% \iffalse meta-comment
%<*internal>
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%<*readme>
notes2bib - Integrating notes into the bibliography
===================================================

The `notes2bib` package defines a new type of note, bibnote,
which will always be added to the bibliography. The package
allows footnotes and endnotes to be moved into the bibliography
in the same way. The package can be used with natbib and
biblatex as well as plain LaTeX citations. Both sorted and
unsorted bibliography styles are supported.

Installation
------------

The package is supplied in `.dtx` format and as a pre-extracted
`.zip` file, `notes2bib.tds.zip`. The later is most convenient
for most users: simply unzip this in your local `texmf`
directory. If you want to unpack the `.dtx` yourself, running
`tex notes2bib.dtx` will extract the package whereas `latex
notes2bib.dtx` will extract it and also typeset the
documentation.

The package requires LaTeX3 support as provided in the
`l3kernel` and `l3packages` bundles. Both of these are available
on [CTAN](http://www.ctan.org/) as ready-to-install `.zip`
files. Suitable versions are available in MiKTeX 2.9 and TeX
Live 2012 (updating the relevant packages online may be
necessary). LaTeX3, and so `notes2bib`, requires the e-TeX
extensions: these are available on all modern TeX systems.

Typesetting the documentation requires a number of packages in
addition to those needed to use the package. This is mainly
because of the number of demonstration items included in the
text. To compile the documentation without error, you will
need the packages:
 - `csquotes`
 - `helvet`
 - `mathpazo`
 - `listings`
%</readme>
%<*internal>
\fi
\def\nameofplainTeX{plain}
\ifx\fmtname\nameofplainTeX\else
  \expandafter\begingroup
\fi
%</internal>
%<*install>
\input l3docstrip.tex
\keepsilent
\askforoverwritefalse
\preamble
---------------------------------------------------------------
notes2bib --- Integrating notes into the bibliography
Maintained by Joseph Wright
E-mail: joseph.wright@morningstar2.co.uk
Released under the LaTeX Project Public License v1.3c or later
See http://www.latex-project.org/lppl.txt
---------------------------------------------------------------

\endpreamble
\postamble

Copyright (C) 2007-2013,2016,2019 by
  Joseph Wright <joseph.wright@morningstar2.co.uk>

It may be distributed and/or modified under the conditions of
the LaTeX Project Public License (LPPL), either version 1.3c of
this license or (at your option) any later version.  The latest
version of this license is in the file:

   http://www.latex-project.org/lppl.txt

This work is "maintained" (as per LPPL maintenance status) by
  Joseph Wright.

This work consists of the file  notes2bib.dtx
          and the derived files notes2bib.ins,
                                notes2bib.pdf and
                                notes2bib.sty.

\endpostamble
\usedir{tex/latex/notes2bib}
\generate{
  \file{\jobname.sty}{\from{\jobname.dtx}{package}}
}
%</install>
%<install>\endbatchfile
%<*internal>
\usedir{source/latex/notes2bib}
\generate{
  \file{\jobname.ins}{\from{\jobname.dtx}{install}}
}
\nopreamble\nopostamble
\usedir{doc/latex/notes2bib}
\generate{
  \file{README.txt}{\from{\jobname.dtx}{readme}}
}
\ifx\fmtname\nameofplainTeX
  \expandafter\endbatchfile
\else
  \expandafter\endgroup
\fi
%</internal>
%<*driver|package>
\RequirePackage{xparse}
%</driver|package>
%<*driver>
\documentclass[full]{l3doc}
\usepackage{csquotes,helvet,notes2bib}
\usepackage[final]{listings}
\usepackage[osf]{mathpazo}
\begin{document}
  \DocInput{\jobname.dtx}
\end{document}
%</driver>
% \fi
%
% \makeatletter
%
% ^^A For creating examples with nice highlighting of code, and so
% ^^A on; based on the system used in the listings source (lstsample).
% \lst@RequireAspects{writefile}
% \newsavebox{\LaTeXdemo@box}
% \lstnewenvironment{LaTeXdemo}[1][code and example]{^^A
%   \global\let\lst@intname\@empty
%   \expandafter\let\expandafter\LaTeXdemo@end
%     \csname LaTeXdemo@#1@end\endcsname
%   \@nameuse{LaTeXdemo@#1}^^A
% }{^^A
%   \LaTeXdemo@end
% }
% \newcommand*\LaTeXdemo@new[3]{^^A
%   \expandafter\newcommand\expandafter*\expandafter
%     {\csname LaTeXdemo@#1\endcsname}{#2}^^A
%   \expandafter\newcommand\expandafter*\expandafter
%     {\csname LaTeXdemo@#1@end\endcsname}{#3}^^A
% }
% \newcommand*\LaTeXdemo@common{^^A
%   \setkeys{lst}{
%     basicstyle   = \small\ttfamily,
%     basewidth    = 0.51em,
%     gobble       = 4,
%     keywordstyle = \color{blue},
%     language     = [LaTeX]{TeX},
%     moretexcs    = {
%       bibnote       ,
%       bibnotemark   ,
%       bibnotesetup  ,
%       bibnotetext   ,
%       printbibnotes
%     }
%   }^^A
% }
% \newcommand*\LaTeXdemo@input{^^A
%   \MakePercentComment
%   \catcode`\^^M=10\relax
%   \small
%   \begingroup
%     \setkeys{lst}{
%       SelectCharTable=\lst@ReplaceInput{\^\^I}{\lst@ProcessTabulator}
%     }^^A
%     \leavevmode
%       \input{\jobname.tmp}^^A
%   \endgroup
%   \MakePercentIgnore
% }
% \LaTeXdemo@new{code and example}{^^A
%   \setbox\LaTeXdemo@box=\hbox\bgroup
%     \lst@BeginAlsoWriteFile{\jobname.tmp}^^A
%     \LaTeXdemo@common
% }{^^A
%     \lst@EndWriteFile
%   \egroup
%   \begin{center}
%     \ifdim\wd\LaTeXdemo@box>0.48\linewidth\relax
%       \hbox to\linewidth{\box\LaTeXdemo@box\hss}^^A
%         \begin{minipage}{\linewidth}
%           \LaTeXdemo@input
%         \end{minipage}
%     \else
%       \begin{minipage}{0.48\linewidth}
%         \LaTeXdemo@input
%       \end{minipage}
%       \hfill
%       \begin{minipage}{0.48\linewidth}
%         \hbox to\linewidth{\box\LaTeXdemo@box\hss}^^A
%       \end{minipage}
%     \fi
%   \end{center}
% }
% \LaTeXdemo@new{code only}{^^A
%   \LaTeXdemo@common
% }{^^A
% }
%
% \providecommand*\opt[1]{\texttt{#1}}
%
% \makeatother
%
% \GetFileInfo{\jobname.sty}
%
% \changes{v1.0}{2007/08/30}{Initial public release}
% \changes{v2.0}{2009/09/24}{Second version of package using \pkg{expl3}
%  internally}
%
% \title{^^A
%   \pkg{notes2bib} --- Integrating notes into the bibliography^^A
%     \thanks{^^A
%       This file describes version \fileversion, last revised
%       \filedate.^^A
%     }^^A
% }
% \author{^^A
%   Joseph Wright\thanks{E-mail: joseph.wright@morningstar2.co.uk}^^A
% }
% \date{Released \filedate}
%
% \maketitle
%
% \begin{abstract}
%   The \pkg{notes2bib} package defines a new type of note, \cs{bibnote},
%   which will always be added to the bibliography. The package allows
%   footnotes and endnotes to be moved into the bibliography in the same
%   way.  The package can be used with \pkg{natbib} and \pkg{biblatex} as
%   well as plain \LaTeX{} citations. Both sorted and unsorted bibliography
%   styles are supported.
