% \iffalse meta-comment
%
% Copyright (c) 2022 David Purton <dcpurton@marshwiggle.net>
%
% This work may be distributed and/or modified under the conditions of
% the LaTeX Project Public License, either version 1.3c of this license
% or (at your option) any later version. The latest version of this
% license is in
%    http://www.latex-project.org/lppl.txt
% and version 1.3c or later is part of all distributions of LaTeX
% version 2005/12/01 or later.
%
%<*driver>
\documentclass[a4paper]{l3doc}
\usepackage[parindent=1em]{scripture}
\usepackage[skins]{tcolorbox}
\newtcolorbox{scriptureexample}[1][]{%
  bicolor, colframe=cyan, colback=cyan!10, colbacklower=white, left=2mm,
  right=2mm, fontupper=\footnotesize, fontlower=\footnotesize, sidebyside,
  sidebyside gap=6mm, sidebyside align=top, lefthand ratio=0.6, before
  skip=\bigskipamount, after skip=\bigskipamount, #1
}
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\begin{document}
\DocInput{\jobname.dtx}
\end{document}
%</driver>
% \fi
%
% \changes{v1.0}{2022/07/27}{First public release}
%
% \title{The \pkg{scripture} package}
% \author{David Purton\thanks{Email: \url{dcpurton@marshwiggle.net}}}
% \date{2022/07/27 v1.0}
%
% \maketitle
%
% \begin{abstract}
%   The \pkg{scripture} package provides a set of macros for typesetting
%   quotations from the Bible. It provides many features commonly seen in
%   Bibles such as dropped text for chapter numbers, superscripts for verse
%   numbers, indented lines for poetry sections, narrow sections and hanging
%   paragraphs. A reference for the quotation can optionally be added.
% \end{abstract}
%
% \tableofcontents
%
% \begin{documentation}
%
% \section{Introduction}
%
% Bibles tend to use a number of standard features when laying out chapters
% and verses. The main goal for the \pkg{scripture} package is to be able to
% quickly and easily input text and have it output nicely with minimal manual
% adjustment.
%
% The package supports dropped text for chapter numbers, superscripts for
% verse numbers, appropriately indented lines for the first and second halves
% of poetry, flush right sections, centred sections, narrow sections and
% hanging sections.
%
% The package could be used for typesetting an entire Bible, but it is mainly
% envisioned that it will be used for producing Scripture quotations. The
% passage reference can be included on the last line if there is space or
% failing that on the following line.
%
% \subsection{Bug reports and feature requests}
%
% Bug reports and feature requests can be made at the \pkg{scripture} package
% GitHub repository. See \url{https://github.com/dcpurton/scripture}.
%
% \subsection{Limitations}
%
% The \pkg{scripture} package makes extensive use of \LaTeX{} \env{list}
% environments and the \cs{parshape} command. This means there are some
% limitations. In particular, you should not:
% \begin{itemize}
%   \item Nest the \env{scripture} environment or any of its internal
%     environments.
%   \item Modify the \cs{parshape} within a \env{scripture} environment.
%   \item Include any other \env{list} based environment within a
%     \env{scripture} environment.
% \end{itemize}
%  
% \section{Documentation}
%
% \subsection{Basic usage}
%
% Scripture quotations must be set within a \env{scripture} environment. A
% simple quotation might be produced as follows:
%
% \begin{scriptureexample}
% \begin{verbatim}
% \begin{scripture}[Isaiah 56:1--2][version=NIVUK]
%   \ch{56}This is what the \textsc{Lord} says:
% 
%   \begin{poetry}
%     `Maintain justice
%     and do what is right,
% 
%     for my salvation is close at hand
%     and my righteousness will soon be revealed.
% 
%     \vs{2}Blessed is the one who does this---
%     the person who holds it fast,
% 
%     who keeps the Sabbath without desecrating it,
%     and keeps their hands from doing any evil.'
%   \end{poetry}
% \end{scripture}
% \end{verbatim}
%
% \tcblower
% 
% \begin{scripture}[Isaiah 56:1--2][version=NIVUK]
%   \ch{56}This is what the \textsc{Lord} says:
% 
%   \begin{poetry}
%     `Maintain justice
%     and do what is right,
% 
%     for my salvation is close at hand
%     and my righteousness will soon be revealed.
% 
%     \vs{2}Blessed is the one who does this---
%     the person who holds it fast,
% 
%     who keeps the Sabbath without desecrating it,
%     and keeps their hands from doing any evil.'
%   \end{poetry}
% \end{scripture}
% \end{scriptureexample}
%
% \subsection{Macros for typesetting scripture quotations}
%
% \subsubsection{Functions}
%
% \begin{function}{\ch, \ch*}
%   \begin{syntax}
%     |\ch|\marg{chapter number}
%     |\ch*|\marg{chapter number}
%   \end{syntax}
%   Format a chapter number. By default these are formatted using drop text
%   taking up two lines and the text is separated from the chapter number by a
%   horizontal space of 0.5\,em.
%
%   If the \opt{dropchap} option is \val{true} (default), then this function
%   attempts to add sufficient space for the dropped chapter when its
%   paragraph contains only one line. The starred version suppresses this
%   behaviour.
% \end{function}
%
% \begin{function}{\extraskip}
%   \begin{syntax}
%     |\extraskip|
%   \end{syntax}
%   Add a small vertical space of \opt{extraskip} between a paragraph. This
%   function attempts to add additional space to avoid a clash with a drop
%   chapter if required.
% \end{function}
%
% \begin{function}{\nohang}
%   \begin{syntax}
%     |\nohang|
%   \end{syntax}
%   In a \env{hanging} environment, this function indents the first line of
%   the paragraph a length of \opt{hanging/hang} $+$ \opt{parindent}.
%   Remaining lines continue to be indented by a length of \opt{hanging/hang}.
% \end{function}
%
% \begin{function}{\scripturesetup}
%   \begin{syntax}
%     |\scripturesetup|\marg{options}
%   \end{syntax}
%   Set default format for quotations. See section \ref{options} for
%   supported formatting \meta{|options|}.
% \end{function}
%
% \begin{function}{\vs}
%   \begin{syntax}
%     |\vs|\marg{verse number}
%   \end{syntax}
%   Format a verse number. By default these are formatted using a superscript.
% \end{function}
%
% \subsubsection{Environments}
% 
% All scripture quotations must be set within a \env{scripture} environment.
% The rest of the environments documented below are only defined with the
% \env{scripture} environment. In most cases there is a default small
% \meta{\opt{aboveskip}} and \meta{\opt{belowskip}} inserted above and below
% these internal environments, but these are ignored if the environment is at
% the start or end of a \env{scripture} environment.
%
% \begin{environment}{center}
%   \begin{syntax}
%     |\begin{center}|\oarg{options}
%       \quad\meta{centred text}
%     |\end{center}|
%   \end{syntax}
% \end{environment}
%
% \noindent Environment for typesetting centred sections of scripture
% quotations.
%
% See section \ref{centeroptions} for supported formatting \meta{|options|}.
%
% \begin{scriptureexample}
% \begin{verbatim}
% \begin{scripture}[Daniel 5:25]
%   \vs{25}‘This is the inscription that was
%   written:
%
%   \begin{center}
%     \textsc{mene, mene, tekel, parsin}
%   \end{center}
% \end{scripture}
% \end{verbatim}
%
% \tcblower
% 
% \begin{scripture}[Daniel 5:25]
%   \vs{25}‘This is the inscription that was
%   written:
%
%   \begin{center}
%     \textsc{mene, mene, tekel, parsin}
%   \end{center}
% \end{scripture}
% \end{scriptureexample}
%
% \begin{environment}{flushright}
%   \begin{syntax}
%     |\begin{flushright}|\oarg{options}
%       \quad\meta{right aligned text}
%     |\end{flushright}|
%   \end{syntax}
% \end{environment}
%
% \noindent Environment for typesetting right aligned sections of scripture
% quotations.
%
% See section \ref{flushrightoptions} for supported formatting
% \meta{|options|}.
%
% \begin{scriptureexample}
% \begin{verbatim}
% \begin{scripture}[Jeremiah 2:29]
%   \begin{poetry}[belowskip=0pt]
%     \vs{5}‘Why do you bring charges against me?
%     You have all rebelled against me,’
%   \end{poetry}
%
%   \begin{flushright}[aboveskip=0pt]
%     declares the \textsc{Lord}.
%   \end{flushright}
% \end{scripture}
% \end{verbatim}
%
% \tcblower
% 
% \begin{scripture}[Jeremiah 2:29]
%   \begin{poetry}[belowskip=0pt]
%     \vs{5}‘Why do you bring charges against me?
%     You have all rebelled against me,’
%   \end{poetry}
%
%   \begin{flushright}[aboveskip=0pt]
%     declares the \textsc{Lord}.
%   \end{flushright}
% \end{scripture}
% \end{scriptureexample}
%
% \begin{environment}{hanging}
%   \begin{syntax}
%     |\begin{hanging}|\oarg{options}
%       \quad\meta{hanging text}
%     |\end{hanging}|
%   \end{syntax}
% \end{environment}
%
% \noindent Environment for typesetting hanging sections of scripture
% quotations.
%
% See section \ref{hangingoptions} for supported formatting \meta{|options|}.
%
% \begin{scriptureexample}
% \begin{verbatim}
% \begin{scripture}[Genesis 1:3--5]
%   \begin{hanging}
%     \vs{3}And God said, ‘Let there be light,’ and
%     there was light. \vs{4}God saw that the light
%     was good, and he separated the light from the
%     darkness. \vs{5}God called the light ‘day’,
%     and the darkness he called ‘night’. And there
%     was evening, and there was morn\-ing---the
%     first day.
%   \end{hanging}
% \end{scripture}
% \end{verbatim}
%
% \tcblower
% 
% \begin{scripture}[Genesis 1:3--5]
%   \begin{hanging}
%     \vs{3}And God said, ‘Let there be light,’ and
%     there was light. \vs{4}God saw that the light
%     was good, and he separated the light from the
%     darkness. \vs{5}God called the light ‘day’,
%     and the darkness he called ‘night’. And there
%     was evening, and there was morn\-ing---the
%     first day.
%   \end{hanging}
% \end{scripture}
% \end{scriptureexample}
%
% \begin{environment}{midparachap}
%   \begin{syntax}
%     |\begin{midparachap}|
%       \quad\meta{text containing a chapter break}
%     |\end{midparachap}|
%   \end{syntax}
% \end{environment}
%
% \noindent Environment for typesetting paragraph with a chapter break within
% it.
%
% \begin{scriptureexample}
% \begin{verbatim}
% \begin{scripture}[1 Corinthians 10:31--11:1]
%   \begin{midparachap}
%     \vs{31}So whether you eat or drink or
%     whatever you do, do it all for the glory of
%     God. \vs{32}Do not cause anyone to stumble,
%     whether Jews, Greeks or the church of
%     God---\vs{33}even as I try to please everyone
%     in every way. For I am not seeking my own
%     good but the good of many, so that they may
%     be saved. \ch{11}Follow my example, as I
%     follow the example of Christ.
