From 33b877a6413cc7b93c7a2c17e6df36c03f55481d Mon Sep 17 00:00:00 2001
From: Norbert Preining <norbert@preining.info>
Date: Thu, 24 Oct 2019 03:02:46 +0000
Subject: CTAN sync 201910240302

---
 macros/latex/contrib/scontents/scontents.dtx | 1083 ++++++++++++++++++++------
 1 file changed, 863 insertions(+), 220 deletions(-)

(limited to 'macros/latex/contrib/scontents/scontents.dtx')

diff --git a/macros/latex/contrib/scontents/scontents.dtx b/macros/latex/contrib/scontents/scontents.dtx
index fd0504e7a2..4b77c043ee 100644
--- a/macros/latex/contrib/scontents/scontents.dtx
+++ b/macros/latex/contrib/scontents/scontents.dtx
@@ -6,68 +6,21 @@
 % 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
+%  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.
-% 
+%
 % This work is "maintained" (as per the LPPL maintenance status)
 % by Pablo González Luengo.
-% 
-% This work consists of the file  scontents.dtx
-% and the derived files           scontents.ins,
-%                                 scontents.pdf and
-%                                 scontents.sty.
-%
-%<*internal>
-\def\nameofplainTeX{plain}
-\ifx\fmtname\nameofplainTeX\else
-  \expandafter\begingroup
-\fi
-%</internal>
-%<*install>
-\input l3docstrip.tex
-\keepsilent
-\askforoverwritefalse
-\preamble
-
-Copyright (C) 2019 by Pablo González L <pablgonz@educarchile.cl>
-
-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.
-
-This work is "maintained" (as per the LPPL maintenance status)
-by Pablo González Luengo.
-
-This work consists of the file  scontents.dtx
-and the derived files           scontents.ins,
-                                scontents.pdf and
-                                scontents.sty.
-
-\endpreamble
-\usedir{tex/latex/scontents}
-\generate{%
-  \file{\jobname.sty}{\from{\jobname.dtx}{package}}%
-}%
-%</install>
-%<install>\endbatchfile
-%<*internal>
-\usedir{source/latex/scontents}
-\generate{
-  \file{\jobname.ins}{\from{\jobname.dtx}{install}}
-}
-\ifx\fmtname\nameofplainTeX
-  \expandafter\endbatchfile
-\else
-  \expandafter\endgroup
-\fi
-%</internal>
+%
+% This work consists of the files scontents.dtx and
+%                                 scontents.ins,
+% and the derived files           scontents.sty,
+%                                 scontents.tex,
+%                                 t-scontents.mkvi and
+%                                 scontents-code.tex.
+%
 %<*driver>
 \documentclass[full]{l3doc}
 % imakeidx also opens a write stream for the .idx file, and that conflicts
@@ -372,8 +325,11 @@ and the derived files           scontents.ins,
 \lstdefinelanguage{scontents-doc}{
     texcsstyle=*,%
     escapechar=`,%
-    showstringspaces=false,%
-    extendedchars=true, %
+    extendedchars=true,%
+    breakatwhitespace=true,%
+    breaklines=true,%
+    keepspaces=true,%
+    columns=fullflexible,%
     stringstyle= {\color{red}},%
     basicstyle=\ttfamily\small,%
     alsoletter=-,%
@@ -382,28 +338,30 @@ and the derived files           scontents.ins,
     commentstyle=\lmmitalic\small\itshape\color{lightgray},%
 % Important words 1
     keywordstyle=[1]{\color{gray}},%
-    keywords=[1]{begin,end},%
+    keywords=[1]{begin,end,Verbatim},%
 % Other words 2
     keywordstyle=[2]{\color{blue!75}},%
-    keywords=[2]{usepackage,section,documentclass},%
+    keywords=[2]{usepackage,section,documentclass,input,usemodule},%
 % Other words 3
     keywordstyle=[3]{\color{optcolor!85}},%
     keywords=[3]{document,article},%
 % Reserved words 4 (scontents pkg)
     keywordstyle=[4]{\color{mypkgcolor}},%
     keywords=[4]{scontents,Scontents,getstored,typestored,verbatimsc,%
-                 endverbatimsc,countsc,meaningsc},%
+                 endverbatimsc,countsc,meaningsc,foreachsc,macros
+                 endscontents,startscontents,stopscontents},%
 % Reserved in red
     keywordstyle=[5]{\color{red}},%
-    keywords=[5]{makeatletter,makeatother,let},%
+    keywords=[5]{makeatletter,makeatother,let,verb,undefined,makebox},%
 % Reserved in orange
     keywordstyle=[6]{\color{optcolor}},%
-    keywords=[6]{verb,myverb,store-cmd,store-env,print-env,write-env,%
-                 write-out,width-tab,force-eol,inner,outer,I,J,M,L,Ascheol},%
+    keywords=[6]{store-cmd,store-env,print-env,write-env,%
+                 start,stopt,wrapper,sep,step,before,after,write-out,%
+                 width-tab,force-eol,inner,outer,I,J,M,L,Ascheol},%
 % Reserved in orange
     keywordstyle=[7]{\color{OrangeRed}},%
-    keywords=[7]{foreach,DefineVerbatimEnvironment,lstnewenvironment,newminted},%
-% literateee
+    keywords=[7]{DefineVerbatimEnvironment,lstnewenvironment,newminted,newenvironment},%
+% literate
     literate=*{\{}{{\textcolor{gray}{\{}}}{1}
               {\}}{{\textcolor{gray}{\}}}}{1}
               {[}{{\textcolor{gray}{[}}}{1}
@@ -440,6 +398,7 @@ and the derived files           scontents.ins,
    escapechar=`,%
    upquote=true,%
    numbersep=1em,%
+   columns=fullflexible,%
    numberstyle=\tiny\color{lightgray}\noaccsupp,%
    literate=*{\%}{{\bfseries\textcolor{gray}{\%}}}{1}
   }
@@ -449,7 +408,7 @@ and the derived files           scontents.ins,
 \lstMakeShortInline[language=scontents-doc,basicstyle=\ttfamily]§
 
 % Get file info
-\GetFileInfo{\jobname.sty}
+\GetFileInfo{scontents.sty}
 
 % Config hyperref
 \hypersetup{
@@ -463,7 +422,7 @@ and the derived files           scontents.ins,
    pdfsubject         = {Documentation for \fileversion{} [\filedate] },%
    pdfcopyright       = {\textcopyright 2019 by Pablo González},
    pdfcontacturl      = {https://github.com/pablgonz/scontents},
-   pdfkeywords        = {contents, external files, expl3, xparse, l3seq, Store contents},
+   pdfkeywords        = {sequences, contents, external files, expl3, xparse, l3seq, store contents},
    pdfstartview       = {FitH},%
    bookmarksopenlevel = 1,%
   }
@@ -554,7 +513,7 @@ and the derived files           scontents.ins,
 % \section{Motivation and Acknowledgments}
 %
 % In \hologo{(La)TeX} there is no direct way to record content for later use, although
-% you can do this using "\macros", recording \mymeta{verbatim content}  is a
+% you can do this using §\macros§, recording \mymeta{verbatim content}  is a
 % problem, usually you can avoid this by creating external files or boxes. The
 % general idea of this package is to try to imitate this implementation
 % \emph{buffers} that has \hologo{ConTeXt} which allows you to save content in
@@ -593,8 +552,8 @@ and the derived files           scontents.ins,
 % \medskip
 %
 % The \mypkg*{scontents} package loads \mypkg{expl3}, \mypkg{xparse} and
-% \mypkg{l3keys2e}. This package can be used with "xelatex", "lualatex"
-% , "pdflatex" and the classical workflow §latex>dvips>ps2pdf§.
+% \mypkg{l3keys2e}. This package can be used with "plain", "context", "xelatex",
+% "lualatex", "pdflatex" and the classical workflow §latex>dvips>ps2pdf§.
 %
 % \thispagestyle{plain}
 %
@@ -616,9 +575,9 @@ and the derived files           scontents.ins,
 % by making use \mymeta{sequences}.