% \end{abstract}
%
% \tableofcontents
%
% \begin{documentation}
%
 %\section{Introduction}
%
% In most subject areas, bibliographic citations and notes are
% separate entities. However, in some parts of the physical sciences
% (chemistry and physics) it is usual for references to the
% literature and notes to be given together in a \enquote{References and
% Notes} section.  By default, this requires that \BibTeX{} users
% create a notes database for each document that they write. This is
% also true if complex references are needed, which cannot be handled
% automatically.
%
% The aim of the \pkg{notes2bib} package is to make integration of notes
% into the bibliography easy.  Notes can be written as normal in the
% \LaTeX{} source, and are automatically moved to the bibliography. The
% package is compatible with sorted and unsorted bibliography styles.
% The package has been designed for use with numerical citations,
% although it will work with other systems.
%
% \section{Installation}
%
% \changes{v2.0b}{2010/01/08}{Better documentation for unpacking and
%   installation}
% The package is supplied in \file{dtx} format and as a pre-extracted
% zip file, \file{\jobname.tds.zip}. The later is most convenient for
% most users: simply unzip this in your local texmf directory and
% run \texttt{texhash} to update the database of file locations. If
% you want to unpack the \file{dtx} yourself, running
% \texttt{tex \jobname.dtx} will extract the package whereas
% \texttt{latex \jobname.dtx} will extract it and also typeset the
% documentation.
%
% The package requires \LaTeX3 support as provided in the
% \pkg{l3kernel} and \pkg{l3packages} bundles. Both of these are available
% on \href{http://www.ctan.org}{\textsc{ctan}} as ready-to-install
% zip files. Suitable versions are available in MiKTeX 2.9 and
% TeX Live 2011 (updating the relevant packages online may be
% necessary). \LaTeX3, and so \pkg{notes2bib}, requires the e-\TeX{}
% extensions: these are available on all modern \TeX{} systems.
%
% Typesetting the documentation requires a number of packages in
% addition to those needed to use the package. This is mainly
% because of the number of demonstration items included in the text. To
% compile the documentation without error, you will need the packages:
% \begin{itemize}
%   \item \pkg{csquotes}
%   \item \pkg{helvet}
%   \item \pkg{mathpazo}
%   \item \pkg{listings}
% \end{itemize}
%
% \section{Using the package}
%
% The package should be loaded as normal in the preamble. The package
% recognises a number of options, which can also be used in teh document
% body. These are described later in this document.
% \begin{LaTeXdemo}[code only]
%   \usepackage[<options>]{notes2bib}
% \end{LaTeXdemo}
%
% \DescribeMacro {\bibnote}
% \begin{syntax}
%   \cs{bibnote} \oarg{name} \marg{text}
% \end{syntax}
% The basic function provided by \pkg{notes2bib} is the \cs{bibnote}
% macro. This is used in exactly the same way as footnotes, taking
% a mandatory argument, the \meta{text} of the note, and an optional
% argument, a \meta{name} for the note. The \meta{text} will be saved to
% a \BibTeX{} database file for later inclusion in the bibliography, and
% a reference will be placed in the body text at the position of the
% note.
% \begin{LaTeXdemo}
%   A very simple example of a bibliography note
%   \bibnote{Note for the first example}.
% \end{LaTeXdemo}
% When used without the optional \meta{name} argument, each note is
% given an automatically-generated name. If notes need to be referred to
% again in a document, the optional argument avoids the need to
% understand the detail of the automated system.
% \begin{LaTeXdemo}
%   An example of a named note \bibnote[labelled]{Note for the second
%   example}. The text can then continue and reference the note again
%   later \bibnotemark[labelled].
% \end{LaTeXdemo}
%
% Verbatim text cannot be added directly to notes (in the same way that
% it cannot be used in footnotes). This means that the normal care
% will be needed with verbatim-like material.
% \begin{LaTeXdemo}
%   The next note contains some awkward text
%   \bibnote{Some \texttt{\textbackslash verb}-like output}.
% \end{LaTeXdemo}
%
% \DescribeMacro {\bibnotemark}
% \begin{syntax}
%   \cs{bibnotemark} \oarg{name}
% \end{syntax}
% \DescribeMacro \bibnotetext
% \begin{syntax}
%   \cs{bibnotetext} \oarg{name} \marg{text}
% \end{syntax}
% In common with \cs{footnote}, the basic \cs{bibnote} macro has
% companion macros \cs{bibnotemark} and \cs{bibnotetext}. In contrast
% to the \LaTeXe{} kernel \cs{footnote} macro, \cs{bibnote} is naturally
% robust and so \cs{bibnotemark} and \cs{bibnotetext} should be needed
% much more rarely than the \cs{footnote} versions.
%
% As with the related \cs{footnote} functions, \cs{bibnotemark} can be
% used alone or will recognise an optional argument giving the
% \meta{name} of the note. \cs{bibnotetext} also recognises the same
% optional \meta{name} argument as well as the mandatory \meta{text}.
% \begin{LaTeXdemo}
%   A note without a name \bibnotemark{} can be given with some
%   text \bibnotetext{Text for the fourth example}. Note can also be
%   given names \bibnotemark[named], which are then used for the
%   text\bibnotetext[named]{More text for the fourth example}.
% \end{LaTeXdemo}
%
% The \cs{bibnotemark} macro can also be used to cross-reference notes
% given earlier in the document. This method is preferred for
% referencing notes over using the \cs{cite} macro as
% \cs{bibnotemark} will cope correctly with out-of-order notes
% (see Section~\ref{out-of-order}).
% \begin{LaTeXdemo}
%   See notes \bibnotemark[labelled] and \bibnotemark[named].
% \end{LaTeXdemo}
%
% \DescribeMacro {\printbibnotes}
% \begin{syntax}
%   \cs{printbibnotes}
% \end{syntax}
% In most cases, there will be both notes and references in a document.
% The notes will be printed along with cited literature in the
% bibliography, produced using the \cs{bibliography} macro (or
% \cs{printbibliography} when using \pkg{biblatex}). However, it is
% possible to print only the notes in a document using the
% \cs{printbibnotes} macro.
% \bibliographystyle{unsrt}
% \begin{LaTeXdemo}
%   \printbibnotes
% \end{LaTeXdemo}
%
% \DescribeMacro {\bibnotesetup}
% \begin{syntax}
%   \cs{bibnotesetup} \marg{key--value list}
% \end{syntax}
% The behaviour of \pkg{notes2bib} can be altered by setting one or
% more package options. These are given as arguments to the
% \cs{bibnotesetup} function, which takes a \meta{key--value list} and
% uses this to set up the package. With the exception of the
% \opt{file-name} option, all of the settings can be altered in the
% preamble or the document body. The various package options are
% described below.
%
% \subsection{Auto-generated note names}
%
% \DescribeOption {note-name}
% When no explicit label is given for a note, one is generated
% automatically by the package. This consists of two parts, a name and
% a number. The text of the name can be set up using the
% \opt{note-name} option. This should not contain any spaces, as
% \BibTeX{} does not support records with spaces in names. The numerical
% part of the label is always generated automatically, and is the
% number of the note. The standard setting for \opt{note-name} is
% \opt{Note}.
