action': 'store_false',
+           'validator': frontend.validate_boolean}),
+         ('Format for block quote attributions: one of "dash" (em-dash '
+          'prefix), "parentheses"/"parens", or "none".  Default: "dash".',
+          ['--attribution'],
+          {'choices': ['dash', 'parentheses', 'parens', 'none'],
+           'default': 'dash', 'metavar': '<format>'}),
+         ('Specify LaTeX packages/stylesheets. '
+          'A style is referenced with "\\usepackage" if extension is '
+          '".sty" or omitted and with "\\input" else. '
+          ' Overrides previous --stylesheet and --stylesheet-path settings.',
+          ['--stylesheet'],
+          {'default': '', 'metavar': '<file[,file,...]>',
+           'overrides': 'stylesheet_path',
+           'validator': frontend.validate_comma_separated_list}),
+         ('Comma separated list of LaTeX packages/stylesheets. '
+          'Relative paths are expanded if a matching file is found in '
+          'the --stylesheet-dirs. With --link-stylesheet, '
+          'the path is rewritten relative to the output *.tex file. ',
+          ['--stylesheet-path'],
+          {'metavar': '<file[,file,...]>', 'overrides': 'stylesheet',
+           'validator': frontend.validate_comma_separated_list}),
+         ('Link to the stylesheet(s) in the output file. (default)',
+          ['--link-stylesheet'],
+          {'dest': 'embed_stylesheet', 'action': 'store_false'}),
+         ('Embed the stylesheet(s) in the output file. '
+          'Stylesheets must be accessible during processing. ',
+          ['--embed-stylesheet'],
+          {'default': False, 'action': 'store_true',
+           'validator': frontend.validate_boolean}),
+         ('Comma-separated list of directories where stylesheets are found. '
+          'Used by --stylesheet-path when expanding relative path arguments. '
+          'Default: ".".',
+          ['--stylesheet-dirs'],
+          {'metavar': '<dir[,dir,...]>',
+           'validator': frontend.validate_comma_separated_list,
+           'default': ['.']}),
+         ('Customization by LaTeX code in the preamble. '
+          'Default: select PDF standard fonts (Times, Helvetica, Courier).',
+          ['--latex-preamble'],
+          {'default': default_preamble}),
+         ('Specify the template file. Default: "%s".' % default_template,
+          ['--template'],
+          {'default': default_template, 'metavar': '<file>'}),
+         ('Table of contents by LaTeX. (default)',
+          ['--use-latex-toc'],
+          {'default': True, 'action': 'store_true',
+           'validator': frontend.validate_boolean}),
+         ('Table of contents by Docutils (without page numbers).',
+          ['--use-docutils-toc'],
+          {'dest': 'use_latex_toc', 'action': 'store_false',
+           'validator': frontend.validate_boolean}),
+         ('Add parts on top of the section hierarchy.',
+          ['--use-part-section'],
+          {'default': False, 'action': 'store_true',
+           'validator': frontend.validate_boolean}),
+         ('Attach author and date to the document info table. (default)',
+          ['--use-docutils-docinfo'],
+          {'dest': 'use_latex_docinfo', 'action': 'store_false',
+           'validator': frontend.validate_boolean}),
+         ('Attach author and date to the document title.',
+          ['--use-latex-docinfo'],
+          {'default': False, 'action': 'store_true',
+           'validator': frontend.validate_boolean}),
+         ("Typeset abstract as topic. (default)",
+          ['--topic-abstract'],
+          {'dest': 'use_latex_abstract', 'action': 'store_false',
+           'validator': frontend.validate_boolean}),
+         ("Use LaTeX abstract environment for the document's abstract.",
+          ['--use-latex-abstract'],
+          {'default': False, 'action': 'store_true',
+           'validator': frontend.validate_boolean}),
+         ('Color of any hyperlinks embedded in text. '
+          'Default: "blue" (use "false" to disable).',
+          ['--hyperlink-color'], {'default': 'blue'}),
+         ('Additional options to the "hyperref" package.',
+          ['--hyperref-options'], {'default': ''}),
+         ('Enable compound enumerators for nested enumerated lists '
+          '(e.g. "1.2.a.ii").',
+          ['--compound-enumerators'],
+          {'default': False, 'action': 'store_true',
+           'validator': frontend.validate_boolean}),
+         ('Disable compound enumerators for nested enumerated lists. '
+          '(default)',
+          ['--no-compound-enumerators'],
+          {'action': 'store_false', 'dest': 'compound_enumerators'}),
+         ('Enable section ("." subsection ...) prefixes for compound '
+          'enumerators.  This has no effect without --compound-enumerators.',
+          ['--section-prefix-for-enumerators'],
+          {'default': None, 'action': 'store_true',
+           'validator': frontend.validate_boolean}),
+         ('Disable section prefixes for compound enumerators. (default)',
+          ['--no-section-prefix-for-enumerators'],
+          {'action': 'store_false', 'dest': 'section_prefix_for_enumerators'}),
+         ('Set the separator between section number and enumerator '
+          'for compound enumerated lists.  Default: "-".',
+          ['--section-enumerator-separator'],
+          {'default': '-', 'metavar': '<char>'}),
+         ('When possible, use the specified environment for literal-blocks. '
+          'Default: "" (fall back to "alltt").',
+          ['--literal-block-env'],
+          {'default': ''}),
+         ('Deprecated alias for "--literal-block-env=verbatim".',
+          ['--use-verbatim-when-possible'],
+          {'action': 'store_true',
+           'validator': frontend.validate_boolean}),
+         ('Table style. "standard" with horizontal and vertical lines, '
+          '"booktabs" (LaTeX booktabs style) only horizontal lines '
+          'above and below the table and below the header, or "borderless". '
+          'Default: "standard"',
+          ['--table-style'],
+          {'default': ['standard'],
+           'metavar': '<format>',
+           'action': 'append',
+           'validator': frontend.validate_comma_separated_list,
+           'choices': table_style_values}),
+         ('LaTeX graphicx package option. '
+          'Possible values are "dvipdfmx", "dvips", "dvisvgm", '
+          '"luatex", "pdftex", and "xetex".'
+          'Default: "".',
+          ['--graphicx-option'],
+          {'default': ''}),
+         ('LaTeX font encoding. '
+          'Possible values are "", "T1" (default), "OT1", "LGR,T1" or '
+          'any other combination of options to the `fontenc` package. ',
+          ['--font-encoding'],
+          {'default': 'T1'}),
+         ('Per default the latex-writer puts the reference title into '
+          'hyperreferences. Specify "ref*" or "pageref*" to get the section '
+          'number or the page number.',
+          ['--reference-label'],
+          {'default': ''}),
+         ('Specify style and database(s) for bibtex, for example '
+          '"--use-bibtex=unsrt,mydb1,mydb2". Provisional!',
+          ['--use-bibtex'],
+          {'default': '',
+           'metavar': '<style,bibfile[,bibfile,...]>',
+           'validator': frontend.validate_comma_separated_list}),
+         ('Use legacy functions with class value list for '
+          '\\DUtitle and \\DUadmonition.',
+          ['--legacy-class-functions'],
+          {'default': False,
+           'action': 'store_true',
+           'validator': frontend.validate_boolean}),
+         ('Use \\DUrole and "DUclass" wrappers for class values. '
+          'Place admonition content in an environment. (default)',
+          ['--new-class-functions'],
+          {'dest': 'legacy_class_functions',
+           'action': 'store_false',
+           'validator': frontend.validate_boolean}),
+         ('Use legacy algorithm to determine table column widths. '
+          '(provisional default)',
+          ['--legacy-column-widths'],
+          {'default': None,
+           'action': 'store_true',
+           'validator': frontend.validate_boolean}),
+         ('Use new algorithm to determine table column widths. '
+          '(future default)',
+          ['--new-column-widths'],
+          {'dest': 'legacy_column_widths',
+           'action': 'store_false',
+           'validator': frontend.validate_boolean}),
+         # TODO: implement "latex footnotes" alternative
+         ('Footnotes with numbers/symbols by Docutils. (default) '
+          '(The alternative, --latex-footnotes, is not implemented yet.)',
+          ['--docutils-footnotes'],
+          {'default': True,
+           'action': 'store_true',
+           'validator': frontend.validate_boolean}),
+         ),
+        )
+
+    relative_path_settings = ('template',)
+    settings_defaults = {'sectnum_depth': 0}  # updated by SectNum transform
+    config_section = 'latex2e writer'
+    config_section_dependencies = ('writers', 'latex writers')
+
+    head_parts = ('head_prefix', 'requirements', 'latex_preamble',
+                  'stylesheet', 'fallbacks', 'pdfsetup', 'titledata')
+    visitor_attributes = head_parts + ('title', 'subtitle',
+                                       'body_pre_docinfo', 'docinfo',
+                                       'dedication', 'abstract', 'body')
+
+    output = None
+    """Final translated form of `document`."""
+
+    def __init__(self):
+        writers.Writer.__init__(self)
+        self.translator_class = LaTeXTranslator
+
+    def get_transforms(self):
+        # Override parent method to add latex-specific transforms
+        return super().get_transforms() + [
+                   # Convert specific admonitions to generic one
+                   writer_aux.Admonitions,
+                   # TODO: footnote collection transform
+                   ]
+
+    def translate(self):
+        visitor = self.translator_class(self.document)
+        self.document.walkabout(visitor)
+        # copy parts
+        for part in self.visitor_attributes:
+            setattr(self, part, getattr(visitor, part))
+        # get template string from file
+        templatepath = Path(self.document.settings.template)
+        if not templatepath.exists():
+            templatepath = self.default_template_path / templatepath.name
+        template = templatepath.read_text(encoding='utf-8')
+        # fill template
+        self.assemble_parts()  # create dictionary of parts
+        self.output = string.Template(template).substitute(self.parts)
+
+    def assemble_parts(self):
+        """Assemble the `self.parts` dictionary of output fragments."""
+        writers.Writer.assemble_parts(self)
+        for part in self.visitor_attributes:
+            lines = getattr(self, part)
+            if part in self.head_parts:
+                if lines:
+                    lines.append('')  # to get a trailing newline
+                self.parts[part] = '\n'.join(lines)
+            else:
+                # body contains inline elements, so join without newline
+                self.parts[part] = ''.join(lines)
+
+
+class Babel:
+    """Language specifics for LaTeX."""
+
+    # TeX (babel) language names:
+    # ! not all of these are supported by Docutils!
+    #
+    # based on LyX' languages file with adaptions to `BCP 47`_
+    # (https://www.rfc-editor.org/rfc/bcp/bcp47.txt) and
+    # http://www.tug.org/TUGboat/Articles/tb29-3/tb93miklavec.pdf
+    # * the key without subtags is the default
+    # * case is ignored
+    # cf. https://docutils.sourceforge.io/docs/howto/i18n.html
+    #     https://www.w3.org/International/articles/language-tags/
+    # and http://www.iana.org/assignments/language-subtag-registry
+    language_codes = {
+        # code          TeX/Babel-name    comment
+        'af':           'afrikaans',
+        'ar':           'arabic',
+        # 'be':           'belarusian',
+        'bg':           'bulgarian',
+        'br':           'breton',
+        'ca':           'catalan',
+        # 'cop':          'coptic',
+        'cs':           'czech',
+        'cy':           'welsh',
+        'da':           'danish',
+        'de':           'ngerman',        # new spelling (de_1996)
+        'de-1901':      'german',         # old spelling
+        'de-AT':        'naustrian',
+        'de-AT-1901':   'austrian',
+        'dsb':          'lowersorbian',
+        'el':           'greek',          # monotonic (el-monoton)
+        'el-polyton':   'polutonikogreek',
+        'en':           'english',        # TeX' default language
+        'en-AU':        'australian',
+        'en-CA':        'canadian',
+        'en-GB':        'british',
+        'en-NZ':        'newzealand',
+        'en-US':        'american',
+        'eo':           'esperanto',
+        'es':           'spanish',
+        'et':           'estonian',
+        'eu':           'basque',
+        # 'fa':           'farsi',
+        'fi':           'finnish',
+        'fr':           'french',
+        'fr-CA':        'canadien',
+        'ga':           'irish',          # Irish Gaelic
+        # 'grc':                          # Ancient Greek
+        'grc-ibycus':   'ibycus',         # Ibycus encoding
+        'gl':           'galician',
+        'he':           'hebrew',
+        'hr':           'croatian',
+        'hsb':          'uppersorbian',
+        'hu':           'magyar',
+        'ia':           'interlingua',
+        'id':           'bahasai',        # Bahasa (Indonesian)
+        'is':           'icelandic',
+        'it':           'italian',
+        'ja':           'japanese',
+        'kk':           'kazakh',
+        'la':           'latin',
+        'lt':           'lithuanian',
+        'lv':           'latvian',
+        'mn':           'mongolian',      # Mongolian, Cyrillic (mn-cyrl)
+        'ms':           'bahasam',        # Bahasa (Malay)
+        'nb':           'norsk',          # Norwegian Bokmal
+        'nl':           'dutch',
+        'nn':           'nynorsk',        # Norwegian Nynorsk
+        'no':           'norsk',          # Norwegian (Bokmal)
+        'pl':           'polish',
+        'pt':           'portuges',
+        'pt-BR':        'brazil',
+        'ro':           'romanian',
+        'ru':           'russian',
+        'se':           'samin',          # North Sami
+        'sh-Cyrl':      'serbianc',       # Serbo-Croatian, Cyrillic
+        'sh-Latn':      'serbian',        # Serbo-Croatian, Latin (cf. 'hr')
+        'sk':           'slovak',
+        'sl':           'slovene',
+        'sq':           'albanian',
+        'sr':           'serbianc',       # Serbian, Cyrillic (contributed)
+        'sr-Latn':      'serbian',        # Serbian, Latin script
+        'sv':           'swedish',
+        # 'th':           'thai',
+        'tr':           'turkish',
+        'uk':           'ukrainian',
+        'vi':           'vietnam',
+        # zh-Latn:      Chinese Pinyin
+        }
+    # normalize (downcase) keys
+    language_codes = {k.lower(): v for k, v in language_codes.items()}
+
+    warn_msg = 'Language "%s" not supported by LaTeX (babel)'
+
+    # "Active characters" are shortcuts that start a LaTeX macro and may need
+    # escaping for literals use. Characters that prevent literal use (e.g.
+    # starting accent macros like "a -> ä) will be deactivated if one of the
+    # defining languages is used in the document.
+    # Special cases:
+    #  ~ (tilde) -- used in estonian, basque, galician, and old versions of
+    #    spanish -- cannot be deactivated as it denotes a no-break space macro,
+    #  " (straight quote) -- used in albanian, austrian, basque
+    #    brazil, bulgarian, catalan, czech, danish, dutch, estonian,
+    #    finnish, galician, german, icelandic, italian, latin, naustrian,
+    #    ngerman, norsk, nynorsk, polish, portuges, russian, serbian, slovak,
+    #    slovene, spanish, swedish, ukrainian, and uppersorbian --
+    #    is escaped as ``\textquotedbl``.
+    active_chars = {
+                    # TeX/Babel-name:  active characters to deactivate
+                    # 'breton':        ':;!?'  # ensure whitespace
+                    # 'esperanto':     '^',
+                    # 'estonian':      '~"`',
+                    # 'french':        ':;!?'  # ensure whitespace
+                    'galician':        '.<>',  # also '~"'
+                    # 'magyar':        '`',  # for special hyphenation cases
+                    'spanish':         '.<>',  # old versions also '~'
+                    # 'turkish':       ':!='  # ensure whitespace
+                   }
+
+    def __init__(self, language_code, reporter=None):
+        self.reporter = reporter
+        self.language = self.language_name(language_code)
+        self.otherlanguages = {}
+
+    def __call__(self):
+        """Return the babel call with correct options and settings"""
+        languages = sorted(self.otherlanguages.keys())
+        languages.append(self.language or 'english')
+        self.setup = [r'\usepackage[%s]{babel}' % ','.join(languages)]
+        # Deactivate "active characters"
+        shorthands = []
+        for c in ''.join(self.active_chars.get(lng, '') for lng in languages):
+            if c not in shorthands:
+                shorthands.append(c)
+        if shorthands:
+            self.setup.append(r'\AtBeginDocument{\shorthandoff{%s}}'
+                              % ''.join(shorthands))
+        # Including '~' in shorthandoff prevents its use as no-break space
+        if 'galician' in languages:
+            self.setup.append(r'\deactivatetilden % restore ~ in Galician')
+        if 'estonian' in languages:
+            self.setup.extend([r'\makeatletter',
+                               r'  \addto\extrasestonian{\bbl@deactivate{~}}',
+                               r'\makeatother'])
+        if 'basque' in languages:
+            self.setup.extend([r'\makeatletter',
+                               r'  \addto\extrasbasque{\bbl@deactivate{~}}',
+                               r'\makeatother'])
+        if (languages[-1] == 'english'
+            and 'french' in self.otherlanguages.keys()):
+            self.setup += ['% Prevent side-effects if French hyphenation '
+                           'patterns are not loaded:',
+                           r'\frenchbsetup{StandardLayout}',
+                           r'\AtBeginDocument{\selectlanguage{%s}'
+                           r'\noextrasfrench}' % self.language]
+        return '\n'.join(self.setup)
+
+    def language_name(self, language_code):
+        """Return TeX language name for `language_code`"""
+        for tag in utils.normalize_language_tag(language_code):
+            try:
+                return self.language_codes[tag]
+            except KeyError:
+                pass
+        if self.reporter is not None:
+            self.reporter.warning(self.warn_msg % language_code)
+        return ''
+
+    def get_language(self):
+        # Obsolete, kept for backwards compatibility with Sphinx
+        return self.language
+
+
+# Building blocks for the latex preamble
+# --------------------------------------
+
+class SortableDict(dict):
+    """Dictionary with additional sorting methods
+
+    Tip: use key starting with with '_' for sorting before small letters
+         and with '~' for sorting after small letters.