 % \end{scontents}
 %
-% The package uses a \myoarg{key \textnormal{\textcolor{gray}{=}} val}
-% system for the options and is loaded in the usual way:
+% The package is loaded in the usual way:
 %
+% \subsubsection*{For \hologo{LaTeX} users}
 % \iffalse
 %<*example>
 % \fi
@@ -640,6 +599,30 @@ and the derived files           scontents.ins,
 %</example>
 % \fi
 %
+% \subsubsection*{For \hologo{plainTeX} users}
+%
+% \iffalse
+%<*example>
+% \fi
+\begin{examplecode}[frame=single]
+\input scontents.tex
+\end{examplecode}
+% \iffalse
+%</example>
+% \fi
+%
+% \subsubsection*{For \hologo{ConTeXt} users}
+%
+% \iffalse
+%<*example>
+% \fi
+\begin{examplecode}[frame=single]
+\usemodule{scontents}
+\end{examplecode}
+% \iffalse
+%</example>
+% \fi
+%
 % \subsection{The TAB character}
 % \label{sec:tabcharacter}
 %
@@ -667,7 +650,7 @@ and the derived files           scontents.ins,
 %
 % As a general recommendation \enquote{Do not use "TAB" character unless strictly
 % necessary}, for example within a \emph{verbatim} environment that supports
-% this character such as §Verbatim§ of the package \mypkg{fancyvrb} or §lstlisting§
+% this character such as \myenv{Verbatim} of the package \mypkg{fancyvrb} or \myenv{lstlisting}
 % of the package \mypkg{listings} or when you want to generate a §MakeFile§ file.
 %
 % \subsection{Configuration of the options}
@@ -718,7 +701,7 @@ and the derived files           scontents.ins,
 % This key is necessary only if the last line is the closing of some
 % environment defined by the \mypkg{fancyvrb} package as §\end{Verbatim}§
 % or another environment that does not support a comments \enquote{\textcolor{gray}{\%}}
-% after closing §\end{...}%§. This key is available for the \myenv*{scontents}
+% after closing §\end{§\textcolor{gray}{...}§}%§. This key is available for the \myenv*{scontents}
 % environment and the \ics*{Scontents} command.
 %
 % \keyexamp{width-tab}{integer}{1}
@@ -776,13 +759,13 @@ and the derived files           scontents.ins,
 %   \end{syntax}
 %
 % The \myenv*{scontents} environment allows you to \mymeta{store} and \mymeta{write}
-% content, including \emph{verbatim} material. After the package has been loaded,
-% the environment can be used both in the preamble and in the body of the document.
+% content, including \emph{verbatim} material. After the package has been
+% loaded, the environment can be used both in the preamble and in the body
+% of the document.
 %
-% For the correct operation §\begin{scontents}§ and §\end{scontents}§ must be in
-% different lines, all \mymeta{keys} must be passed in a \mymeta{single line} separated
-% by commas \enquote{without vertical spaces} and \enquote{without separation} of
-% the start of the environment.
+% For the correct operation §\begin{scontents}§ and §\end{scontents}§ must
+% be in different lines, all \mymeta{keys} must be passed separated by
+% commas and \enquote{without separation} of the start of the environment.
 % \end{function}
 %
 % Comments \enquote{\textcolor{gray}{\%}} or \enquote{any character} after
@@ -818,6 +801,11 @@ This text is in the outer environment (after nested).
 % It is advisable to store content within sequences with different names,
 % so as not to get lost in the order in which content is stored.
 %
+% In \hologo{plainTeX} there is not environments as in \hologo{LaTeX}.
+% Instead of using the environment \myenv*{scontents}, one should use a
+% \emph{pseudo environment} delimited by \ics*{scontents} and \ics*{endscontents}.
+% \hologo{ConTeXt} users should use \ics*{startscontents} and \ics*{stopscontents}.
+%
 % \subsection*{Options for environment}
 %
 % The environment options can be configured globally using option
@@ -836,7 +824,7 @@ This text is in the outer environment (after nested).
 % running the environment. The content is extracted from the \mymeta{sequence}
 % in which it is stored.
 %
-% \newpage
+% \medskip
 %
 % \keyexamp{write-env}{file.ext}{not used}
 % Sets the name of the \mymeta{external file} in which the \mymeta{contents} of
@@ -925,11 +913,63 @@ This text is in the outer environment (after nested).
 %   \end{syntax}
 % \end{function}
 %
-% The command \ics*{getstored} gets the content stored in \mymeta{seq name}
+% The command \ics*{getstored} gets the content stored in \mymarg{seq name}
 % according to the \mymeta{index} in which it was stored. The command is
 % robust and can be used as an \mymeta{argument} for another command. If the
 % optional argument is not passed it defaults to the first element stored
-% in the \mymeta{seq name}.
+% in the \mymarg{seq name}.
+%
+% \subsection{The command \cs{foreachsc}}
+% \label{sec:foreachsc}
+%
+% \vspace*{-10pt}
+%
+% \begin{function}{\foreachsc}
+%   \begin{syntax}
+%     \cmdexamp{foreachsc}[key \textnormal{\textcolor{gray}{=}} val]{seq name}
+%   \end{syntax}
+% \end{function}
+%
+% The command \ics*{foreachsc} goes through and executes the command §\getstored§
+% on the contents stored in \mymarg{seq name}. If you pass without options run
+% §\getstored§ on all contents stored in \mymarg{seq name}.
+%
+% \subsection*{Options for command}
+% \label{sec:optcmdfor}
+%
+% \keyexamp{sep}{code}{empty}
+% Establishes the separation between each content stored in \mymarg{seq name}.
+% For example, you can use §sep={\\[10pt]}§ for vertical separation of stored
+% contents.
+%
+% \keyexamp{step}{integer}{1}
+% Sets the increment (\mymeta{step}) applied to the value set by key §start§
+% for each element stored in the \mymarg{seq name}. The value must be a
+% \mymeta{positive integer}.
+%
+% \keyexamp{start}{integer}{1}
+% Sets the \mymeta{index} number of the \mymarg{seq name} from which execution
+% will start. The value must be a \mymeta{positive integer}.
+%
+% \keyexamp{stop}{integer}{total}
+% Sets the \mymeta{index} number of the \mymarg{seq name} from which execution
+% it will finish executing. The value must be a \mymeta{positive integer}.
+%
+% \keyexamp{before}{code}{empty}
+% Sets the \mymarg{code} that will be executed \mymeta{before} each content stored
+% in \mymarg{seq name}. The \mymarg{code} must be passed between braces.
+%
+% \medskip
+%
+% \keyexamp{after}{code}{empty}
+% Sets the \mymarg{code} that will be executed \mymeta{after} each content stored
+% in \mymarg{seq name}. The \mymarg{code} must be passed between braces.
+%
+% \keyexamp{wrapper}{code \textnormal{\textcolor{gray}{\{\#1\}}} more code}{empty}
+% Wraps the content stored in \mymarg{seq name} referenced by \mymarg{\#1}.
+% The \mymarg{code} must be passed between braces. For example
+% §\foreachsc[wrapper={\makebox[1em][l]{#1}}]{contents}§.
+%
 %
 % \subsection{The command \cs{typestored}}
 % \label{sec:typestored}
@@ -941,13 +981,12 @@ This text is in the outer environment (after nested).
 %      \cmdexamp{typestored}[index\textnormal{\textcolor{gray}{,}} width-tab \textnormal{\textcolor{gray}{=}} number]{seq name}
 %   \end{syntax}
 % The command \ics*{typestored} internally places the content stored in
-% the \mymeta{seq name} into the \myenv*{verbatimsc} environment. The \mymeta{index}
-% number corresponds to the position in which the content is stored in
-% the \mymeta{seq name}.
+% the \mymarg{seq name} into the \myenv*{verbatimsc} environment. The \mymeta{index}
+% corresponds to the position in which the content is stored in the \mymarg{seq name}.
 % \end{function}
 %
 % If the optional argument is not passed it defaults to the first element
-% stored in the \mymeta{seq name}. The key §width-tab§ is available for
+% stored in the \mymarg{seq name}. The key §width-tab§ is available for
 % this command.
 %
 % The \mypkg{verbatim} package is not compatible with the implementation
@@ -955,8 +994,6 @@ This text is in the outer environment (after nested).
 % a user of that package consider customizing the \myenv*{verbatimsc}
 % environment.
 %
-% \newpage
-%
 % \subsection{The environment \env{verbatimsc}}
 % \label{sec:verbatimsc}
 %
@@ -1043,12 +1080,12 @@ This text is in the outer environment (after nested).
 %      \cmdexamp{meaningsc}[index\textnormal{\textcolor{gray}{,}} width-tab \textnormal{\textcolor{gray}{=}} number]{seq name}
 %   \end{syntax}
 % The command \ics*{meaningsc} executes \ics{meaning} on the content stored
-% in \mymeta{seq name}. The \mymeta{index} number corresponds to the position
-% in which the content is stored in the \mymeta{seq name}.
+% in \mymarg{seq name}. The \mymeta{index} corresponds to the position
+% in which the content is stored in the \mymarg{seq name}.
 % \end{function}
 %
 % If the optional argument is not passed it defaults to the first element
-% stored in the \mymeta{seq name}. The key §width-tab§ is available for
+% stored in the \mymarg{seq name}. The key §width-tab§ is available for
 % this command.