%   \end{midparachap}
% \end{scripture}
% \end{verbatim}
%
% \tcblower
% 
% \begin{scripture}[1 Corinthians 10:31--11:1]
%   \begin{midparachap}
%     \vs{31}So whether you eat or drink or
%     whatever you do, do it all for the glory of
%     God. \vs{32}Do not cause anyone to stumble,
%     whether Jews, Greeks or the church of
%     God---\vs{33}even as I try to please everyone
%     in every way. For I am not seeking my own
%     good but the good of many, so that they may
%     be saved. \ch{11}Follow my example, as I
%     follow the example of Christ.
%   \end{midparachap}
% \end{scripture}
% \end{scriptureexample}
%
% \begin{environment}{narrow}
%   \begin{syntax}
%     |\begin{narrow}|\oarg{options}
%       \quad\meta{quotation}
%     |\end{narrow}|
%   \end{syntax}
% \end{environment}
%
% \noindent Environment for typesetting narrow sections of scripture
% quotations.
%
% See section \ref{narrowoptions} for supported formatting \meta{|options|}.
%
% \begin{scriptureexample}
% \begin{verbatim}
% \begin{scripture}[2 Kings 18:18--19]
%   \vs{18}They called for the king; and Eliakim
%   son of Hilkiah the palace administrator, Shebna
%   the secretary, and Joah son of Asaph the
%   recorder went out to them.
%
%   \vs{19}The field commander said to them, ‘Tell
%   Hezekiah:
%
%   \begin{narrow}
%     ‘“This is what the great king, the king of
%     Assyria, says: on what are you basing this
%     confidence of yours?
%   \end{narrow}
% \end{scripture}
% \end{verbatim}
%
% \tcblower
% 
% \begin{scripture}[2 Kings 18:18--19]
%   \vs{18}They called for the king; and Eliakim
%   son of Hilkiah the palace administrator, Shebna
%   the secretary, and Joah son of Asaph the
%   recorder went out to them.
%
%   \vs{19}The field commander said to them, ‘Tell
%   Hezekiah:
%
%   \begin{narrow}
%     ‘“This is what the great king, the king of
%     Assyria, says: on what are you basing this
%     confidence of yours?
%   \end{narrow}
% \end{scripture}
% \end{scriptureexample}
%
% \begin{environment}{poetry}
%   \begin{syntax}
%     |\begin{poetry}|\oarg{options}
%       \quad\meta{first half of verse}
%       \quad\meta{second half of verse}
%       \quad
%       \quad\meta{first half of verse}
%       \quad\meta{second half of verse}
%     |\end{poetry}|
%   \end{syntax}
% \end{environment}
%
% \noindent Environment for typesetting poetry sections of scripture
% quotations.
%
% Poetry sections of the Bible often have a first have and a parallel second
% half which is indented a little. These should be set on separate consecutive
% lines. Leaving a blank line indicates that the next line should return to
% the first half indent.
%
% See section \ref{poetryoptions} for supported formatting \meta{|options|}.
%
% \begin{scriptureexample}
% \begin{verbatim}
% \begin{scripture}[Isaiah 1:2]
%   \begin{poetry}
%     \vs{2}Hear me, you heavens! Listen, earth!
%     For the \textsc{Lord} has spoken:
%
%     ‘I reared children and brought them up,
%     but they have rebelled against me.
%   \end{poetry}
% \end{scripture}
% \end{verbatim}
%
% \tcblower
% 
% \begin{scripture}[Isaiah 1:2]
%   \begin{poetry}
%     \vs{2}Hear me, you heavens! Listen, earth!
%     For the \textsc{Lord} has spoken:
%
%     ‘I reared children and brought them up,
%     but they have rebelled against me.
%   \end{poetry}
% \end{scripture}
% \end{scriptureexample}
%
% \begin{environment}{scripture}
%   \begin{syntax}
%     |\begin{scripture}|\oarg{reference}\oarg{options}
%       \quad\meta{quotation}
%     |\end{scripture}|
%   \end{syntax}
% \end{environment}
%
% \noindent Main environment for typesetting scripture quotations.
%
% The optional \meta{|reference|} is printed at the end of the quotation. See
% section \ref{options} for supported formatting \meta{|options|}.
%
% \begin{scriptureexample}
% \begin{verbatim}
% \begin{scripture}[John 3:16][version=NIV]
%   \vs{16}For God so loved the world that he gave
%   his one and only Son, that whoever believes in
%   him shall not perish but have eternal life.
% \end{scripture}
% \end{verbatim}
%
% \tcblower
% 
% \begin{scripture}[John 3:16][version=NIV]
%   \vs{16}For God so loved the world that he gave
%   his one and only Son, that whoever believes in
%   him shall not perish but have eternal life.
% \end{scripture}
% \end{scriptureexample}
%
% \subsection{Options}
% \label{options}
%
% Default formatting \meta{|options|} can be set using
% \cs{usepackage}|[|\meta{|options|}|]{scripture}| or
% \cs{scripturesetup}|{|\meta{|options|}|}|. Local formatting \meta{|options|}
% can be set by passing them to the various environments described above.
%
% \begin{option}{aboveskip}
%   \begin{syntax}
%     |aboveskip =| \meta{skip} \hfill Default: 0pt
%   \end{syntax}
%   \meta{|skip|} inserted above the \env{scripture} environment.
% \end{option}
%
% \begin{option}{belowskip}
%   \begin{syntax}
%     |belowskip =| \meta{skip} \hfill Default: 0pt
%   \end{syntax}
%   \meta{|skip|} inserted below the \env{scripture} environment.
% \end{option}
%
% \begin{option}{leftmargin}
%   \begin{syntax}
%     |leftmargin =| \meta{dimen} \hfill Default: 0pt
%   \end{syntax}
%   \meta{|dimen|} used for the left margin of the \env{scripture}
%   environment.
% \end{option}
%
% \begin{option}{rightmargin}
%   \begin{syntax}
%     |rightmargin =| \meta{dimen} \hfill Default: 0pt
%   \end{syntax}
%   \meta{|dimen|} used for the right margin of the \env{scripture}
%   environment.
% \end{option}
%
% \begin{option}{chapter/font}
%   \begin{syntax}
%     |chapter/font =| \meta{font} \hfill Default: \cs{bfseries}
%   \end{syntax}
%   \meta{|font|} used for the \cs{ch} function.
% \end{option}
%
% \begin{option}{chapter/drop}
%   \begin{syntax}
%     |chapter/drop =| \meta{boolean} \hfill Default: true
%   \end{syntax}
%   Whether the chapter should be set as a drop letter taking up two
%   lines or as a normal letter taking up one line. The value of
%   \meta{|boolean|} is optional and assumed to be \val{true} if not present.
%   This option is the opposite of \opt{chapter/nodrop}.
% \end{option}
%
% \begin{option}{chapter/nodrop}
%   \begin{syntax}
%     |chapter/nodrop =| \meta{boolean} \hfill Default: false
%   \end{syntax}
%   Whether the chapter should be set as a drop letter taking up two lines or
%   as a normal letter taking up one line. The value of \meta{|boolean|} is
%   optional and assumed to be \val{true} if not present. This option is the
%   opposite of \opt{chapter/drop}.
% \end{option}
%
% \begin{option}{chapter/sep}
%   \begin{syntax}
%     |chapter/sep =| \meta{dimen} \hfill Default: 0.5em
%   \end{syntax}
%   \meta{|dimen|} used to separate a \cs{ch} from the following text.
% \end{option}
%
% \begin{option}{extraskip}
%   \begin{syntax}
%     |extraskip =| \meta{skip} \hfill Default: \cs{medskip}
%   \end{syntax}
%   \meta{|skip|} used for the \cs{extraskip} function.
% \end{option}
%
% \begin{option}{font}
%   \begin{syntax}
%     |font =| \meta{font} \hfill Default: \emph{Empty}
%   \end{syntax}
%   \meta{|font|} used for the \env{scripture} environment.
% \end{option}
%
% \begin{option}{indent}
%   \begin{syntax}
%     |indent =| \meta{boolean} \hfill Default: true
%   \end{syntax}
%   Whether to indent the first line of a \env{scripture} environment or not
%   by \cs{parindent}. The value of \meta{|boolean|} is optional and assumed to
%   be \val{true} if not present. This option is the opposite of
%   \opt{noindent}.
% \end{option}
%
% \begin{option}{noindent}
%   \begin{syntax}
%     |noindent =| \meta{boolean} \hfill Default: false
%   \end{syntax}
%   Whether to indent the first line of a \env{scripture} environment or not
%   by \cs{parindent}. The value of \meta{|boolean|} is optional and assumed to
%   be \val{true} if not present. This option is the opposite of
%   \opt{indent}.
% \end{option}
%
% \begin{option}{parindent}
%   \begin{syntax}
%     |parindent =| \meta{dimen} \hfill Default: \cs{parindent}
%   \end{syntax}
%   \meta{|dimen|} to use when indenting the first line of a paragraph in the
%   \env{scripture} environment.
% \end{option}
%
% \begin{option}{parskip}
%   \begin{syntax}
%     |parskip =| \meta{skip} \hfill Default: \cs{parskip}
%   \end{syntax}
%   \meta{|skip|} to use between paragraphs in the \env{scripture} environment.
% \end{option}
%
% \begin{option}{reference/delim}
%   \begin{syntax}
%     |reference/delim =| \meta{delim} \hfill Default: \cs{hfill}
%   \end{syntax}
%   \meta{|delim|} to use between the \env{scripture} quotation and its
%   \val{reference}.
% \end{option}
%
% \begin{option}{reference/font}
%   \begin{syntax}
%     |reference/font =| \meta{font} \hfill Default: bfseries
%   \end{syntax}
%   \meta{|font|} used when printing the \val{reference} for a \env{scripture}
%   quotation.
% \end{option}
%
% \begin{option}{reference/format}
%   \begin{syntax}
%     |reference/format =| \meta{macro} \hfill Default: \#1
%   \end{syntax}
%   \meta{|macro|} used to format the \val{reference} for a \env{scripture}
%   quotation. |#1| contains the text of the \val{reference}.
% \end{option}
%
% \begin{option}{reference/sep}
%   \begin{syntax}
%     |reference/sep =| \meta{dimen} \hfill Default: 2em
%   \end{syntax}
%   The minimum \meta{|dimen|} allowed between the end of a \env{scripture}
%   quotation and its \val{reference} before the \val{reference} is pushed to
%   the following line.
% \end{option}
%
% \begin{option}{verse/font}
%   \begin{syntax}
%     |verse/font =| \meta{font} \hfill Default: \emph{Empty}
%   \end{syntax}
%   \meta{|font|} used for the \cs{vs} function.