%
% \DescribeOption {refsection-name}
% \DescribeOption {refsection-separator}
% When using \pkg{biblatex}'s \texttt{refsection} system, additional
% information is added to all labels from the second \texttt{refsection}
% onward (\emph{i.e.}~to all except \texttt{refsection} 0). This
% additional text is added before the note name, and always includes the
% \texttt{refsection} number. The settings \opt{refsection-name} and
% \opt{refsection-separator} determine the exact text added:
% \opt{refsection-name} comes before the \texttt{refsection} number and
% has default \opt{Refsection}, while \opt{refsection-separator} comes
% after it and has default value \opt{-}.
%
% \subsection{Underlying citation system}
%
% \DescribeOption {cite-function}
% \pkg{notes2bib} works by making the text of notes into citations.
% To do this, each note has to be \enquote{cited} in the appropriate
% place. \pkg{notes2bib} does not carry out any low-level citation
% itself: instead, a general citation macro is called. The nature of
% the function is set up using the \opt{cite-function} option,
% which should be set to a citation macro taking one mandatory
% argument. The initial setting is \opt{cite-function = \cs{cite}}.
%
% \subsection{Controlling the temporary database}
%
% \DescribeOption {file-name}
% The file name used for the database of notes is set using the
% \opt{file-name} option. The standard setting is to call the file
% |notes2bib-\jobname|, which may not be appropriate (for example, file
% names containing spaces may be problematic). Setting the
% \opt{file-name} option will alter the name of the file, with the
% file extension fixed as \file{bib}. In contrast to the other package
% options, this value can only be set in the preamble.
%
% \DescribeOption {record-type}
% Each note is written to the database as a standard \BibTeX{} record.
% The type of record created is set using the \opt{record-type}
% option. Usually, this will be set to \opt{misc}; \pkg{biblatex} v1.1a
% upwards provides the \opt{bibnote} record type, and this is used if
% available. Some \BibTeX{} styles have dedicated support for notes: if
% so, the appropriate value should be set for this option.
%
% \DescribeOption {note-field}
% The database field used to store the text of the note is available
% for change \emph{via} the \opt{note-field} option. The standard
% setting is \opt{note}.
%
% \DescribeOption {keyword-entry}
% Some styles (most notably \pkg{biblatex}) recognise keywords in
% \BibTeX{} records, stored in a \texttt{keywords} field. To allow the
% selective printing of notes, \pkg{notes2bib} includes a keyword in
% each note record. The keyword is set using the \opt{keyword-entry}
% option: the standard setting is \opt{note}.
%
% \subsection{Ordering notes in relation to citations}
% \label{out-of-order}
%
% \DescribeOption {placement}
% The standard method used by \pkg{notes2bib} places notes into the
% bibliography with no particular control of the relative position of
% notes with respect to citations. For unsorted bibliography styles,
% this will result in the notes appearing mixed in with citations.
% However, \pkg{notes2bib} can create notes so that they appear before
% or after citations, with both sorted an unsorted bibliography styles.
% This is controlled by the \opt{placement} option, which recognises
% the values \opt{before}, \opt{after} and \opt{mixed}. Setting
% \opt{placement = before} places notes before citations, with
% the \opt{after} setting forcing notes to appear after citation.
% The standard setting is \opt{placement = mixed}, which will result
% in mixing of notes and citations.
%
% When notes are placed in the bibliography without any change of order,
% it is possible to cross-reference to them using the standard \cs{cite}
% macro. However, when notes are out of the normal order this can lead
% to problems. These can be avoided by using the \cs{bibnotemark} macro
% to cross-reference notes. As this method will always work correctly,
% it is the recommended method for referencing notes under all
% circumstances.
%
% \DescribeOption {presort-before}
% \DescribeOption {presort-mixed}
% \DescribeOption {presort-after}
% \DescribeOption {sort-key-before}
% \DescribeOption {sort-key-mixed}
% \DescribeOption {sort-key-after}
% There are a number of different mechanisms used by \pkg{notes2bib} to
% achieve the desired ordering. Most standard \BibTeX{} styles recognise
% a \texttt{key} field, which can be used to override sorting by author
% or title. This is used by \pkg{notes2bib}, with the note name prefixed
% by a string to force the sort order. The appropriate strings are
% stored using the options \opt{sort-key-before}, \opt{sort-key-mixed}
% and \opt{sort-key-after}. These have standard settings
% \opt{aaa}, \opt{\meta{blank}} and \opt{zzz}, respectively. When the
% \pkg{biblatex} package is in use, a more powerful method is available
% to control sorting: the \texttt{presort} field. Data to be written
% to this field is set up using the \opt{presort-before},
% \opt{presort-mixed} and \opt{presort-after} options. Here, the
% standard values are \opt{ml}, \opt{mm} and \opt{mn}, respectively.
% These standard values will probably be appropriate in almost all
% cases.
%
% \subsection{Converting footnotes and endnotes}
%
% \DescribeOption {convert-endnotes}
% \DescribeOption {convert-footnotes}
% It is possible to convert both \cs{footnote} and \cs{endnote}
% entries in a file into \cs{bibnote} entries in a flexible manner.
% This behaviour is controlled using the \opt{convert-endnotes} and
% \opt{convert-footnotes} options; both recognise the values
% \opt{true} and \opt{false}. The original definitions for the
% appropriate macros are stored by \pkg{notes2bib}, and so it is
% possible to switch this behaviour on and off.
%
% \DescribeMacro {\thanks}
% The package is designed so that converting footnotes to bibliographic
% notes will not affect the \cs{thanks} macro. Thus the option
% \opt{convert-footnotes = true} can be given before \cs{maketitle}
% with no implication for and \cs{thanks}.
%
% \subsection{Using unsorted bibliography styles}
%
% \changes{v2.0b}{2010/01/08}{Improvements to details concerning
%   \opt{use-sort-key} option}
% \DescribeOption {use-sort-key}
% Some bibliography styles (most notably those using the
% author--date system) may not work well with the settings
% of the package as supplied. Some of the data written by
% \pkg{notes2bib} can be misunderstood by styles such as
% \file{unsrtnat}. To suppress creating a \texttt{key} field in the
% database, the option \opt{use-sort-key} should be set to \opt{false}
% with these problematic styles. At the same time, it may be necessary
% to alter the \opt{note-name} option to a blank value.
% \begin{LaTeXdemo}[code only]
%   \bibnotesetup{
%     note-name    = ,
%     use-sort-key = false
%   }
% \end{LaTeXdemo}
%
% \section{Data written to the \texttt{aux} file}
%
% \pkg{notes2bib} writes some information to the \file{aux} file, so
% that it is available between runs. The functions added to the
% file are not needed directly by the user, but are documented here
% for completeness. However, it may be necessary to worry about the
% \file{aux} file when splitting bibliographies.
%
% \DescribeMacro {\recordnotes}
% \begin{syntax}
%   \cs{recordnotes}
% \end{syntax}
% When notes are placed out-of-order in in a document (using
% \opt{placement = before} or \opt{placement = after}) \pkg{notes2bib}
% has to record information in the current \file{aux} file. When using
% multiple bibliographies, this will not necessarily happen totally
% automatically. To force \pkg{notes2bib} to write the current
% out-of-order notes to the \file{aux} file, the macro
% \cs{recordnotes} is available. It should be used immediately
% before changing between auxiliary files.
%
% \DescribeMacro {\TotalNotes}
% \begin{syntax}
%   \cs{TotalNotes} \marg{number}
% \end{syntax}
% Records the total number of auto-numbered notes in a run. This
% information is needed to check if zero-filling is needed for the
% numbers used.