 %
 % \subsection{The command \cs{countsc}}
@@ -1060,7 +1097,7 @@ This text is in the outer environment (after nested).
 %   \begin{syntax}
 %      \cmdexamp{countsc}{seq name}
 %   \end{syntax}
-% The command \ics*{countsc} count a number of contents stored in \mymeta{seq name}.
+% The command \ics*{countsc} count a number of contents stored in \mymarg{seq name}.
 % \end{function}
 %
 % \subsection{The command \cs{cleanseqsc}}
@@ -1072,7 +1109,7 @@ This text is in the outer environment (after nested).
 %   \begin{syntax}
 %      \cmdexamp{cleanseqsc}{seq name}
 %   \end{syntax}
-% The command \ics*{cleanseqsc} remove all contents stored in \mymeta{seq name}.
+% The command \ics*{cleanseqsc} remove all contents stored in \mymarg{seq name}.
 % \end{function}
 %
 % \newpage
@@ -1158,7 +1195,6 @@ by making use \mymeta{sequences}.
 \begin{scontents}[write-out=scexamp1.ltx]
 \documentclass[12pt,a4paper]{article}
 \usepackage[store-cmd=solutions]{scontents}
-\usepackage{pgffor}
 \newtheorem{ex}{Exercise}
 \begin{document}
 \section{Problems}
@@ -1177,9 +1213,7 @@ Second exercise
 \end{ex}
 
 \section{Solutions}
-\foreach \i in {1,...,\countsc{solutions}} {
-\noindent\textbf{\i} \getstored[\i]{solutions}\par
-}
+\foreachsc[sep={\\[10pt]}]{solutions}
 \end{document}
 \end{scontents}
 % \iffalse
@@ -1200,7 +1234,6 @@ Second exercise
 \begin{scontents}[write-out=scexamp2.ltx]
 \documentclass{article}
 \usepackage[store-env=defexercise,store-cmd=defexercise]{scontents}
-\usepackage{pgffor}
 \pagestyle{empty}
 \begin{document}
 % not starred
@@ -1218,10 +1251,9 @@ advance evidence from knowledge of the names of its employees in the
 seventies that the \NSA\ has known that for 40 years.\par
 \end{scontents}
 % see all stored
-\foreach \i in {1,...,3} {
 \begin{itemize}
-\item \getstored[\i]{defexercise}
-\end{itemize}}
+\foreachsc[before={\item }]{defexercise}
+\end{itemize}
 % \getstored are robust :)
 \section{\getstored[2]{defexercise}}
 \end{document}
@@ -1286,7 +1318,6 @@ seventies that the \NSA\ has known that for 40 years.\par
 \begin{scontents}[write-out=scexamp4.ltx]
 \documentclass{article}
 \usepackage{scontents}
-\usepackage{pgffor}
 \pagestyle{empty}
 \begin{document}
 \begin{scontents}[store-env=a]
@@ -1306,9 +1337,8 @@ Something with no label
 This is a: \getstored[1]{a}\par
 This is b: \getstored[2]{a}
 
-\textbf{Print all of them}
-
-\foreach \i in {1,...,\countsc{a}} {\getstored[\i]{a}\par}
+\textbf{Print all of them}\par
+\foreachsc[sep={\\[10pt]}]{a}
 \end{document}
 \end{scontents}
 % \iffalse
@@ -1554,13 +1584,21 @@ No tab
 % \begin{description}[font=\small\sffamily,wide=0pt,style=multiline,leftmargin=\descrwidth,nosep,noitemsep]
 % \item [\fileversion{} (ctan), \filedate]
 %    \begin{itemize}
+%        \item Add support for \hologo{plainTeX} and \hologo{ConTeXt}.
+%        \item Split internal code for optimization.
+%        \item Add support for vertical spaces in |key=val|.
+%        \item Add |\foreachsc| command.
+%        \item Check if |verbatim| package is loaded.
+%    \end{itemize}
+% \item [v1.4 (ctan), 2019-10-03]
+%    \begin{itemize}
 %        \item Add |store-all| key.
 %        \item Messages and keys were separated.
 %        \item Restructuring of documentation.
 %        \item Now the version of |expl3| is checked instead of |xparse|.
 %        \item The internal behavior of \verb+force-eol+ has been modified.
 %    \end{itemize}
-% \item [v1.3 (ctan), 2019/09/24]
+% \item [v1.3 (ctan), 2019-09-24]
 %    \begin{itemize}
 %        \item The environment can now nest.
 %        \item Added \verb+force-eol+, \verb+verb-font+ and \verb+width-tab+ keys.
@@ -1570,17 +1608,17 @@ No tab
 %        \item Remove \verb+filecontentsdef+ dependency.
 %        \item Changing \verb+\regex_replace_all:+ for \verb+\tl_replace_all:+.
 %    \end{itemize}
-% \item [v1.2 (ctan), 2019/08/28]
+% \item [v1.2 (ctan), 2019-08-28]
 %    \begin{itemize}
 %        \item Restructuring of documentation.
 %        \item Added copy of \verb+\tex_scantokens:D+.
 %    \end{itemize}
-% \item [v1.1 (ctan), 2019/08/12]
+% \item [v1.1 (ctan), 2019-08-12]
 %    \begin{itemize}
 %        \item Extension of documentation.
 %        \item Replace \verb+\tex_endinput:D+ by \verb+\file_input_stop:+.
 %    \end{itemize}
-% \item [v1.0 (ctan), 2019/07/30]
+% \item [v1.0 (ctan), 2019-07-30]
 %    \begin{itemize}
 %        \item First public release,
 %    \end{itemize}
@@ -1604,10 +1642,6 @@ No tab
 % \label{sec:Implementation}
 % \addtocontents{toc}{\protect\setcounter{tocdepth}{0}}
 %
-% \iffalse
-%<*package>
-% \fi
-%
 % \subsection{Declaration of the package}
 %
 % First we set up the module name for \pkg{l3doc}:
@@ -1615,30 +1649,155 @@ No tab
 %<@@=scontents>
 %    \end{macrocode}
 %
-% Then, we can give the traditional declaration of a package written with
-% \pkg{expl3} and the necessary packages for its operation.
-%
+% Now we define some common macros to hold the package date and version:
 %    \begin{macrocode}
-\RequirePackage{l3keys2e}
-\RequirePackage{xparse}[2019/05/28]
-\ProvidesExplPackage{scontents}{2019/10/03}{1.4}
-  {Stores LaTeX contents in memory or files}
+%<loader>\def\ScontentsFileDate{2019-10-24}%
+%<core>\def\ScontentsCoreFileDate{2019-10-24}%
+%<*loader>
+\def\ScontentsFileVersion{1.5}%
+\def\ScontentsFileDescription{Stores LaTeX contents in memory or files}%
 %    \end{macrocode}
 %
-% A check to make sure that \pkg{expl3} is not too old
+% The \LaTeX{} loader is fairly simple: just load the dependencies, load the
+% core code, and then set interfaces up.
 %
+% We also check if the \pkg{verbatim} package is loaded and show a compatibility
+% warning.
 %    \begin{macrocode}
-\@ifpackagelater { expl3 } { 2019/09/19 }
-  { }
+%<*latex>
+\RequirePackage{expl3,xparse,l3keys2e}[2019/05/28]
+\ProvidesExplPackage
+  {scontents} {\ScontentsFileDate} {\ScontentsFileVersion} {\ScontentsFileDescription}
+\@ifpackageloaded { verbatim }
   {
-    \PackageError { scontents } { Support~package~expl3~too~old }
+    \iow_term:n
       {
-        You~need~to~update~your~installation~of~the~bundles~
-        'l3kernel'~and~'l3packages'.\MessageBreak
-        Loading~scontents~will~abort!
+        The~implementation~of~the~'verbatimsc'~environment~\\
+        used~by~\tl_to_str:n{\typestored}~is~not~compatible~with~package\\
+        'verbatim'.~Review~the~documentation~and~redefine~\\
+        the~'verbatimsc'~environment.