+    """
+    def sortedkeys(self):
+        """Return sorted list of keys"""
+        return sorted(self.keys())
+
+    def sortedvalues(self):
+        """Return list of values sorted by keys"""
+        return [self[key] for key in self.sortedkeys()]
+
+
+# PreambleCmds
+# `````````````
+# A container for LaTeX code snippets that can be
+# inserted into the preamble if required in the document.
+#
+# .. The package 'makecmds' would enable shorter definitions using the
+#    \providelength and \provideenvironment commands.
+#    However, it is pretty non-standard (texlive-latex-extra).
+
+class PreambleCmds:
+    """Building blocks for the latex preamble."""
+
+
+# Requirements and Setup
+
+PreambleCmds.color = r"""\usepackage{color}"""
+
+PreambleCmds.float = r"""\usepackage{float} % extended float configuration
+\floatplacement{figure}{H} % place figures here definitely"""
+
+PreambleCmds.linking = r"""%% hyperlinks:
+\ifthenelse{\isundefined{\hypersetup}}{
+  \usepackage[%s]{hyperref}
+  \usepackage{bookmark}
+  \urlstyle{same} %% normal text font (alternatives: tt, rm, sf)
+}{}"""
+
+PreambleCmds.minitoc = r"""%% local table of contents
+\usepackage{minitoc}"""
+
+PreambleCmds.table = r"""\usepackage{longtable,ltcaption,array}
+\setlength{\extrarowheight}{2pt}
+\newlength{\DUtablewidth} % internal use in tables"""
+
+PreambleCmds.table_columnwidth = (
+    r'\newcommand{\DUcolumnwidth}[1]'
+    r'{\dimexpr#1\DUtablewidth-2\tabcolsep\relax}')
+
+PreambleCmds.textcomp = r"""\usepackage{textcomp} % text symbol macros"""
+# TODO? Options [force,almostfull] prevent spurious error messages,
+# see de.comp.text.tex/2005-12/msg01855
+
+# backwards compatibility definitions
+
+PreambleCmds.abstract_legacy = r"""
+% abstract title
+\providecommand*{\DUtitleabstract}[1]{\centerline{\textbf{#1}}}"""
+
+# see https://sourceforge.net/p/docutils/bugs/339/
+PreambleCmds.admonition_legacy = r"""
+% admonition (specially marked topic)
+\providecommand{\DUadmonition}[2][class-arg]{%
+  % try \DUadmonition#1{#2}:
+  \ifcsname DUadmonition#1\endcsname%
+    \csname DUadmonition#1\endcsname{#2}%
+  \else
+    \begin{center}
+      \fbox{\parbox{0.9\linewidth}{#2}}
+    \end{center}
+  \fi
+}"""
+
+PreambleCmds.error_legacy = r"""
+% error admonition title
+\providecommand*{\DUtitleerror}[1]{\DUtitle{\color{red}#1}}"""
+
+PreambleCmds.title_legacy = r"""
+% title for topics, admonitions, unsupported section levels, and sidebar
+\providecommand*{\DUtitle}[2][class-arg]{%
+  % call \DUtitle#1{#2} if it exists:
+  \ifcsname DUtitle#1\endcsname%
+    \csname DUtitle#1\endcsname{#2}%
+  \else
+    \smallskip\noindent\textbf{#2}\smallskip%
+  \fi
+}"""
+
+PreambleCmds.toc_list = r"""
+\providecommand*{\DUCLASScontents}{%
+  \renewenvironment{itemize}%
+    {\begin{list}{}{\setlength{\partopsep}{0pt}
+                    \setlength{\parsep}{0pt}}
+                   }%
+    {\end{list}}%
+}"""
+
+PreambleCmds.ttem = r"""
+% character width in monospaced font
+\newlength{\ttemwidth}
+\settowidth{\ttemwidth}{\ttfamily M}"""
+
+## PreambleCmds.caption = r"""% configure caption layout
+## \usepackage{caption}
+## \captionsetup{singlelinecheck=false}% no exceptions for one-liners"""
+
+
+# Definitions from docutils.sty::
+
+def _read_block(fp):
+    block = [next(fp)]  # first line (empty)
+    for line in fp:
+        if not line.strip():
+            break
+        block.append(line)
+    return ''.join(block).rstrip()
+
+
+with open(LATEX_WRITER_DIR/'docutils.sty', encoding='utf-8') as fp:
+    for line in fp:
+        line = line.strip('% \n')
+        if not line.endswith('::'):
+            continue
+        block_name = line.rstrip(':')
+        if not block_name:
+            continue
+        definitions = _read_block(fp)
+        if block_name in ('color', 'float', 'table', 'textcomp'):
+            definitions = definitions.strip()
+        # print('Block: `%s`'% block_name)
+        # print(definitions)
+        setattr(PreambleCmds, block_name, definitions)
+
+
+# LaTeX encoding maps
+# -------------------
+# ::
+
+class CharMaps:
+    """LaTeX representations for active and Unicode characters."""
+
+    # characters that need escaping even in `alltt` environments:
+    alltt = {
+        ord('\\'): '\\textbackslash{}',
+        ord('{'): '\\{',
+        ord('}'): '\\}',
+    }
+    # characters that normally need escaping:
+    special = {
+        ord('#'): '\\#',
+        ord('$'): '\\$',
+        ord('%'): '\\%',
+        ord('&'): '\\&',
+        ord('~'): '\\textasciitilde{}',
+        ord('_'): '\\_',
+        ord('^'): '\\textasciicircum{}',
+        # straight double quotes are 'active' in many languages
+        ord('"'): '\\textquotedbl{}',
+        # Square brackets are ordinary chars and cannot be escaped with '\',
+        # so we put them in a group '{[}'. (Alternative: ensure that all
+        # macros with optional arguments are terminated with {} and text
+        # inside any optional argument is put in a group ``[{text}]``).
+        # Commands with optional args inside an optional arg must be put in a
+        # group, e.g. ``\item[{\hyperref[label]{text}}]``.
+        ord('['): '{[}',
+        ord(']'): '{]}',
+        # the soft hyphen is unknown in 8-bit text
+        # and not properly handled by XeTeX
+        0x00AD: '\\-',  # SOFT HYPHEN
+    }
+    # Unicode chars that are not recognized by LaTeX's utf8 encoding
+    unsupported_unicode = {
+        # TODO: ensure white space also at the beginning of a line?
+        # 0x00A0: '\\leavevmode\\nobreak\\vadjust{}~'
+        0x2000: '\\enskip',                        # EN QUAD
+        0x2001: '\\quad',                          # EM QUAD
+        0x2002: '\\enskip',                        # EN SPACE
+        0x2003: '\\quad',                          # EM SPACE
+        0x2008: '\\,',                             # PUNCTUATION SPACE
+        0x200b: '\\hspace{0pt}',                   # ZERO WIDTH SPACE
+        0x202F: '\\,',                             # NARROW NO-BREAK SPACE
+        # 0x02d8: '\\\u{ }',                       # BREVE
+        0x2011: '\\hbox{-}',                       # NON-BREAKING HYPHEN
+        0x212b: '\\AA',                            # ANGSTROM SIGN
+        0x21d4: '\\ensuremath{\\Leftrightarrow}',  # LEFT RIGHT DOUBLE ARROW
+        0x2260: '\\ensuremath{\\neq}',             # NOT EQUAL TO
+        0x2261: '\\ensuremath{\\equiv}',           # IDENTICAL TO
+        0x2264: '\\ensuremath{\\le}',              # LESS-THAN OR EQUAL TO
+        0x2265: '\\ensuremath{\\ge}',              # GREATER-THAN OR EQUAL TO
+        # Docutils footnote symbols:
+        0x2660: '\\ensuremath{\\spadesuit}',
+        0x2663: '\\ensuremath{\\clubsuit}',
+        0xfb00: 'ff',                              # LATIN SMALL LIGATURE FF
+        0xfb01: 'fi',                              # LATIN SMALL LIGATURE FI
+        0xfb02: 'fl',                              # LATIN SMALL LIGATURE FL
+        0xfb03: 'ffi',                             # LATIN SMALL LIGATURE FFI
+        0xfb04: 'ffl',                             # LATIN SMALL LIGATURE FFL
+    }
+    # Unicode chars that are recognized by LaTeX's utf8 encoding
+    utf8_supported_unicode = {
+        0x00A0: '~',                   # NO-BREAK SPACE
+        0x00AB: '\\guillemotleft{}',   # LEFT-POINTING DOUBLE ANGLE QUOTATION
+        0x00bb: '\\guillemotright{}',  # RIGHT-POINTING DOUBLE ANGLE QUOTATION
+        0x200C: '\\textcompwordmark{}',  # ZERO WIDTH NON-JOINER
+        0x2013: '\\textendash{}',
+        0x2014: '\\textemdash{}',
+        0x2018: '\\textquoteleft{}',
+        0x2019: '\\textquoteright{}',
+        0x201A: '\\quotesinglbase{}',    # SINGLE LOW-9 QUOTATION MARK
+        0x201C: '\\textquotedblleft{}',
+        0x201D: '\\textquotedblright{}',
+        0x201E: '\\quotedblbase{}',      # DOUBLE LOW-9 QUOTATION MARK
+        0x2030: '\\textperthousand{}',   # PER MILLE SIGN
+        0x2031: '\\textpertenthousand{}',  # PER TEN THOUSAND SIGN
+        0x2039: '\\guilsinglleft{}',
+        0x203A: '\\guilsinglright{}',
+        0x2423: '\\textvisiblespace{}',  # OPEN BOX
+        0x2020: '\\dag{}',
+        0x2021: '\\ddag{}',
+        0x2026: '\\dots{}',
+        0x2122: '\\texttrademark{}',
+    }
+    # recognized with 'utf8', if textcomp is loaded
+    textcomp = {
+        # Latin-1 Supplement
+        0x00a2: '\\textcent{}',              # ¢ CENT SIGN
+        0x00a4: '\\textcurrency{}',          # ¤ CURRENCY SYMBOL
+        0x00a5: '\\textyen{}',               # ¥ YEN SIGN
+        0x00a6: '\\textbrokenbar{}',         # ¦ BROKEN BAR
+        0x00a7: '\\textsection{}',           # § SECTION SIGN
+        0x00a8: '\\textasciidieresis{}',     # ¨ DIAERESIS
+        0x00a9: '\\textcopyright{}',         # © COPYRIGHT SIGN
+        0x00aa: '\\textordfeminine{}',       # ª FEMININE ORDINAL INDICATOR
+        0x00ac: '\\textlnot{}',              # ¬ NOT SIGN
+        0x00ae: '\\textregistered{}',        # ® REGISTERED SIGN
+        0x00af: '\\textasciimacron{}',       # ¯ MACRON
+        0x00b0: '\\textdegree{}',            # ° DEGREE SIGN
+        0x00b1: '\\textpm{}',                # ± PLUS-MINUS SIGN
+        0x00b2: '\\texttwosuperior{}',       # ² SUPERSCRIPT TWO
+        0x00b3: '\\textthreesuperior{}',     # ³ SUPERSCRIPT THREE
+        0x00b4: '\\textasciiacute{}',        # ´ ACUTE ACCENT
+        0x00b5: '\\textmu{}',                # µ MICRO SIGN
+        0x00b6: '\\textparagraph{}',         # ¶ PILCROW SIGN # != \textpilcrow
+        0x00b9: '\\textonesuperior{}',       # ¹ SUPERSCRIPT ONE
+        0x00ba: '\\textordmasculine{}',      # º MASCULINE ORDINAL INDICATOR
+        0x00bc: '\\textonequarter{}',        # 1/4 FRACTION
+        0x00bd: '\\textonehalf{}',           # 1/2 FRACTION
+        0x00be: '\\textthreequarters{}',     # 3/4 FRACTION
+        0x00d7: '\\texttimes{}',             # × MULTIPLICATION SIGN
+        0x00f7: '\\textdiv{}',               # ÷ DIVISION SIGN
+        # others
+        0x0192: '\\textflorin{}',            # LATIN SMALL LETTER F WITH HOOK
+        0x02b9: '\\textasciiacute{}',        # MODIFIER LETTER PRIME
+        0x02ba: '\\textacutedbl{}',          # MODIFIER LETTER DOUBLE PRIME
+        0x2016: '\\textbardbl{}',            # DOUBLE VERTICAL LINE
+        0x2022: '\\textbullet{}',            # BULLET
+        0x2032: '\\textasciiacute{}',        # PRIME
+        0x2033: '\\textacutedbl{}',          # DOUBLE PRIME
+        0x2035: '\\textasciigrave{}',        # REVERSED PRIME
+        0x2036: '\\textgravedbl{}',          # REVERSED DOUBLE PRIME
+        0x203b: '\\textreferencemark{}',     # REFERENCE MARK
+        0x203d: '\\textinterrobang{}',       # INTERROBANG
+        0x2044: '\\textfractionsolidus{}',   # FRACTION SLASH
+        0x2045: '\\textlquill{}',            # LEFT SQUARE BRACKET WITH QUILL
+        0x2046: '\\textrquill{}',            # RIGHT SQUARE BRACKET WITH QUILL
+        0x2052: '\\textdiscount{}',          # COMMERCIAL MINUS SIGN
+        0x20a1: '\\textcolonmonetary{}',     # COLON SIGN
+        0x20a3: '\\textfrenchfranc{}',       # FRENCH FRANC SIGN
+        0x20a4: '\\textlira{}',              # LIRA SIGN
+        0x20a6: '\\textnaira{}',             # NAIRA SIGN
+        0x20a9: '\\textwon{}',               # WON SIGN
+        0x20ab: '\\textdong{}',              # DONG SIGN
+        0x20ac: '\\texteuro{}',              # EURO SIGN
+        0x20b1: '\\textpeso{}',              # PESO SIGN
+        0x20b2: '\\textguarani{}',           # GUARANI SIGN
+        0x2103: '\\textcelsius{}',           # DEGREE CELSIUS
+        0x2116: '\\textnumero{}',            # NUMERO SIGN
+        0x2117: '\\textcircledP{}',          # SOUND RECORDING COPYRIGHT
+        0x211e: '\\textrecipe{}',            # PRESCRIPTION TAKE
+        0x2120: '\\textservicemark{}',       # SERVICE MARK
+        0x2122: '\\texttrademark{}',         # TRADE MARK SIGN
+        0x2126: '\\textohm{}',               # OHM SIGN
+        0x2127: '\\textmho{}',               # INVERTED OHM SIGN
+        0x212e: '\\textestimated{}',         # ESTIMATED SYMBOL
+        0x2190: '\\textleftarrow{}',         # LEFTWARDS ARROW
+        0x2191: '\\textuparrow{}',           # UPWARDS ARROW
+        0x2192: '\\textrightarrow{}',        # RIGHTWARDS ARROW
+        0x2193: '\\textdownarrow{}',         # DOWNWARDS ARROW
+        0x2212: '\\textminus{}',             # MINUS SIGN
+        0x2217: '\\textasteriskcentered{}',  # ASTERISK OPERATOR
+        0x221a: '\\textsurd{}',              # SQUARE ROOT
+        0x2422: '\\textblank{}',             # BLANK SYMBOL
+        0x25e6: '\\textopenbullet{}',        # WHITE BULLET
+        0x25ef: '\\textbigcircle{}',         # LARGE CIRCLE
+        0x266a: '\\textmusicalnote{}',       # EIGHTH NOTE
+        0x26ad: '\\textmarried{}',           # MARRIAGE SYMBOL
+        0x26ae: '\\textdivorced{}',          # DIVORCE SYMBOL
+        0x27e8: '\\textlangle{}',            # MATHEMATICAL LEFT ANGLE BRACKET
+        0x27e9: '\\textrangle{}',            # MATHEMATICAL RIGHT ANGLE BRACKET
+    }
+    # Unicode chars that require a feature/package to render
+    pifont = {
+        0x2665: '\\ding{170}',               # black heartsuit
+        0x2666: '\\ding{169}',               # black diamondsuit
+        0x2713: '\\ding{51}',                # check mark
+        0x2717: '\\ding{55}',                # check mark
+    }
+    # TODO: greek alphabet ... ?
+    # see also LaTeX codec
+    # http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/252124
+    # and unimap.py from TeXML
+
+
+class DocumentClass:
+    """Details of a LaTeX document class."""
+
+    def __init__(self, document_class, with_part=False):
+        self.document_class = document_class
+        self._with_part = with_part
+        self.sections = ['section', 'subsection', 'subsubsection',
+                         'paragraph', 'subparagraph']
+        if self.document_class in ('book', 'memoir', 'report',
+                                   'scrbook', 'scrreprt'):
+            self.sections.insert(0, 'chapter')
+        if self._with_part:
+            self.sections.insert(0, 'part')
+
+    def section(self, level):
+        """Return the LaTeX section name for section `level`.
+
+        The name depends on the specific document class.
+        Level is 1,2,3..., as level 0 is the title.
+        """
+        if level <= len(self.sections):
+            return self.sections[level-1]
+        # unsupported levels
+        return 'DUtitle'
+
+    def latex_section_depth(self, depth):
+        """
+        Return LaTeX equivalent of Docutils section level `depth`.
+
+        Given the value of the ``:depth:`` option of the "contents" or
+        "sectnum" directive, return the corresponding value for the
+        LaTeX ``tocdepth`` or ``secnumdepth`` counters.
+        """
+        depth = min(depth, len(self.sections))  # limit to supported levels
+        if 'chapter' in self.sections:
+            depth -= 1
+        if self.sections[0] == 'part':
+            depth -= 1
+        return depth
+
+
+class Table:
+    """Manage a table while traversing.