%
% \DescribeMacro {\NotesAfterCitations}
%  \begin{syntax}
%    \cs{NotesAfterCitations} \marg{note-list}
%  \end{syntax}
% \DescribeMacro {\NotesBeforeCitations}
% \begin{syntax}
%   \cs{NotesBeforeCitations} \marg{note-list}
% \end{syntax}
% These functions record the notes which have been placed outside of
% the normal order by the package. This information is used to check
% for changes in note order between \LaTeX{} runs, so that the need for
% re-running \LaTeX{} and \BibTeX{} can be detected.
%
% \section{Notes for upgrading from version one}
%
% Documents which compile with version one of \pkg{notes2bib} should
% work equally well with version two. The package recognises the
% older options and user functions (for example \cs{niibsetup}). These
% are not documented here as all new documents should use the improved
% structures provided here. As some auxiliary file functions have been
% altered, it may be necessary to delete \file{aux} files for documents
% processed initially with older versions of \pkg{notes2bib}.
%
% \section{Code-level interfaces}
%
% In common with other \LaTeX3 modules, \pkg{notes2bib} makes functionality
% available at a code (\cs{ExplSyntaxOn}) level. End users \emph{do not}
% need to read this section!
%
% Programmers should note that \pkg{notes2bib} uses the module prefix
% \texttt{notestobib}, but that the options use the \pkg{l3keys} module
% name \texttt{notes2bib}.
%
% \begin{function}{\notestobib_write_note:nn, \notestobib_write_note:xn}
%   \begin{syntax}
%     \cs{notestobib_write_note:nn} \marg{note} \marg{text}
%   \end{syntax}
%   Adds the \meta{text} for the \meta{note} to the dynamic database
%   created by \pkg{notes2bib}. Note that the \meta{note} name should be
%   unique and that the writing operation is delayed by the package until
%   either the end of the document or an explicit write request.
% \end{function}
%
% \end{documentation}
%
% \begin{implementation}
%
% \section{Implementation}
%
%    \begin{macrocode}
%<*package>
%    \end{macrocode}
%
%    \begin{macrocode}
%<@@=notestobib>
%    \end{macrocode}
%
% Version data to start with.
%    \begin{macrocode}
\ProvidesExplPackage {notes2bib} {2019-09-28} {2.0m}
  {Integrating notes into the bibliography}
\RequirePackage{l3keys2e}
%    \end{macrocode}
%
% \subsection{Variables and constants}
%
% \begin{macro}{\c_@@_file_message_tl}
%   A short piece of text that is added to the top of an auto-generated
%   file. Setting this up as a constant means that it can be changed
%   (for example for translation) if necessary.
%    \begin{macrocode}
\tl_const:Nn \c_@@_file_message_tl
  {
    \iow_char:N \% ~
    This~is~an~auxiliary~file~used~by~the~'notes2bib'~package.
      \iow_newline:
    \iow_char:N \% ~
    This~file~may~safely~be~deleted.
      \iow_newline:
    \iow_char:N \% ~
    It~will~be~recreated~as~required.
      \iow_newline:
  }
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}{\g_@@_after_clist, \g_@@_before_clist}
%   Notes to be placed either before or after citations need to be tracked
%   by the module. Simple comma lists will achieve this.
%    \begin{macrocode}
\clist_new:N \g_@@_after_clist
\clist_new:N \g_@@_before_clist
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}{\g_@@_all_after_clist, \g_@@_all_before_clist}
%   As notes after citations can be flushed, there is a need for a second
%   list which is never emptied.
%    \begin{macrocode}
\clist_new:N \g_@@_all_after_clist
\clist_new:N \g_@@_all_before_clist
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}{\g_@@_note_int}
%   A counter for the automatically-created notes is needed. This is a
%   global value (life will get very complicated if not).
%    \begin{macrocode}
\int_new:N \g_@@_note_int
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}{\l_@@_presort_tl, \l_@@_sortkey_tl}
%   The text used for sorting citations is stored here: it is never set
%   directly, as it depends on the type of sorting taking place.
%    \begin{macrocode}
\tl_new:N \l_@@_presort_tl
\tl_new:N \l_@@_sortkey_tl
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}{\g_@@_previous_after_clist, \g_@@_previous_before_clist}
%   For comparison purposes, the lists of out-of-order notes from the
%   previous \LaTeX{} run are needed.
%    \begin{macrocode}
\clist_new:N \g_@@_previous_after_clist
\clist_new:N \g_@@_previous_before_clist
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}{\g_@@_previous_notes_int}
%   The total number of notes created is needed, as this is used to see
%   if any zero-padding is required for the numbers. Of course, for this
%   to work there has to be a second \LaTeX{} run.
%    \begin{macrocode}
\int_new:N \g_@@_previous_notes_int
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}{\g_@@_notes_tl}
%   Used to collect up the note text for writing in a single block
%   at the end of the document.
%    \begin{macrocode}
\tl_new:N \g_@@_notes_tl
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}{\l_@@_sortkey_field_tl}
%   The key for sorting is called \texttt{key} by standard \BibTeX{} and
%   \texttt{sortkey} by \pkg{biblatex}. It keeps everything clearer if
%   the appropriate name is stored in a token list. The value itself is
%   set up later.
%    \begin{macrocode}
\tl_new:N \l_@@_sortkey_field_tl
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}{\g_@@_total_notes_int}
%   Tracks the total number of notes created, so that the module can tell
%   if any have been used.
%    \begin{macrocode}
\int_new:N \g_@@_total_notes_int
%    \end{macrocode}
% \end{macro}
%
% \subsection{Control options}
%
% \begin{macro}{\@@_cite:w}
%   The underlying function for citation starts off with no value:
%   this is then set up by the key--value settings given next.
%    \begin{macrocode}
\cs_new:Npn \@@_cite:w { }
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}{\g_@@_filename_tl}
% \begin{macro}
%   {
%     \l_@@_keyword_tl        ,
%     \l_@@_note_field_tl     ,
%     \l_@@_note_name_tl      ,
%     \l_@@_presort_after_tl  ,
%     \l_@@_presort_before_tl ,
%     \l_@@_presort_mixed_tl  ,
%     \l_@@_record_type_tl    ,
%     \l_@@_refsection_name_tl,
%     \l_@@_refsection_sep_tl ,
%     \l_@@_record_type_tl    ,
%     \l_@@_sortkey_after_tl  ,
%     \l_@@_sortkey_before_tl ,
%     \l_@@_sortkey_mixed_tl  ,
%     \l_@@_write_sortkey_bool
%  }
%   The various package options are created.