       }
+  } { }
+%</latex>
+%    \end{macrocode}
+% The Plain and \hologo{ConTeXt} loaders are similar (probably because I don't
+% know how to make a proper \hologo{ConTeXt} module :-). We define a
+% \LaTeX{}-style ver@scontents.sty macro with version info (just in case):
+%    \begin{macrocode}
+%<*!latex>
+%<context>\writestatus{loading}{User Module scontents v\ScontentsFileVersion}
+%<context>\unprotect
+\input expl3-generic.tex
+\ExplSyntaxOn
+\tl_gset:cx { ver @ scontents . sty } { \ScontentsFileDate\space
+  v\ScontentsFileVersion\space \ScontentsFileDescription }
+\iow_log:x { Package: ~ scontents ~ \use:c { ver @ scontents . sty } }
+%</!latex>
+%    \end{macrocode}
+%
+% In Plain, check that the package isn't being loaded twice (\LaTeX{} and
+% \hologo{ConTeXt} already defend against that):
+%    \begin{macrocode}
+%<*plain>
+\msg_gset:nnn { scontents } { already-loaded }
+  { The~`scontents'~package~is~already~loaded.~Aborting~input~\msg_line_context:. }
+\cs_if_exist:NT \@@_rescan_tokens:n
+  {
+    \msg_warning:nn { scontents } { already-loaded }
+    \ExplSyntaxOff
     \file_input_stop:
   }
+%</plain>
+%    \end{macrocode}
+%
+% \begin{macro}{\g_@@_end_verbatimsc_tl,\c_@@_end_env_tl}
+%   A token list to match when ending \env{verbatimsc} and \env{scontents}
+%   environments.
+%
+%    \begin{macrocode}
+\tl_new:N \g_@@_end_verbatimsc_tl
+\tl_gset_rescan:Nnn
+  \g_@@_end_verbatimsc_tl
+  {
+    \char_set_catcode_other:N \\
+%<*latex>
+    \char_set_catcode_other:N \{
+    \char_set_catcode_other:N \}
+%</latex>
+  }
+%<latex>  { \end{verbatimsc} }
+%<plain>  { \endverbatimsc }
+%<context>  { \stopverbatimsc }
+\tl_const:Nx \c_@@_end_env_tl
+  {
+    \c_backslash_str
+%<latex|plain>    end
+%<context>    stop
+%<latex>    \c_left_brace_str
+      scontents
+%<latex>    \c_right_brace_str
+  }
+%    \end{macrocode}
+% \end{macro}
+%
+% Now we load the core \mypkg*{scontents} code:
+%    \begin{macrocode}
+\file_input:n { scontents-code.tex }
+%    \end{macrocode}
+%
+% Sometimes we need to detect the format from within a macro:
+%    \begin{macrocode}
+\cs_new:Npn \@@_format_case:nnn #1 #2 #3
+%<latex>  {#1} % LaTeX
+%<plain>  {#2} % Plain/Generic
+%<context>  {#3} % ConTeXt
+%    \end{macrocode}
+%
+% Checking that the package was loaded with the proper loader code. This code
+% was copied from \texttt{expl3-code.tex}.
+%    \begin{macrocode}
+%</loader>
+%<*core>
+\begingroup
+  \def\next{\endgroup}%
+  \expandafter\ifx\csname PackageError\endcsname\relax
+    \begingroup
+      \def\next{\endgroup\endgroup}%
+      \def\PackageError#1#2#3%
+        {%
+          \endgroup
+          \errhelp{#3}%
+          \errmessage{#1 Error: #2!}%
+        }%
+  \fi
+  \expandafter\ifx\csname ScontentsFileDate\endcsname\relax
+    \def\next
+      {%
+        \PackageError{scontents}{No scontents loader detected}
+          {%
+            You have attempted to use the scontents code directly rather than using
+            the correct loader. Loading of scontents will abort.
+          }%
+        \endgroup
+        \endinput
+      }
+  \else
+    \ifx\ScontentsFileDate\ScontentsCoreFileDate
+    \else
+      \def\next
+        {%
+          \PackageError{scontents}{Mismatched~scontents~files~detected}
+            {%
+              You~have~attempted~to~load~scontents~with~mismatched~files:~
+              probably~you~have~one~or~more~files~'locally~installed'~which~
+              are~in~conflict.~Loading~of~scontents~will~abort.
+            }%
+          \endgroup
+          \endinput
+        }%
+    \fi
+\fi
+\next
 %    \end{macrocode}
 %
 % \subsection{Definition of common keys}
@@ -1656,7 +1815,6 @@ No tab
     store-cmd .initial:n        = contents,
     store-cmd .value_required:n = true,
     verb-font .tl_set:N         = \l_@@_verb_font_tl,
-    verb-font .initial:n        = \ttfamily,
     verb-font .value_required:n = true,
     print-env .bool_set:N       = \l_@@_print_env_bool,
     print-env .initial:n        = false,
@@ -1675,14 +1833,18 @@ No tab
     store-all .meta:n           = { store-env = #1 , store-cmd = #1 },
     store-all .value_required:n = true
   }
+%</core>
+%<loader>\keys_define:nn { scontents }
+%<latex>  { verb-font .initial:n = \ttfamily }
+%<plain|context>  { verb-font .initial:n = \tt }
 %    \end{macrocode}
 %
-% We process the \mymeta{keys} as options passed on to the package, the
-% package \pkg{l3keys2e} will verify the \mymeta{keys} and will return
-% an error when they are \emph{unknown}.
-%
+% In \LaTeX{} mode we load \mypkg{l3keys2e} process the \mymeta{keys} as options
+% passed on to the package, the package \pkg{l3keys2e} will verify the
+% \mymeta{keys} and will return an error when they are \emph{unknown}.
 %    \begin{macrocode}
-\ProcessKeysOptions { scontents }
+%<latex>\ProcessKeysOptions { scontents }
+%<*core>
 %    \end{macrocode}
 %
 % \subsection{Internal variables}
@@ -1690,28 +1852,41 @@ No tab
 % Now we declare the internal variables we will use.
 %
 % \begin{macro}{\l_@@_macro_tmp_tl,\l_@@_fname_out_tl,\l_@@_temp_tl,
-%     \l_@@_file_tl,\g_@@_temp_tl}
+%               \l_@@_file_tl,\g_@@_temp_tl,\l_@@_foreach_name_seq_tl,
+%               \l_@@_foreach_before_tl,\l_@@_foreach_after_tl}
 %   \cs{l_@@_macro_tmp_tl} is a temporary token list to hold the contents
 %   of the macro/environment, \cs{l_@@_fname_out_tl} is used as the name
 %   of the output file, when there's one, \cs{l_@@_file_tl} holds the contents
 %   of an environment as it's being read, and \cs{l_@@_temp_tl} and
 %   \cs{g_@@_temp_tl} are generic temporary token lists.
 %
+%   \cs{l_@@_foreach_name_seq_tl} is the name assigned to the sequence on
+%   which the loop will be made, \cs{l_@@_foreach_before_tl} and \cs{l_@@_foreach_after_tl}
+%   are token lists in which the assigned material will be placed before
+%   and after the execution of the §\foreachsc§ loop.
+%
 %    \begin{macrocode}
 \tl_new:N \l_@@_macro_tmp_tl
 \tl_new:N \l_@@_fname_out_tl
 \tl_new:N \l_@@_temp_tl
 \tl_new:N \l_@@_file_tl
 \tl_new:N \g_@@_temp_tl
+\tl_new:N \l_@@_foreach_name_seq_tl
+\tl_new:N \l_@@_foreach_before_tl
+\tl_new:N \l_@@_foreach_after_tl
 %    \end{macrocode}
 % \end{macro}
 %
-% \begin{macro}{\l_@@_seq_item_int,\l_@@_env_nesting_int,\l_@@_tmpa_int}
+% \begin{macro}{\l_@@_seq_item_int,\l_@@_env_nesting_int,\l_@@_tmpa_int,
+%    \l_@@_foreach_stop_int}
 %   \cs{l_@@_seq_item_int} stores the index in the sequence of the item
 %   requested to \cs{typestored} or \cs{meaningsc}. \cs{l_@@_env_nesting_int}
 %   stores the current nesting level of the \env{scontents} environment.
+%  \cs{l_@@_foreach_stop_int} will save the value at which the §\foreachsc§
+%  loop will stop.
 %
 %    \begin{macrocode}
+\int_new:N \l_@@_foreach_stop_int
 \int_new:N \l_@@_seq_item_int
 \int_new:N \l_@@_env_nesting_int
 \int_new:N \l_@@_tmpa_int
@@ -1731,22 +1906,28 @@ No tab
 %    \end{macrocode}
 % \end{macro}
 %
-% \begin{macro}{\g_@@_end_verbatimsc_tl,\c_@@_end_env_tl}
-%   A token list to match when ending \env{verbatimsc} and \env{scontents}
-%   environments.
+%
+% \begin{macro}{\l_@@_foreach_before_bool,\l_@@_foreach_after_bool
+%               \l_@@_foreach_stop_bool,\l_@@_foreach_wrapper_bool}
+%   Boolean variables used by the §\foreachsc§ loop.