% \end{option}
%
% \begin{option}{verse/format}
%   \begin{syntax}
%     |verse/format =| \meta{macro} \hfill Default: \cs{textsuperscript}\{\#1\}
%   \end{syntax}
%   \meta{|macro|} used to format the \cs{vs} function. |#1| contains the
%   argument of \cs{vs}.
% \end{option}
%
% \begin{option}{version}
%   \begin{syntax}
%     |version =| \meta{version} \hfill Default: \emph{Empty}
%   \end{syntax}
%   \meta{|version|} added to the \val{reference} for a \env{scripture}
%   quotation.
% \end{option}
%
% \begin{option}{version/delim}
%   \begin{syntax}
%     |version/delim =| \meta{delim} \hfill Default: \{\ \}
%   \end{syntax}
%   \meta{|delim|} to use between the \val{reference} and the \val{version} of a
%   \env{scripture} quotation.
% \end{option}
%
% \begin{option}{version/format}
%   \begin{syntax}
%     |version/format =| \meta{macro} \hfill Default: (\#1)
%   \end{syntax}
%   \meta{|macro|} used to format the \val{version} for a \env{scripture}
%   quotation. |#1| contains the text of the \val{version}.
% \end{option}
%
% \subsubsection{Options for the \env{center} environment}
% \label{centeroptions}
%
% If these options are passed directly to the \env{center} environment rather
% than to the package, \cs{scripturesetup} or the \env{scripture} environment,
% then the |center/| prefix should be dropped.
%
% \begin{option}{center/aboveskip}
%   \begin{syntax}
%     |center/aboveskip =| \meta{skip} \hfill Default: \cs{medskip}
%   \end{syntax}
%   \meta{|skip|} inserted above the \env{center} environment.
% \end{option}
%
% \begin{option}{center/belowskip}
%   \begin{syntax}
%     |center/belowskip =| \meta{skip} \hfill Default: \cs{medskip}
%   \end{syntax}
%   \meta{|skip|} inserted below the \env{center} environment.
% \end{option}
%
% \begin{option}{center/leftmargin}
%   \begin{syntax}
%     |center/leftmargin =| \meta{dimen} \hfill Default: 0pt
%   \end{syntax}
%   \meta{|dimen|} used for the left margin of the \env{center} environment.
% \end{option}
%
% \begin{option}{center/rightmargin}
%   \begin{syntax}
%     |center/rightmargin =| \meta{dimen} \hfill Default: 0pt
%   \end{syntax}
%   \meta{|dimen|} used for the right margin of the \env{center} environment.
% \end{option}
%
% \subsubsection{Options for the \env{flushright} environment}
% \label{flushrightoptions}
%
% If these options are passed directly to the \env{flushright} environment rather
% than to the package, \cs{scripturesetup} or the \env{scripture} environment,
% then the |flushright/| prefix should be dropped.
%
% \begin{option}{flushright/aboveskip}
%   \begin{syntax}
%     |flushright/aboveskip =| \meta{skip} \hfill Default: \cs{medskip}
%   \end{syntax}
%   \meta{|skip|} inserted above the \env{flushright} environment.
% \end{option}
%
% \begin{option}{flushright/belowskip}
%   \begin{syntax}
%     |flushright/belowskip =| \meta{skip} \hfill Default: \cs{medskip}
%   \end{syntax}
%   \meta{|skip|} inserted below the \env{flushright} environment.
% \end{option}
%
% \begin{option}{flushright/leftmargin}
%   \begin{syntax}
%     |flushright/leftmargin =| \meta{dimen} \hfill Default: 0pt
%   \end{syntax}
%   \meta{|dimen|} used for the left margin of the \env{flushright} environment.
% \end{option}
%
% \begin{option}{flushright/rightmargin}
%   \begin{syntax}
%     |flushright/rightmargin =| \meta{dimen} \hfill Default: 0pt
%   \end{syntax}
%   \meta{|dimen|} used for the right margin of the \env{flushright} environment.
% \end{option}
%
% \subsubsection{Options for the \env{hanging} environment}
% \label{hangingoptions}
%
% If these options are passed directly to the \env{hanging} environment rather
% than to the package, \cs{scripturesetup} or the \env{scripture} environment,
% then the |hanging/| prefix should be dropped.
%
% \begin{option}{hanging/aboveskip}
%   \begin{syntax}
%     |hanging/aboveskip =| \meta{skip} \hfill Default: \cs{medskip}
%   \end{syntax}
%   \meta{|skip|} inserted above the \env{hanging} environment.
% \end{option}
%
% \begin{option}{hanging/belowskip}
%   \begin{syntax}
%     |hanging/belowskip =| \meta{skip} \hfill Default: \cs{medskip}
%   \end{syntax}
%   \meta{|skip|} inserted below the \env{hanging} environment.
% \end{option}
%
% \begin{option}{hanging/hang}
%   \begin{syntax}
%     |hanging/hang =| \meta{dimen} \hfill Default: 2em
%   \end{syntax}
%   \meta{|dimen|} used for the indent of subsequent lines of the
%   \env{hanging} environment.
% \end{option}
%
% \begin{option}{hanging/leftmargin}
%   \begin{syntax}
%     |hanging/leftmargin =| \meta{dimen} \hfill Default: 1em
%   \end{syntax}
%   \meta{|dimen|} used for the left margin of the \env{hanging} environment.
% \end{option}
%
% \begin{option}{hanging/rightmargin}
%   \begin{syntax}
%     |hanging/rightmargin =| \meta{dimen} \hfill Default: 1em
%   \end{syntax}
%   \meta{|dimen|} used for the right margin of the \env{hanging} environment.
% \end{option}
%
% \subsubsection{Options for the \env{narrow} environment}
% \label{narrowoptions}
%
% If these options are passed directly to the \env{narrow} environment rather
% than to the package, \cs{scripturesetup} or the \env{scripture} environment,
% then the |narrow/| prefix should be dropped.
%
% \begin{option}{narrow/aboveskip}
%   \begin{syntax}
%     |narrow/aboveskip =| \meta{skip} \hfill Default: \cs{medskip}
%   \end{syntax}
%   \meta{|skip|} inserted above the \env{narrow} environment.
% \end{option}
%
% \begin{option}{narrow/belowskip}
%   \begin{syntax}
%     |narrow/belowskip =| \meta{skip} \hfill Default: \cs{medskip}
%   \end{syntax}
%   \meta{|skip|} inserted below the \env{narrow} environment.
% \end{option}
%
% \begin{option}{narrow/leftmargin}
%   \begin{syntax}
%     |narrow/leftmargin =| \meta{dimen} \hfill Default: 1em
%   \end{syntax}
%   \meta{|dimen|} used for the left margin of the \env{narrow} environment.
% \end{option}
%
% \begin{option}{narrow/rightmargin}
%   \begin{syntax}
%     |narrow/rightmargin =| \meta{dimen} \hfill Default: 1em
%   \end{syntax}
%   \meta{|dimen|} used for the right margin of the \env{narrow} environment.
% \end{option}
%
% \subsubsection{Options for the \env{poetry} environment}
% \label{poetryoptions}
%
% If these options are passed directly to the \env{poetry} environment rather
% than to the package, \cs{scripturesetup} or the \env{scripture} environment,
% then the |poetry/| prefix should be dropped.
%
% \begin{option}{poetry/aboveskip}
%   \begin{syntax}
%     |poetry/aboveskip =| \meta{skip} \hfill Default: \cs{medskip}
%   \end{syntax}
%   \meta{|skip|} inserted above the \env{poetry} environment.
% \end{option}
%
% \begin{option}{poetry/belowskip}
%   \begin{syntax}
%     |poetry/belowskip =| \meta{skip} \hfill Default: \cs{medskip}
%   \end{syntax}
%   \meta{|skip|} inserted below the \env{poetry} environment.
% \end{option}
%
% \begin{option}{poetry/bigindent}
%   \begin{syntax}
%     |poetry/bigindent =| \meta{dimen} \hfill Default: 4em
%   \end{syntax}
%   \meta{|dimen|} used for the indent subsequent lines of a line of poetry in
%   a \env{poetry} environment if it needs to flow on to the following line.
% \end{option}
%
% \begin{option}{poetry/indent}
%   \begin{syntax}
%     |poetry/indent =| \meta{dimen} \hfill Default: 1em
%   \end{syntax}
%   \meta{|dimen|} used for the second half of a line of poetry in a
%   \env{poetry} environment.
% \end{option}
%
% \begin{option}{poetry/leftmargin}
%   \begin{syntax}
%     |poetry/leftmargin =| \meta{dimen} \hfill Default: 1em
%   \end{syntax}
%   \meta{|dimen|} used for the left margin of the \env{poetry} environment.
% \end{option}
%
% \begin{option}{poetry/rightmargin}
%   \begin{syntax}
%     |poetry/rightmargin =| \meta{dimen} \hfill Default: 0pt
%   \end{syntax}
%   \meta{|dimen|} used for the right margin of the \env{poetry} environment.
% \end{option}
%
% \end{documentation}
%
% \begin{implementation}
% 
% \section{Implementation}
%
%    \begin{macrocode}
%<*package>
%<@@=scripture>
%    \end{macrocode}
%
%    \begin{macrocode}
\NeedsTeXFormat{LaTeX2e}[2021-11-15]
\ProvidesExplPackage{scripture}{2022/07/27}{1.0}
  {Format Scripture Quotations (DCP)}
\RequirePackage{l3keys2e}
%    \end{macrocode}
%
% \subsection{Messages}
%
% \env{scripture} environments along with all internal environments can not be
% nested.
%
%    \begin{macrocode}
\msg_new:nnnn { scripture } { nested-environment }
  { Nesting~of~scripture~environments~not~supported. }
  { You~have~tried~to~nest~a~scripture~environment~or \\
    one~of~its~internal~environments,~which~is~not~supported. }
%    \end{macrocode}
%
% \subsection{Options}
%
% Key-value settings for the \env{scripture} environment and its inner
% environments.