%    \begin{macrocode}
\keys_define:nn { notes2bib }
  {
    cite-function        .code:n      =
      { \AtBeginDocument { \cs_set_eq:NN \@@_cite:w #1 } }     ,
    file-name            .tl_gset_x:N = \g_@@_filename_tl      ,
    convert-endnotes     .choice:                              ,
    convert-endnotes
      / false   .code:n =
      { \AtBeginDocument { \@@_from_bibnote:n { endnote } } }  ,
    convert-endnotes
      / true   .code:n  =
      { \AtBeginDocument { \@@_to_bibnote:n { endnote } } }    ,
    convert-footnotes    .choice:                              ,
    convert-footnotes
      / false   .code:n =
      { \AtBeginDocument { \@@_from_bibnote:n { footnote } } }  ,
    convert-footnotes
      / true   .code:n =
      { \AtBeginDocument { \@@_to_bibnote:n { footnote } } }    ,
    keyword-entry        .tl_set:N    = \l_@@_keyword_tl        ,
    note-field           .tl_set:N    = \l_@@_note_field_tl     ,
    note-name            .tl_set:N    = \l_@@_note_name_tl      ,
    placement            .choice:                               ,
    placement
      / after  .code:n =
      {
        \cs_set_eq:NN \@@_mark_note:n \@@_mark_note_after:n
        \tl_set_eq:NN \l_@@_presort_tl \l_@@_presort_after_tl
        \tl_set_eq:NN \l_@@_sortkey_tl \l_@@_sortkey_after_tl
      },
    placement
      / before .code:n =
      {
        \cs_set_eq:NN \@@_mark_note:n \@@_mark_note_before:n
        \tl_set_eq:NN \l_@@_presort_tl \l_@@_presort_before_tl
        \tl_set_eq:NN \l_@@_sortkey_tl \l_@@_sortkey_before_tl
      },
    placement
      / mixed  .code:n =
      {
        \cs_set_eq:NN \@@_mark_note:n \@@_mark_note_mixed:n
        \tl_set_eq:NN \l_@@_presort_tl \l_@@_presort_mixed_tl
        \tl_set_eq:NN \l_@@_sortkey_tl \l_@@_sortkey_mixed_tl
      },
    presort-after        .tl_set:N    = \l_@@_presort_after_tl   ,
    presort-before       .tl_set:N    = \l_@@_presort_before_tl  ,
    presort-mixed        .tl_set:N    = \l_@@_presort_mixed_tl   ,
    record-type          .tl_set:N    = \l_@@_record_type_tl     ,
    refsection-name      .tl_set:N    = \l_@@_refsection_name_tl ,
    refsection-separator .tl_set:N    = \l_@@_refsection_sep_tl  ,
    sort-key-after       .tl_set:N    = \l_@@_sortkey_before_tl  ,
    sort-key-before      .tl_set:N    = \l_@@_sortkey_after_tl   ,
    sort-key-mixed       .tl_set:N    = \l_@@_sortkey_mixed_tl   ,
    use-sort-key         .bool_set:N  = \l_@@_write_sortkey_bool
  }
%    \end{macrocode}
% \end{macro}
% \end{macro}
%
% Default values for the keys are set up. Many of these probably never
% change, but done in this way the package is much more flexible.
%    \begin{macrocode}
\keys_set:nn { notes2bib }
  {
    cite-function        = \cite              ,
    file-name            = notes2bib-\jobname ,
    keyword-entry        = note               ,
    note-field           = note               ,
    note-name            = Note               ,
    presort-after        = mn                 ,
    presort-before       = ml                 ,
    presort-mixed        = mm                 ,
    record-type          = misc               ,
    refsection-name      = Refsection         ,
    refsection-separator = -                  ,
    sort-key-after       = zzz                ,
    sort-key-before      = aaa                ,
    use-sort-key         = true
}
%    \end{macrocode}
%
% A few options need to be altered or deactivated at the start of
% the document.
%    \begin{macrocode}
\AtBeginDocument
  {
    \@ifpackageloaded { biblatex }
      {
        \@ifpackagelater { biblatex } { 2011/01/08 }
          {
            \keys_set:nn { notes2bib } { record-type = bibnote }
            \DeclareBibliographyDriver { bibnote }
              {
                \usebibmacro { begentry }
                \printfield  { note }
                \setunit { \bibpagerefpunct }
                \newblock
                \usebibmacro { pageref }
                \usebibmacro { finentry }
              }
          }
          { }
      }
      { }
    \keys_define:nn { notes2bib }
      {
        cite-function     .code:n      =
          { \cs_set_eq:NN \@@_cite:w #1 }                                 ,
        file-name .code:n =
          { \msg_info:nnn { notes2bib } { preamble-only } { file-name } } ,
        convert-endnotes / false .code:n =
          { \@@_from_bibnote:n { endnote } }                              ,
        convert-endnotes / true .code:n  =
          { \@@_to_bibnote:n { endnote } }                                ,
        convert-footnotes / false .code:n =
          { \@@_from_bibnote:n { footnote } }                             ,
        convert-footnotes / true .code:n =
          { \@@_to_bibnote:n { footnote } }
      }
  }
\msg_new:nnn { notes2bib } { preamble-only }
  { The~option~'#1'~can~only~be~used~in~the~preamble. }
%    \end{macrocode}
%
% \subsection{Support for \pkg{biblatex} \texttt{refsection} system}
%
% \begin{macro}[EXP]{\@@_insert_refsection:}
%   When using \pkg{biblatex}, it's possible that \texttt{refsection}s are
%   in use. If so, to ensure that labels are always unique the
%   \texttt{refsection} number is added to the label.
%    \begin{macrocode}
\cs_new:Npn \@@_insert_refsection: { }
\AtBeginDocument
  {
    \@ifpackageloaded { biblatex }
      {
        \cs_set:Npn \@@_insert_refsection:
          {
            \int_compare:nNnT { \value { refsection } } > { 0 }
              {
                \tl_use:N \l_@@_refsection_name_tl
                \arabic { refsection }
                \tl_use:N \l_@@_refsection_sep_tl
            }
          }
      }
      { }
  }
%    \end{macrocode}
% \end{macro}
%
% \subsection{Options from version one}
%
% The new option names are preferred, but the old ones still need to
% work correctly.
%    \begin{macrocode}
\keys_define:nn { notes2bib }
  {
    cite        .code:n =
      {
        \use:x
          { \keys_set:nn { notes2bib } { cite-function = \exp_not:c {#1} } }
      } ,
    debug       .code:n = { }                                 ,
    endnotes    .meta:n = { convert-footnotes = #1 }          ,
    etex        .code:n = { }                                 ,
    field       .meta:n = { note-field        = #1 }          ,
    footnotes   .meta:n = { convert-footnotes = #1 }          ,
    head        .meta:n = { placement         = before }      ,
    keyhead     .meta:n = { sort-key-before   = #1 }          ,
    keytail     .meta:n = { sort-key-after    = #1 }          ,
    keynone     .meta:n = { sort-key-mixed    = #1 }          ,
    keyword     .meta:n = { keyword-entry     = #1 }          ,
    log         .meta:n = { }                                 ,
    name        .meta:n = { note-name         = #1 }          ,
    prefix      .meta:n = { file-name         = #1 \jobname } ,
    presorthead .meta:n = { presort-before    = #1 }          ,
    presorttail .meta:n = { presort-after     = #1 }          ,
    presortnone .meta:n = { presort-mixed     = #1 }          ,
    record      .meta:n = { record-type       = #1 }          ,
    sort        .choice:                                      ,
    sort / head .meta:n = { placement         = before }      ,
    sort / none .meta:n = { placement         = after }       ,
    sort / tail .meta:n = { placement         = mixed }       ,
    tail        .meta:n = { placement         = after }       ,
    writekey    .meta:n = { use-sort-key      = #1 }
  }
%    \end{macrocode}
%
% \subsection{Utility functions}
%
% \begin{macro}[EXP]{\@@_note_name:}
%   When note citations are generated automatically, the text to indicate
%   a note plus the number of the current note needs to be turned into
%   something printable. The value tests here mean that if there are more
%   than nine notes, notes 1--9 have the number padded to get proper
%   sorting. This needs two passes, as the total number of notes is only
%   available at the end of the \LaTeX{} run.