 %
 %    \begin{macrocode}
-\tl_new:N \g_@@_end_verbatimsc_tl
-\tl_gset_rescan:Nnn
-  \g_@@_end_verbatimsc_tl
-  {
-    \char_set_catcode_other:N \\
-    \char_set_catcode_other:N \{
-    \char_set_catcode_other:N \}
-  }
-  { \end{verbatimsc} }
-\tl_const:Nx \c_@@_end_env_tl
-  { \c_backslash_str end \c_left_brace_str scontents \c_right_brace_str }
+\bool_new:N \l_@@_foreach_before_bool
+\bool_set_false:N \l_@@_foreach_before_bool
+\bool_new:N \l_@@_foreach_after_bool
+\bool_set_false:N \l_@@_foreach_after_bool
+\bool_new:N \l_@@_foreach_stop_bool
+\bool_set_false:N \l_@@_foreach_stop_bool
+\bool_new:N \l_@@_foreach_wrapper_bool
+\bool_set_false:N \l_@@_foreach_wrapper_bool
+%    \end{macrocode}
+% \end{macro}
+%
+% \begin{macro}{\l_@@_foreach_print_seq}
+%   The \cs{l_@@_foreach_print_seq} is the sequence used by §\foreachsc§.
+%
+%    \begin{macrocode}
+\seq_new:N \l_@@_foreach_print_seq
 %    \end{macrocode}
 % \end{macro}
 %
@@ -1809,6 +1990,7 @@ No tab
 %    \begin{macrocode}
 \cs_generate_variant:Nn \tl_remove_once:Nn { NV }
 \cs_generate_variant:Nn \tl_replace_all:Nnn { Nx, Nxx, Nnx }
+\cs_generate_variant:Nn \msg_error:nnnn { nnx }
 \prg_generate_conditional_variant:Nnn \tl_if_empty:n { f } { TF }
 %    \end{macrocode}
 % \end{macro}
@@ -1862,6 +2044,46 @@ No tab
   }
 %    \end{macrocode}
 %
+% \subsubsection{Keys for command \cs{foreachsc}}
+%
+% We define a set of \mymeta{keys} for command §\foreachsc§.
+%
+%    \begin{macrocode}
+\keys_define:nn { scontents / foreachsc }
+  {
+    before  .code:n           = {
+                                  \bool_set_true:N \l_@@_foreach_before_bool
+                                  \tl_set:Nn \l_@@_foreach_before_tl {#1}
+                                },
+    before  .value_required:n = true,
+    after   .code:n           = {
+                                  \bool_set_true:N \l_@@_foreach_after_bool
+                                  \tl_set:Nn \l_@@_foreach_after_tl {#1}
+                                },
+    after   .value_required:n = true,
+    start   .int_set:N        = \l_@@_foreach_start_int,
+    start   .value_required:n = true,
+    start   .initial:n        = 1,
+    stop    .code:n           = {
+                                  \bool_set_true:N \l_@@_foreach_stop_bool
+                                  \int_set:Nn \l_@@_foreach_stop_int {#1}
+                                 },
+    stop    .value_required:n = true,
+    step    .int_set:N        = \l_@@_foreach_step_int,
+    step    .value_required:n = true,
+    step    .initial:n        = 1,
+    wrapper .code:n           = {
+                                  \bool_set_true:N \l_@@_foreach_wrapper_bool
+                                  \cs_set_protected:Npn \@@_foreach_wrapper:n ##1 {#1}
+                                },
+    wrapper .value_required:n = true,
+    sep     .tl_set:N         = \l_@@_foreach_sep_tl,
+    sep     .initial:n        = {},
+    sep     .value_required:n = true,
+    unknown .code:n           = { \@@_parse_foreach_keys:n {#1} }
+  }
+%    \end{macrocode}
+%
 % \subsubsection{Key for commands \cs{typestored} and \cs{meaningsc}}
 %
 % We define a \mymeta{key} for command §\typestored§ and §\meaningsc§.
@@ -1923,6 +2145,27 @@ No tab
 %    \end{macrocode}
 % \end{macro}
 %
+% \subsubsection{Undefined keys for \cs{foreachsc}}
+%
+% \begin{macro}{\@@_parse_foreach_keys:n,
+%               \@@_parse_foreach_keys:nn}
+%
+%   We check the \meta{keys} passed to command §\foreachsc§ and process
+%   it with \cs{@@_parse_foreach_keys:n}, if the \mymeta{key} is
+%   \emph{unknown} we return an error message.
+%
+%    \begin{macrocode}
+\cs_new_protected:Npn \@@_parse_foreach_keys:nn #1#2
+  {
+    \tl_if_blank:nTF {#2}
+      { \msg_error:nnn { scontents } { for-key-unknown } {#1} }
+      { \msg_error:nnnn { scontents } { for-key-value-unknown } {#1} {#2} }
+  }
+\cs_new_protected:Npn \@@_parse_foreach_keys:n #1
+  { \exp_args:NV \@@_parse_foreach_keys:nn \l_keys_key_tl {#1} }
+%    \end{macrocode}
+% \end{macro}
+%
 % \subsubsection{Undefined keys for \cs{typestored} and \cs{meaningsc}}
 %
 % \begin{macro}{\@@_parse_type_meaning_key:n,
@@ -1963,6 +2206,112 @@ No tab
 %    \end{macrocode}
 % \end{macro}
 %
+% \subsection{Compatibility layer with Plain}
+%
+% When loading the package outside of \LaTeX{} we can't usually use \pkg{xparse}.
+% However since \pkg{xparse} doesn't actually hold any dependency with \LaTeX{}
+% except for package-loading commands, we can emulate those commands (much like
+% in \pkg{miniltx}) so that \pkg{xparse} is loadable in any format.
+%
+% The bunch of macros below is adapted from the \LaTeX{} kernel (greatly simplified).
+%  \begin{macrocode}
+%</core>
+%<*loader&!latex>
+\seq_new:N \l_@@_compat_seq
+\cs_new_protected:Npn \@@_compat_redefine:Npn #1
+  {
+    \seq_put_right:Nn \l_@@_compat_seq {#1}
+    \cs_set_eq:cN { @@_saved_\cs_to_str:N #1: } #1
+    \cs_new_protected:Npn #1
+  }
+\cs_new_protected:Npn \@@_compat_restore:
+  { \seq_map_function:NN \l_@@_compat_seq \@@_compat_restore:N }
+\cs_new_protected:Npn \@@_compat_restore:N #1
+  {
+    \cs_set_eq:Nc #1 { @@_saved_\cs_to_str:N #1: }
+    \cs_undefine:c { @@_saved_\cs_to_str:N #1: }
+  }
+\cs_generate_variant:Nn \@@_compat_redefine:Npn { c }
+\cs_new_protected:Npn \@@_optarg:nn #1 #2
+  { \peek_charcode_ignore_spaces:NTF [ {#1} {#1[#2]} }
+\cs_new_protected:Npn \@@_stararg:nn #1 #2
+  { \peek_charcode_remove_ignore_spaces:NTF * {#1} {#2} }
+\@@_compat_redefine:Npn \RequirePackage
+  { \@@_optarg:nn { \@@_require_auxi:wn } { } }
+\cs_new_protected:Npn \@@_require_auxi:wn [#1] #2
+  { \@@_optarg:nn { \@@_require_auxii:wnw [{#1}]{#2} } { } }
+\cs_new:Npn \@@_zap_space:ww #1~#2
+  {
+    #1 \if_meaning:w #2 \q_mark
+      \exp_after:wN \use_none:n
+    \else:
+      \exp_after:wN \@@_zap_space:ww
+    \fi: #2
+  }
+\cs_new_protected:Npn \@@_require_auxii:wnw [#1] #2 [#3]
+  {
+    \tl_set:Nx \l_@@_temp_tl { \@@_zap_space:ww #2 ~ \q_mark }
+    \clist_map_function:NN \l_@@_temp_tl \@@_require_auxiii:n
+  }
+\cs_new_protected:Npn \@@_require_auxiii:n #1
+  { \str_if_eq:eeF {expl3} {#1} { \msg_error:nnn { scontents } { invalid-package } {#1} } }
+\msg_new:nnn { scontents } { invalid-package }
+  { Package~`#1'~invalid~in~scontents.~This~is~an~error~in~scontents. }
+\@@_compat_redefine:cpn { @ifpackagelater } #1
+  { \exp_args:Nc \@@_package_later_aux:Nn { ver@#1.sty } }
+\cs_new_protected:Npn \@@_package_later_aux:Nn #1 #2
+  {
+    \int_compare:nNnTF
+      { \exp_after:wN \@@_parse_version:w #1 //00 \q_mark } <
+      { \exp_after:wN \@@_parse_version:w #2 //00 \q_mark }
+  }
+\cs_new:Npn \@@_parse_version:w #1 { \@@_parse_version_auxi:w 0#1 }
+\cs_new:Npn \@@_parse_version_auxi:w #1/#2/#3#4#5 \q_mark
+  { \@@_parse_version_auxii:w #1-#2-#3#4 \q_mark }
+\cs_new:Npn \@@_parse_version_auxii:w #1-#2-#3#4#5 \q_mark
+  { \tl_if_blank:nF {#2} {#1} #2 #3 #4 }
+\@@_compat_redefine:Npn \ProvidesExplPackage #1 #2 #3 #4
+  { \@@_provides_aux:nn {#1} { #2 \ifx\relax#3\relax\else v#3\space\fi #4 } }
+\cs_new_protected:Npn \@@_provides_aux:nn #1 #2
+  {
+    \tl_gset:cx { ver@#1.sty } {#2}
+    \iow_log:n { Package~#1:~#2 }
+    \ExplSyntaxOn
+  }
+\@@_compat_redefine:Npn \DeclareOption
+  { \@@_stararg:nn { \use_none:n } { \use_none:nn } }
+\@@_compat_redefine:Npn \ProcessOptions
+  { \@@_stararg:nn { } { } }
+%    \end{macrocode}
+%
+% Now that the compatibility layer is defined, we can finally load \pkg{xparse}.