%    \begin{macrocode}
\keys_define:nn { scripture }
  {
    , aboveskip                .tl_set:N           = \l_@@_aboveskip_tl
    , aboveskip                .value_required:n   = true
    , aboveskip                .initial:n          = \c_zero_skip
    , belowskip                .tl_set:N           = \l_@@_belowskip_tl
    , belowskip                .value_required:n   = true
    , belowskip                .initial:n          = \c_zero_skip
    , leftmargin               .tl_set:N           = \l_@@_leftmargin_tl
    , leftmargin               .value_required:n   = true
    , leftmargin               .initial:n          = \c_zero_dim
    , rightmargin              .tl_set:N           = \l_@@_rightmargin_tl
    , rightmargin              .value_required:n   = true
    , rightmargin              .initial:n          = \c_zero_dim
    , chapter / font           .tl_set:N           = \l_@@_chap_font_tl
    , chapter / font           .value_required:n   = true
    , chapter / font           .initial:n          = \bfseries
    , chapter / drop           .bool_set:N         = \l_@@_chap_drop_bool
    , chapter / drop           .default:n          = true
    , chapter / drop           .initial:n          = true
    , chapter / nodrop         .bool_set_inverse:N = \l_@@_chap_drop_bool
    , chapter / nodrop         .default:n          = true
    , chapter / sep            .tl_set:N           = \l_@@_chap_sep_tl
    , chapter / sep            .value_required:n   = true
    , chapter / sep            .initial:n          = 0.5 em
    , extraskip                .tl_set:N           = \l_@@_extraskip_tl
    , extraskip                .value_required:n   = true
    , extraskip                .initial:n          = \medskipamount
    , font                     .tl_set:N           = \l_@@_font_tl
    , font                     .value_required:n   = true
    , font                     .initial:n          =
    , indent                   .bool_set:N         = \l_@@_indent_bool
    , indent                   .default:n          = true
    , indent                   .initial:n          = true
    , noindent                 .bool_set_inverse:N = \l_@@_indent_bool
    , noindent                 .default:n          = true
    , parindent                .tl_set:N           = \l_@@_parindent_tl
    , parindent                .value_required:n   = true
    , parindent                .initial:n          = \parindent
    , parskip                  .tl_set:N           = \l_@@_parskip_tl
    , parskip                  .value_required:n   = true
    , parskip                  .initial:n          = \parskip
    , reference / delim        .tl_set:N           = \l_@@_ref_delim_tl
    , reference / delim        .value_required:n   = true
    , reference / delim        .initial:n          = \hfill
    , reference / font         .tl_set:N           = \l_@@_ref_font_tl
    , reference / font         .value_required:n   = true
    , reference / font         .initial:n          = \bfseries
    , reference / format       .cs_set:Np          = \@@_ref_format:n #1
    , reference / format       .value_required:n   = true
    , reference / format       .initial:n          = #1
    , reference / sep          .tl_set:N           = \l_@@_ref_sep_tl
    , reference / sep          .value_required:n   = true
    , reference / sep          .initial:n          = 2 em
    , verse / font             .tl_set:N           = \l_@@_verse_font_tl
    , verse / font             .value_required:n   = true
    , verse / font             .initial:n          = 
    , verse / format           .cs_set:Np          = \@@_verse_format:n #1
    , verse / format           .value_required:n   = true
    , verse / format           .initial:n          = \textsuperscript{#1}
    , version                  .tl_set:N           = \l_@@_version_tl
    , version                  .value_required:n   = true
    , version                  .initial:n          =
    , version / delim          .tl_set:N           = \l_@@_version_delim_tl
    , version / delim          .value_required:n   = true
    , version / delim          .initial:n          = \c_space_tl
    , version / format         .cs_set:Np          = \@@_version_format:n #1
    , version / format         .value_required:n   = true
    , version / format         .initial:n          = (#1)
%    \end{macrocode}
% Options for the \env{center} environment.
%    \begin{macrocode}
    , center / aboveskip       .tl_set:N           = \l_@@_center_aboveskip_tl
    , center / aboveskip       .value_required:n   = true
    , center / aboveskip       .initial:n          = \medskipamount
    , center / belowskip       .tl_set:N           = \l_@@_center_belowskip_tl
    , center / belowskip       .value_required:n   = true
    , center / belowskip       .initial:n          = \medskipamount
    , center / leftmargin      .tl_set:N           = \l_@@_center_leftmargin_tl
    , center / leftmargin      .value_required:n   = true
    , center / leftmargin      .initial:n          = \c_zero_dim
    , center / rightmargin     .tl_set:N           = \l_@@_center_rightmargin_tl
    , center / rightmargin     .value_required:n   = true
    , center / rightmargin     .initial:n          = \c_zero_dim
%    \end{macrocode}
% Options for the \env{flushright} environment.
%    \begin{macrocode}
    , flushright / aboveskip   .tl_set:N           = \l_@@_flushright_aboveskip_tl
    , flushright / aboveskip   .value_required:n   = true
    , flushright / aboveskip   .initial:n          = \medskipamount
    , flushright / belowskip   .tl_set:N           = \l_@@_flushright_belowskip_tl
    , flushright / belowskip   .value_required:n   = true
    , flushright / belowskip   .initial:n          = \medskipamount
    , flushright / leftmargin  .tl_set:N           = \l_@@_flushright_leftmargin_tl
    , flushright / leftmargin  .value_required:n   = true
    , flushright / leftmargin  .initial:n          = \c_zero_dim
    , flushright / rightmargin .tl_set:N           = \l_@@_flushright_rightmargin_tl
    , flushright / rightmargin .value_required:n   = true
    , flushright / rightmargin .initial:n          = \c_zero_dim
%    \end{macrocode}
% Options for the \env{hanging} environment.
%    \begin{macrocode}
    , hanging / aboveskip      .tl_set:N           = \l_@@_hanging_aboveskip_tl
    , hanging / aboveskip      .value_required:n   = true
    , hanging / aboveskip      .initial:n          = \medskipamount
    , hanging / belowskip      .tl_set:N           = \l_@@_hanging_belowskip_tl
    , hanging / belowskip      .value_required:n   = true
    , hanging / belowskip      .initial:n          = \medskipamount
    , hanging / hang           .tl_set:N           = \l_@@_hanging_hang_tl
    , hanging / hang           .value_required:n   = true
    , hanging / hang           .initial:n          = 2 em
    , hanging / leftmargin     .tl_set:N           = \l_@@_hanging_leftmargin_tl
    , hanging / leftmargin     .value_required:n   = true
    , hanging / leftmargin     .initial:n          = 1 em
    , hanging / rightmargin    .tl_set:N           = \l_@@_hanging_rightmargin_tl
    , hanging / rightmargin    .value_required:n   = true
    , hanging / rightmargin    .initial:n          = \c_zero_dim
%    \end{macrocode}
% Options for the \env{narrow} environment.
%    \begin{macrocode}
    , narrow / aboveskip       .tl_set:N           = \l_@@_narrow_aboveskip_tl
    , narrow / aboveskip       .value_required:n   = true
    , narrow / aboveskip       .initial:n          = \medskipamount
    , narrow / belowskip       .tl_set:N           = \l_@@_narrow_belowskip_tl
    , narrow / belowskip       .value_required:n   = true
    , narrow / belowskip       .initial:n          = \medskipamount
    , narrow / leftmargin      .tl_set:N           = \l_@@_narrow_leftmargin_tl
    , narrow / leftmargin      .value_required:n   = true
    , narrow / leftmargin      .initial:n          = 1 em
    , narrow / rightmargin     .tl_set:N           = \l_@@_narrow_rightmargin_tl
    , narrow / rightmargin     .value_required:n   = true
    , narrow / rightmargin     .initial:n          = 1 em
%    \end{macrocode}
% Options for the \env{poetry} environment.
%    \begin{macrocode}
    , poetry / aboveskip       .tl_set:N           = \l_@@_poetry_aboveskip_tl
    , poetry / aboveskip       .value_required:n   = true
    , poetry / aboveskip       .initial:n          = \medskipamount
    , poetry / belowskip       .tl_set:N           = \l_@@_poetry_belowskip_tl
    , poetry / belowskip       .value_required:n   = true
    , poetry / belowskip       .initial:n          = \medskipamount
    , poetry / bigindent       .tl_set:N           = \l_@@_poetry_big_indent_tl
    , poetry / bigindent       .value_required:n   = true
    , poetry / bigindent       .initial:n          = 4 em
    , poetry / indent          .tl_set:N           = \l_@@_poetry_indent_tl
    , poetry / indent          .value_required:n   = true
    , poetry / indent          .initial:n          = 1 em
    , poetry / leftmargin      .tl_set:N           = \l_@@_poetry_leftmargin_tl
    , poetry / leftmargin      .value_required:n   = true
    , poetry / leftmargin      .initial:n          = 1 em
    , poetry / rightmargin     .tl_set:N           = \l_@@_poetry_rightmargin_tl
    , poetry / rightmargin     .value_required:n   = true
    , poetry / rightmargin     .initial:n          = \c_zero_dim
  }
%    \end{macrocode}
% Process package options using \pkg{l3keys2e} package.
%    \begin{macrocode}
\ProcessKeysOptions { scripture }
%    \end{macrocode}
%
% \subsection{The main \env{scripture} environment}
%
% \begin{macro}{\l_@@_active_bool, \l_@@_active_inner_bool}
%   Flags to ensure that environments are not nested.
%    \begin{macrocode}
\bool_new:N \l_@@_active_bool
\bool_new:N \l_@@_active_inner_bool
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}{\@@_extra_skip:}
%   Insert a little extra vertical space between two paragraphs. This function
%   tests if the previous paragraph is only one line in length and began
%   with a \cs{ch} function. If this condition is met, more space is added
%   if necessary to avoid the following paragraph clashing with the drop
%   chapter.
%    \begin{macrocode}
\cs_new_protected:Nn \@@_extra_skip:
  {
    \int_compare:nNnT
      \l_@@_chap_par_prevgraf_int = 1
      {
        \dim_compare:nNnT
          { \parskip + \l_@@_extraskip_tl } < \baselineskip
          {
            \addvspace { \baselineskip }
          }
        \int_zero:N \l_@@_chap_par_prevgraf_int
      }
    \addvspace { \l_@@_extraskip_tl }
  }
%    \end{macrocode}
% \end{macro}
%
% \subsubsection{Formatting and printing quotation references}
%
% \begin{macro}{\@@_format_full_ref:n}
%   Format a scripture quotation with its reference.
%    \begin{macrocode}
\cs_new_protected:Nn \@@_format_full_ref:n
  {
    \group_begin:
    \l_@@_ref_font_tl
    \@@_ref_format:n { #1 }
%    \end{macrocode}
% Append a Bible version if it has been specified.
%    \begin{macrocode}
    \tl_if_empty:NF \l_@@_version_tl
      {
        \l_@@_version_delim_tl
        \@@_version_format:n { \l_@@_version_tl }
      }
    \group_end:
  }
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}{\@@_reference:n}
%   Output the reference for the Scripture quotation.
%    \begin{macrocode}
\cs_new_protected:Nn \@@_reference:n
  {
    \hbox_set:Nn \l_tmpa_box
      {
        \skip_horizontal:N \l_@@_ref_sep_tl
        \@@_format_full_ref:n { #1 }
      }
%    \end{macrocode}
% Since the \env{poetry} environment uses \cs{@@_obeylines:} there is always
% an extra \cs{parskip} when a \env{scripture} quotation ends with a
% \env{poetry}
% environment.