%    \begin{macrocode}
\cs_new:Npn \@@_note_name:
  {
    \@@_insert_refsection:
    \tl_use:N \l_@@_note_name_tl
    \int_compare:nNnT \g_@@_previous_notes_int > 9
      { \int_compare:nNnT \g_@@_note_int < { 10 } { 0 } }
    \int_to_arabic:n { \g_@@_note_int }
  }
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}{\@@_filesw:}
%   Making sorting work means messing about with \cs{if@filesw}. The
%   function created here is used to store the current status of the
%   flag. As this is needed for saving \TeX{} true/false status, it's
%   best to set it up from the start as a conditional.
%    \begin{macrocode}
\cs_new_eq:NN \@@_filesw: \tex_iftrue:D
%    \end{macrocode}
% \end{macro}
%
% \subsection{Marking notes in the text}
%
% \begin{macro}{\@@_mark_note:n, \@@_mark_note:x}
%   The function to mark note positions is initially declared with no
%   expansion. The real meaning will be set by the key--value setting,
%   and depends on the placement of notes compared with real citations.
%    \begin{macrocode}
\cs_new_protected:Npn \@@_mark_note:n #1 { }
\cs_generate_variant:Nn \@@_mark_note:n { x }
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}{\@@_mark_note_after:n}
% \begin{macro}[aux]{\@@_mark_note_after_aux:n}
%   For notes which come after citations, the entry is recorded and an
%   auxiliary is called. The nature of the second function is dependent
%   on the other packages loaded.
%    \begin{macrocode}
\cs_new_protected:Npn \@@_mark_note_after:n #1
  {
    \int_gincr:N \g_@@_total_notes_int
    \clist_gput_right:Nx \g_@@_after_clist {#1}
    \@@_mark_note_after_aux:n {#1}
  }
\cs_new_protected:Npn \@@_mark_note_after_aux:n #1 { }
%    \end{macrocode}
% \end{macro}
% \end{macro}
%
% \begin{macro}{\@@_mark_note_before:n}
%   Notes to appear before all citations are simple recorded, as they will
%   be set up on the next \LaTeX{} run.
%    \begin{macrocode}
\cs_new_protected:Npn \@@_mark_note_before:n #1
  {
    \int_gincr:N \g_@@_total_notes_int
    \clist_gput_right:Nx \g_@@_before_clist {#1}
    \@@_cite:w {#1}
  }
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}{\@@_mark_note_mixed:n}
%   Mixed citations are very easy to handle: just use whatever cite
%   command is current.
%    \begin{macrocode}
\cs_new_protected:Npn \@@_mark_note_mixed:n #1
  {
    \int_gincr:N \g_@@_total_notes_int
    \@@_cite:w {#1}
  }
%    \end{macrocode}
% \end{macro}
%
% \subsection{Writing note text to the database}
%
% \begin{macro}[EXP]{\@@_write_field:nn, \@@_write_field:Vn}
%   To keep the auto-generated database readable, there needs to be some
%   formatting. This is provided by using a dedicated function to
%   write the various fields to it. Although the \texttt{V} variant is
%   not technically needed (writing expands everything), it helps to keep
%   the intention of the code here clearer.
%    \begin{macrocode}
\cs_new:Npn \@@_write_field:nn #1#2
  {
    \c_space_tl \c_space_tl #1 \c_space_tl = \c_space_tl {#2} ,
    \iow_newline:
  }
\cs_generate_variant:Nn \@@_write_field:nn { V }
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}{\notestobib_write_note:nn, \notestobib_write_note:xn}
% \begin{macro}[aux]{\@@_write_note:nn}
%    The writing function takes two arguments: the name of the note, and
%    the text itself. There is a need to check on the \LaTeXe{} system to
%    turn off writing, with a hand-over so there is no problem with
%    balancing ifs.
%    \begin{macrocode}
\cs_new_protected:Npn \notestobib_write_note:nn
  {
    \if@filesw
      \exp_after:wN \@@_write_note:nn
    \else:
      \exp_after:wN \use_none:nn
    \fi:
  }
\cs_generate_variant:Nn \notestobib_write_note:nn { x }
\cs_new_protected:Npn \@@_write_note:nn #1#2
  {
    \tl_gput_right:Nx \g_@@_notes_tl
      {
        @ \l_@@_record_type_tl
          {
            #1 , \iow_newline:
            \@@_write_field:Vn \l_@@_note_field_tl { \exp_not:n {#2} }
            \bool_if:NT \l_@@_write_sortkey_bool
              {
                \@@_write_field:Vn \l_@@_sortkey_field_tl
                  { \l_@@_sortkey_tl #1 }
              }
            \@@_write_field:nn { keywords } { \l_@@_keyword_tl }
            \@@_write_field:nn { presort } { \l_@@_presort_tl }
          }
        \iow_newline:
        \iow_newline:
      }
  }
%    \end{macrocode}

% \end{macro}
% \end{macro}
%
% \subsection{Handling out of order notes}
%
% \begin{macro}{\@@_record_notes:}
% \begin{macro}[aux]{\@@_flush_notes_aux:}
%   Notes after citations are not written to the \file{aux} file when
%   given, but are held in a queue. This is flushed here, which means
%   actually doing the citation and also recording the notes so they
%   are available in the next \LaTeX{} run. The list is also transferred
%   to a secondary one, which is used for comparison purposes right at the
%   end of the document.
%    \begin{macrocode}
\cs_new_protected:Npn \@@_record_notes:
  {
    \if@filesw
      \exp_after:wN \@@_flush_notes_aux:
    \fi
  }
\cs_new_protected:Npn \@@_flush_notes_aux:
  {
    \clist_if_empty:NF \g_@@_before_clist
      {
        \iow_now:Nx \@auxout
          { \NotesBeforeCitations { \exp_not:V \g_@@_before_clist } }
        \clist_gput_right:NV \g_@@_all_before_clist \g_@@_before_clist
        \clist_gclear:N \g_@@_before_clist
      }
    \clist_if_empty:NF \g_@@_after_clist
      {
        \iow_now:Nx \@auxout
          { \NotesAfterCitations { \exp_not:V \g_@@_after_clist } }
        \exp_args:NV \nocite \g_@@_after_clist
        \clist_gput_right:NV \g_@@_all_after_clist \g_@@_after_clist
        \clist_gclear:N \g_@@_after_clist
      }
  }
%    \end{macrocode}
% \end{macro}
% \end{macro}
%
% \subsection{Interchanging note types}
%
% \begin{macro}{\@@_to_bibnote:n}
%   Converting other notes to bibliography notes is simple: just set
%   them equal.
%    \begin{macrocode}
\cs_new_protected:Npn \@@_to_bibnote:n #1
  {
    \cs_set_eq:cN {#1}        \bibnote
    \cs_set_eq:cN { #1 mark } \bibnotemark
    \cs_set_eq:cN { #1 text } \bibnotetext
  }
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}{\@@_from_bibnote:n}
%   The reverse process needs the original definitions, which are saved
%   by the module for later recovery.
%    \begin{macrocode}
\cs_new_protected:Npn \@@_from_bibnote:n #1
  {
    \cs_set_eq:cc {#1}        { @@_ #1 :w }
    \cs_set_eq:cc { #1 mark } { @@_ #1 mark:w }
    \cs_set_eq:cc { #1 text } { @@_ #1 text:w }
  }
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}
%   {
%     \@@_endnote:w     ,
%     \@@_endnotemark:w ,
%     \@@_endnotetext:w ,
%     \@@_footnote:w    ,
%     \@@_footnotemark:w,
%     \@@_footnotetext:w
%   }
%   At the start of the document, the definitions for endnotes and
%   footnotes are saved so that footnotes and endnotes can be turned into
%   bibliography notes and back again.