+% \pkg{xparse} expects to be loaded with \cs{ExplSyntaxOff} (not much harm would
+% be done otherwise, but just to be on the safe side).
+%
+% Within \pkg{xparse} a §\RequirePackage{expl3}§ is done. We can ignore that since
+% we have already loaded \pkg{expl3}. Next, a §\@ifpackagelater§ test is done:
+% we do that test too to ensure that \pkg{xparse} is compatible with the current
+% running version of \pkg{expl3}. The following §\ProvidesExplPackage§ simply
+% defines §\ver@xparse.sty§ for any other package that might uset it, and then
+% does \cs{ExplSyntaxOn}. At the end of the package, \pkg{xparse} parses (heh)
+% the package options. Since we don't have those in non-\LaTeX{} formats, they are
+% ignored. Okay, so load \pkg{xparse}:
+%    \begin{macrocode}
+\int_set:Nn \l_@@_tmpa_int { \char_value_catcode:n { `\@ } }
+\char_set_catcode_letter:N \@
+\exp_after:wN
+\ExplSyntaxOff
+\file_input:n { xparse.sty }
+\ExplSyntaxOn
+\char_set_catcode:nn { `\@ } { \l_@@_tmpa_int }
+\@@_compat_restore:
+%</loader&!latex>
+%<*core>
+%    \end{macrocode}
+% (actually we don't need to do \cs{ExplSyntaxOn} there because we don't have
+%  \LaTeX{}'s full package loading mechanism, so the \pkg{expl3} syntax remains
+%  active after \pkg{xparse} is loaded, but it doesn't harm either).
+%
 % \subsection{Programming of the sequences}
 %
 %   The storage of the package is done using |seq| variables.  Here we
@@ -2013,7 +2362,7 @@ No tab
 %
 % \begin{macro}{\@@_lastfrom_seq:n}
 %   \cs{@@_lastfrom_seq:n} retrieves the last saved item from the
-%   sequence when \cs{l_@@__print_env_bool} or \cs{l_@@__print_cmd_bool}
+%   sequence when \cs{l_@@_print_env_bool} or \cs{l_@@_print_cmd_bool}
 %   is true.
 %
 %    \begin{macrocode}
@@ -2048,15 +2397,39 @@ No tab
 % is divided into three parts. This implementation is taken from answer
 % by Enrico Gregorio in \url{https://tex.stackexchange.com/a/487746/7832}.
 %
-% \begin{macro}{scontents}
+% \begin{macro}{
+%     scontents,
+%     \scontents,
+%     \startscontents,
+%     \endscontents,
+%     \stopscontents,
+%     \@@_scontents_env_begin:,
+%     \@@_scontents_env_end:,
+%   }
 %   This is the main environment used in the document.
 %
 %    \begin{macrocode}
-\NewDocumentEnvironment { scontents } { }
+%</core>
+%<*loader>
+%<!context>\NewDocumentEnvironment { scontents } { }
+%<context>\cs_new_protected:Npn \startscontents
+  {
+%<plain|context>    \group_begin:
+    \@@_scontents_env_begin:
+  }
+%<context>\cs_new_protected:Npn \stopscontents
+  {
+    \@@_scontents_env_end:
+%<plain|context>    \group_end:
+  }
+%</loader>
+%<*core>
+\cs_new_protected:Npn \@@_scontents_env_begin:
   {
     \char_set_catcode_active:N \^^M
     \@@_start_environment:w
   }
+\cs_new_protected:Npn \@@_scontents_env_end:
   {
     \@@_stop_environment:
     \@@_atend_environment:
@@ -2069,54 +2442,58 @@ No tab
 % Define a \myoarg{key \textnormal{\textcolor{gray}{=}} val} for
 % environment \env{scontents}
 %
-% \begin{macro}{\@@_environment_inline:w,\@@_environment_keys:w,
-%      \@@_environment_junk:nw,\@@_environment_junk:xw}
-%   The macro \cs{@@_environment_inline:w} is called from the
+% \begin{macro}{\@@_grab_optional:n,\@@_grab_optional:w}
+%   The macro \cs{@@_grab_optional:w} is called from the
 %   \env{scontents} environment with the tokens following the
-%   §\begin{scontents}§. If the immediate next token (ignoring spaces)
-%   is a §[§, then we look for an optional argument delimited by a §]§.
-%   All the remaining tokens are treated as junk and an error is raised
-%   if they are non-blank.
+%   §\begin{scontents}§ when the next character is a §[§. This function
+%   is defined using \mypkg{xparse} to exploit its delimited argument
+%   processor.
 %
+%   The function is called from a context where §^^M§ is active, so
+%   \cs{@@_normalise_line_ends:N} is used to replace active §^^M§
+%   characters by spaces.
 %    \begin{macrocode}
-\cs_new_protected:Npn \@@_environment_inline:w
+%</core>
+%<*loader>
+\NewDocumentCommand \@@_grab_optional:w { r[] }
+  { \@@_grab_optional:n {#1} }
+%</loader>
+%<*core>
+\cs_new_protected:Npn \@@_grab_optional:n #1
   {
-    \peek_charcode_ignore_spaces:NTF [ % ]
-      { \@@_environment_keys:w }
+    \tl_if_novalue:nF {#1}
       {
-        \@@_environment_junk:xw
-          { after~\c_backslash_str begin{scontents} }
+        \tl_set:Nn \l_@@_temp_tl {#1}
+        \@@_normalise_line_ends:N \l_@@_temp_tl
+        \keys_set:nV { scontents / scontents } \l_@@_temp_tl
       }
+    \@@_start_after_option:w
   }
-\cs_new_protected:Npn \@@_environment_keys:w [ #1 ]
-  {
-    \keys_set:nn { scontents / scontents } {#1}
-    \@@_environment_junk:xw
-      { after~optional~argument~to~\c_backslash_str begin{scontents} }
-  }
-\cs_new_protected:Npn \@@_environment_junk:nw #1 #2 \q_@@_mark
-  {
-    \tl_if_blank:nF {#2}
-      { \msg_error:nnnn { scontents } { junk-after-begin } {#1} {#2} }
-  }
-\cs_generate_variant:Nn \@@_environment_junk:nw { x }
 %    \end{macrocode}
 % \end{macro}
 %
 % \subsubsection{The environment itself}
 %
-% \begin{macro}{\@@_start_environment:w,\@@_stop_environment:}
+% \begin{macro}{\@@_start_environment:w,\@@_start_after_option:w,
+%     \@@_check_line_and_process:xn,\@@_stop_environment:}
 %   Here we make §^^I§, §^^L§ and §^^M§ active characters so that the end of
 %   line can be \enquote{seen} to be used as a delimiter, and \hologo{TeX} doesn't try to
-%   eliminate space-like characters.  First we check if the line
-%   directly after §\begin{scontents}§ contains an optional argument
-%   enclosed in §[...]§ or other tokens. The trailing tokens are
-%   treated as junk and an error is raised.  The
-%   \cs{@@_environment_inline:w} macro checks for those cases.
+%   eliminate space-like characters.
+%
+%   First we check if the immediate next token after §\begin{scontents}§
+%   is a §[§. If it is, then \cs{@@_grab_optional:w} is called
+%   to do the heavy lifting. \cs{@@_grab_optional:w} processes the optional
+%   argument and calls \cs{@@_start_after_option:w}.
 %
-%   \cs{@@_start_environment:w} calls the \cs{@@_file_tl_write_start:V}
-%   function, which will then read the contents of the environment and
-%   optionally store them in a token list or write to an external file.
+%   \cs{@@_start_after_option:w} also checks for trailing tokens after
+%   the optional argument and issues an error if any.