%    \begin{macrocode}
    \bool_if:NT \g_@@_poetry_end_bool
      { \skip_vertical:n { -\parskip } }
    \dim_compare:nNnT
      { \box_wd:N \l_tmpa_box + \g_@@_final_line_dim }
      >
      { \linewidth - \@totalleftmargin }
      { \skip_vertical:N \baselineskip }
%    \end{macrocode}
% If a \env{scripture} quotation ends with an inner environment, there will
% be an extra space of \cs{baselineskip}.
%    \begin{macrocode}
    \int_compare:nNnT \prevgraf = \c_zero_int
      { \skip_vertical:n { -\baselineskip } }
    \l_@@_ref_delim_tl
    \box_use:N \l_tmpa_box
  }
%    \end{macrocode}
% \end{macro}
%
% \subsubsection{Formatting and printing chapter numbers}
%
% \begin{macro}{\l_@@_chap_fontsize_dim}
%   Calculated font size of a drop chapter number.
%    \begin{macrocode}
\dim_new:N \l_@@_chap_fontsize_dim
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}{\l_@@_chap_height_dim}
%   Calculated height of a drop chapter number.
%    \begin{macrocode}
\dim_new:N \l_@@_chap_height_dim
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}{\l_@@_chap_width_dim}
%   Calculated width of drop chapter number.
%    \begin{macrocode}
\dim_new:N \l_@@_chap_width_dim
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}{\l_@@_chap_par_prevgraf_int}
%   Store the number of lines a chapter paragraph takes up.
%    \begin{macrocode}
\int_new:N \l_@@_chap_par_prevgraf_int
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}{\l_@@_chap_X_height_dim}
%   Calculated height of X at current font size. This is used as the height
%   for a drop chapter.
%    \begin{macrocode}
\dim_new:N \l_@@_chap_X_height_dim
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}{\@@_drop_chap_set_up:n}
%   Set up chapter drop cap and calculate its various dimensions.
%    \begin{macrocode}
\cs_new_protected:Nn \@@_drop_chap_set_up:n
  {
    \hbox_set:Nn \l_tmpa_box { X }
    \dim_set:Nn \l_@@_chap_X_height_dim
      { \box_ht:N \l_tmpa_box }
    \dim_set:Nn \l_@@_chap_height_dim
      { \baselineskip + \l_@@_chap_X_height_dim }
    \dim_set:Nn \l_@@_chap_fontsize_dim
      {
        \f@size pt *
        \dim_ratio:nn
          { \l_@@_chap_height_dim }
          { \l_@@_chap_X_height_dim }
      }
    \hbox_set:Nn \l_tmpa_box
      {
        \l_@@_chap_font_tl
        \fontsize
          { \l_@@_chap_fontsize_dim }
          { \l_@@_chap_fontsize_dim }
          \selectfont
        #1
      }
    \dim_set:Nn \l_@@_chap_width_dim
      { \box_wd:N \l_tmpa_box }
  }
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}{\@@_drop_chap_output:}
%   Output a drop chapter.
%    \begin{macrocode}
\cs_new_protected:Nn \@@_drop_chap_output:
  {
    \noindent
    \parshape 3 ~
      \dim_eval:n
        { \@totalleftmargin + \l_@@_chap_width_dim + \l_@@_chap_sep_tl } ~
      \dim_eval:n
        { \linewidth - \l_@@_chap_width_dim - \l_@@_chap_sep_tl } ~
      \dim_eval:n
        { \@totalleftmargin + \l_@@_chap_width_dim + \l_@@_chap_sep_tl } ~
      \dim_eval:n
        { \linewidth - \l_@@_chap_width_dim - \l_@@_chap_sep_tl } ~
      \@totalleftmargin ~
      \linewidth
    \box_use:N \l_tmpb_box
  }
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}{\@@_nodrop_chap:n}
%   Format a non-drop chapter.
%    \begin{macrocode}
\cs_new_protected:Nn \@@_nodrop_chap:n
  {
    \group_begin:
    \l_@@_chap_font_tl
    #1
    \group_end:
    \skip_horizontal:N \l_@@_chap_sep_tl
  }
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}{\@@_chap:n}
%   Position a drop chapter.
%    \begin{macrocode}
\cs_new_protected:Nn \@@_chap:n
  {
    \@@_drop_chap_set_up:n { #1 }
    \hbox_set:Nn \l_tmpb_box
      {
        \box_move_down:nn
          { \baselineskip }
          { 
            \hbox_overlap_left:n
              {
                \box_use:N \l_tmpa_box
                \skip_horizontal:N \l_@@_chap_sep_tl
              }
          }
      }
    \box_set_ht:Nn \l_tmpb_box { \c_zero_dim }
    \box_set_dp:Nn \l_tmpb_box { \c_zero_dim }
    \bool_if:NTF \l_@@_mid_para_chap_bool
      { \@@_mid_para_drop_chap_output: }
      {
        \par
        \@@_drop_chap_output:
      }
    \hook_gput_next_code:nn { para / after }
      { \int_set_eq:NN \l_@@_chap_par_prevgraf_int \prevgraf }
    \hook_gput_next_code:nn { para / before }
      {
        \int_zero:N \l_@@_chap_par_prevgraf_int
        \int_compare:nNnT
          \@listdepth > \c_zero_int
          { \parshape 1 ~ \@totalleftmargin ~ \linewidth }
      }
  }
%    \end{macrocode}
% \end{macro}
%
% \subsubsection{Formatting and printing verse numbers}
%
% \begin{macro}{\@@_verse_output:n}
%   Output a formatted verse.
%    \begin{macrocode}
\cs_new_protected:Nn \@@_verse_output:n
  {
    \mode_if_vertical:T
      { \mode_leave_vertical: }
    \group_begin:
    \l_@@_verse_font_tl
    \@@_verse_format:n { #1 }
    \group_end:
  }
%    \end{macrocode}
% \end{macro}
%
% \subsubsection{Calculating the length of the final line in a paragraph}
%
% \begin{macro}{\g_@@_final_line_dim}
%   Store the length of the final line in a paragraph.
%    \begin{macrocode}
\dim_new:N \g_@@_final_line_dim
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}{\@@_calc_final_line_length:}
%   Calculate the length of the final line in a paragraph.
%    \begin{macrocode}
\cs_new_protected:Nn \@@_calc_final_line_length:
  {
    \skip_set:Nn \abovedisplayshortskip { -\baselineskip }
    \skip_set_eq:NN \abovedisplayskip \abovedisplayshortskip
    \skip_zero:N \belowdisplayshortskip
    \skip_zero:N \belowdisplayskip
    $$
      \dim_compare:nNnT \predisplaysize > \c_zero_dim
        {
          \dim_gset:Nn \g_@@_final_line_dim
            { \predisplaysize - 2 em }
        }
      \cs_gset_nopar:Nx \@@_reset_spacing:
        {
          \dim_set:Nn \predisplaysize { \dim_use:N \predisplaysize }
          \int_set:Nn \prevgraf { \int_use:N \prevgraf }
        }
    $$
    \@@_reset_spacing:
    \dim_compare:nNnT \g_@@_final_line_dim > \linewidth
      {
        \dim_gset_eq:NN \g_@@_final_line_dim \linewidth
      }
    \dim_compare:nNnT \g_@@_final_line_dim > { \c_zero_dim - 1 sp }
      {
        \skip_vertical:n { -\baselineskip - \parskip }
      }
  }
%    \end{macrocode}
% \end{macro}
%
% \subsubsection{The \env{scripture} environment}
%
% \begin{macro}{\g_@@_start_bool}
%   Flag indicating whether we are currently setting the first paragraph in a
%   \env{scripture} environment. If this is \val{true}, any \opt{aboveskip}
%   for an inner environment will be ignored.
%    \begin{macrocode}
\bool_new:N \g_@@_start_bool
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}{\@@_begin:n}
%   Begin a scripture quotation.
%    \begin{macrocode}
\cs_new_protected:Nn \@@_begin:n
  {
    \bool_if:NT \l_@@_active_bool
      {
        \msg_error:nn { scripture } { nested-environment }
      }
    \bool_set_true:N \l_@@_active_bool
    \tl_if_novalue:nF { #1 }
      {
        \keys_set:nn { scripture } { #1 }
      }
%    \end{macrocode}
% If the \env{scripture} environment begins immediately after an \cs{item},
% then insert a new paragraph and apply a negative skip. Life is much easier
% if all paragraphs in a \env{scripture} are the same rather than the first
% one being in the first paragraph of an \cs{item}.
%    \begin{macrocode}
    \legacy_if:nT { @newlist }
      {
        \strut
        \par
        \vspace* { \dim_eval:n { -\baselineskip - \parskip } }
      }
    \mode_if_vertical:T
      {
        \addvspace { \l_@@_aboveskip_tl }
      }
    \DeclareDocumentCommand { \ch } { sm }
      {
        \bool_if:NTF \l_@@_chap_drop_bool
          {
            \@@_chap:n { ##2 }
            \bool_if:nT { ##1 }
              {
                \hook_gput_next_code:nn { para / after }
                  { \int_zero:N \l_@@_chap_par_prevgraf_int }
              }
          }
          { \@@_nodrop_chap:n { ##2 } }
      }
    \bool_gset_true:N \g_@@_start_bool
    \bool_gset_false:N \g_@@_poetry_end_bool
    \dim_set_eq:NN \parindent \l_@@_parindent_tl
    \cs_set_eq:NN \extraskip \@@_extra_skip:
    \cs_set_eq:NN \vs \@@_verse_output:n
    \hook_gclear_next_code:n { para / before }
    \hook_gput_next_code:nn { para / end }
      { \skip_set_eq:NN \parskip \l_@@_parskip_tl }
    \hook_gput_next_code:nn { para / after }
      { \bool_gset_false:N \g_@@_start_bool }
    \l_@@_font_tl
%    \end{macrocode}
% For left and right margins, use \cs{parshape} is already in a list,
% otherwise use \cs{leftskip} and \cs{rightskip}
%    \begin{macrocode}
    \bool_lazy_or:nnT
      { \dim_compare_p:n { \l_@@_leftmargin_tl > 0pt } }
      { \dim_compare_p:n { \l_@@_rightmargin_tl > 0pt } }
      {
        \dim_sub:Nn \linewidth
          { \l_@@_leftmargin_tl + \l_@@_rightmargin_tl }
        \int_compare:nNnTF
          \@listdepth > \c_zero_int
          {
            \dim_add:Nn \@totalleftmargin \l_@@_leftmargin_tl
            \parshape 1 ~ \@totalleftmargin ~ \linewidth
          }
          {
            \dim_add:Nn \leftskip \l_@@_leftmargin_tl
            \dim_add:Nn \rightskip \l_@@_rightmargin_tl
          }
      }
    \bool_if:NF \l_@@_indent_bool
      { \noindent }
  }
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}{\@@_end:n}
%   End a scripture quotation with a reference.
%    \begin{macrocode}
\cs_new_protected:Nn \@@_end:n
  {
%    \end{macrocode}
% Normally \cs{unskip} does not work in vertical mode, but there are some
% situations where it does work. The following condition is true if the
% \env{scripture} environment has ended with one of its internal
% environments. This removes any unwanted \opt{belowskip} if present and
% leaves the previously calculated line length of the final paragraph intact.