%    \begin{macrocode}
\AtBeginDocument
  {
    \cs_new_eq:NN \@@_endnote:w     \endnote
    \cs_new_eq:NN \@@_endnotemark:w \endnotemark
    \cs_new_eq:NN \@@_endnotetext:w \endnotetext
    \cs_new_eq:NN \@@_footnote:w     \footnote
    \cs_new_eq:NN \@@_footnotemark:w \footnotemark
    \cs_new_eq:NN \@@_footnotetext:w \footnotetext
  }
%    \end{macrocode}
% \end{macro}
%
% \subsection{Package-dependent code}
%
% \begin{macro}{\@@_create_print_notes:, \@@_print_notes:}
%   The method for printing notes depends on whether \pkg{biblatex} is
%   in use. If it is, then a selective call to \cs{printbibliography} is
%   made. Otherwise, the original \cs{bibliography} function is called,
%   and passed the name of the notes file.
%    \begin{macrocode}
\AtBeginDocument
  {
    \@ifpackageloaded { biblatex }
      {
        \cs_new_protected:Npn \@@_print_notes:
          {
            \cs_set:Npx \@@_create_print_notes:
              {
                \printbibliography
                  [ keyword = \exp_not:V \l_@@_keyword_tl ]
              }
              \@@_create_print_notes:
          }
      }
      {
        \cs_new_protected:Npn \@@_print_notes:
          { \exp_args:NV \@@_bibliography:n \g_@@_filename_tl }
      }
  }
\cs_new_protected:Npn \@@_create_print_notes: { }
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}{\@@_attach_bibliography:}
% \begin{macro}{\bibliography}
% \begin{macro}{\@@_bibliography:n}
%   Getting the database created here to be scanned by \BibTeX{} is
%   dependant on whether \pkg{biblatex} is being used. If it is, and it is
%   already loaded, then the data can be added now. On the other hand, if
%   it is not already loaded a check is made at the end of the preamble.
%   The \cs{bibliography} function has to be patched if \pkg{biblatex} is
%   not in use.
%    \begin{macrocode}
\cs_new_protected:Npn \@@_attach_bibliography:
  {
    \@ifpackageloaded { biblatex }
      {
        \@ifpackagelater { biblatex } { 2011/01/08 }
          {
            \@ifpackagelater { biblatex } { 2011/02/12 }
              { \exp_args:No \addglobalbib { \g_@@_filename_tl .bib } }
              { \exp_args:NNV \bibliography * \g_@@_filename_tl }
          }
          { \exp_args:NV \bibliography \g_@@_filename_tl }
      }
      {
        \cs_new_eq:NN \@@_bibliography:n \bibliography
        \RenewDocumentCommand \bibliography { m }
          {
            \int_compare:nNnTF \g_@@_total_notes_int = 0
              { \@@_bibliography:n {##1} }
              {
                \cs_set:Npx \@@_attach_bibliography:
                  {
                    \exp_not:N \@@_bibliography:n
                      { \exp_not:n {##1} , \exp_not:V \g_@@_filename_tl }
                  }
                \@@_attach_bibliography:
              }
          }
      }
  }
\@ifpackageloaded { biblatex }
  {
    \@ifpackagelater { biblatex } { 2011/01/08 }
      {
        \@ifpackagelater { biblatex } { 2011/02/12 }
          { \exp_args:No \addglobalbib { \g_@@_filename_tl .bib } }
          { \exp_args:NNV \bibliography * \g_@@_filename_tl }
      }
      { \exp_args:NV \bibliography \g_@@_filename_tl }
  }
  { \AtBeginDocument { \@@_attach_bibliography: } }
%    \end{macrocode}
% \end{macro}
% \end{macro}
% \end{macro}
%
% \pkg{biblatex} uses the name \texttt{sortkey} for a key to sort by,
% whereas other style call the same concept \texttt{key}.
%    \begin{macrocode}
\AtBeginDocument
  {
    \@ifpackageloaded { biblatex }
      { \tl_set:Nn \l_@@_sortkey_field_tl { sortkey } }
      { \tl_set:Nn \l_@@_sortkey_field_tl { key } }
  }
%    \end{macrocode}
%
% To get the correct ordering for notes, writing to the \file{aux} file
% needs to be turned on and off. With \pkg{biblatex}, there is a
% convenient hook for this. Otherwise, everything has to happen after
% the citation command.
%    \begin{macrocode}
\AtBeginDocument
  {
    \@ifpackageloaded { biblatex }
      {
        \cs_set_protected:Npn \@@_mark_note_after_aux:n #1
          {
            \AtNextCite { \@fileswfalse }
            \@@_cite:w {#1}
          }
      }
      {
        \cs_set_protected:Npn \@@_mark_note_after_aux:n #1
          {
            \cs_set_eq:NN \@@_filesw: \if@filesw
            \@fileswfalse
            \@@_cite:w {#1}
            \cs_set_eq:NN \if@filesw \@@_filesw:
          }
      }
  }
%    \end{macrocode}
%
% \begin{macro}{\@@_aux_hook:}
%   If the \pkg{cite} package is loaded, then there is a hook to
%   reset the \file{aux} file after the citation. This means that moving
%   punctuation will still work under these circumstances.  However, the
%   way \pkg{cite} sets things up is a little complicated. The link needs
%   to be made at the end of the \cs{document} macro.
%    \begin{macrocode}
\AtBeginDocument
  {
    \@ifpackageloaded { cite }
      {
        \cs_set_protected:Npn \@@_mark_note_after_aux:n #1
          {
            \cs_set_eq:NN \@@_filesw: \if@filesw
            \@fileswfalse
            \cs_set:Npn \@@_aux_hook:
              {
                \cs_set_eq:NN \if@filesw \@@_filesw:
                \cs_set:Npn \@@_aux_hook: { }
              }
            \@@_cite:w {#1}
          }
        \cs_new:Npn \@@_aux_hook: { }
        \tl_gput_right:Nn \g_@@_document_hook_tl
          {
            \cs_if_exist:NF \@restore@auxhandle
              { \tl_new:N \@restore@auxhandle }
            \tl_put_right:Nn \@restore@auxhandle { \@@_aux_hook: }
          }
      }
      { }
  }
%    \end{macrocode}
% \end{macro}
%
%\subsection{User functions}
%
% \begin{macro}{\bibnote}
% \begin{macro}{\@@_bibnote:nn, \@@_bibnote:xn}
%   Creating a not from scratch is a multi-step operation. First, check
%   if a label was given by the user. If it was not, then one is created
%   by incrementing the automatic number and fully expanding
%   \cs{@@_note_name:}. The second phase is to create the note. The text
%   is dealt with first as this leaves the note-marking code at the end
%   of the function (needed if punctuation is to be moved).
%    \begin{macrocode}
\NewDocumentCommand \bibnote { o +m }
  {
    \IfNoValueTF {#1}
      {
        \int_gincr:N \g_@@_note_int
        \@@_bibnote:xn { \@@_note_name: } {#2}
      }
      { \@@_bibnote:xn { \@@_insert_refsection: #1 } {#2} }
  }
\cs_new_protected:Npn \@@_bibnote:nn #1#2
  {
    \notestobib_write_note:nn {#1} {#2}
    \@@_mark_note:n {#1}
  }
\cs_generate_variant:Nn \@@_bibnote:nn { x }
%    \end{macrocode}
% \end{macro}
% \end{macro}
%
% \begin{macro}{\bibnotemark}
%   Simply marking a note has similar requirements, but as there is only
%   a single internal function to call the code is less complex.