+%
+%   In all cases \cs{@@_check_line_and_process:xn} is called to check that
+%   the rest of the §\begin{scontents}§ is empty and then process
+%   the environment. \cs{@@_check_line_and_process:xn} calls the
+%   \cs{@@_file_tl_write_start:V} function, which will then read the contents
+%   of the environment and optionally store them in a token list or write to
+%   an external file.
 %
 %   When that's done, \cs{@@_file_write_stop:N} does the cleanup and the
 %   read token list is smuggled out of the verbatim group. This part of
@@ -2132,9 +2509,27 @@ No tab
   \char_set_catcode_active:N \^^I
   \char_set_catcode_active:N \^^L
   \char_set_catcode_active:N \^^M
+  \cs_new_protected:Npn \@@_normalise_line_ends:N #1
+    { \tl_replace_all:Nnn #1 { ^^M } { ~ } }
   \cs_new_protected:Npn \@@_start_environment:w #1 ^^M
     {
-      \@@_environment_inline:w #1 \q_@@_mark
+      \tl_if_head_is_N_type:nTF {#1}
+        {
+          \str_if_eq:eeTF { \tl_head:n {#1} } { [ }
+            { \@@_grab_optional:w #1 ^^M }
+            { \@@_check_line_and_process:xn { } {#1} }
+        }
+        { \@@_check_line_and_process:xn { } {#1} }
+    }
+  \cs_new_protected:Npn \@@_start_after_option:w #1 ^^M
+    { \@@_check_line_and_process:xn { [...] } {#1} }
+  \cs_new_protected:Npn \@@_check_line_and_process:xn #1 #2
+    {
+      \tl_if_blank:nF {#2}
+        {
+          \msg_error:nnxn { scontents } { junk-after-begin }
+            { after~\c_backslash_str begin{scontents} #1 } {#2}
+        }
       \@@_make_control_chars_active:
       \group_begin:
         \@@_file_tl_write_start:V \l_@@_fname_out_tl
@@ -2145,6 +2540,8 @@ No tab
         \exp_args:NNNV
       \group_end:
       \tl_set:Nn \l_@@_macro_tmp_tl \l_@@_macro_tmp_tl
+      \tl_if_empty:NT \l_@@_macro_tmp_tl
+        { \msg_warning:nnn { scontents } { empty-environment } }
     }
 %    \end{macrocode}
 % \end{macro}
@@ -2217,7 +2614,10 @@ No tab
                   { \@@_verb_processor_output:n {#1} }
                 \cs_set_protected:Npx \@@_ret:w
                   {
-                    \exp_not:N \end{scontents}
+                    \@@_format_case:nnn
+                      { \exp_not:N \end{scontents} } % LaTeX
+                      { \endscontents } % Plain/Generic
+                      { \stopscontents } % ConTeXt
                     \bool_lazy_or:nnF
                       { \tl_if_blank_p:n {#2} }
                       { \str_if_eq_p:ee {#2} { \c_percent_str } }
@@ -2246,7 +2646,21 @@ No tab
         }
     }
   \cs_new:Npn \@@_remove_leading_nl:n #1
-    { \exp_not:o { \@@_remove_leading_nl:w #1 } }
+    {
+      \tl_if_head_is_N_type:nTF {#1}
+        {
+          \exp_args:Nf
+            \@@_remove_leading_nl:nn
+              { \tl_head:n {#1} } {#1}
+        }
+        { \exp_not:n {#1} }
+    }
+  \cs_new:Npn \@@_remove_leading_nl:nn #1 #2
+    {
+      \token_if_eq_meaning:NNTF ^^J #1
+        { \exp_not:o { \@@_remove_leading_nl:w #2 } }
+        { \exp_not:n {#2} }
+    }
   \cs_new:Npn \@@_remove_leading_nl:w ^^J { }
 %    \end{macrocode}
 % \end{macro}
@@ -2344,15 +2758,87 @@ No tab
           { \@@_lastfrom_seq:n \l_@@_name_seq_env_tl }
       }
   }
+%</core>
+%    \end{macrocode}
+% \end{macro}
+%
+% \begin{macro}[int]{\verbatim,\endverbatim}
+%   In Plain we emulate \LaTeX's \env{verbatim} environment.
+%    \begin{macrocode}
+%<*plain>
+\bool_new:N \l_@@_temp_bool
+\cs_new_protected:Npn \verbatim
+  { \@@_verbatim_aux: \frenchspacing \@@_vobeyspaces: \@@_xverb: }
+\cs_new_protected:Npn \@@_verbatim_aux:
+  {
+    \skip_vertical:N \parskip
+    \int_set:Nn \parindent { 0pt }
+    \skip_set:Nn \parfillskip { 0pt plus 1fil }
+    \int_set:Nn \parskip { 0pt plus0pt minus0pt }
+    \tex_par:D
+    \bool_set_false:N \l_@@_temp_bool
+    \cs_set:Npn \par
+      {
+        \bool_if:NTF \l_@@_temp_bool
+          {
+            \mode_leave_vertical:
+            \null
+            \tex_par:D
+            \penalty \interlinepenalty
+          }
+          {
+            \bool_set_true:N \l_@@_temp_bool
+            \mode_if_horizontal:T
+              { \tex_par:D \penalty \interlinepenalty }
+          }
+      }
+    \cs_set_eq:NN \do \char_set_catcode_other:N
+    \dospecials \obeylines
+    \tl_use:N \l_@@_verb_font_tl
+    \cs_set_eq:NN \do \@@_do_noligs:N
+    \@@_nolig_list:
+    \tex_everypar:D \exp_after:wN
+      { \tex_the:D \tex_everypar:D \tex_unpenalty:D }
+  }
+\cs_new_protected:Npn \@@_nolig_list:
+  { \do\`\do\<\do\>\do\,\do\'\do\- }
+\cs_new_protected:Npn \@@_vobeyspaces:
+  { \@@_set_active_eq:NN \  \@@_xobeysp: }
+\cs_new_protected:Npn \@@_xobeysp:
+  { \mode_leave_vertical: \nobreak \ }
+%</plain>
 %    \end{macrocode}
 % \end{macro}
 %
-% \subsection{The \cs{Scontents} command}
+% \begin{macro}[int]{\dospecials}
+%   \pkg{xparse} also requires \LaTeX's \cs{dospecials}. In case it doesn't
+%   exist (at the time \pkg{scontents} is loaded) we define \cs{dospecials}
+%   to use the \cs{l_char_special_seq}.
+%    \begin{macrocode}
+%<*!latex>
+\cs_if_exist:NF \dospecials
+  {
+    \cs_new:Npn \dospecials
+      { \seq_map_function:NN \l_char_special_seq \do }
+  }
+%</!latex>
+%    \end{macrocode}
+% \end{macro}
+%
+% \subsection{The command \cs{Scontents}}
 %
 % User command to \mymeta{stored content}, adapted from
 % \url{https://tex.stackexchange.com/a/500281/7832}.
 %
-% \begin{macro}{\Scontents,\@@_norm_arg:n,\@@_verb_arg:w}
+% \begin{macro}{
+%     \Scontents,
+%     \@@_norm_arg:n,
+%     \@@_Scontents_auxi:N,
+%     \Scontents code,
+%     \@@_Scontents_internal:nn,
+%     \@@_verb_arg:w,
+%     \@@_verb_arg_internal:n,
+%   }
 %   The §\Scontents§ macro starts by parsing an optional argument and
 %   then delegates to \cs{@@_verb_arg:w} or \cs{@@_norm_arg:n} depending whether
 %   a star (§*§) argument is present.
@@ -2364,13 +2850,18 @@ No tab
 %   argument parser.
 %
 %    \begin{macrocode}
+%<*loader>
 \NewDocumentCommand { \Scontents }{ !s !O{} }
+  { \@@_Scontents_internal:nn {#1} {#2} }
+%</loader>
+%<*core>
+\cs_new_protected:Npn \@@_Scontents_internal:nn #1 #2
   {
     \group_begin:
-      \IfNoValueF {#2}
+      \tl_if_novalue:nF {#2}
         { \keys_set:nn { scontents / Scontents } {#2} }
       \char_set_catcode_active:n { 9 }
-      \IfBooleanTF {#1}
+      \bool_if:NTF #1
         { \@@_verb_arg:w }
         { \@@_norm_arg:n }
   }
@@ -2383,7 +2874,13 @@ No tab
         { \@@_lastfrom_seq:n \l_@@_name_seq_cmd_tl }
     \group_end:
   }
+%</core>
+%<*loader>
 \NewDocumentCommand { \@@_verb_arg:w } { +v }
+  { \@@_verb_arg_internal:n {#1} }
+%</loader>
+%<*core>
+\cs_new_protected:Npn \@@_verb_arg_internal:n #1
   {
       \tl_set:Nx \l_@@_temp_tl { \exp_not:n {#1} }
       \tl_replace_all:Nxx \l_@@_temp_tl { \iow_char:N \^^M } { \iow_char:N \^^J }
@@ -2404,9 +2901,16 @@ No tab
 %   (robust).