%    \begin{macrocode}
    \mode_if_vertical:TF
      {
        \unskip
        \unskip
      }
      { \@@_calc_final_line_length: }
%    \end{macrocode}
% Restore left margin by resetting the \cs{parshape} if in a list
% based environment, otherwise the space required for the reference is
% incorrectly calculated.
%    \begin{macrocode}
    \bool_lazy_or:nnT
      { \dim_compare_p:n { \l_@@_leftmargin_tl > 0pt } }
      { \dim_compare_p:n { \l_@@_rightmargin_tl > 0pt } }
      {
        \dim_add:Nn \linewidth \l_@@_leftmargin_tl
        \int_compare:nNnT
          \@listdepth > \c_zero_int
          {
            \dim_sub:Nn \@totalleftmargin \l_@@_leftmargin_tl
            \parshape 1 ~ \@totalleftmargin ~ \linewidth
          }
      }
    \tl_if_novalue:nF { #1 }
      {
        \@@_reference:n { #1 }
      }
    \par
%    \end{macrocode}
% Restore right margin by resetting the \cs{parshape} if in a \LaTeX{} list
% based environment, since only the left margin was restored above.
%    \begin{macrocode}
    \bool_lazy_or:nnT
      { \dim_compare_p:n { \l_@@_leftmargin_tl > 0pt } }
      { \dim_compare_p:n { \l_@@_rightmargin_tl > 0pt } }
      {
        \int_compare:nNnT
          \@listdepth > \c_zero_int
          {
            \dim_add:Nn \linewidth \l_@@_rightmargin_tl
            \parshape 1 ~ \@totalleftmargin ~ \linewidth
          }
      }
    \dim_compare:nNnTF
      \l_@@_belowskip_tl > \parskip
      {
        \addvspace
          {
            \skip_eval:n { \l_@@_belowskip_tl - \parskip }
          }
      }
      {
        \addvspace { \l_@@_belowskip_tl }
      }
  }
%    \end{macrocode}
% \end{macro}
%
% \subsection{Scripture internal environments}
%
% \begin{macro}{\l_@@_delta_below_skip}
%   Correction to \tn{@topsepadd} for internal environments. This enables a
%   different \opt{aboveskip} and \opt{belowskip} which are normally the
%   same for \LaTeX{} lists.
%    \begin{macrocode}
\skip_new:N \l_@@_delta_below_skip
%    \end{macrocode}
% \end{macro}
%
% \subsubsection{The \env{center} environment}
%
% \begin{macro}{\@@_center_begin:n}
%   Begin a centred section in a scripture quotation.
%    \begin{macrocode}
\cs_new_protected:Nn \@@_center_begin:n
  {
    \bool_if:NT \l_@@_active_inner_bool
      {
        \msg_error:nn { scripture } { nested-environment }
      }
    \bool_set_true:N \l_@@_active_inner_bool
    \tl_if_novalue:nF { #1 }
      {
        \keys_set:nn
          { scripture / center }
          { #1 }
      }
    \par
    \list { }
      {
        \skip_set_eq:NN \l_@@_delta_below_skip \l_@@_center_belowskip_tl
%    \end{macrocode}
% Ignore \opt{aboveskip} if at the beginning of a \env{scripture} environment.
%    \begin{macrocode}
        \bool_if:NTF \g_@@_start_bool
          { \skip_zero:N \topsep }
          {
            \dim_compare:nTF
              { \parskip >= \l_@@_center_aboveskip_tl > \c_zero_skip }
              {
                \skip_zero:N \topsep
                \skip_zero:N \l_@@_delta_below_skip
              }
              {
                \skip_set_eq:NN \topsep \l_@@_center_aboveskip_tl
                \skip_sub:Nn \l_@@_delta_below_skip \l_@@_center_aboveskip_tl
              }
          }
        \skip_set_eq:NN \parsep \parskip
        \skip_zero:N \partopsep
        \dim_zero:N \leftmargin
        \dim_zero:N \labelsep
      }
    \centering
    \item
    \relax
  }
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}{\@@_center_end:}
%   End a centred section in a scripture quotation.
%    \begin{macrocode}
\cs_new_protected:Nn \@@_center_end:
  {
    \@@_calc_final_line_length:
    \skip_add:Nn \@topsepadd \l_@@_delta_below_skip
    \endlist
  }
%    \end{macrocode}
% \end{macro}
%
% \subsubsection{The \env{flushright} environment}
%
% \begin{macro}{\@@_flushright_begin:n}
%   Begin a flushright section in a scripture quotation.
%    \begin{macrocode}
\cs_new_protected:Nn \@@_flushright_begin:n
  {
    \bool_if:NT \l_@@_active_inner_bool
      {
        \msg_error:nn { scripture } { nested-environment }
      }
    \bool_set_true:N \l_@@_active_inner_bool
    \tl_if_novalue:nF { #1 }
      {
        \keys_set:nn
          { scripture / flushright }
          { #1 }
      }
    \par
    \list { }
      {
        \skip_set_eq:NN \l_@@_delta_below_skip \l_@@_flushright_belowskip_tl
%    \end{macrocode}
% Ignore \opt{aboveskip} if at the beginning of a \env{scripture} environment.
%    \begin{macrocode}
        \bool_if:NTF \g_@@_start_bool
          { \skip_zero:N \topsep }
          {
            \dim_compare:nTF
              { \parskip >= \l_@@_flushright_aboveskip_tl > \c_zero_skip }
              {
                \skip_zero:N \topsep
                \skip_zero:N \l_@@_delta_below_skip
              }
              {
                \skip_set_eq:NN \topsep \l_@@_flushright_aboveskip_tl
                \skip_sub:Nn \l_@@_delta_below_skip \l_@@_flushright_aboveskip_tl
              }
          }
        \dim_set_eq:NN \leftmargin \l_@@_flushright_leftmargin_tl
        \dim_set_eq:NN \rightmargin \l_@@_flushright_rightmargin_tl
        \skip_set_eq:NN \parsep \parskip
        \skip_zero:N \partopsep
        \dim_zero:N \leftmargin
        \dim_zero:N \labelsep
      }
    \raggedleft
    \item
    \relax
  }
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}{\@@_flushright_end:}
%   End a flushright section in a scripture quotation.
%    \begin{macrocode}
\cs_new_protected:Nn \@@_flushright_end:
  {
    \@@_calc_final_line_length:
    \skip_add:Nn \@topsepadd \l_@@_delta_below_skip
    \endlist
  }
%    \end{macrocode}
% \end{macro}
%
% \subsubsection{The \env{hanging} environment}
%
% \begin{macro}{\l_@@_hanging_parindent_saved_dim}
%   Save the \cs{parindent} for later use in \env{hanging} environment.
%    \begin{macrocode}
\dim_new:N \l_@@_hanging_parindent_saved_dim
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}{\@@_hanging_chap:n}
%   Position a drop chapter in a \env{hanging} environment.
%    \begin{macrocode}
\cs_new_protected:Nn \@@_hanging_chap:n
  {
    \@@_drop_chap_set_up:n { #1 }
    \dim_compare:nNnTF
      \l_@@_chap_width_dim < \leftmargin
      {
        \tl_set:Nx \l_@@_chap_sep_tl
          {
            \dim_eval:n { \leftmargin - \l_@@_chap_width_dim }
          }
      }
      {
        \parshape 3 ~
          \dim_eval:n
            {
              \@totalleftmargin - \leftmargin + \l_@@_chap_width_dim +
              \l_@@_chap_sep_tl
            } ~
          \dim_eval:n
            {
              \linewidth + \leftmargin - \l_@@_chap_width_dim -
              \l_@@_chap_sep_tl
            } ~
          \dim_eval:n
            {
              \@totalleftmargin - \leftmargin + \l_@@_chap_width_dim +
              \l_@@_chap_sep_tl
            } ~
          \dim_eval:n
            {
              \linewidth + \leftmargin - \l_@@_chap_width_dim -
              \l_@@_chap_sep_tl
            } ~
          \@totalleftmargin ~ \linewidth
      }
    \mode_if_vertical:T
      {
        \tl_set:Nx \l_@@_chap_sep_tl
          {
            \dim_eval:n
              {
                \l_@@_chap_sep_tl + \l_@@_hanging_parindent_saved_dim
              }
          }
        \@@_nohang:
      }
    \hbox_set:Nn \l_tmpb_box
      {
        \box_move_down:nn
          { \baselineskip }
          { 
            \hbox_overlap_left:n
              {
                \box_use:N \l_tmpa_box
                \skip_horizontal:N \l_@@_chap_sep_tl
              }
          }
      }
    \box_set_ht:Nn \l_tmpb_box { \c_zero_dim }
    \box_set_dp:Nn \l_tmpb_box { \c_zero_dim }
    \box_use:N \l_tmpb_box
    \hook_gput_next_code:nn { para / begin }
      { \parshape 1 ~ \@totalleftmargin ~ \linewidth }
  }
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}{\@@_hanging_verse:n}
%   Position a \cs{vs} in a \env{hanging} environment. The verse is set to
%   overlap to the left if at the beginning of a hanging paragraph.
%    \begin{macrocode}
\cs_new_protected:Nn \@@_hanging_verse:n
  {
    \mode_if_vertical:TF
      {
        \strut
        \hbox_overlap_left:n
          {
            \@@_verse_output:n { #1 }
          }
      }
      { \@@_verse_output:n { #1 } }
  }
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}{\@@_nohang:}
%   Don't hang a paragraph in a \env{hanging} environment. Instead the
%   paragraph is indented by \cs{parindent} from its normal hanging position.
%    \begin{macrocode}
\cs_new_protected_nopar:Nn \@@_nohang:
  {
    \para_raw_noindent:
    \hbox_to_wd:nn { \l_@@_hanging_parindent_saved_dim } { }
  }
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}{\@@_hanging_begin:n}
%   Begin a hanging section in a scripture quotation.
%    \begin{macrocode}
\cs_new_protected:Nn \@@_hanging_begin:n
  {
    \bool_if:NT \l_@@_active_inner_bool
      {
        \msg_error:nn { scripture } { nested-environment }
      }
    \bool_set_true:N \l_@@_active_inner_bool
    \tl_if_novalue:nF { #1 }
      {
        \keys_set:nn
          { scripture / hanging }
          { #1 }
      }
    \par
    \list { }
      {
        \skip_set_eq:NN \l_@@_delta_below_skip \l_@@_hanging_belowskip_tl
%    \end{macrocode}
% Ignore \opt{aboveskip} if at the beginning of a \env{scripture} environment.