+
+    Table style might be
+
+    :standard:   horizontal and vertical lines
+    :booktabs:   only horizontal lines (requires "booktabs" LaTeX package)
+    :borderless: no borders around table cells
+    :nolines:    alias for borderless
+
+    :colwidths-auto:  column widths determined by LaTeX
+    """
+    def __init__(self, translator, latex_type):
+        self._translator = translator
+        self._latex_type = latex_type
+        self.legacy_column_widths = False
+
+        self.close()
+        self._colwidths = []
+        self._rowspan = []
+        self._in_thead = 0
+
+    def open(self):
+        self._open = True
+        self._col_specs = []
+        self.caption = []
+        self._attrs = {}
+        self._in_head = False  # maybe context with search
+
+    def close(self):
+        self._open = False
+        self._col_specs = None
+        self.caption = []
+        self._attrs = {}
+        self.stubs = []
+        self.colwidths_auto = False
+
+    def is_open(self):
+        return self._open
+
+    def set_table_style(self, node, settings):
+        self.legacy_column_widths = settings.legacy_column_widths
+        if 'align' in node:
+            self.set('align', node['align'])
+        # TODO: elif 'align' in classes/settings.table-style:
+        #           self.set('align', ...)
+        borders = [cls.replace('nolines', 'borderless')
+                   for cls in (['standard']
+                               + settings.table_style
+                               + node['classes'])
+                   if cls in ('standard', 'booktabs', 'borderless', 'nolines')]
+        self.borders = borders[-1]
+        self.colwidths_auto = (('colwidths-auto' in node['classes']
+                                or 'colwidths-auto' in settings.table_style)
+                               and 'colwidths-given' not in node['classes']
+                               and 'width' not in node)
+
+    def get_latex_type(self):
+        if self._latex_type == 'longtable' and not self.caption:
+            # do not advance the "table" counter (requires "ltcaption" package)
+            return 'longtable*'
+        return self._latex_type
+
+    def set(self, attr, value):
+        self._attrs[attr] = value
+
+    def get(self, attr):
+        if attr in self._attrs:
+            return self._attrs[attr]
+        return None
+
+    def get_vertical_bar(self):
+        if self.borders == 'standard':
+            return '|'
+        return ''
+
+    def get_opening(self, width=r'\linewidth'):
+        align_map = {'left': '[l]',
+                     'center': '[c]',
+                     'right': '[r]',
+                     None: ''}
+        align = align_map.get(self.get('align'))
+        latex_type = self.get_latex_type()
+        if align and latex_type not in ("longtable", "longtable*"):
+            opening = [r'\noindent\makebox[\linewidth]%s{%%' % (align,),
+                       r'\begin{%s}' % (latex_type,)]
+        else:
+            opening = [r'\begin{%s}%s' % (latex_type, align)]
+        if not self.colwidths_auto:
+            if self.borders == 'standard' and not self.legacy_column_widths:
+                opening.insert(-1, r'\setlength{\DUtablewidth}'
+                               r'{\dimexpr%s-%i\arrayrulewidth\relax}%%'
+                               % (width, len(self._col_specs)+1))
+            else:
+                opening.insert(-1, r'\setlength{\DUtablewidth}{%s}%%' % width)
+        return '\n'.join(opening)
+
+    def get_closing(self):
+        closing = []
+        if self.borders == 'booktabs':
+            closing.append(r'\bottomrule')
+        # elif self.borders == 'standard':
+        #     closing.append(r'\hline')
+        closing.append(r'\end{%s}' % self.get_latex_type())
+        if (self.get('align')
+            and self.get_latex_type() not in ("longtable", "longtable*")):
+            closing.append('}')
+        return '\n'.join(closing)
+
+    def visit_colspec(self, node):
+        self._col_specs.append(node)
+        # "stubs" list is an attribute of the tgroup element:
+        self.stubs.append(node.attributes.get('stub'))
+
+    def get_colspecs(self, node):
+        """Return column specification for longtable.
+        """
+        bar = self.get_vertical_bar()
+        self._rowspan = [0] * len(self._col_specs)
+        if self.colwidths_auto:
+            self._colwidths = []
+            latex_colspecs = ['l'] * len(self._col_specs)
+        elif self.legacy_column_widths:
+            # use old algorithm for backwards compatibility
+            width = 80  # assumed standard line length
+            factor = 0.93  # do not make it full linewidth
+            # first see if we get too wide.
+            total_width = sum(node['colwidth']+1 for node in self._col_specs)
+            if total_width > width:
+                factor *= width / total_width
+            self._colwidths = [(factor * (node['colwidth']+1)/width)
+                               + 0.005 for node in self._col_specs]
+            latex_colspecs = ['p{%.3f\\DUtablewidth}' % colwidth
+                              for colwidth in self._colwidths]
+        else:
+            # No of characters corresponding to table width = 100%
+            #   Characters/line with LaTeX article, A4, Times, default margins
+            #   depends on character:  M: 40, A: 50, x: 70, i: 120.
+            norm_length = 40
+            # Allowance to prevent unpadded columns like
+            #   === ==
+            #   ABC DE
+            #   === ==
+            # getting too narrow:
+            if 'colwidths-given' not in node.parent.parent['classes']:
+                allowance = 1
+            else:
+                allowance = 0  # "widths" option specified, use exact ratio
+            self._colwidths = [(node['colwidth']+allowance)/norm_length
+                               for node in self._col_specs]
+            total_width = sum(self._colwidths)
+            # Limit to 100%, force 100% if table width is specified:
+            if total_width > 1 or 'width' in node.parent.parent.attributes:
+                self._colwidths = [colwidth/total_width
+                                   for colwidth in self._colwidths]
+            latex_colspecs = ['p{\\DUcolumnwidth{%.3f}}' % colwidth
+                              for colwidth in self._colwidths]
+        return bar + bar.join(latex_colspecs) + bar
+
+    def get_column_width(self):
+        """Return columnwidth for current cell (not multicell)."""
+        try:
+            if self.legacy_column_widths:
+                return '%.2f\\DUtablewidth'%self._colwidths[self._cell_in_row]
+            return '\\DUcolumnwidth{%.2f}'%self._colwidths[self._cell_in_row]
+        except IndexError:
+            return '*'
+
+    def get_multicolumn_width(self, start, len_):
+        """Return sum of columnwidths for multicell."""
+        try:
+            multicol_width = sum(self._colwidths[start + co]
+                                 for co in range(len_))
+            if self.legacy_column_widths:
+                return 'p{%.2f\\DUtablewidth}' % multicol_width
+            return 'p{\\DUcolumnwidth{%.3f}}' % multicol_width
+        except IndexError:
+            return 'l'
+
+    def get_caption(self):
+        """Deprecated. Will be removed in Docutils 0.22."""
+        warnings.warn('`writers.latex2e.Table.get_caption()` is obsolete'
+                      ' and will be removed in Docutils 0.22.',
+                      DeprecationWarning, stacklevel=2)
+
+        if not self.caption:
+            return ''
+        caption = ''.join(self.caption)
+        if 1 == self._translator.thead_depth():
+            return r'\caption{%s}\\' '\n' % caption
+        return r'\caption[]{%s (... continued)}\\' '\n' % caption
+
+    def need_recurse(self):
+        if self._latex_type == 'longtable':
+            return 1 == self._translator.thead_depth()
+        return 0
+
+    def visit_thead(self):
+        self._in_thead += 1
+        if self.borders == 'standard':
+            return ['\\hline\n']
+        elif self.borders == 'booktabs':
+            return ['\\toprule\n']
+        return []
+
+    def depart_thead(self):
+        a = []
+        ## if self.borders == 'standard':
+        ##     a.append('\\hline\n')
+        if self.borders == 'booktabs':
+            a.append('\\midrule\n')
+        if self._latex_type == 'longtable':
+            if 1 == self._translator.thead_depth():
+                a.append('\\endfirsthead\n')
+            else:
+                n_c = len(self._col_specs)
+                a.append('\\endhead\n')
+                # footer on all but last page (if it fits):
+                twidth = sum(node['colwidth']+2 for node in self._col_specs)
+                if twidth > 30 or (twidth > 12 and not self.colwidths_auto):
+                    a.append(r'\multicolumn{%d}{%s}'
+                             % (n_c, self.get_multicolumn_width(0, n_c))
+                             + r'{\raggedleft\ldots continued on next page}\\'
+                             + '\n')
+                a.append('\\endfoot\n\\endlastfoot\n')
+            # for longtable one could add firsthead, foot and lastfoot
+        self._in_thead -= 1
+        return a
+
+    def visit_row(self):
+        self._cell_in_row = 0
+
+    def depart_row(self):
+        res = [' \\\\\n']
+        self._cell_in_row = None  # remove cell counter
+        for i in range(len(self._rowspan)):
+            if self._rowspan[i] > 0:
+                self._rowspan[i] -= 1
+
+        if self.borders == 'standard':
+            rowspans = [i+1 for i in range(len(self._rowspan))
+                        if self._rowspan[i] <= 0]
+            if len(rowspans) == len(self._rowspan):
+                res.append('\\hline\n')
+            else:
+                cline = ''
+                rowspans.reverse()
+                # TODO merge clines
+                while True:
+                    try:
+                        c_start = rowspans.pop()
+                    except IndexError:
+                        break
+                    cline += '\\cline{%d-%d}\n' % (c_start, c_start)
+                res.append(cline)
+        return res
+
+    def set_rowspan(self, cell, value):
+        try:
+            self._rowspan[cell] = value
+        except IndexError:
+            pass
+
+    def get_rowspan(self, cell):
+        try:
+            return self._rowspan[cell]
+        except IndexError:
+            return 0
+
+    def get_entry_number(self):
+        return self._cell_in_row
+
+    def visit_entry(self):
+        self._cell_in_row += 1
+
+    def is_stub_column(self):
+        if len(self.stubs) >= self._cell_in_row:
+            return self.stubs[self._cell_in_row]
+        return False
+
+
+class LaTeXTranslator(nodes.NodeVisitor):
+    """
+    Generate code for 8-bit LaTeX from a Docutils document tree.
+
+    See the docstring of docutils.writers._html_base.HTMLTranslator for
+    notes on and examples of safe subclassing.
+    """
+
+    # When options are given to the documentclass, latex will pass them
+    # to other packages, as done with babel.
+    # Dummy settings might be taken from document settings
+
+    # Generate code for typesetting with 8-bit latex/pdflatex vs.
+    # xelatex/lualatex engine. Overwritten by the XeTeX writer
+    is_xetex = False
+
+    # Config setting defaults
+    # -----------------------
+
+    # TODO: use mixins for different implementations.
+    # list environment for docinfo. else tabularx
+    ## use_optionlist_for_docinfo = False # TODO: NOT YET IN USE
+
+    # Use compound enumerations (1.A.1.)
+    compound_enumerators = False
+
+    # If using compound enumerations, include section information.
+    section_prefix_for_enumerators = False
+
+    # This is the character that separates the section ("." subsection ...)
+    # prefix from the regular list enumerator.
+    section_enumerator_separator = '-'
+
+    # Auxiliary variables
+    # -------------------
+
+    has_latex_toc = False  # is there a toc in the doc? (needed by minitoc)
+    section_level = 0
+
+    # Flags to encode():
+    # inside citation reference labels underscores dont need to be escaped
+    inside_citation_reference_label = False
+    verbatim = False                    # do not encode
+    insert_non_breaking_blanks = False  # replace blanks by "~"
+    insert_newline = False              # add latex newline commands
+    literal = False                     # literal text (block or inline)
+    alltt = False                       # inside `alltt` environment
+
+    def __init__(self, document, babel_class=Babel):
+        super().__init__(document)
+        # Reporter
+        # ~~~~~~~~
+        self.warn = self.document.reporter.warning
+        self.error = self.document.reporter.error
+
+        # Settings
+        # ~~~~~~~~
+        self.settings = settings = document.settings
+        # warn of deprecated settings and changing defaults:
+        if settings.use_latex_citations is None and not settings.use_bibtex:
+            settings.use_latex_citations = False
+            warnings.warn('The default for the setting "use_latex_citations" '
+                          'will change to "True" in Docutils 1.0.',
+                          FutureWarning, stacklevel=7)
+        if settings.legacy_column_widths is None:
+            settings.legacy_column_widths = True
+            warnings.warn('The default for the setting "legacy_column_widths" '
+                          'will change to "False" in Docutils 1.0.)',
+                          FutureWarning, stacklevel=7)
+        if settings.use_verbatim_when_possible is not None:
+            warnings.warn(
+                'The configuration setting "use_verbatim_when_possible" '
+                'will be removed in Docutils 2.0. '
+                'Use "literal_block_env: verbatim".',
+                FutureWarning, stacklevel=7)
+
+        self.latex_encoding = self.to_latex_encoding(settings.output_encoding)
+        self.use_latex_toc = settings.use_latex_toc
+        self.use_latex_docinfo = settings.use_latex_docinfo
+        self.use_latex_citations = settings.use_latex_citations
+        self.reference_label = settings.reference_label
+        self.hyperlink_color = settings.hyperlink_color
+        self.compound_enumerators = settings.compound_enumerators
+        self.font_encoding = getattr(settings, 'font_encoding', '')
+        self.section_prefix_for_enumerators = (
+            settings.section_prefix_for_enumerators)
+        self.section_enumerator_separator = (
+            settings.section_enumerator_separator.replace('_', r'\_'))
+        # literal blocks:
+        self.literal_block_env = ''
+        self.literal_block_options = ''
+        if settings.literal_block_env:
+            (none,
+             self.literal_block_env,
+             self.literal_block_options,
+             none) = re.split(r'(\w+)(.*)', settings.literal_block_env)
+        elif settings.use_verbatim_when_possible:
+            self.literal_block_env = 'verbatim'
+
+        if settings.use_bibtex:
+            self.use_latex_citations = True
+        self.bibtex = settings.use_bibtex
+        # language module for Docutils-generated text
+        # (labels, bibliographic_fields, and author_separators)
+        self.language_module = languages.get_language(settings.language_code,
+                                                      document.reporter)
+        self.babel = babel_class(settings.language_code, document.reporter)
+        self.author_separator = self.language_module.author_separators[0]
+        d_options = [settings.documentoptions]
+        if self.babel.language not in ('english', ''):
+            d_options.append(self.babel.language)
+        self.documentoptions = ','.join(filter(None, d_options))
+        self.d_class = DocumentClass(settings.documentclass,
+                                     settings.use_part_section)
+        # graphic package options:
+        if settings.graphicx_option == '':
+            self.graphicx_package = r'\usepackage{graphicx}'
+        else:
+            self.graphicx_package = (r'\usepackage[%s]{graphicx}' %
+                                     settings.graphicx_option)
+        # footnotes: TODO: implement LaTeX footnotes
+        self.docutils_footnotes = settings.docutils_footnotes
+
+        # Output collection stacks
+        # ~~~~~~~~~~~~~~~~~~~~~~~~
+
+        # Document parts
+        self.head_prefix = [r'\documentclass[%s]{%s}' %
+                            (self.documentoptions,
+                             settings.documentclass)]
+        self.requirements = SortableDict()  # made a list in depart_document()
+        self.requirements['__static'] = r'\usepackage{ifthen}'
+        self.latex_preamble = [settings.latex_preamble]
+        self.fallbacks = SortableDict()  # made a list in depart_document()
+        self.pdfsetup = []  # PDF properties (hyperref package)
+        self.title = []
+        self.subtitle = []
+        self.titledata = []  # \title, \author, \date
+        ## self.body_prefix = ['\\begin{document}\n']
+        self.body_pre_docinfo = []  # \maketitle
+        self.docinfo = []
+        self.dedication = []
+        self.abstract = []
+        self.body = []
+        ## self.body_suffix = ['\\end{document}\n']
+
+        self.context = []
+        """Heterogeneous stack.
+
+        Used by visit_* and depart_* functions in conjunction with the tree
+        traversal. Make sure that the pops correspond to the pushes."""
+
+        # Title metadata:
+        self.title_labels = []
+        self.subtitle_labels = []
+        # (if use_latex_docinfo: collects lists of
+        # author/organization/contact/address lines)
+        self.author_stack = []
+        self.date = []
+
+        # PDF properties: pdftitle, pdfauthor
+        self.pdfauthor = []
+        self.pdfinfo = []
+        if settings.language_code != 'en':
+            self.pdfinfo.append('  pdflang={%s},'%settings.language_code)
+
+        # Stack of section counters so that we don't have to use_latex_toc.
+        # This will grow and shrink as processing occurs.
+        # Initialized for potential first-level sections.
+        self._section_number = [0]
+
+        # The current stack of enumerations so that we can expand
+        # them into a compound enumeration.
+        self._enumeration_counters = []
+        # The maximum number of enumeration counters we've used.
+        # If we go beyond this number, we need to create a new
+        # counter; otherwise, just reuse an old one.
+        self._max_enumeration_counters = 0
+
+        self._bibitems = []
+
+        # object for a table while processing.