%    \begin{macrocode}
\NewDocumentCommand \bibnotemark { o }
  {
    \IfNoValueTF {#1}
      {
        \int_gincr:N \g_@@_note_int
        \@@_mark_note:x { \@@_note_name: }
      }
      { \@@_mark_note:x { \@@_insert_refsection: #1 } }
  }
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}{\bibnotetext}
%   As text for a note uses the same number as the preceding mark,
%   things are slightly less complex here. The basic \texttt{o} argument
%   type is used as this means that full expansion of the note name can
%   take place \enquote{early}.
%    \begin{macrocode}
\NewDocumentCommand \bibnotetext { o +m }
  {
    \IfNoValueTF {#1}
      { \notestobib_write_note:xn { \@@_note_name: } {#2} }
      { \notestobib_write_note:xn { \@@_insert_refsection: #1 } {#2} }
  }
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}{\recordnotes}
%   A direct call to the internal function: no arguments are needed.
%    \begin{macrocode}
\NewDocumentCommand \recordnotes { }
  { \@@_record_notes: }
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}{\bibnotesetup}
% A user set up function.
%    \begin{macrocode}
\NewDocumentCommand \bibnotesetup { m }
  { \keys_set:nn { notes2bib } {#1} }
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}{\printbibnotes}
%   A direct translation for the internal function.
%    \begin{macrocode}
\NewDocumentCommand \printbibnotes { }
  { \@@_print_notes: }
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}{\citenote}
% \begin{macro}{\flushnotestack}
% \begin{macro}{\niibsetup}
%   A few functions which are depreciated in version two.
%    \begin{macrocode}
\NewDocumentCommand \citenote { m }
  { \@@_mark_note:n {#1} }
\cs_new_eq:NN \flushnotestack \recordnotes
\cs_new_eq:NN \niibsetup      \bibnotesetup
%    \end{macrocode}
% \end{macro}
% \end{macro}
% \end{macro}
%
% \subsection{Auxiliary file functions}
%
% \pkg{notes2bib} needs to write information to the \file{aux} file
% for carrying information between runs. Rather than give them cryptic
% names, they have long design-level ones. They are also declared
% as protected functions so that writing to the \file{aux} file is
% easier.
%
% \begin{macro}{\NotesAfterCitations}
% \begin{macro}{\NotesBeforeCitations}
%   The functions to pass information on out-of-order notes from one
%   run to another both add the information to the appropriate lists.
%   For notes before citations, there is also a need to put the
%   \cs{citation} calls into the \file{aux} file at the correct stage.
%    \begin{macrocode}
\cs_new_protected:Npn \NotesAfterCitations #1
  { \clist_gput_right:Nn \g_@@_previous_after_clist {#1} }
\cs_new_protected:Npn \NotesBeforeCitations #1
  {
    \clist_gput_right:Nn \g_@@_previous_after_clist {#1}
    \tl_gput_right:Nn \g_@@_document_hook_tl { \nocite {#1} }
  }
%    \end{macrocode}
% \end{macro}
% \end{macro}
%
% \begin{macro}{\TotalNotes}
%   This function allows the total number of bibliography notes to be
%   carried forward from one run to the next.
%    \begin{macrocode}
\cs_new_protected:Npn \TotalNotes #1
  { \int_gset:Nn \g_@@_previous_notes_int {#1} }
%    \end{macrocode}
% \end{macro}
%
% \subsection{Code at the start of the document}
%
% \begin{macro}{\g_@@_document_hook_tl}
%   \pkg{notes2bib} needs to be able to carry out a few tasks right at the
%   beginning of the document. To do that, a hook is added to the
%   \cs{document} macro, which can be treated as a token list variable
%   as it has no arguments.
%    \begin{macrocode}
\tl_gput_right:Nn \document { \g_@@_document_hook_tl }
\tl_new:N \g_@@_document_hook_tl
%    \end{macrocode}
% \end{macro}
%
% \subsection{Code at end of the document}
%
% There are a few tasks which have to be carried out a the end of
% the \LaTeX{} run, so that data is available for the next run.
%
% First, all of the notes need to be added to the auxiliary file.
% This ensures that the comparisons made in the next step make sense.
%    \begin{macrocode}
\AtEndDocument { \@@_record_notes: }
%    \end{macrocode}
%
% The list of out-of-order notes from the current run needs to match
% that from the previous run. If not, then there is a need to re-run
% \LaTeX{}.
%    \begin{macrocode}
\AtEndDocument
  {
    \tl_if_eq:NNTF \g_@@_all_before_clist \g_@@_previous_before_clist
      {
        \tl_if_eq:NNF \g_@@_all_after_clist \g_@@_previous_after_clist
          { \msg_info:nn { notes2bib } { rerun } }
      }
      { \msg_info:nn { notes2bib } { rerun } }
  }
\msg_new:nnn { notes2bib } { rerun }
  {
    To~get~notes~in~the~correct~order,~please~run: \\%
    \c_space_tl 1)~LaTeX  \\
    \c_space_tl 2)~BibTeX \\
    \c_space_tl 3)~LaTeX
  }
%    \end{macrocode}
%
% \begin{macro}{\@@_write_note_file:}
% \begin{macro}{\g_@@_file_iow}
% The notes themselves are now written in one block: this avoids
% using up a stream for any longer than necessary.
%    \begin{macrocode}
\AtEndDocument
  {
    \if@filesw
      \exp_after:wN \@@_write_note_file:
    \fi:
  }
\cs_new_protected:Npn \@@_write_note_file:
  {
    \tl_if_empty:NF \g_@@_notes_tl
      {
        \iow_open:Nn \g_@@_file_iow { \g_@@_filename_tl .bib }
        \iow_now:Nx \g_@@_file_iow { \c_@@_file_message_tl }
        \iow_now:Nx \g_@@_file_iow { \exp_not:V \g_@@_notes_tl }
        \iow_close:N \g_@@_file_iow
      }
  }
\iow_new:N \g_@@_file_iow
%    \end{macrocode}
% \end{macro}
% \end{macro}
%
% The total number of bibliography notes from the current run is
% recorded to the \file{aux} file. This will then be picked up in the
%    \begin{macrocode}
\AtEndDocument
  {
    \int_compare:nNnT \g_@@_note_int > 0
      {
        \iow_now:Nx \@auxout
          { \TotalNotes { \int_to_arabic:n { \g_@@_note_int } } }
      }
  }
%    \end{macrocode}
%
% \subsection{Tidying up}
%
% \begin{macro}{\thanks}
%   The \cs{thanks} macro has to be replaced by one that uses the original
%   \cs{footnotemark} and \cs{footnotetext} under all circumstances. This
%   is the kernel definition modified: if an alternative version is in use
%   things may go wrong.
%    \begin{macrocode}
\cs_set:Npn \thanks #1
  {
    \@@_footnotemark:w
    \protected@xdef \@thanks
      {
        \@thanks
        \protect \@@_footnotetext:w [ \the \c@footnote ] {#1}
      }
  }
%    \end{macrocode}
% \end{macro}
%
% The final job is to set note placement: this is done here as various
% parts of the module need to be in place for this to work correctly.
%    \begin{macrocode}
\keys_set:nn { notes2bib } { placement = mixed }
%    \end{macrocode}
%
% Any load time options are processed.
%    \begin{macrocode}
\ProcessKeysOptions { notes2bib }
%    \end{macrocode}
%
%    \begin{macrocode}
%</package>
%    \end{macrocode}
%
% \end{implementation}
%
% \PrintChanges
% \PrintIndex