%    \begin{macrocode}
        \bool_if:NTF \g_@@_start_bool
          { \dim_zero:N \topsep }
          {
            \dim_compare:nTF
              { \parskip >= \l_@@_hanging_aboveskip_tl > \c_zero_skip }
              {
                \skip_zero:N \topsep
                \skip_zero:N \l_@@_delta_below_skip
              }
              {
                \skip_set_eq:NN \topsep \l_@@_hanging_aboveskip_tl
                \skip_sub:Nn \l_@@_delta_below_skip \l_@@_hanging_aboveskip_tl
              }
            \int_compare:nNnT \l_@@_chap_par_prevgraf_int = 1
              { \addvspace { \baselineskip } }
            \int_zero:N \l_@@_chap_par_prevgraf_int
          }
        \dim_set:Nn \leftmargin
          { \l_@@_hanging_leftmargin_tl + \l_@@_hanging_hang_tl }
        \dim_set_eq:NN \rightmargin \l_@@_hanging_rightmargin_tl
        \dim_set:Nn \itemindent { -\l_@@_hanging_hang_tl }
        \dim_set:Nn \listparindent { -\l_@@_hanging_hang_tl }
        \skip_set_eq:NN \parsep \parskip
        \skip_zero:N \partopsep
        \dim_zero:N \labelsep
        \dim_set_eq:NN \l_@@_hanging_parindent_saved_dim \parindent
      }
    \bool_if:NTF \l_@@_chap_drop_bool
      { \cs_set_eq:NN \ch \@@_hanging_chap:n }
      { \cs_set_eq:NN \ch \@@_nodrop_chap:n }
    \cs_set_eq:NN \vs \@@_hanging_verse:n
    \cs_set_eq:NN \nohang \@@_nohang:
    \item
    \relax
  }
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}{\@@_hanging_end:}
%   End a hanging section in a scripture quotation.
%    \begin{macrocode}
\cs_new_protected:Nn \@@_hanging_end:
  {
    \@@_calc_final_line_length:
    \skip_add:Nn \@topsepadd \l_@@_delta_below_skip
    \endlist
  }
%    \end{macrocode}
% \end{macro}
%
% \subsubsection{The \env{midparachap} environment}
%
% \begin{macro}{\@@_vbox_set_top:Nw}
%   Define missing \cs{vbox_set_top:Nw} function.
%    \begin{macrocode}
\cs_new_protected:Npn \@@_vbox_set_top:Nw #1
  {
    \tex_setbox:D #1 \tex_vtop:D
      \c_group_begin_token
        \color_group_begin:
  }
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}{\l_@@_mid_para_chap_bool}
%   Flag if setting a paragraph containing a mid-paragraph chapter.
%    \begin{macrocode}
\bool_new:N \l_@@_mid_para_chap_bool
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}{\l_@@_mid_para_chap_line_box}
%   Store last line before a mid-paragraph chapter.
%    \begin{macrocode}
\box_new:N \l_@@_mid_para_chap_line_box
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}{\g_@@_mid_para_chap_prevgraf_int}
%   Store the number of lines a paragraph containing a mid-paragraph chapter
%   takes up.
%    \begin{macrocode}
\int_new:N \g_@@_mid_para_chap_prevgraf_int
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}{\l_@@_mid_para_chap_snap_box}
%   Store unpacked last line before a mid-paragraph chapter.
%    \begin{macrocode}
\box_new:N \l_@@_mid_para_chap_snap_box
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}{\l_@@_mid_para_chap_spacefactor_int}
%   Store space factor before a mid-paragraph chapter.
%    \begin{macrocode}
\int_new:N \l_@@_mid_para_chap_spacefactor_int
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}{\l_@@_mid_para_chap_box}
%   Box containing a paragraph with a chapter break.
%    \begin{macrocode}
\box_new:N \l_@@_mid_para_chap_box
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}{\@@_mid_para_drop_chap_output:}
%   Output a mid-paragraph drop chapter.
%    \begin{macrocode}
\cs_new_protected:Nn \@@_mid_para_drop_chap_output:
  {
    \unskip
    \int_set_eq:NN \l_@@_mid_para_chap_spacefactor_int \spacefactor
    \strut
    \par
    \int_gset_eq:NN \g_@@_mid_para_chap_prevgraf_int \prevgraf
    \box_set_to_last:N \l_@@_mid_para_chap_line_box
    \hbox_set:Nn \l_@@_mid_para_chap_snap_box
      {
        \hbox_unpack_drop:N \l_@@_mid_para_chap_line_box
        \unskip
        \unskip
        \unpenalty
      }
    \nointerlineskip
    \dim_compare:nNnTF
      {
        \box_wd:N \l_@@_mid_para_chap_snap_box +
        \l_@@_chap_width_dim +
        \l_@@_chap_sep_tl
      }
      <
      { \linewidth - \leftskip - \rightskip - 3 em }
      {
        \@@_drop_chap_output:
        \hbox_unpack_drop:N \l_@@_mid_para_chap_snap_box
        \int_set_eq:NN \spacefactor \l_@@_mid_para_chap_spacefactor_int
        \c_space_tl
        \@@_verse_output:n { 1 }
      }
      {
        \group_begin:
        \noindent
        \skip_horizontal:n { -\leftskip }
        \hbox_unpack_drop:N \l_@@_mid_para_chap_snap_box
        \skip_zero:N \parfillskip
        \par
        \int_gadd:Nn \g_@@_mid_para_chap_prevgraf_int \prevgraf
        \group_end:
        \@@_drop_chap_output:
      }
  }
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}{\@@_mid_para_chap_begin:}
%   Begin a paragraph containing a mid-paragraph chapter.
%    \begin{macrocode}
\cs_new_protected:Nn \@@_mid_para_chap_begin:
  {
    \par
    \bool_set_true:N \l_@@_mid_para_chap_bool
    \skip_zero:N \parskip
    \@@_vbox_set_top:Nw \l_@@_mid_para_chap_box
  }
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}{\@@_mid_para_chap_end:}
%   End a paragraph containing a mid-paragraph chapter.
%    \begin{macrocode}
\cs_new_protected:Nn \@@_mid_para_chap_end:
  {
    \@@_calc_final_line_length:
    \int_gadd:Nn \g_@@_mid_para_chap_prevgraf_int { \prevgraf - 1 }
    \vbox_set_end:
%    \end{macrocode}
% Attempt to allow the mid-paragraph chapter box to break across pages.
%    \begin{macrocode}
    \dim_compare:nNnTF
      { \box_ht_plus_dp:N \l_@@_mid_para_chap_box }
      >
      { \pagegoal - \pagetotal - \baselineskip }
      {
        \int_set:Nn \vbadness { 10000 }
        \vbox_set_split_to_ht:NNn
          \l_tmpa_box \l_@@_mid_para_chap_box
          { \pagegoal - \pagetotal - \baselineskip }
        \box_use_drop:N \l_tmpa_box
        \goodbreak
        \box_use_drop:N \l_@@_mid_para_chap_box
      }
      {
        \box_use_drop:N \l_@@_mid_para_chap_box
        \skip_vertical:n { \baselineskip - \lineskip }
      }
    \par
    \noindent
    \skip_horizontal:N \g_@@_final_line_dim
    \@@_reset_spacing:
  }
%    \end{macrocode}
% \end{macro}
%
% \subsubsection{The \env{narrow} environment}
%
% \begin{macro}{\@@_narrow_begin:n}
%   Begin a narrow section in a scripture quotation.
%    \begin{macrocode}
\cs_new_protected:Nn \@@_narrow_begin:n
  {
    \bool_if:NT \l_@@_active_inner_bool
      {
        \msg_error:nn { scripture } { nested-environment }
      }
    \bool_set_true:N \l_@@_active_inner_bool
    \tl_if_novalue:nF { #1 }
      {
        \keys_set:nn
          { scripture / narrow }
          { #1 }
      }
    \par
    \list { }
      {
        \skip_set_eq:NN \l_@@_delta_below_skip \l_@@_narrow_belowskip_tl
%    \end{macrocode}
% Ignore \opt{aboveskip} if at the beginning of a \env{scripture} environment.
%    \begin{macrocode}
        \bool_if:NTF \g_@@_start_bool
          { \skip_zero:N \topsep }
          {
            \dim_compare:nTF
              { \parskip >= \l_@@_narrow_aboveskip_tl > \c_zero_skip }
              {
                \skip_zero:N \topsep
                \skip_zero:N \l_@@_delta_below_skip
              }
              {
                \skip_set_eq:NN \topsep \l_@@_narrow_aboveskip_tl
                \skip_sub:Nn \l_@@_delta_below_skip \l_@@_narrow_aboveskip_tl
              }
          }
        \dim_set_eq:NN \leftmargin \l_@@_narrow_leftmargin_tl
        \dim_set_eq:NN \rightmargin \l_@@_narrow_rightmargin_tl
        \dim_set_eq:NN \listparindent \parindent
        \dim_set_eq:NN \itemindent \parindent
        \skip_set_eq:NN \parsep \parskip
        \skip_zero:N \partopsep
        \dim_zero:N \labelsep
      }
    \item
    \relax
  }
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}{\@@_narrow_end:}
%   End a narrow section in a scripture quotation.
%    \begin{macrocode}
\cs_new_protected:Nn \@@_narrow_end:
  {
    \@@_calc_final_line_length:
    \skip_add:Nn \@topsepadd \l_@@_delta_below_skip
    \endlist
  }
%    \end{macrocode}
% \end{macro}
%
% \subsubsection{The \env{poetry} environment}
%
% \begin{macro}{\g_@@_poetry_end_bool}
%   Flag indicating that a \env{poetry} environment just ended.
%    \begin{macrocode}
\bool_new:N \g_@@_poetry_end_bool
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}{\l_@@_poetry_prevgraf_int}
%   Store the number of lines a line of poetry takes up.
%    \begin{macrocode}
\int_new:N \l_@@_poetry_prevgraf_int
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}{\@@_poetry_chap:n}
%   Position a chapter in a \env{poetry} environment.