+        self.table_stack = []
+        self.active_table = Table(self, 'longtable')
+
+        # Where to collect the output of visitor methods (default: body)
+        self.out = self.body
+        self.out_stack = []  # stack of output collectors
+
+        # Process settings
+        # ~~~~~~~~~~~~~~~~
+        # Encodings:
+        # Docutils' output-encoding => TeX input encoding
+        if self.latex_encoding not in ('ascii', 'unicode', 'utf8'):
+            self.requirements['_inputenc'] = (r'\usepackage[%s]{inputenc}'
+                                              % self.latex_encoding)
+        # TeX font encoding
+        if not self.is_xetex:
+            if self.font_encoding:
+                self.requirements['_fontenc'] = (r'\usepackage[%s]{fontenc}' %
+                                                 self.font_encoding)
+            # ensure \textquotedbl is defined:
+            for enc in self.font_encoding.split(','):
+                enc = enc.strip()
+                if enc == 'OT1':
+                    self.requirements['_textquotedblOT1'] = (
+                        r'\DeclareTextSymbol{\textquotedbl}{OT1}{`\"}')
+                elif enc not in ('T1', 'T2A', 'T2B', 'T2C', 'T4', 'T5'):
+                    self.requirements['_textquotedbl'] = (
+                        r'\DeclareTextSymbolDefault{\textquotedbl}{T1}')
+        # page layout with typearea (if there are relevant document options)
+        if (settings.documentclass.find('scr') == -1
+            and (self.documentoptions.find('DIV') != -1
+                 or self.documentoptions.find('BCOR') != -1)):
+            self.requirements['typearea'] = r'\usepackage{typearea}'
+
+        # Stylesheets
+        # (the name `self.stylesheet` is singular because only one
+        # stylesheet was supported before Docutils 0.6).
+        stylesheet_list = utils.get_stylesheet_list(settings)
+        self.fallback_stylesheet = 'docutils' in stylesheet_list
+        if self.fallback_stylesheet:
+            stylesheet_list.remove('docutils')
+            if settings.legacy_class_functions:
+                # docutils.sty is incompatible with legacy functions
+                self.fallback_stylesheet = False
+            else:
+                # require a minimal version:
+                self.fallbacks['docutils.sty'] = (
+                    r'\usepackage{docutils}[2020/08/28]')
+
+        self.stylesheet = [self.stylesheet_call(path)
+                           for path in stylesheet_list]
+
+        # PDF setup
+        if self.hyperlink_color.lower() in ('0', 'false', ''):
+            self.hyperref_options = ''
+        else:
+            self.hyperref_options = ('colorlinks=true,'
+                                     f'linkcolor={self.hyperlink_color},'
+                                     f'urlcolor={self.hyperlink_color}')
+        if settings.hyperref_options:
+            self.hyperref_options += ',' + settings.hyperref_options
+
+        # LaTeX Toc
+        # include all supported sections in toc and PDF bookmarks
+        # (or use documentclass-default (as currently))?
+
+        # Section numbering
+        if settings.sectnum_xform:  # section numbering by Docutils
+            PreambleCmds.secnumdepth = r'\setcounter{secnumdepth}{0}'
+        else:  # section numbering by LaTeX:
+            secnumdepth = settings.sectnum_depth
+            # Possible values of settings.sectnum_depth:
+            # None  "sectnum" directive without depth arg -> LaTeX default
+            #  0    no "sectnum" directive -> no section numbers
+            # >0    value of "depth" argument -> translate to LaTeX levels:
+            #       -1  part    (0 with "article" document class)
+            #        0  chapter (missing in "article" document class)
+            #        1  section
+            #        2  subsection
+            #        3  subsubsection
+            #        4  paragraph
+            #        5  subparagraph
+            if secnumdepth is not None:
+                PreambleCmds.secnumdepth = (
+                    r'\setcounter{secnumdepth}{%d}'
+                    % self.d_class.latex_section_depth(secnumdepth))
+            # start with specified number:
+            if (hasattr(settings, 'sectnum_start')
+                and settings.sectnum_start != 1):
+                self.requirements['sectnum_start'] = (
+                    r'\setcounter{%s}{%d}' % (self.d_class.sections[0],
+                                              settings.sectnum_start-1))
+            # TODO: currently ignored (configure in a stylesheet):
+            ## settings.sectnum_prefix
+            ## settings.sectnum_suffix
+
+    # Auxiliary Methods
+    # -----------------
+
+    def stylesheet_call(self, path):
+        """Return code to reference or embed stylesheet file `path`"""
+        path = Path(path)
+        # is it a package (no extension or *.sty) or "normal" tex code:
+        is_package = path.suffix in ('.sty', '')
+        # Embed content of style file:
+        if self.settings.embed_stylesheet:
+            if is_package:
+                path = path.with_suffix('.sty')  # ensure extension
+            try:
+                content = path.read_text(encoding='utf-8')
+            except OSError as err:
+                msg = f'Cannot embed stylesheet:\n {err}'.replace('\\\\', '/')
+                self.document.reporter.error(msg)
+                return '% ' + msg.replace('\n', '\n% ')
+            else:
+                self.settings.record_dependencies.add(path.as_posix())
+            if is_package:
+                # allow '@' in macro names:
+                content = (f'\\makeatletter\n{content}\n\\makeatother')
+            return (f'% embedded stylesheet: {path.as_posix()}\n'
+                    f'{content}')
+        # Link to style file:
+        if is_package:
+            path = path.parent / path.stem  # drop extension
+            cmd = r'\usepackage{%s}'
+        else:
+            cmd = r'\input{%s}'
+        if self.settings.stylesheet_path:
+            # adapt path relative to output (cf. config.html#stylesheet-path)
+            return cmd % utils.relative_path(self.settings._destination, path)
+        return cmd % path.as_posix()
+
+    def to_latex_encoding(self, docutils_encoding):
+        """Translate docutils encoding name into LaTeX's.
+
+        Default method is remove "-" and "_" chars from docutils_encoding.
+        """
+        tr = {'iso-8859-1': 'latin1',     # west european
+              'iso-8859-2': 'latin2',     # east european
+              'iso-8859-3': 'latin3',     # esperanto, maltese
+              'iso-8859-4': 'latin4',     # north european
+              'iso-8859-5': 'iso88595',   # cyrillic (ISO)
+              'iso-8859-9': 'latin5',     # turkish
+              'iso-8859-15': 'latin9',    # latin9, update to latin1.
+              'mac_cyrillic': 'maccyr',   # cyrillic (on Mac)
+              'windows-1251': 'cp1251',   # cyrillic (on Windows)
+              'koi8-r': 'koi8-r',         # cyrillic (Russian)
+              'koi8-u': 'koi8-u',         # cyrillic (Ukrainian)
+              'windows-1250': 'cp1250',   #
+              'windows-1252': 'cp1252',   #
+              'us-ascii': 'ascii',        # ASCII (US)
+              # unmatched encodings
+              # '': 'applemac',
+              # '': 'ansinew',  # windows 3.1 ansi
+              # '': 'ascii',    # ASCII encoding for the range 32--127.
+              # '': 'cp437',    # dos latin us
+              # '': 'cp850',    # dos latin 1
+              # '': 'cp852',    # dos latin 2
+              # '': 'decmulti',
+              # '': 'latin10',
+              # 'iso-8859-6': ''   # arabic
+              # 'iso-8859-7': ''   # greek
+              # 'iso-8859-8': ''   # hebrew
+              # 'iso-8859-10': ''  # latin6, more complete iso-8859-4
+              }
+        encoding = docutils_encoding.lower()  # normalize case
+        encoding = encoding.split(':')[0]     # strip the error handler
+        if encoding in tr:
+            return tr[encoding]
+        # drop HYPHEN or LOW LINE from "latin_1", "utf-8" and similar
+        return encoding.replace('_', '').replace('-', '')
+
+    def language_label(self, docutil_label):
+        return self.language_module.labels[docutil_label]
+
+    def encode(self, text):
+        """Return text with 'problematic' characters escaped.
+
+        * Escape the special printing characters ``# $ % & ~ _ ^ \\ { }``,
+          square brackets ``[ ]``, double quotes and (in OT1) ``< | >``.
+        * Translate non-supported Unicode characters.
+        * Separate ``-`` (and more in literal text) to prevent input ligatures.
+        """
+        if self.verbatim:
+            return text
+        # Set up the translation table:
+        table = CharMaps.alltt.copy()
+        if not self.alltt:
+            table.update(CharMaps.special)
+        # keep the underscore in citation references
+        if self.inside_citation_reference_label and not self.alltt:
+            del table[ord('_')]
+        # Workarounds for OT1 font-encoding
+        if self.font_encoding in ['OT1', ''] and not self.is_xetex:
+            # * out-of-order characters in cmtt
+            if self.literal:
+                # replace underscore by underlined blank,
+                # because this has correct width.
+                table[ord('_')] = '\\underline{~}'
+                # the backslash doesn't work, so we use a mirrored slash.
+                # \reflectbox is provided by graphicx:
+                self.requirements['graphicx'] = self.graphicx_package
+                table[ord('\\')] = '\\reflectbox{/}'
+            # * ``< | >`` come out as different chars (except for cmtt):
+            else:
+                table[ord('|')] = '\\textbar{}'
+                table[ord('<')] = '\\textless{}'
+                table[ord('>')] = '\\textgreater{}'
+        if self.insert_non_breaking_blanks:
+            table[ord(' ')] = '~'
+            # tab chars may occur in included files (literal or code)
+            # quick-and-dirty replacement with spaces
+            # (for better results use `--literal-block-env=lstlisting`)
+            table[ord('\t')] = '~' * self.settings.tab_width
+        # Unicode replacements for 8-bit tex engines (not required with XeTeX)
+        if not self.is_xetex:
+            if not self.latex_encoding.startswith('utf8'):
+                table.update(CharMaps.unsupported_unicode)
+                table.update(CharMaps.utf8_supported_unicode)
+                table.update(CharMaps.textcomp)
+            table.update(CharMaps.pifont)
+            # Characters that require a feature/package to render
+            for ch in text:
+                cp = ord(ch)
+                if cp in CharMaps.textcomp and not self.fallback_stylesheet:
+                    self.requirements['textcomp'] = PreambleCmds.textcomp
+                elif cp in CharMaps.pifont:
+                    self.requirements['pifont'] = '\\usepackage{pifont}'
+                # preamble-definitions for unsupported Unicode characters
+                elif (self.latex_encoding == 'utf8'
+                      and cp in CharMaps.unsupported_unicode):
+                    self.requirements['_inputenc'+str(cp)] = (
+                        '\\DeclareUnicodeCharacter{%04X}{%s}'
+                        % (cp, CharMaps.unsupported_unicode[cp]))
+        text = text.translate(table)
+
+        # Break up input ligatures e.g. '--' to '-{}-'.
+        if not self.is_xetex:  # Not required with xetex/luatex
+            separate_chars = '-'
+            # In monospace-font, we also separate ',,', '``' and "''" and some
+            # other characters which can't occur in non-literal text.
+            if self.literal:
+                separate_chars += ',`\'"<>'
+            for char in separate_chars * 2:
+                # Do it twice ("* 2") because otherwise we would replace
+                # '---' by '-{}--'.
+                text = text.replace(char + char, char + '{}' + char)
+
+        # Literal line breaks (in address or literal blocks):
+        if self.insert_newline:
+            lines = text.split('\n')
+            # Add a protected space to blank lines (except the last)
+            # to avoid ``! LaTeX Error: There's no line here to end.``
+            for i, line in enumerate(lines[:-1]):
+                if not line.lstrip():
+                    lines[i] += '~'
+            text = (r'\\' + '\n').join(lines)
+        if self.literal and not self.insert_non_breaking_blanks:
+            # preserve runs of spaces but allow wrapping
+            text = text.replace('  ', ' ~')
+        return text
+
+    def attval(self, text,
+               whitespace=re.compile('[\n\r\t\v\f]')):
+        """Cleanse, encode, and return attribute value text."""
+        return self.encode(whitespace.sub(' ', text))
+
+    # TODO: is this used anywhere? -> update (use template) or delete
+    ## def astext(self):
+    ##     """Assemble document parts and return as string."""
+    ##     head = '\n'.join(self.head_prefix + self.stylesheet + self.head)
+    ##     body = ''.join(self.body_prefix  + self.body + self.body_suffix)
+    ##     return head + '\n' + body
+
+    def is_inline(self, node):
+        """Check whether a node represents an inline or block-level element"""
+        return isinstance(node.parent, nodes.TextElement)
+
+    def append_hypertargets(self, node):
+        """Append hypertargets for all ids of `node`"""
+        # hypertarget places the anchor at the target's baseline,
+        # so we raise it explicitly
+        self.out.append('%\n'.join('\\raisebox{1em}{\\hypertarget{%s}{}}' %
+                                   id for id in node['ids']))
+
+    def ids_to_labels(self, node, set_anchor=True, protect=False,
+                      newline=False):
+        """Return list of label definitions for all ids of `node`
+
+        If `set_anchor` is True, an anchor is set with \\phantomsection.
+        If `protect` is True, the \\label cmd is made robust.
+        If `newline` is True, a newline is added if there are labels.
+        """
+        prefix = '\\protect' if protect else ''
+        labels = [prefix + '\\label{%s}' % id for id in node['ids']]
+        if set_anchor and labels:
+            labels.insert(0, '\\phantomsection')
+        if newline and labels:
+            labels.append('\n')
+        return labels
+
+    def set_align_from_classes(self, node):
+        """Convert ``align-*`` class arguments into alignment args."""
+        # separate:
+        align = [cls for cls in node['classes'] if cls.startswith('align-')]
+        if align:
+            node['align'] = align[-1].replace('align-', '')
+            node['classes'] = [cls for cls in node['classes']
+                               if not cls.startswith('align-')]
+
+    def insert_align_declaration(self, node, default=None):
+        align = node.get('align', default)
+        if align == 'left':
+            self.out.append('\\raggedright\n')
+        elif align == 'center':
+            self.out.append('\\centering\n')
+        elif align == 'right':
+            self.out.append('\\raggedleft\n')
+
+    def duclass_open(self, node):
+        """Open a group and insert declarations for class values."""
+        if not isinstance(node.parent, nodes.compound):
+            self.out.append('\n')
+        for cls in node['classes']:
+            if cls.startswith('language-'):
+                language = self.babel.language_name(cls[9:])
+                if language:
+                    self.babel.otherlanguages[language] = True
+                    self.out.append('\\begin{selectlanguage}{%s}\n' % language)
+            elif (isinstance(node, nodes.table)
+                  and cls in Writer.table_style_values + ['colwidths-given']):
+                pass
+            else:
+                if not self.fallback_stylesheet:
+                    self.fallbacks['DUclass'] = PreambleCmds.duclass
+                self.out.append('\\begin{DUclass}{%s}\n' % cls)
+
+    def duclass_close(self, node):
+        """Close a group of class declarations."""
+        for cls in reversed(node['classes']):
+            if cls.startswith('language-'):
+                language = self.babel.language_name(cls[9:])
+                if language:
+                    self.out.append('\\end{selectlanguage}\n')
+            elif (isinstance(node, nodes.table)
+                  and cls in Writer.table_style_values + ['colwidths-given']):
+                pass
+            else:
+                if not self.fallback_stylesheet:
+                    self.fallbacks['DUclass'] = PreambleCmds.duclass
+                self.out.append('\\end{DUclass}\n')
+
+    def push_output_collector(self, new_out):
+        self.out_stack.append(self.out)
+        self.out = new_out
+
+    def pop_output_collector(self):
+        self.out = self.out_stack.pop()
+
+    def term_postfix(self, node):
+        """
+        Return LaTeX code required between term or field name and content.
+
+        In a LaTeX "description" environment (used for definition
+        lists and non-docinfo field lists), a ``\\leavevmode``
+        between an item's label and content ensures the correct
+        placement of certain block constructs.
+        """
+        for child in node:
+            if not isinstance(child, (nodes.Invisible, nodes.footnote,
+                                      nodes.citation)):
+                break
+        else:
+            return ''
+        if isinstance(child, (nodes.container, nodes.compound)):
+            return self.term_postfix(child)
+        if isinstance(child, nodes.image):
+            return '\\leavevmode\n'  # Images get an additional newline.
+        if not isinstance(child, (nodes.paragraph, nodes.math_block)):
+            return '\\leavevmode'
+        return ''
+
+    # Visitor methods
+    # ---------------
+
+    def visit_Text(self, node):
+        self.out.append(self.encode(node.astext()))
+
+    def depart_Text(self, node):
+        pass
+
+    def visit_abbreviation(self, node):
+        node['classes'].insert(0, 'abbreviation')
+        self.visit_inline(node)
+
+    def depart_abbreviation(self, node):
+        self.depart_inline(node)
+
+    def visit_acronym(self, node):
+        node['classes'].insert(0, 'acronym')
+        self.visit_inline(node)
+
+    def depart_acronym(self, node):
+        self.depart_inline(node)
+
+    def visit_address(self, node):
+        self.visit_docinfo_item(node, 'address')
+
+    def depart_address(self, node):
+        self.depart_docinfo_item(node)
+
+    def visit_admonition(self, node):
+        # strip the generic 'admonition' from the list of classes
+        node['classes'] = [cls for cls in node['classes']
+                           if cls != 'admonition']
+        if self.settings.legacy_class_functions:
+            self.fallbacks['admonition'] = PreambleCmds.admonition_legacy
+            if 'error' in node['classes']:
+                self.fallbacks['error'] = PreambleCmds.error_legacy
+            self.out.append('\n\\DUadmonition[%s]{'%','.join(node['classes']))
+            return
+        if not self.fallback_stylesheet:
+            self.fallbacks['admonition'] = PreambleCmds.admonition
+        if 'error' in node['classes'] and not self.fallback_stylesheet:
+            self.fallbacks['error'] = PreambleCmds.error
+        self.duclass_open(node)
+        self.out.append('\\begin{DUadmonition}')
+
+    def depart_admonition(self, node):
+        if self.settings.legacy_class_functions:
+            self.out.append('}\n')
+            return
+        self.out.append('\\end{DUadmonition}\n')
+        self.duclass_close(node)
+
+    def visit_author(self, node):
+        self.pdfauthor.append(self.attval(node.astext()))
+        self.visit_docinfo_item(node, 'author')
+
+    def depart_author(self, node):
+        self.depart_docinfo_item(node)
+
+    def visit_authors(self, node):
+        # not used: visit_author is called anyway for each author.
+        pass
+
+    def depart_authors(self, node):
+        pass
+
+    def visit_block_quote(self, node):
+        self.duclass_open(node)
+        self.out.append('\\begin{quote}')
+
+    def depart_block_quote(self, node):
+        self.out.append('\\end{quote}\n')
+        self.duclass_close(node)
+
+    def visit_bullet_list(self, node):
+        self.duclass_open(node)
+        self.out.append('\\begin{itemize}')
+
+    def depart_bullet_list(self, node):
+        self.out.append('\\end{itemize}\n')
+        self.duclass_close(node)
+
+    def visit_superscript(self, node):
+        self.out.append(r'\textsuperscript{')
+        self.visit_inline(node)
+
+    def depart_superscript(self, node):
+        self.depart_inline(node)
+        self.out.append('}')
+
+    def visit_subscript(self, node):
+        self.out.append(r'\textsubscript{')
+        self.visit_inline(node)
+
+    def depart_subscript(self, node):
+        self.depart_inline(node)
+        self.out.append('}')
+
+    def visit_caption(self, node):
+        self.out.append('\n\\caption{')
+
+    def depart_caption(self, node):
+        self.out.append('}\n')
+
+    def visit_title_reference(self, node):
+        if not self.fallback_stylesheet:
+            self.fallbacks['titlereference'] = PreambleCmds.titlereference
+        self.out.append(r'\DUroletitlereference{')
+        self.visit_inline(node)
+
+    def depart_title_reference(self, node):
+        self.depart_inline(node)
+        self.out.append('}')
+
+    def visit_citation(self, node):
+        if self.use_latex_citations:
+            self.push_output_collector([])
+        else:
+            # self.requirements['~fnt_floats'] = PreambleCmds.footnote_floats
+            self.out.append(r'\begin{figure}[b]')
+            self.append_hypertargets(node)
+
+    def depart_citation(self, node):
+        if self.use_latex_citations:
+            # TODO: normalize label
+            label = self.out[0]
+            text = ''.join(self.out[1:])
+            self._bibitems.append([label, text])
+            self.pop_output_collector()
+        else:
+            self.out.append('\\end{figure}\n')
+
+    def visit_citation_reference(self, node):
+        if self.bibtex:
+            self._bibitems.append([node.astext()])
+        if self.use_latex_citations:
+            if not self.inside_citation_reference_label:
+                self.out.append(r'\cite{')
+                self.inside_citation_reference_label = True
+            else:
+                assert self.out[-1] in (' ', '\n'),\
+                        'unexpected non-whitespace while in reference label'
+                del self.out[-1]
+        else:
+            href = ''
+            if 'refid' in node:
+                href = node['refid']
+            elif 'refname' in node:
+                href = self.document.nameids[node['refname']]
+            self.out.append('\\hyperlink{%s}{[' % href)
+
+    def depart_citation_reference(self, node):
+        # TODO: normalize labels
+        if self.use_latex_citations:
+            followup_citation = False
+            # check for a following citation separated by a space or newline
+            sibling = node.next_node(descend=False, siblings=True)
+            if (isinstance(sibling, nodes.Text)
+                and sibling.astext() in (' ', '\n')):
+                sibling2 = sibling.next_node(descend=False, siblings=True)
+                if isinstance(sibling2, nodes.citation_reference):
+                    followup_citation = True
+            if followup_citation:
+                self.out.append(',')
+            else:
+                self.out.append('}')
+                self.inside_citation_reference_label = False
+        else:
+            self.out.append(']}')
+
+    def visit_classifier(self, node):
+        self.out.append('(\\textbf{')
+
+    def depart_classifier(self, node):
+        self.out.append('})')
+        if node.next_node(nodes.term, descend=False, siblings=True):
+            self.out.append('\n')
+
+    def visit_colspec(self, node):
+        self.active_table.visit_colspec(node)
+
+    def depart_colspec(self, node):
+        pass
+
+    def visit_comment(self, node):
+        if not isinstance(node.parent, nodes.compound):
+            self.out.append('\n')
+        # Precede every line with a comment sign, wrap in newlines
+        self.out.append('%% %s\n' % node.astext().replace('\n', '\n% '))
+        raise nodes.SkipNode
+
+    def depart_comment(self, node):
+        pass
+
+    def visit_compound(self, node):
+        if isinstance(node.parent, nodes.compound):
+            self.out.append('\n')
+        node['classes'].insert(0, 'compound')
+        self.duclass_open(node)
+
+    def depart_compound(self, node):
+        self.duclass_close(node)
+
+    def visit_contact(self, node):
+        self.visit_docinfo_item(node, 'contact')
+
+    def depart_contact(self, node):
+        self.depart_docinfo_item(node)
+
+    def visit_container(self, node):
+        self.duclass_open(node)
+
+    def depart_container(self, node):
+        self.duclass_close(node)
+
+    def visit_copyright(self, node):
+        self.visit_docinfo_item(node, 'copyright')
+
+    def depart_copyright(self, node):
+        self.depart_docinfo_item(node)
+
+    def visit_date(self, node):
+        self.visit_docinfo_item(node, 'date')
+
+    def depart_date(self, node):
+        self.depart_docinfo_item(node)
+
+    def visit_decoration(self, node):
+        # header and footer
+        pass
+
+    def depart_decoration(self, node):
+        pass
+
+    def visit_definition(self, node):
+        pass
+
+    def depart_definition(self, node):
+        pass
+
+    def visit_definition_list(self, node):
+        self.duclass_open(node)
+        self.out.append('\\begin{description}\n')
+
+    def depart_definition_list(self, node):
+        self.out.append('\\end{description}\n')
+        self.duclass_close(node)
+
+    def visit_definition_list_item(self, node):
+        pass
+
+    def depart_definition_list_item(self, node):
+        if node.next_node(descend=False, siblings=True) is not None:
+            self.out.append('\n')                # TODO: just pass?
+
+    def visit_description(self, node):
+        self.out.append(' ')
+
+    def depart_description(self, node):
+        pass
+
+    def visit_docinfo(self, node):
+        self.push_output_collector(self.docinfo)
+
+    def depart_docinfo(self, node):
+        self.pop_output_collector()
+        # Some itmes (e.g. author) end up at other places
+        if self.docinfo:
+            # tabularx: automatic width of columns, no page breaks allowed.
+            self.requirements['tabularx'] = r'\usepackage{tabularx}'
+            if not self.fallback_stylesheet:
+                self.fallbacks['_providelength'] = PreambleCmds.providelength
+                self.fallbacks['docinfo'] = PreambleCmds.docinfo
+            #
+            self.docinfo.insert(0, '\n% Docinfo\n'
+                                '\\begin{center}\n'
+                                '\\begin{tabularx}{\\DUdocinfowidth}{lX}\n')
+            self.docinfo.append('\\end{tabularx}\n'
+                                '\\end{center}\n')
+
+    def visit_docinfo_item(self, node, name):
+        if self.use_latex_docinfo:
+            if name in ('author', 'organization', 'contact', 'address'):
+                # We attach these to the last author.  If any of them precedes
+                # the first author, put them in a separate "author" group
+                # (in lack of better semantics).
+                if name == 'author' or not self.author_stack:
+                    self.author_stack.append([])
+                if name == 'address':   # newlines are meaningful
+                    self.insert_newline = True
+                    text = self.encode(node.astext())
+                    self.insert_newline = False
+                else:
+                    text = self.attval(node.astext())
+                self.author_stack[-1].append(text)
+                raise nodes.SkipNode
+            elif name == 'date':
+                self.date.append(self.attval(node.astext()))
+                raise nodes.SkipNode
+        self.out.append('\\textbf{%s}: &\n\t' % self.language_label(name))
+        if name == 'address':
+            self.insert_newline = True
+            self.out.append('{\\raggedright\n')
+            self.context.append(' } \\\\\n')
+        else:
+            self.context.append(' \\\\\n')
+
+    def depart_docinfo_item(self, node):
+        self.out.append(self.context.pop())
+        # for address we did set insert_newline
+        self.insert_newline = False
+
+    def visit_doctest_block(self, node):
+        self.visit_literal_block(node)
+
+    def depart_doctest_block(self, node):
+        self.depart_literal_block(node)
+
+    def visit_document(self, node):
+        # titled document?
+        if (self.use_latex_docinfo or len(node)
+            and isinstance(node[0], nodes.title)):
+            protect = (self.settings.documentclass == 'memoir')
+            self.title_labels += self.ids_to_labels(node, set_anchor=False,
+                                                    protect=protect)
+
+    def depart_document(self, node):
+        # Complete "parts" with information gained from walkabout
+        # * language setup
+        if (self.babel.otherlanguages
+            or self.babel.language not in ('', 'english')):
+            self.requirements['babel'] = self.babel()
+        # * conditional requirements (before style sheet)
+        self.requirements = self.requirements.sortedvalues()
+        # * coditional fallback definitions (after style sheet)
+        self.fallbacks = self.fallbacks.sortedvalues()
+        # * PDF properties
+        self.pdfsetup.append(PreambleCmds.linking % self.hyperref_options)
+        if self.pdfauthor:
+            authors = self.author_separator.join(self.pdfauthor)
+            self.pdfinfo.append('  pdfauthor={%s}' % authors)
+        if self.pdfinfo:
+            self.pdfsetup += [r'\hypersetup{'] + self.pdfinfo + ['}']
+        # * title (including author(s) and date if using "latex_docinfo")
+        if self.title or (self.use_latex_docinfo
+                          and (self.author_stack or self.date)):
+            self.make_title()  # see below
+        # * bibliography
+        if self._bibitems:
+            self.append_bibliogaphy()  # see below
+        # * make sure to generate a toc file if needed for local contents:
+        if 'minitoc' in self.requirements and not self.has_latex_toc:
+            self.out.append('\n\\faketableofcontents % for local ToCs\n')
+
+    def make_title(self):
+        # Auxiliary function called by `self.depart_document()`.
+        #
+        # Append ``\title``, ``\author``, and ``\date`` to "titledata".
+        # (We need all three, even if empty, to prevent errors
+        # and/or automatic display of the current date by \maketitle.)
+        # Append ``\maketitle`` to "body_pre_docinfo" parts.
+        #
+        # \title
+        title_arg = [''.join(self.title)]  # ensure len == 1
+        if self.title:
+            title_arg += self.title_labels
+        if self.subtitle:
+            title_arg += [r'\\',
+                          r'\DUdocumentsubtitle{%s}' % ''.join(self.subtitle),
+                          ] + self.subtitle_labels
+        self.titledata.append(r'\title{%s}' % '%\n  '.join(title_arg))
+        # \author
+        author_arg = ['\\\\\n'.join(author_entry)
+                      for author_entry in self.author_stack]
+        self.titledata.append(r'\author{%s}' %
+                              ' \\and\n'.join(author_arg))
+        # \date
+        self.titledata.append(r'\date{%s}' % ', '.join(self.date))
+        # \maketitle
+        # Must be in the document body. We add it to `body_pre_docinfo`
+        # to allow templates to put `titledata` into the document preamble.
+        self.body_pre_docinfo.append('\\maketitle\n')
+
+    def append_bibliogaphy(self):
+        # Add bibliography at end of document.
+        # TODO insertion point should be configurable.
+        # Auxiliary function called by `depart_document`.
+        if self.bibtex:
+            self.out.append('\n\\bibliographystyle{%s}\n' % self.bibtex[0])
+            self.out.append('\\bibliography{%s}\n' % ','.join(self.bibtex[1:]))
+        elif self.use_latex_citations:
+            # TODO: insert citations at point of definition.
+            widest_label = ''
+            for bibitem in self._bibitems:
+                if len(widest_label) < len(bibitem[0]):
+                    widest_label = bibitem[0]
+            self.out.append('\n\\begin{thebibliography}{%s}\n' %
+                            widest_label)
+            for bibitem in self._bibitems:
+                # cite_key: underscores must not be escaped
+                cite_key = bibitem[0].replace(r'\_', '_')
+                self.out.append('\\bibitem[%s]{%s}{%s}\n' %
+                                (bibitem[0], cite_key, bibitem[1]))
+            self.out.append('\\end{thebibliography}\n')
+
+    def visit_emphasis(self, node):
+        self.out.append('\\emph{')
+        self.visit_inline(node)
+
+    def depart_emphasis(self, node):
+        self.depart_inline(node)
+        self.out.append('}')
+
+    # Append column delimiters and advance column counter,
+    # if the current cell is a multi-row continuation."""
+    def insert_additional_table_colum_delimiters(self):
+        while self.active_table.get_rowspan(
+                                self.active_table.get_entry_number()):
+            self.out.append(' & ')
+            self.active_table.visit_entry()  # increment cell count
+
+    def visit_entry(self, node):
+        # cell separation
+        if self.active_table.get_entry_number() == 0:
+            self.insert_additional_table_colum_delimiters()
+        else:
+            self.out.append(' & ')
+
+        # multirow, multicolumn
+        if 'morerows' in node and 'morecols' in node:
+            raise NotImplementedError('Cells that span multiple rows *and* '
+                                      'columns currently not supported '
+                                      'by the LaTeX writer')
+            # TODO: should be possible with LaTeX, see e.g.
+            # http://texblog.org/2012/12/21/multi-column-and-multi-row-cells-in-latex-tables/
+        # multirow in LaTeX simply will enlarge the cell over several rows
+        # (the following n if n is positive, the former if negative).
+        if 'morerows' in node:
+            self.requirements['multirow'] = r'\usepackage{multirow}'
+            mrows = node['morerows'] + 1
+            self.active_table.set_rowspan(
+                            self.active_table.get_entry_number(), mrows)
+            self.out.append('\\multirow{%d}{%s}{' %
+                            (mrows, self.active_table.get_column_width()))
+            self.context.append('}')
+        elif 'morecols' in node:
+            # the vertical bar before column is missing if it is the first
+            # column. the one after always.
+            if self.active_table.get_entry_number() == 0:
+                bar1 = self.active_table.get_vertical_bar()
+            else:
+                bar1 = ''
+            mcols = node['morecols'] + 1
+            self.out.append('\\multicolumn{%d}{%s%s%s}{' %
+                            (mcols,
+                             bar1,
+                             self.active_table.get_multicolumn_width(
+                                 self.active_table.get_entry_number(), mcols),
+                             self.active_table.get_vertical_bar()))
+            self.context.append('}')
+        else:
+            self.context.append('')
+
+        # bold header/stub-column
+        if len(node) and (isinstance(node.parent.parent, nodes.thead)
+                          or self.active_table.is_stub_column()):
+            self.out.append('\\textbf{')
+            self.context.append('}')
+        else:
+            self.context.append('')
+
+        # if line ends with '{', mask line break
+        if (not self.active_table.colwidths_auto
+            and self.out[-1].endswith("{")
+            and node.astext()):
+            self.out.append("%")
+
+        self.active_table.visit_entry()  # increment cell count
+
+    def depart_entry(self, node):
+        self.out.append(self.context.pop())  # header / not header
+        self.out.append(self.context.pop())  # multirow/column
+        # insert extra "&"s, if following rows are spanned from above:
+        self.insert_additional_table_colum_delimiters()
+
+    def visit_row(self, node):
+        self.active_table.visit_row()
+
+    def depart_row(self, node):
+        self.out.extend(self.active_table.depart_row())
+
+    def visit_enumerated_list(self, node):
+        # enumeration styles:
+        types = {'': '',
+                 'arabic': 'arabic',
+                 'loweralpha': 'alph',
+                 'upperalpha': 'Alph',
+                 'lowerroman': 'roman',
+                 'upperroman': 'Roman'}
+        # default LaTeX enumeration labels:
+        default_labels = [
+                          # (präfix, enumtype, suffix)
+                          ('',  'arabic', '.'),  # 1.
+                          ('(', 'alph',   ')'),  # (a)
+                          ('',  'roman',  '.'),  # i.
+                          ('',  'Alph',   '.')]  # A.
+
+        prefix = ''
+        if self.compound_enumerators:
+            if (self.section_prefix_for_enumerators and self.section_level
+                and not self._enumeration_counters):
+                prefix = '.'.join(str(n) for n in
+                                  self._section_number[:self.section_level]
+                                  ) + self.section_enumerator_separator
+            if self._enumeration_counters:
+                prefix += self._enumeration_counters[-1]
+        prefix += node.get('prefix', '')
+        enumtype = types[node.get('enumtype', 'arabic')]
+        suffix = node.get('suffix', '.')
+
+        enum_level = len(self._enumeration_counters)+1
+        counter_name = 'enum' + roman.toRoman(enum_level).lower()
+        label = r'%s\%s{%s}%s' % (prefix, enumtype, counter_name, suffix)
+        self._enumeration_counters.append(label)
+
+        self.duclass_open(node)
+        if enum_level <= 4:
+            self.out.append('\\begin{enumerate}')
+            if (prefix, enumtype, suffix) != default_labels[enum_level-1]:
+                self.out.append('\n\\renewcommand{\\label%s}{%s}' %
+                                (counter_name, label))
+        else:
+            self.fallbacks[counter_name] = '\\newcounter{%s}' % counter_name
+            self.out.append('\\begin{list}')
+            self.out.append('{%s}' % label)
+            self.out.append('{\\usecounter{%s}}' % counter_name)
+        if 'start' in node:
+            self.out.append('\n\\setcounter{%s}{%d}' %
+                            (counter_name, node['start']-1))
+
+    def depart_enumerated_list(self, node):
+        if len(self._enumeration_counters) <= 4:
+            self.out.append('\\end{enumerate}\n')
+        else:
+            self.out.append('\\end{list}\n')
+        self.duclass_close(node)
+        self._enumeration_counters.pop()
+
+    def visit_field(self, node):
+        # output is done in field_body, field_name
+        pass
+
+    def depart_field(self, node):
+        pass
+
+    def visit_field_body(self, node):
+        if not isinstance(node.parent.parent, nodes.docinfo):
+            self.out.append(self.term_postfix(node))
+
+    def depart_field_body(self, node):
+        if self.out is self.docinfo:
+            self.out.append(r'\\'+'\n')
+
+    def visit_field_list(self, node):
+        self.duclass_open(node)
+        if self.out is not self.docinfo:
+            if not self.fallback_stylesheet:
+                self.fallbacks['fieldlist'] = PreambleCmds.fieldlist
+            self.out.append('\\begin{DUfieldlist}')
+
+    def depart_field_list(self, node):
+        if self.out is not self.docinfo:
+            self.out.append('\\end{DUfieldlist}\n')
+        self.duclass_close(node)
+
+    def visit_field_name(self, node):
+        if self.out is self.docinfo:
+            self.out.append('\\textbf{')
+        else:
+            # Commands with optional args inside an optional arg must be put
+            # in a group, e.g. ``\item[{\hyperref[label]{text}}]``.