%    \begin{macrocode}
\cs_new_protected:Nn \@@_poetry_chap:n
  {
    \@@_drop_chap_set_up:n { #1 }
    \dim_compare:nNnT \l_@@_chap_width_dim < \l_@@_poetry_leftmargin_tl
      {
        \tl_set:Nx \l_@@_chap_sep_tl
          {
            \dim_eval:n
              {
                \l_@@_poetry_leftmargin_tl - \l_@@_chap_width_dim
              }
          }
      }
    \hbox_set:Nn \l_tmpb_box
      {
        \box_move_down:nn
          { \baselineskip }
          { 
            \hbox_overlap_left:n
              {
                \box_use:N \l_tmpa_box
                \skip_horizontal:N \l_@@_chap_sep_tl
              }
          }
      }
    \box_set_ht:Nn \l_tmpb_box { \c_zero_dim }
    \box_set_dp:Nn \l_tmpb_box { \c_zero_dim }
    \parshape 2 ~
      \dim_eval:n
        {
          \@totalleftmargin - \l_@@_poetry_leftmargin_tl +
          \l_@@_chap_width_dim + \l_@@_chap_sep_tl
        } ~
      \dim_eval:n
        {
          \linewidth - \@totalleftmargin + \l_@@_poetry_leftmargin_tl -
          \l_@@_chap_width_dim - \l_@@_chap_sep_tl
        } ~
      \dim_eval:n
        { \@totalleftmargin + \l_@@_poetry_big_indent_tl } ~
      \dim_eval:n
        { \linewidth - \l_@@_poetry_big_indent_tl }
    \dim_compare:nNnT
      { \l_@@_chap_width_dim + \l_@@_chap_sep_tl }
      >
      { \l_@@_poetry_leftmargin_tl + \listparindent }
      {
        \hook_gput_next_code:nn { para / begin }
          {
            \int_compare:nNnT \l_@@_poetry_prevgraf_int = 1
              {
                \parshape 2 ~ 
                  \dim_eval:n
                    {
                      \@totalleftmargin - \l_@@_poetry_leftmargin_tl +
                      \l_@@_chap_width_dim + \l_@@_chap_sep_tl -
                      \listparindent
                    } ~
                  \dim_eval:n
                    {
                      \linewidth - \@totalleftmargin + \l_@@_poetry_leftmargin_tl -
                      \l_@@_chap_width_dim - \l_@@_chap_sep_tl +
                      \listparindent
                    } ~
                  \dim_eval:n
                    { \@totalleftmargin + \l_@@_poetry_big_indent_tl } ~
                  \dim_eval:n
                    { \linewidth - \l_@@_poetry_big_indent_tl }
              }
          }
      }
    \box_use:N \l_tmpb_box
  }
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}{\@@_poetry_nodrop_chap:n}
%   Format a non-drop chapter for \env{poetry} environment in a
%   \env{scripture} quotation.
%    \begin{macrocode}
\cs_new_protected:Nn \@@_poetry_nodrop_chap:n
  {
    \hbox_overlap_left:n
      {
        \group_begin:
        \l_@@_chap_font_tl
        #1
        \group_end:
        \skip_horizontal:N \l_@@_chap_sep_tl
      }
  }
%    \end{macrocode}
% \end{macro}
%
%
% \begin{macro}{\@@_poetry_mode_vertical_verse:n}
%   Format a verse for poetry scripture quotations in vertical and horizontal
%   mode.
%    \begin{macrocode}
\cs_new_protected:Nn \@@_poetry_mode_vertical_verse:n
  {
    \strut
    \hbox_overlap_left:n
      {
        \@@_verse_output:n { #1 }
      }
  }
\cs_new_protected:Nn \@@_poetry_mode_horizontal_verse:n
  {
    \skip_horizontal:n { -\listparindent }
    \@@_poetry_mode_vertical_verse:n { #1 }
    \skip_horizontal:N \listparindent
  }
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}{\@@_poetry_par:}
%   par macro for poetry sections
%    \begin{macrocode}
\cs_new_protected:Nn \@@_poetry_par:
  {
    \mode_if_vertical:TF
      {
        \cs_set_eq:NN \vs \@@_poetry_mode_vertical_verse:n
        \noindent
      }
      {
        \cs_set_eq:NN \vs \@@_poetry_mode_horizontal_verse:n
        \@@_tmp_para_end:
      }
    \parshape 2 ~ 
      \@totalleftmargin ~
      \linewidth ~
      \dim_eval:n
        { \@totalleftmargin + \l_@@_poetry_big_indent_tl } ~
      \dim_eval:n
        { \linewidth - \l_@@_poetry_big_indent_tl }
  }
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}{\@@_obeylines:}
%   Special version of obeylines which doesn't insert par at end of
%   environment.
%    \begin{macrocode}
\group_begin:
  \char_set_catcode_active:N \^^M
  \cs_gset_protected_nopar:Nn \@@_obeylines: %
    {%
      \char_set_catcode_active:N \^^M%
      \cs_set_eq:NN ^^M \@@_obeylines_end:%
    }%
\group_end:
\cs_new_protected:Nn \@@_obeylines_end:
  {
    \peek_meaning:NF \end
      {
        \par
        \int_set:Nn \l_@@_poetry_prevgraf_int { \int_use:N \prevgraf }
      }
  }
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}{\@@_poetry_begin:}
%   Begin a poetry section in a scripture quotation.
%    \begin{macrocode}
\cs_new_protected:Nn \@@_poetry_begin:
  {
    \bool_if:NT \l_@@_active_inner_bool
      {
        \msg_error:nn { scripture } { nested-environment }
      }
    \bool_set_true:N \l_@@_active_inner_bool
    \par
    \list { }
      {
        \skip_set_eq:NN \l_@@_delta_below_skip \l_@@_poetry_belowskip_tl
        \bool_if:NTF \g_@@_start_bool
          {
            \skip_zero:N \topsep
          }
          {
            \dim_compare:nTF
              { \parskip >= \l_@@_poetry_aboveskip_tl > \c_zero_skip }
              {
                \skip_zero:N \topsep
                \skip_zero:N \l_@@_delta_below_skip
              }
              {
                \skip_set_eq:NN \topsep \l_@@_poetry_aboveskip_tl
                \skip_sub:Nn \l_@@_delta_below_skip \l_@@_poetry_aboveskip_tl
              }
            \int_compare:nNnT \l_@@_chap_par_prevgraf_int = 1
              { \addvspace { \baselineskip } }
            \int_zero:N \l_@@_chap_par_prevgraf_int
          }
        \dim_set_eq:NN \leftmargin \l_@@_poetry_leftmargin_tl
        \dim_set_eq:NN \rightmargin \l_@@_poetry_rightmargin_tl
        \dim_set_eq:NN \itemindent \l_@@_poetry_indent_tl
        \dim_set_eq:NN \listparindent \l_@@_poetry_indent_tl
        \skip_zero:N \parsep
        \skip_zero:N \partopsep
        \dim_zero:N \labelsep
      }
    \raggedright
    \dim_set_eq:NN \listparindent \l_@@_poetry_indent_tl
    \dim_set_eq:NN \parindent \l_@@_poetry_indent_tl
    \bool_if:NTF \l_@@_chap_drop_bool
      { \cs_set_eq:NN \ch \@@_poetry_chap:n }
      { \cs_set_eq:NN \ch \@@_poetry_nodrop_chap:n }
    \cs_set_eq:NN \vs \@@_poetry_mode_vertical_verse:n
    \item
    \relax
    \cs_set_eq:NN \@@_tmp_para_end: \par
    \cs_set_eq:NN \par \@@_poetry_par:
  }
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}{\@@_poetry_end:}
%   End a poetry section in a scripture quotation.
%    \begin{macrocode}
\cs_new_protected:Nn \@@_poetry_end:
  {
    \@@_calc_final_line_length:
    \skip_add:Nn \@topsepadd \l_@@_delta_below_skip
    \endlist
    \bool_gset_true:N \g_@@_poetry_end_bool
    \hook_gput_next_code:nn { para / begin }
      { \bool_gset_false:N \g_@@_poetry_end_bool }
  }
%    \end{macrocode}
% \end{macro}
%
%
% \subsection{Public \LaTeX{} Interface}
%
% \begin{macro}{\scripturesetup}
%   \begin{arguments}
%     \item \meta{|options|} to set.
%   \end{arguments}
%   Set key-value settings.
%    \begin{macrocode}
\NewDocumentCommand { \scripturesetup } { m }
  {
    \keys_set:nn { scripture } { #1 }
  }
%    \end{macrocode}
% \end{macro}
%
% \begin{envmacro}{scripture}
%   \begin{arguments}
%     \item \meta{|reference|} of quotation.
%     \item \meta{|options|} to set.
%   \end{arguments}
%   Format a scripture quotation with optional reference.
%    \begin{macrocode}
\NewDocumentEnvironment { scripture } { oo }
  {
    \@@_begin:n { #2 }
%    \end{macrocode}
% \begin{envmacro}{center}
%   \begin{arguments}
%     \item \meta{|options|} to set.
%   \end{arguments}
%    \begin{macrocode}
    \DeclareDocumentEnvironment { center } { o }
      {
        \@@_center_begin:n { ##1 }
        \ignorespaces
      }
      { \@@_center_end: }
%    \end{macrocode}
% \end{envmacro}
% \begin{envmacro}{flushright}
%   \begin{arguments}
%     \item \meta{|options|} to set.
%   \end{arguments}
%    \begin{macrocode}
    \DeclareDocumentEnvironment { flushright } { o }
      {
        \@@_flushright_begin:n { ##1 }
        \ignorespaces
      }
      { \@@_flushright_end: }
%    \end{macrocode}
% \end{envmacro}
% \begin{envmacro}{hanging}
%   \begin{arguments}
%     \item \meta{|options|} to set.
%   \end{arguments}
%    \begin{macrocode}
    \DeclareDocumentEnvironment { hanging } { o }
      {
        \@@_hanging_begin:n { ##1 }
        \ignorespaces
      }
      { \@@_hanging_end: }
%    \end{macrocode}
% \end{envmacro}
% \vspace{-2\baselineskip}
% \begin{envmacro}{midparachap}
%    \begin{macrocode}
    \DeclareDocumentEnvironment { midparachap } { }
      {
        \@@_mid_para_chap_begin:
        \ignorespaces
      }
      { \@@_mid_para_chap_end: }
%    \end{macrocode}
% \end{envmacro}
% \begin{envmacro}{narrow}
%   \begin{arguments}
%     \item \meta{|options|} to set.
%   \end{arguments}
%    \begin{macrocode}
    \DeclareDocumentEnvironment { narrow } { o }
      {
        \@@_narrow_begin:n { ##1 }
        \ignorespaces
      }
      { \@@_narrow_end: }
%    \end{macrocode}
% \end{envmacro}
% \begin{envmacro}{poetry}
%   \begin{arguments}
%     \item \meta{|options|} to set.
%   \end{arguments}
% The \env{poetryaux} environment is required because \cs{@@_obeylines:}
% breaks the reading of optional arguments.
%    \begin{macrocode}
    \DeclareDocumentEnvironment { poetryaux } { o }
      {
        \tl_if_novalue:nF { ##1 }
        {
          \keys_set:nn
            { scripture / poetry }
            { ##1 }
        }
        \@@_poetry_begin:
        \ignorespaces
      }
      { \@@_poetry_end: }
    \DeclareDocumentEnvironment { poetry } { }
      {
        \@@_obeylines:
        \poetryaux
      }
      { \endpoetryaux }
%    \end{macrocode}
% \end{envmacro}
%    \begin{macrocode}
    \ignorespaces
  }
  {
    \@@_end:n { #1 }
  }
%    \end{macrocode}
% \end{envmacro}
%    \begin{macrocode}
%</package>
%    \end{macrocode}
% \end{implementation}
%
% \PrintChanges
%
% \PrintIndex