+            self.out.append('\n\\item[{')
+
+    def depart_field_name(self, node):
+        if self.out is self.docinfo:
+            self.out.append('}: &')
+        else:
+            self.out.append(':}]')
+
+    def visit_figure(self, node):
+        self.requirements['float'] = PreambleCmds.float
+        self.duclass_open(node)
+        # The 'align' attribute sets the "outer alignment",
+        # for "inner alignment" use LaTeX default alignment (similar to HTML)
+        alignment = node.attributes.get('align', 'center')
+        if alignment != 'center':
+            # The LaTeX "figure" environment always uses the full linewidth,
+            # so "outer alignment" is ignored. Just write a comment.
+            # TODO: use the wrapfigure environment?
+            self.out.append('\\begin{figure} %% align = "%s"\n' % alignment)
+        else:
+            self.out.append('\\begin{figure}\n')
+        self.out += self.ids_to_labels(node, newline=True)
+
+    def depart_figure(self, node):
+        self.out.append('\\end{figure}\n')
+        self.duclass_close(node)
+
+    def visit_footer(self, node):
+        self.push_output_collector([])
+        self.out.append(r'\newcommand{\DUfooter}{')
+
+    def depart_footer(self, node):
+        self.out.append('}')
+        self.requirements['~footer'] = ''.join(self.out)
+        self.pop_output_collector()
+
+    def visit_footnote(self, node):
+        try:
+            backref = node['backrefs'][0]
+        except IndexError:
+            backref = node['ids'][0]  # no backref, use self-ref instead
+        if self.docutils_footnotes:
+            if not self.fallback_stylesheet:
+                self.fallbacks['footnotes'] = PreambleCmds.footnotes
+            num = node[0].astext()
+            if self.settings.footnote_references == 'brackets':
+                num = '[%s]' % num
+            self.out.append('%%\n\\DUfootnotetext{%s}{%s}{%s}{' %
+                            (node['ids'][0], backref, self.encode(num)))
+            if node['ids'] == node['names']:
+                self.out += self.ids_to_labels(node)
+            # prevent spurious whitespace if footnote starts with paragraph:
+            if len(node) > 1 and isinstance(node[1], nodes.paragraph):
+                self.out.append('%')
+        # TODO: "real" LaTeX \footnote{}s (see visit_footnotes_reference())
+
+    def depart_footnote(self, node):
+        self.out.append('}\n')
+
+    def visit_footnote_reference(self, node):
+        href = ''
+        if 'refid' in node:
+            href = node['refid']
+        elif 'refname' in node:
+            href = self.document.nameids[node['refname']]
+        # if not self.docutils_footnotes:
+        #     # TODO: insert footnote content at (or near) this place
+        #     #       see also docs/dev/todo.txt
+        #     try:
+        #         referenced_node = self.document.ids[node['refid']]
+        #     except (AttributeError, KeyError):
+        #         self.document.reporter.error(
+        #             'unresolved footnote-reference %s' % node)
+        #     print('footnote-ref to %s' % referenced_node)
+        format = self.settings.footnote_references
+        if format == 'brackets':
+            self.append_hypertargets(node)
+            self.out.append('\\hyperlink{%s}{[' % href)
+            self.context.append(']}')
+        else:
+            if not self.fallback_stylesheet:
+                self.fallbacks['footnotes'] = PreambleCmds.footnotes
+            self.out.append(r'\DUfootnotemark{%s}{%s}{' %
+                            (node['ids'][0], href))
+            self.context.append('}')
+
+    def depart_footnote_reference(self, node):
+        self.out.append(self.context.pop())
+
+    # footnote/citation label
+    def label_delim(self, node, bracket, superscript):
+        if isinstance(node.parent, nodes.footnote):
+            raise nodes.SkipNode
+        else:
+            assert isinstance(node.parent, nodes.citation)
+            if not self.use_latex_citations:
+                self.out.append(bracket)
+
+    def visit_label(self, node):
+        """footnote or citation label: in brackets or as superscript"""
+        self.label_delim(node, '[', '\\textsuperscript{')
+
+    def depart_label(self, node):
+        self.label_delim(node, ']', '}')
+
+    # elements generated by the framework e.g. section numbers.
+    def visit_generated(self, node):
+        pass
+
+    def depart_generated(self, node):
+        pass
+
+    def visit_header(self, node):
+        self.push_output_collector([])
+        self.out.append(r'\newcommand{\DUheader}{')
+
+    def depart_header(self, node):
+        self.out.append('}')
+        self.requirements['~header'] = ''.join(self.out)
+        self.pop_output_collector()
+
+    def to_latex_length(self, length_str, pxunit=None):
+        """Convert `length_str` with rst length to LaTeX length
+        """
+        if pxunit is not None:
+            warnings.warn(
+                'The optional argument `pxunit` '
+                'of LaTeXTranslator.to_latex_length() is ignored '
+                'and will be removed in Docutils 0.21 or later',
+                DeprecationWarning, stacklevel=2)
+        match = re.match(r'(\d*\.?\d*)\s*(\S*)', length_str)
+        if not match:
+            return length_str
+        value, unit = match.groups()[:2]
+        # no unit or "DTP" points (called 'bp' in TeX):
+        if unit in ('', 'pt'):
+            length_str = '%sbp' % value
+        # percentage: relate to current line width
+        elif unit == '%':
+            length_str = '%.3f\\linewidth' % (float(value)/100.0)
+        elif self.is_xetex and unit == 'px':
+            # XeTeX does not know the length unit px.
+            # Use \pdfpxdimen, the macro to set the value of 1 px in pdftex.
+            # This way, configuring works the same for pdftex and xetex.
+            if not self.fallback_stylesheet:
+                self.fallbacks['_providelength'] = PreambleCmds.providelength
+            self.fallbacks['px'] = '\n\\DUprovidelength{\\pdfpxdimen}{1bp}\n'
+            length_str = r'%s\pdfpxdimen' % value
+        return length_str
+
+    def visit_image(self, node):
+        self.requirements['graphicx'] = self.graphicx_package
+        attrs = node.attributes
+        # Convert image URI to a local file path
+        imagepath = url2pathname(attrs['uri']).replace('\\', '/')
+        # alignment defaults:
+        if 'align' not in attrs:
+            # Set default align of image in a figure to 'center'
+            if isinstance(node.parent, nodes.figure):
+                attrs['align'] = 'center'
+            self.set_align_from_classes(node)
+        # pre- and postfix (prefix inserted in reverse order)
+        pre = []
+        post = []
+        include_graphics_options = []
+        align_codes = {
+            # inline images: by default latex aligns the bottom.
+            'bottom': ('', ''),
+            'middle': (r'\raisebox{-0.5\height}{', '}'),
+            'top':    (r'\raisebox{-\height}{', '}'),
+            # block level images:
+            'center': (r'\noindent\makebox[\linewidth][c]{', '}'),
+            'left':   (r'\noindent{', r'\hfill}'),
+            'right':  (r'\noindent{\hfill', '}'),
+            }
+        if 'align' in attrs:
+            # TODO: warn or ignore non-applicable alignment settings?
+            try:
+                align_code = align_codes[attrs['align']]
+                pre.append(align_code[0])
+                post.append(align_code[1])
+            except KeyError:
+                pass                    # TODO: warn?
+        if 'height' in attrs:
+            include_graphics_options.append(
+                'height=%s' % self.to_latex_length(attrs['height']))
+        if 'scale' in attrs:
+            include_graphics_options.append(
+                'scale=%f' % (attrs['scale'] / 100.0))
+        if 'width' in attrs:
+            include_graphics_options.append(
+                'width=%s' % self.to_latex_length(attrs['width']))
+        if not (self.is_inline(node)
+                or isinstance(node.parent, (nodes.figure, nodes.compound))):
+            pre.append('\n')
+        if not (self.is_inline(node)
+                or isinstance(node.parent, nodes.figure)):
+            post.append('\n')
+        pre.reverse()
+        self.out.extend(pre)
+        options = ''
+        if include_graphics_options:
+            options = '[%s]' % (','.join(include_graphics_options))
+        self.out.append('\\includegraphics%s{%s}' % (options, imagepath))
+        self.out.extend(post)
+
+    def depart_image(self, node):
+        self.out += self.ids_to_labels(node, newline=True)
+
+    def visit_inline(self, node):  # <span>, i.e. custom roles
+        for cls in node['classes']:
+            if cls.startswith('language-'):
+                language = self.babel.language_name(cls[9:])
+                if language:
+                    self.babel.otherlanguages[language] = True
+                    self.out.append(r'\foreignlanguage{%s}{' % language)
+            else:
+                if not self.fallback_stylesheet:
+                    self.fallbacks['inline'] = PreambleCmds.inline
+                self.out.append(r'\DUrole{%s}{' % cls)
+
+    def depart_inline(self, node):
+        self.out.append('}' * len(node['classes']))
+
+    def visit_legend(self, node):
+        if not self.fallback_stylesheet:
+            self.fallbacks['legend'] = PreambleCmds.legend
+        self.out.append('\\begin{DUlegend}')
+
+    def depart_legend(self, node):
+        self.out.append('\\end{DUlegend}\n')
+
+    def visit_line(self, node):
+        self.out.append(r'\item[] ')
+
+    def depart_line(self, node):
+        self.out.append('\n')
+
+    def visit_line_block(self, node):
+        if not self.fallback_stylesheet:
+            self.fallbacks['_providelength'] = PreambleCmds.providelength
+            self.fallbacks['lineblock'] = PreambleCmds.lineblock
+        self.set_align_from_classes(node)
+        if isinstance(node.parent, nodes.line_block):
+            self.out.append('\\item[]\n'
+                            '\\begin{DUlineblock}{\\DUlineblockindent}\n')
+            # nested line-blocks cannot be given class arguments
+        else:
+            self.duclass_open(node)
+            self.out.append('\\begin{DUlineblock}{0em}\n')
+            self.insert_align_declaration(node)
+
+    def depart_line_block(self, node):
+        self.out.append('\\end{DUlineblock}\n')
+        self.duclass_close(node)
+
+    def visit_list_item(self, node):
+        self.out.append('\n\\item ')
+
+    def depart_list_item(self, node):
+        pass
+
+    def visit_literal(self, node):
+        self.literal = True
+        if ('code' in node['classes']
+            and self.settings.syntax_highlight != 'none'):
+            self.requirements['color'] = PreambleCmds.color
+            if not self.fallback_stylesheet:
+                self.fallbacks['code'] = PreambleCmds.highlight_rules
+        self.out.append('\\texttt{')
+        self.visit_inline(node)
+
+    def depart_literal(self, node):
+        self.literal = False
+        self.depart_inline(node)
+        self.out.append('}')
+
+    # Literal blocks are used for '::'-prefixed literal-indented
+    # blocks of text, where the inline markup is not recognized,
+    # but are also the product of the "parsed-literal" directive,
+    # where the markup is respected.
+    #
+    # In both cases, we want to use a typewriter/monospaced typeface.
+    # For "real" literal-blocks, we can use \verbatim, while for all
+    # the others we must use \ttfamily and \raggedright.
+    #
+    # We can distinguish between the two kinds by the number of
+    # siblings that compose this node: if it is composed by a
+    # single element, it's either
+    # * a real one,
+    # * a parsed-literal that does not contain any markup, or
+    # * a parsed-literal containing just one markup construct.
+    def is_plaintext(self, node):
+        """Check whether a node can be typeset verbatim"""
+        return (len(node) == 1) and isinstance(node[0], nodes.Text)
+
+    def visit_literal_block(self, node):
+        """Render a literal block.
+
+        Corresponding rST elements: literal block, parsed-literal, code.
+        """
+        packages = {'lstlisting':  r'\usepackage{listings}' '\n'
+                                   r'\lstset{xleftmargin=\leftmargin}',
+                    'listing': r'\usepackage{moreverb}',
+                    'Verbatim': r'\usepackage{fancyvrb}',
+                    'verbatimtab': r'\usepackage{moreverb}'}
+
+        literal_env = self.literal_block_env
+
+        # Check, if it is possible to use a literal-block environment
+        _plaintext = self.is_plaintext(node)
+        _in_table = self.active_table.is_open()
+        # TODO: fails if normal text precedes the literal block.
+        #       Check parent node instead?
+        _autowidth_table = _in_table and self.active_table.colwidths_auto
+        _no_env_nodes = (nodes.footnote, nodes.sidebar)
+        if self.settings.legacy_class_functions:
+            _no_env_nodes += (nodes.admonition, nodes.system_message)
+        _use_env = _plaintext and not isinstance(node.parent, _no_env_nodes)
+        _use_listings = (literal_env == 'lstlisting') and _use_env
+
+        # Labels and classes:
+        self.duclass_open(node)
+        self.out += self.ids_to_labels(node, newline=True)
+        # Highlight code?
+        if (not _plaintext
+            and 'code' in node['classes']
+            and self.settings.syntax_highlight != 'none'):
+            self.requirements['color'] = PreambleCmds.color
+            if not self.fallback_stylesheet:
+                self.fallbacks['code'] = PreambleCmds.highlight_rules
+        # Wrap?
+        if _in_table and _use_env and not _autowidth_table:
+            # Wrap in minipage to prevent extra vertical space
+            # with alltt and verbatim-like environments:
+            self.fallbacks['ttem'] = PreambleCmds.ttem
+            self.out.append(
+                '\\begin{minipage}{%d\\ttemwidth}\n' %
+                (max(len(line) for line in node.astext().split('\n'))))
+            self.context.append('\n\\end{minipage}\n')
+        elif not _in_table and not _use_listings:
+            # Wrap in quote to set off vertically and indent
+            self.out.append('\\begin{quote}\n')
+            self.context.append('\n\\end{quote}\n')
+        else:
+            self.context.append('\n')
+
+        # Use verbatim-like environment, if defined and possible
+        # (in an auto-width table, only listings works):
+        if literal_env and _use_env and (not _autowidth_table
+                                         or _use_listings):
+            try:
+                self.requirements['literal_block'] = packages[literal_env]
+            except KeyError:
+                pass
+            self.verbatim = True
+            if _in_table and _use_listings:
+                self.out.append('\\lstset{xleftmargin=0pt}\n')
+            self.out.append('\\begin{%s}%s\n' %
+                            (literal_env, self.literal_block_options))
+            self.context.append('\n\\end{%s}' % literal_env)
+        elif _use_env and not _autowidth_table:
+            self.alltt = True
+            self.requirements['alltt'] = r'\usepackage{alltt}'
+            self.out.append('\\begin{alltt}\n')
+            self.context.append('\n\\end{alltt}')
+        else:
+            self.literal = True
+            self.insert_newline = True
+            self.insert_non_breaking_blanks = True
+            # \raggedright ensures leading blanks are respected but
+            # leads to additional leading vspace if the first line
+            # of the block is overfull :-(
+            self.out.append('\\ttfamily\\raggedright\n')
+            self.context.append('')
+
+    def depart_literal_block(self, node):
+        self.insert_non_breaking_blanks = False
+        self.insert_newline = False
+        self.literal = False
+        self.verbatim = False
+        self.alltt = False
+        self.out.append(self.context.pop())
+        self.out.append(self.context.pop())
+        self.duclass_close(node)
+
+    def visit_meta(self, node):
+        name = node.attributes.get('name')
+        content = node.attributes.get('content')
+        if not name or not content:
+            return
+        if name in ('author', 'creator', 'keywords', 'subject', 'title'):
+            # fields with dedicated hyperref options:
+            self.pdfinfo.append('  pdf%s={%s},'%(name, content))
+        elif name == 'producer':
+            self.pdfinfo.append('  addtopdfproducer={%s},'%content)
+        else:
+            # generic interface (case sensitive!)
+            # TODO: filter irrelevant nodes ("http-equiv", ...)?
+            self.pdfinfo.append('  pdfinfo={%s={%s}},'%(name, content))
+
+    def depart_meta(self, node):
+        pass
+
+    def visit_math(self, node, math_env='$'):
+        """math role"""
+        self.visit_inline(node)
+        self.requirements['amsmath'] = r'\usepackage{amsmath}'
+        math_code = node.astext().translate(unichar2tex.uni2tex_table)
+        if math_env == '$':
+            if self.alltt:
+                wrapper = ['\\(', '\\)']
+            else:
+                wrapper = ['$', '$']
+        else:
+            labels = self.ids_to_labels(node, set_anchor=False, newline=True)
+            wrapper = ['%%\n\\begin{%s}\n' % math_env,
+                       '\n',
+                       ''.join(labels),
+                       '\\end{%s}' % math_env]
+        wrapper.insert(1, math_code)
+        self.out.extend(wrapper)
+        self.depart_inline(node)
+        # Content already processed:
+        raise nodes.SkipNode
+
+    def depart_math(self, node):
+        pass  # never reached
+
+    def visit_math_block(self, node):
+        math_env = pick_math_environment(node.astext())
+        self.visit_math(node, math_env=math_env)
+
+    def depart_math_block(self, node):
+        pass  # never reached
+
+    def visit_option(self, node):
+        if self.context[-1]:
+            # this is not the first option
+            self.out.append(', ')
+
+    def depart_option(self, node):
+        # flag that the first option is done.
+        self.context[-1] += 1
+
+    def visit_option_argument(self, node):
+        """Append the delimiter between an option and its argument to body."""
+        self.out.append(node.get('delimiter', ' '))
+
+    def depart_option_argument(self, node):
+        pass
+
+    def visit_option_group(self, node):
+        self.out.append('\\item[')
+        # flag for first option
+        self.context.append(0)
+
+    def depart_option_group(self, node):
+        self.context.pop()  # the flag
+        self.out.append('] ')
+
+    def visit_option_list(self, node):
+        if not self.fallback_stylesheet:
+            self.fallbacks['_providelength'] = PreambleCmds.providelength
+            self.fallbacks['optionlist'] = PreambleCmds.optionlist
+        self.duclass_open(node)
+        self.out.append('\\begin{DUoptionlist}\n')
+
+    def depart_option_list(self, node):
+        self.out.append('\\end{DUoptionlist}\n')
+        self.duclass_close(node)
+
+    def visit_option_list_item(self, node):
+        pass
+
+    def depart_option_list_item(self, node):
+        pass
+
+    def visit_option_string(self, node):
+        ## self.out.append(self.starttag(node, 'span', '', CLASS='option'))
+        pass
+
+    def depart_option_string(self, node):
+        ## self.out.append('</span>')
+        pass
+
+    def visit_organization(self, node):
+        self.visit_docinfo_item(node, 'organization')
+
+    def depart_organization(self, node):
+        self.depart_docinfo_item(node)
+
+    def visit_paragraph(self, node):
+        # insert blank line, unless
+        # * the paragraph is first in a list item, compound, or container
+        # * follows a non-paragraph node in a compound,
+        # * is in a table with auto-width columns
+        index = node.parent.index(node)
+        if index == 0 and isinstance(node.parent,
+                                     (nodes.list_item, nodes.description,
+                                      nodes.compound, nodes.container)):
+            pass
+        elif (index > 0
+              and isinstance(node.parent, nodes.compound)
+              and not isinstance(node.parent[index - 1],
+                                 (nodes.paragraph, nodes.compound))):
+            pass
+        elif self.active_table.colwidths_auto:
+            if index == 1:  # second paragraph
+                self.warn('LaTeX merges paragraphs in tables '
+                          'with auto-sized columns!', base_node=node)
+            if index > 0:
+                self.out.append('\n')
+        else:
+            self.out.append('\n')
+        self.out += self.ids_to_labels(node, newline=True)
+        self.visit_inline(node)
+
+    def depart_paragraph(self, node):
+        self.depart_inline(node)
+        if not self.active_table.colwidths_auto:
+            self.out.append('\n')
+
+    def visit_problematic(self, node):
+        self.requirements['color'] = PreambleCmds.color
+        self.out.append('%\n')
+        self.append_hypertargets(node)
+        self.out.append(r'\hyperlink{%s}{\textbf{\color{red}' % node['refid'])
+
+    def depart_problematic(self, node):
+        self.out.append('}}')
+
+    def visit_raw(self, node):
+        if 'latex' not in node.get('format', '').split():
+            raise nodes.SkipNode
+        if not (self.is_inline(node)
+                or isinstance(node.parent, nodes.compound)):
+            self.out.append('\n')
+        self.visit_inline(node)
+        # append "as-is" skipping any LaTeX-encoding
+        self.verbatim = True
+
+    def depart_raw(self, node):
+        self.verbatim = False
+        self.depart_inline(node)
+        if not self.is_inline(node):
+            self.out.append('\n')
+
+    def has_unbalanced_braces(self, string):
+        """Test whether there are unmatched '{' or '}' characters."""
+        level = 0
+        for ch in string:
+            if ch == '{':
+                level += 1
+            if ch == '}':
+                level -= 1
+            if level < 0:
+                return True
+        return level != 0
+
+    def visit_reference(self, node):
+        # We need to escape #, \, and % if we use the URL in a command.
+        special_chars = {ord('#'): '\\#',
+                         ord('%'): '\\%',
+                         ord('\\'): '\\\\',
+                         }
+        # external reference (URL)
+        if 'refuri' in node:
+            href = str(node['refuri']).translate(special_chars)
+            # problematic chars double caret and unbalanced braces:
+            if href.find('^^') != -1 or self.has_unbalanced_braces(href):
+                self.error(
+                    f'External link "{href}" not supported by LaTeX.\n'
+                    ' (Must not contain "^^" or unbalanced braces.)')
+            if node['refuri'] == node.astext():
+                self.out.append(r'\url{%s}' % href)
+                raise nodes.SkipNode
+            self.out.append(r'\href{%s}{' % href)
+            return
+        # internal reference
+        if 'refid' in node:
+            href = node['refid']
+        elif 'refname' in node:
+            href = self.document.nameids[node['refname']]
+        else:
+            raise AssertionError('Unknown reference.')
+        if not self.is_inline(node):
+            self.out.append('\n')
+        self.out.append('\\hyperref[%s]{' % href)
+        if self.reference_label:
+            # TODO: don't use \hyperref if self.reference_label is True
+            self.out.append('\\%s{%s}}' %
+                            (self.reference_label, href.replace('#', '')))
+            raise nodes.SkipNode
+
+    def depart_reference(self, node):
+        self.out.append('}')
+        if not self.is_inline(node):
+            self.out.append('\n')
+
+    def visit_revision(self, node):
+        self.visit_docinfo_item(node, 'revision')
+
+    def depart_revision(self, node):
+        self.depart_docinfo_item(node)
+
+    def visit_rubric(self, node):
+        if not self.fallback_stylesheet:
+            self.fallbacks['rubric'] = PreambleCmds.rubric
+        # class wrapper would interfere with ``\section*"`` type commands
+        # (spacing/indent of first paragraph)
+        self.out.append('\n\\DUrubric{')
+
+    def depart_rubric(self, node):
+        self.out.append('}\n')
+
+    def visit_section(self, node):
+        self.section_level += 1
+        # Initialize counter for potential subsections:
+        self._section_number.append(0)
+        # Counter for this section's level (initialized by parent section):
+        self._section_number[self.section_level - 1] += 1
+
+    def depart_section(self, node):
+        # Remove counter for potential subsections:
+        self._section_number.pop()
+        self.section_level -= 1
+
+    def visit_sidebar(self, node):
+        self.duclass_open(node)
+        self.requirements['color'] = PreambleCmds.color
+        if not self.fallback_stylesheet:
+            self.fallbacks['sidebar'] = PreambleCmds.sidebar
+        self.out.append('\\DUsidebar{')
+
+    def depart_sidebar(self, node):
+        self.out.append('}\n')
+        self.duclass_close(node)
+
+    attribution_formats = {'dash': ('—', ''),  # EM DASH
+                           'parentheses': ('(', ')'),
+                           'parens': ('(', ')'),
+                           'none': ('', '')}
+
+    def visit_attribution(self, node):
+        prefix, suffix = self.attribution_formats[self.settings.attribution]
+        self.out.append('\\nopagebreak\n\n\\raggedleft ')
+        self.out.append(prefix)
+        self.context.append(suffix)
+
+    def depart_attribution(self, node):
+        self.out.append(self.context.pop() + '\n')
+
+    def visit_status(self, node):
+        self.visit_docinfo_item(node, 'status')
+
+    def depart_status(self, node):
+        self.depart_docinfo_item(node)
+
+    def visit_strong(self, node):
+        self.out.append('\\textbf{')
+        self.visit_inline(node)
+
+    def depart_strong(self, node):
+        self.depart_inline(node)
+        self.out.append('}')
+
+    def visit_substitution_definition(self, node):
+        raise nodes.SkipNode
+
+    def visit_substitution_reference(self, node):
+        self.unimplemented_visit(node)
+
+    def visit_subtitle(self, node):
+        if isinstance(node.parent, nodes.document):
+            self.push_output_collector(self.subtitle)
+            if not self.fallback_stylesheet:
+                self.fallbacks['documentsubtitle'] = PreambleCmds.documentsubtitle  # noqa:E501
+            protect = (self.settings.documentclass == 'memoir')
+            self.subtitle_labels += self.ids_to_labels(node, set_anchor=False,
+                                                       protect=protect)
+        # section subtitle: "starred" (no number, not in ToC)
+        elif isinstance(node.parent, nodes.section):
+            self.out.append(r'\%s*{' %
+                            self.d_class.section(self.section_level + 1))
+        else:
+            if not self.fallback_stylesheet:
+                self.fallbacks['subtitle'] = PreambleCmds.subtitle
+            self.out.append('\n\\DUsubtitle{')
+
+    def depart_subtitle(self, node):
+        if isinstance(node.parent, nodes.document):
+            self.pop_output_collector()
+        else:
+            self.out.append('}\n')
+
+    def visit_system_message(self, node):
+        self.requirements['color'] = PreambleCmds.color
+        if not self.fallback_stylesheet:
+            self.fallbacks['title'] = PreambleCmds.title
+        if self.settings.legacy_class_functions:
+            self.fallbacks['title'] = PreambleCmds.title_legacy
+        node['classes'] = ['system-message']
+        self.visit_admonition(node)
+        if self.settings.legacy_class_functions:
+            self.out.append('\n\\DUtitle[system-message]{system-message\n')
+        else:
+            self.out.append('\n\\DUtitle{system-message\n')
+        self.append_hypertargets(node)
+        try:
+            line = ', line~%s' % node['line']
+        except KeyError:
+            line = ''
+        self.out.append('}\n\n{\\color{red}%s/%s} in \\texttt{%s}%s\n' %
+                        (node['type'], node['level'],
+                         self.encode(node['source']), line))
+        if len(node['backrefs']) == 1:
+            self.out.append('\n\\hyperlink{%s}{' % node['backrefs'][0])
+            self.context.append('}')
+        else:
+            backrefs = ['\\hyperlink{%s}{%d}' % (href, i+1)
+                        for (i, href) in enumerate(node['backrefs'])]
+            self.context.append('backrefs: ' + ' '.join(backrefs))
+
+    def depart_system_message(self, node):
+        self.out.append(self.context.pop())
+        self.depart_admonition(node)
+
+    def visit_table(self, node):
+        self.duclass_open(node)
+        self.requirements['table'] = PreambleCmds.table
+        if not self.settings.legacy_column_widths:
+            self.requirements['table1'] = PreambleCmds.table_columnwidth
+        if self.active_table.is_open():
+            self.table_stack.append(self.active_table)
+            # nesting longtable does not work (e.g. 2007-04-18)
+            self.active_table = Table(self, 'tabular')
+        # A longtable moves before \paragraph and \subparagraph
+        # section titles if it immediately follows them:
+        if (self.active_table._latex_type == 'longtable'
+            and isinstance(node.parent, nodes.section)
+            and node.parent.index(node) == 1
+            and self.d_class.section(
+                   self.section_level).find('paragraph') != -1):
+            self.out.append('\\leavevmode')
+        self.active_table.open()
+        self.active_table.set_table_style(node, self.settings)
+        if self.active_table.borders == 'booktabs':
+            self.requirements['booktabs'] = r'\usepackage{booktabs}'
+        self.push_output_collector([])
+
+    def depart_table(self, node):
+        # wrap content in the right environment:
+        content = self.out
+        self.pop_output_collector()
+        try:
+            width = self.to_latex_length(node['width'])
+        except KeyError:
+            width = r'\linewidth'
+        # Insert hyperlabel and anchor before the table
+        # if it has no caption/title.
+        # See visit_thead() for tables with caption.
+        if not self.active_table.caption:
+            self.out.extend(self.ids_to_labels(
+                node, set_anchor=len(self.table_stack) != 1,
+                newline=True))
+        # TODO: Don't use a longtable or add \noindent before
+        #       the next paragraph, when in a "compound paragraph".
+        #       Start a new line or a new paragraph?
+        #       if (isinstance(node.parent, nodes.compound)
+        #       and self._latex_type != 'longtable')?
+        self.out.append(self.active_table.get_opening(width))
+        self.out += content
+        self.out.append(self.active_table.get_closing() + '\n')
+        self.active_table.close()
+        if len(self.table_stack) > 0:
+            self.active_table = self.table_stack.pop()
+        self.duclass_close(node)
+
+    def visit_target(self, node):
+        # Skip indirect targets:
+        if ('refuri' in node        # external hyperlink
+            or 'refid' in node      # resolved internal link
+            or 'refname' in node):  # unresolved internal link
+            ## self.out.append('%% %s\n' % node)   # for debugging
+            return
+        self.out.append('%\n')
+        # do we need an anchor (\phantomsection)?
+        set_anchor = not isinstance(node.parent, (nodes.caption, nodes.title))
+        # TODO: where else can/must we omit the \phantomsection?
+        self.out += self.ids_to_labels(node, set_anchor)
+
+    def depart_target(self, node):
+        pass
+
+    def visit_tbody(self, node):
+        # BUG write preamble if not yet done (colspecs not [])
+        # for tables without heads.
+        if not self.active_table.get('preamble written'):
+            self.visit_thead(node)
+            self.depart_thead(None)
+
+    def depart_tbody(self, node):
+        pass
+
+    def visit_term(self, node):
+        """definition list term"""
+        # Commands with optional args inside an optional arg must be put
+        # in a group, e.g. ``\item[{\hyperref[label]{text}}]``.
+        self.out.append('\\item[{')
+
+    def depart_term(self, node):
+        self.out.append('}] ')
+        # Do we need a \leavevmode (line break if the field body begins
+        # with a list or environment)?
+        next_node = node.next_node(descend=False, siblings=True)
+        if isinstance(next_node, nodes.term):
+            self.out.append('\n')
+        elif not isinstance(next_node, nodes.classifier):
+            self.out.append(self.term_postfix(next_node))
+
+    def visit_tgroup(self, node):
+        pass
+
+    def depart_tgroup(self, node):
+        pass
+
+    _thead_depth = 0
+
+    def thead_depth(self):
+        return self._thead_depth
+
+    def visit_thead(self, node):
+        self._thead_depth += 1
+        if 1 == self.thead_depth():
+            self.out.append('{%s}\n' % self.active_table.get_colspecs(node))
+            self.active_table.set('preamble written', 1)
+        if self.active_table.caption:
+            if self._thead_depth == 1:
+                pre = [r'\caption{']
+                post = self.ids_to_labels(node.parent.parent, False) + [r'}\\']
+            else:
+                pre = [r'\caption[]{']
+                post = [r' (... continued)}\\']
+            self.out.extend(pre + self.active_table.caption + post + ['\n'])
+        self.out.extend(self.active_table.visit_thead())
+
+    def depart_thead(self, node):
+        if node is not None:
+            self.out.extend(self.active_table.depart_thead())
+            if self.active_table.need_recurse():
+                node.walkabout(self)
+        self._thead_depth -= 1
+
+    def visit_title(self, node):
+        """Append section and other titles."""
+        # Document title
+        if isinstance(node.parent, nodes.document):
+            self.push_output_collector(self.title)
+            self.context.append('')
+            self.pdfinfo.append('  pdftitle={%s},' %
+                                self.encode(node.astext()))
+        # Topic titles (topic, admonition, sidebar)
+        elif (isinstance(node.parent, nodes.topic)
+              or isinstance(node.parent, nodes.admonition)
+              or isinstance(node.parent, nodes.sidebar)):
+            classes = node.parent['classes'] or [node.parent.tagname]
+            if self.settings.legacy_class_functions:
+                self.fallbacks['title'] = PreambleCmds.title_legacy
+                self.out.append('\n\\DUtitle[%s]{' % ','.join(classes))
+            else:
+                if not self.fallback_stylesheet:
+                    self.fallbacks['title'] = PreambleCmds.title
+                self.out.append('\n\\DUtitle{')
+            self.context.append('}\n')
+        # Table caption
+        elif isinstance(node.parent, nodes.table):
+            self.push_output_collector(self.active_table.caption)
+            self.context.append('')
+        # Section title
+        else:
+            if hasattr(PreambleCmds, 'secnumdepth'):
+                self.requirements['secnumdepth'] = PreambleCmds.secnumdepth
+            level = self.section_level
+            section_name = self.d_class.section(level)
+            self.out.append('\n\n')
+            if level > len(self.d_class.sections):
+                # section level not supported by LaTeX
+                if self.settings.legacy_class_functions:
+                    self.fallbacks['title'] = PreambleCmds.title_legacy
+                    section_name += '[section%s]' % roman.toRoman(level)
+                else:
+                    if not self.fallback_stylesheet:
+                        self.fallbacks['title'] = PreambleCmds.title
+                        self.fallbacks['DUclass'] = PreambleCmds.duclass
+                    self.out.append('\\begin{DUclass}{section%s}\n'
+                                    % roman.toRoman(level))
+
+            # System messages heading in red:
+            if 'system-messages' in node.parent['classes']:
+                self.requirements['color'] = PreambleCmds.color
+                section_title = self.encode(node.astext())
+                self.out.append(r'\%s[%s]{\color{red}' % (
+                                section_name, section_title))
+            else:
+                self.out.append(r'\%s{' % section_name)
+
+            # label and ToC entry:
+            bookmark = ['']
+            # add sections with unsupported level to toc and pdfbookmarks?
+            ## if level > len(self.d_class.sections):
+            ##     section_title = self.encode(node.astext())
+            ##     bookmark.append(r'\addcontentsline{toc}{%s}{%s}' %
+            ##               (section_name, section_title))
+            bookmark += self.ids_to_labels(node.parent, set_anchor=False)
+            self.context.append('%\n  '.join(bookmark) + '%\n}\n')
+            if (level > len(self.d_class.sections)
+                and not self.settings.legacy_class_functions):
+                self.context[-1] += '\\end{DUclass}\n'
+            # MAYBE postfix paragraph and subparagraph with \leavevmode to
+            # ensure floats stay in the section and text starts on a new line.
+
+    def depart_title(self, node):
+        self.out.append(self.context.pop())
+        if isinstance(node.parent, (nodes.table, nodes.document)):
+            self.pop_output_collector()
+
+    def visit_contents(self, node):
+        """Write the table of contents.
+
+        Called from visit_topic() for "contents" topics.
+        """
+        # requirements/setup for local ToC with package "minitoc",
+        if self.use_latex_toc and 'local' in node['classes']:
+            section_name = self.d_class.section(self.section_level)
+            # minitoc only supports "part" and toplevel sections
+            minitoc_names = {'part': 'part',
+                             'chapter': 'mini',
+                             'section': 'sect'}
+            if 'chapter' in self.d_class.sections:
+                del minitoc_names['section']
+            try:
+                mtc_name = minitoc_names[section_name]
+            except KeyError:
+                self.warn('Skipping local ToC at "%s" level.\n'
+                          '  Feature not supported with option "use-latex-toc"'
+                          % section_name, base_node=node)
+                raise nodes.SkipNode
+
+        # labels and PDF bookmark (sidebar entry)
+        self.out.append('\n')  # start new paragraph
+        if node['names']:  # don't add labels just for auto-ids
+            self.out += self.ids_to_labels(node, newline=True)
+        if (isinstance(node.next_node(), nodes.title)
+            and 'local' not in node['classes']
+            and self.settings.documentclass != 'memoir'):
+            self.out.append('\\pdfbookmark[%d]{%s}{%s}\n' %
+                            (self.section_level+1,
+                             node.next_node().astext(),
+                             node.get('ids', ['contents'])[0]))
+
+        # Docutils generated contents list (no page numbers)
+        if not self.use_latex_toc:
+            self.fallbacks['toc-list'] = PreambleCmds.toc_list
+            self.duclass_open(node)
+            return
+
+        # ToC by LaTeX
+        depth = node.get('depth', 0)
+        maxdepth = len(self.d_class.sections)
+        if isinstance(node.next_node(), nodes.title):
+            title = self.encode(node[0].astext())
+        else:
+            title = ''
+        if 'local' in node['classes']:
+            # use the "minitoc" package
+            self.requirements['minitoc'] = PreambleCmds.minitoc
+            self.requirements['minitoc-'+mtc_name] = r'\do%stoc'%mtc_name
+            self.requirements['minitoc-%s-depth' % mtc_name] = (
+                r'\mtcsetdepth{%stoc}{%d}' % (mtc_name, maxdepth))
+            # "depth" option: Docutils stores a relative depth while
+            # minitoc  expects an absolute depth!:
+            offset = {'sect': 1, 'mini': 0, 'part': 0}
+            if 'chapter' in self.d_class.sections:
+                offset['part'] = -1
+            if depth:
+                self.out.append('\\setcounter{%stocdepth}{%d}' %
+                                (mtc_name, depth + offset[mtc_name]))
+            # title:
+            self.out.append('\\mtcsettitle{%stoc}{%s}\n' % (mtc_name, title))
+            # the toc-generating command:
+            self.out.append('\\%stoc\n' % mtc_name)
+        else:
+            if depth:
+                self.out.append('\\setcounter{tocdepth}{%d}\n'
+                                % self.d_class.latex_section_depth(depth))
+            if title != 'Contents':
+                self.out.append('\\renewcommand{\\contentsname}{%s}\n' % title)
+            self.out.append('\\tableofcontents\n')
+            self.has_latex_toc = True
+        # ignore rest of node content
+        raise nodes.SkipNode
+
+    def visit_topic(self, node):
+        # Topic nodes can be generic topic, abstract, dedication, or ToC.
+        # table of contents:
+        if 'contents' in node['classes']:
+            self.visit_contents(node)
+        elif ('abstract' in node['classes']
+              and self.settings.use_latex_abstract):
+            self.push_output_collector(self.abstract)
+            self.out.append('\\begin{abstract}')
+            if isinstance(node.next_node(), nodes.title):
+                node.pop(0)  # LaTeX provides its own title
+        else:
+            # special topics:
+            if 'abstract' in node['classes']:
+                if not self.fallback_stylesheet:
+                    self.fallbacks['abstract'] = PreambleCmds.abstract
+                if self.settings.legacy_class_functions:
+                    self.fallbacks['abstract'] = PreambleCmds.abstract_legacy
+                self.push_output_collector(self.abstract)
+            elif 'dedication' in node['classes']:
+                if not self.fallback_stylesheet:
+                    self.fallbacks['dedication'] = PreambleCmds.dedication
+                self.push_output_collector(self.dedication)
+            else:
+                node['classes'].insert(0, 'topic')
+            self.visit_block_quote(node)
+
+    def depart_topic(self, node):
+        if ('abstract' in node['classes']
+            and self.settings.use_latex_abstract):
+            self.out.append('\\end{abstract}\n')
+        elif 'contents' in node['classes']:
+            self.duclass_close(node)
+        else:
+            self.depart_block_quote(node)
+        if ('abstract' in node['classes']
+            or 'dedication' in node['classes']):
+            self.pop_output_collector()
+
+    def visit_transition(self, node):
+        if not self.fallback_stylesheet:
+            self.fallbacks['transition'] = PreambleCmds.transition
+        self.out.append('\n%' + '_' * 75 + '\n')
+        self.out.append('\\DUtransition\n')
+
+    def depart_transition(self, node):
+        pass
+
+    def visit_version(self, node):
+        self.visit_docinfo_item(node, 'version')
+
+    def depart_version(self, node):
+        self.depart_docinfo_item(node)
+
+    def unimplemented_visit(self, node):
+        raise NotImplementedError('visiting unimplemented node type: %s' %
+                                  node.__class__.__name__)
+
+#    def unknown_visit(self, node):
+#    def default_visit(self, node):
+
+# vim: set ts=4 et ai :
diff --git a/.venv/lib/python3.12/site-packages/docutils/writers/latex2e/default.tex b/.venv/lib/python3.12/site-packages/docutils/writers/latex2e/default.tex
new file mode 100644
index 00000000..86552ab6
--- /dev/null
+++ b/.venv/lib/python3.12/site-packages/docutils/writers/latex2e/default.tex
@@ -0,0 +1,14 @@
+$head_prefix% generated by Docutils <https://docutils.sourceforge.io/>
+\usepackage{cmap} % fix search and cut-and-paste in Acrobat
+$requirements
+%%% Custom LaTeX preamble
+$latex_preamble
+%%% User specified packages and stylesheets
+$stylesheet
+%%% Fallback definitions for Docutils-specific commands
+$fallbacks
+$pdfsetup
+%%% Body
+\begin{document}
+$titledata$body_pre_docinfo$docinfo$dedication$abstract$body
+\end{document}
diff --git a/.venv/lib/python3.12/site-packages/docutils/writers/latex2e/docutils.sty b/.venv/lib/python3.12/site-packages/docutils/writers/latex2e/docutils.sty
new file mode 100644
index 00000000..52386bb9
--- /dev/null
+++ b/.venv/lib/python3.12/site-packages/docutils/writers/latex2e/docutils.sty
@@ -0,0 +1,223 @@
+%% docutils.sty: macros for Docutils LaTeX output.
+%%
+%%   Copyright © 2020 Günter Milde
+%%   Released under the terms of the `2-Clause BSD license`, in short:
+%%
+%%      Copying and distribution of this file, with or without modification,
+%%      are permitted in any medium without royalty provided the copyright
+%%      notice and this notice are preserved.
+%%      This file is offered as-is, without any warranty.
+
+% .. include:: README.md
+%
+% Implementation
+% ==============
+%
+% ::
+
+\NeedsTeXFormat{LaTeX2e}
+\ProvidesPackage{docutils}
+  [2021/05/18 macros for Docutils LaTeX output]
+
+% Helpers
+% -------
+%
+% duclass::
+
+% class handling for environments (block-level elements)
+% \begin{DUclass}{spam} tries \DUCLASSspam and
+% \end{DUclass}{spam} tries \endDUCLASSspam
+\ifx\DUclass\undefined % poor man's "provideenvironment"
+ \newenvironment{DUclass}[1]%
+  {% "#1" does not work in end-part of environment.
+   \def\DocutilsClassFunctionName{DUCLASS#1}
+     \csname \DocutilsClassFunctionName \endcsname}%
+  {\csname end\DocutilsClassFunctionName \endcsname}%
+\fi
+
+% providelength::
+
+% Provide a length variable and set default, if it is new
+\providecommand*{\DUprovidelength}[2]{
+  \ifthenelse{\isundefined{#1}}{\newlength{#1}\setlength{#1}{#2}}{}
+}
+
+
+% Configuration defaults
+% ----------------------
+%
+% See `Docutils LaTeX Writer`_ for details.
+%
+% abstract::
+
+\providecommand*{\DUCLASSabstract}{
+  \renewcommand{\DUtitle}[1]{\centerline{\textbf{##1}}}
+}
+
+% dedication::
+
+% special topic for dedications
+\providecommand*{\DUCLASSdedication}{%
+  \renewenvironment{quote}{\begin{center}}{\end{center}}%
+}
+
+% TODO: add \em to set dedication text in italics?
+%
+% docinfo::
+
+% width of docinfo table
+\DUprovidelength{\DUdocinfowidth}{0.9\linewidth}
+
+% error::
+
+\providecommand*{\DUCLASSerror}{\color{red}}
+
+% highlight_rules::
+
+% basic code highlight:
+\providecommand*\DUrolecomment[1]{\textcolor[rgb]{0.40,0.40,0.40}{#1}}
+\providecommand*\DUroledeleted[1]{\textcolor[rgb]{0.40,0.40,0.40}{#1}}
+\providecommand*\DUrolekeyword[1]{\textbf{#1}}
+\providecommand*\DUrolestring[1]{\textit{#1}}
+
+% Elements
+% --------
+%
+% Definitions for unknown or to-be-configured Docutils elements.
+%
+% admonition::
+
+% admonition environment (specially marked topic)
+\ifx\DUadmonition\undefined % poor man's "provideenvironment"
+ \newbox{\DUadmonitionbox}
+ \newenvironment{DUadmonition}%
+  {\begin{center}
+     \begin{lrbox}{\DUadmonitionbox}
+       \begin{minipage}{0.9\linewidth}
+  }%
+  {    \end{minipage}
+     \end{lrbox}
+     \fbox{\usebox{\DUadmonitionbox}}
+   \end{center}
+  }
+\fi
+
+% fieldlist::
+
+% field list environment (for separate configuration of `field lists`)
+\ifthenelse{\isundefined{\DUfieldlist}}{
+  \newenvironment{DUfieldlist}%
+    {\quote\description}
+    {\enddescription\endquote}
+}{}
+
+% footnotes::
+
+% numerical or symbol footnotes with hyperlinks and backlinks
+\providecommand*{\DUfootnotemark}[3]{%
+  \raisebox{1em}{\hypertarget{#1}{}}%
+  \hyperlink{#2}{\textsuperscript{#3}}%
+}
+\providecommand{\DUfootnotetext}[4]{%
+  \begingroup%
+  \renewcommand{\thefootnote}{%
+    \protect\raisebox{1em}{\protect\hypertarget{#1}{}}%
+    \protect\hyperlink{#2}{#3}}%
+  \footnotetext{#4}%
+  \endgroup%
+}
+
+% inline::
+
+% custom inline roles: \DUrole{#1}{#2} tries \DUrole#1{#2}
+\providecommand*{\DUrole}[2]{%
+  \ifcsname DUrole#1\endcsname%
+    \csname DUrole#1\endcsname{#2}%
+  \else%
+    #2%
+  \fi%
+}
+
+% legend::
+
+% legend environment (in figures and formal tables)
+\ifthenelse{\isundefined{\DUlegend}}{
+  \newenvironment{DUlegend}{\small}{}
+}{}
+
+% lineblock::
+
+% line block environment
+\DUprovidelength{\DUlineblockindent}{2.5em}
+\ifthenelse{\isundefined{\DUlineblock}}{
+  \newenvironment{DUlineblock}[1]{%
+    \list{}{\setlength{\partopsep}{\parskip}
+            \addtolength{\partopsep}{\baselineskip}
+            \setlength{\topsep}{0pt}
+            \setlength{\itemsep}{0.15\baselineskip}
+            \setlength{\parsep}{0pt}
+            \setlength{\leftmargin}{#1}}
+    \raggedright
+  }
+  {\endlist}
+}{}
+
+% optionlist::
+
+% list of command line options
+\providecommand*{\DUoptionlistlabel}[1]{\bfseries #1 \hfill}
+\DUprovidelength{\DUoptionlistindent}{3cm}
+\ifthenelse{\isundefined{\DUoptionlist}}{
+  \newenvironment{DUoptionlist}{%
+    \list{}{\setlength{\labelwidth}{\DUoptionlistindent}
+            \setlength{\rightmargin}{1cm}
+            \setlength{\leftmargin}{\rightmargin}
+            \addtolength{\leftmargin}{\labelwidth}
+            \addtolength{\leftmargin}{\labelsep}
+            \renewcommand{\makelabel}{\DUoptionlistlabel}}
+  }
+  {\endlist}
+}{}
+
+% rubric::
+
+% informal heading
+\providecommand*{\DUrubric}[1]{\subsubsection*{\emph{#1}}}
+
+% sidebar::
+
+% text outside the main text flow
+\providecommand{\DUsidebar}[1]{%
+  \begin{center}
+    \colorbox[gray]{0.80}{\parbox{0.9\linewidth}{#1}}
+  \end{center}
+}
+
+% title::
+
+% title for topics, admonitions, unsupported section levels, and sidebar
+\providecommand*{\DUtitle}[1]{%
+  \smallskip\noindent\textbf{#1}\smallskip}
+
+% subtitle::
+
+% subtitle (for sidebar)
+\providecommand*{\DUsubtitle}[1]{\par\emph{#1}\smallskip}
+
+% documentsubtitle::
+
+% subtitle (in document title)
+\providecommand*{\DUdocumentsubtitle}[1]{{\large #1}}
+
+% titlereference::
+
+% titlereference standard role
+\providecommand*{\DUroletitlereference}[1]{\textsl{#1}}
+
+% transition::
+
+% transition (break / fancybreak / anonymous section)
+\providecommand*{\DUtransition}{%
+  \hspace*{\fill}\hrulefill\hspace*{\fill}
+  \vskip 0.5\baselineskip
+}
diff --git a/.venv/lib/python3.12/site-packages/docutils/writers/latex2e/titlepage.tex b/.venv/lib/python3.12/site-packages/docutils/writers/latex2e/titlepage.tex
new file mode 100644
index 00000000..278fba80
--- /dev/null
+++ b/.venv/lib/python3.12/site-packages/docutils/writers/latex2e/titlepage.tex
@@ -0,0 +1,19 @@
+% generated by Docutils <https://docutils.sourceforge.io/>
+$head_prefix
+\usepackage{cmap} % fix search and cut-and-paste in Acrobat
+$requirements
+%%% Custom LaTeX preamble
+$latex_preamble
+%%% User specified packages and stylesheets
+$stylesheet
+%%% Fallback definitions for Docutils-specific commands
+$fallbacks$pdfsetup
+$titledata
+%%% Body
+\begin{document}
+\begin{titlepage}
+$body_pre_docinfo$docinfo$dedication$abstract
+\thispagestyle{empty}
+\end{titlepage}
+$body
+\end{document}
diff --git a/.venv/lib/python3.12/site-packages/docutils/writers/latex2e/titlingpage.tex b/.venv/lib/python3.12/site-packages/docutils/writers/latex2e/titlingpage.tex
new file mode 100644
index 00000000..1e96806d
--- /dev/null
+++ b/.venv/lib/python3.12/site-packages/docutils/writers/latex2e/titlingpage.tex
@@ -0,0 +1,18 @@
+% generated by Docutils <https://docutils.sourceforge.io/>
+$head_prefix
+$requirements
+%%% Custom LaTeX preamble
+$latex_preamble
+%%% User specified packages and stylesheets
+$stylesheet
+%%% Fallback definitions for Docutils-specific commands
+$fallbacks$pdfsetup
+$titledata
+%%% Body
+\begin{document}
+\begin{titlingpage}
+\thispagestyle{empty}
+$body_pre_docinfo$docinfo$dedication$abstract
+\end{titlingpage}
+$body
+\end{document}
diff --git a/.venv/lib/python3.12/site-packages/docutils/writers/latex2e/xelatex.tex b/.venv/lib/python3.12/site-packages/docutils/writers/latex2e/xelatex.tex
new file mode 100644
index 00000000..4d802805
--- /dev/null
+++ b/.venv/lib/python3.12/site-packages/docutils/writers/latex2e/xelatex.tex
@@ -0,0 +1,21 @@
+$head_prefix% generated by Docutils <https://docutils.sourceforge.io/>
+% rubber: set program xelatex
+\usepackage{fontspec}
+% \defaultfontfeatures{Scale=MatchLowercase}
+% straight double quotes (defined T1 but missing in TU):
+\ifdefined \UnicodeEncodingName
+  \DeclareTextCommand{\textquotedbl}{\UnicodeEncodingName}{%
+    {\addfontfeatures{RawFeature=-tlig,Mapping=}\char34}}%
+\fi
+$requirements
+%%% Custom LaTeX preamble
+$latex_preamble
+%%% User specified packages and stylesheets
+$stylesheet
+%%% Fallback definitions for Docutils-specific commands
+$fallbacks$pdfsetup
+$titledata
+%%% Body
+\begin{document}
+$body_pre_docinfo$docinfo$dedication$abstract$body
+\end{document}