 %
 %    \begin{macrocode}
+%</core>
+%<*loader>
 \NewDocumentCommand { \getstored } { O{1} m }
+  { \@@_getstored_internal:nn {#1} {#2} }
+%</loader>
+%<*core>
+\cs_new_protected:Npn \@@_getstored_internal:nn #1 #2
   {
     \group_begin:
+      \int_set:Nn \tex_newlinechar:D { `\^^J }
       \@@_rescan_tokens:x
         { \@@_getfrom_seq:nn {#1} {#2} }
     \group_end:
@@ -2414,7 +2918,55 @@ No tab
 %    \end{macrocode}
 % \end{macro}
 %
-% \subsection{The \cs{typestored} command}
+% \subsection{The command \cs{foreachsc}}
+%
+% \begin{macro}{\foreachsc}
+%   User command §\foreachsc§ to loop over \mymeta{stored content} in |seq|.
+%
+%    \begin{macrocode}
+%</core>
+%<*loader>
+\NewDocumentCommand { \foreachsc } { o m }
+  { \@@_foreachsc_internal:nn {#1} {#2} }
+%</loader>
+%<*core>
+\cs_new_protected:Npn \@@_foreachsc_internal:nn #1 #2
+  {
+    \group_begin:
+      \tl_if_novalue:nF {#1} { \keys_set:nn { scontents / foreachsc } {#1} }
+      \tl_set:Nn \l_@@_foreach_name_seq_tl {#2}
+      \seq_clear:N \l_@@_foreach_print_seq
+      \bool_if:NF \l_@@_foreach_stop_bool
+        {
+          \int_set:Nn \l_@@_foreach_stop_int
+            { \seq_count:c { g_@@_name_#2_seq } }
+        }
+      \int_step_function:nnnN
+        { \l_@@_foreach_start_int }
+        { \l_@@_foreach_step_int }
+        { \l_@@_foreach_stop_int }
+        \@@_foreach_add_body:n
+      \seq_use:Nn \l_@@_foreach_print_seq { \tl_use:N \l_@@_foreach_sep_tl }
+    \group_end:
+  }
+\cs_new_protected:Npn \@@_foreach_add_body:n #1
+  {
+    \seq_put_right:Nx \l_@@_foreach_print_seq
+      {
+        \bool_if:NT \l_@@_foreach_before_bool
+          { \exp_not:V \l_@@_foreach_before_tl }
+        \bool_if:NTF \l_@@_foreach_wrapper_bool
+          { \@@_foreach_wrapper:n }
+          { \use:n }
+            { \getstored [#1] { \tl_use:N \l_@@_foreach_name_seq_tl } }
+        \bool_if:NT \l_@@_foreach_after_bool
+          { \exp_not:V \l_@@_foreach_after_tl }
+      }
+  }
+%    \end{macrocode}
+% \end{macro}
+%
+% \subsection{The command \cs{typestored}}
 %
 % This implementation is an adaptation taken from answer by Phelype Oleinik
 % in (\url{https://tex.stackexchange.com/a/497651/7832}).
@@ -2424,15 +2976,19 @@ No tab
 %   to the log file, and then calls \cs{@@_verb_print:N}.
 %
 %    \begin{macrocode}
+%</core>
+%<*loader>
 \NewDocumentCommand { \typestored } { o m }
+  { \@@_typestored_internal:nn {#1} {#2} }
+%</loader>
+%<*core>
+\cs_new_protected:Npn \@@_typestored_internal:nn #1 #2
   {
     \group_begin:
       \int_set:Nn \l_@@_seq_item_int { 1 }
-      \IfValueT {#1} { \keys_set:nn { scontents / typemeaning } {#1} }
+      \tl_if_novalue:nF {#1} { \keys_set:nn { scontents / typemeaning } {#1} }
       \tl_set:Nx \l_@@_temp_tl
-        {
-          \exp_args:NV \@@_getfrom_seq:nn \l_@@_seq_item_int {#2}
-        }
+        { \exp_args:NV \@@_getfrom_seq:nn \l_@@_seq_item_int {#2} }
       \tl_remove_once:NV \l_@@_temp_tl \c_@@_hidden_space_str
       \tl_log:N \l_@@_temp_tl
       \tl_if_empty:NF \l_@@_temp_tl
@@ -2456,9 +3012,14 @@ No tab
       \cs_set_eq:NN \@@_verb_print_EOL: ^^M
       \cs_set_eq:NN ^^M \scan_stop:
       \cs_set_eq:cN { do@noligs } \@@_do_noligs:N
+      \int_set:Nn \tex_newlinechar:D { `\^^J }
       \@@_rescan_tokens:x
         {
-          \exp_not:N \begin{verbatimsc} ^^M
+          \@@_format_case:nnn
+            { \exp_not:N \begin{verbatimsc} } % LaTeX
+            { \verbatimsc } % Plain/Generic
+            { \startverbatimsc } % ConTeXt
+            ^^M
           \exp_not:V #1 ^^M
           \g_@@_end_verbatimsc_tl
         }
@@ -2476,18 +3037,30 @@ No tab
     \char_set_active_eq:nN { 9 } \@@_tabs_to_spaces:
     \@@_xverb:w
   }
+%</core>
+%<*loader>
 \use:x
   {
     \cs_new_protected:Npn \exp_not:N \@@_xverb:w
       ##1 \g_@@_end_verbatimsc_tl
+%<latex>      { ##1 \exp_not:N \end{verbatimsc} }
+%<plain>      { ##1 \exp_not:N \endverbatimsc }
+%<context>      { ##1 \exp_not:N \stopverbatimsc }
   }
-      { #1 \end{verbatimsc} }
+%<*!context>
 \NewDocumentEnvironment { verbatimsc } { }
   {
-    \cs_set_eq:cN { @xverbatim } \@@_xverb:
+%<plain>    \group_begin:
+%<latex>    \cs_set_eq:cN { @xverbatim } \@@_xverb:
     \verbatim
   }
-  { }
+  {
+%<plain>    \group_end:
+  }
+%</!context>
+%<context>\definetyping[verbatimsc]
+%</loader>
+%<*core>
 %    \end{macrocode}
 % \end{macro}
 %
@@ -2532,19 +3105,42 @@ No tab
 %     \@@_make_control_chars_active:,
 %   }
 %   Shortcut definitions for common catcode changes.
-%
+%   The §^^L§ needs a special treatment in non-\LaTeX{} mode
+%   because in Plain\,\TeX{} it is an \cs{outer} token.
 %    \begin{macrocode}
 \cs_new_protected:Npn \@@_set_active_eq:NN #1
   {
     \char_set_catcode_active:N #1
     \char_set_active_eq:NN #1
   }
-\cs_new_protected:Npn \@@_make_control_chars_active:
-  {
-    \@@_set_active_eq:NN \^^I \@@_tab:
-    \@@_set_active_eq:NN \^^L \@@_par:
-    \@@_set_active_eq:NN \^^M \@@_ret:w
-  }
+%</core>
+%<*loader>
+\group_begin:
+%<plain>  \char_set_catcode_active:n { `\* }
+  \cs_new_protected:Npn \@@_plain_disable_outer_par:
+%<*plain>
+    {
+      \group_begin:
+        \char_set_lccode:nn { `\* } { `\^^L }
+        \tex_lowercase:D { \group_end:
+        \tex_let:D * \scan_stop:
+      }
+    }
+%</plain>
+%<latex|context>    { }
+\group_end:
+%</loader>
+%<*core>
+\group_begin:
+  \char_set_catcode_active:N \*
+  \cs_new_protected:Npn \@@_make_control_chars_active:
+    {
+      \@@_plain_disable_outer_par:
+      \@@_set_active_eq:NN \^^I \@@_tab:
+      \@@_set_active_eq:NN \^^L \@@_par:
+      \@@_set_active_eq:NN \^^M \@@_ret:w
+    }
+\group_end:
 %    \end{macrocode}
 % \end{macro}
 %
@@ -2556,22 +3152,32 @@ No tab
 %   A user-level wrapper for \cs{keys_set:nn}§{ scontents }§.
 %
 %    \begin{macrocode}
+%</core>
+%<*loader>
 \NewDocumentCommand { \setupsc } { +m }
   { \keys_set:nn { scontents } {#1} }
+%</loader>
+%<*core>
 %    \end{macrocode}
 % \end{macro}
 %
-% \subsection{The command meaningsc}
+% \subsection{The command \cs{meaningsc}}
 %
 % \begin{macro}{\meaningsc}
 %   User command §\meaningsc§ to see content stored in |seq|.
 %
 %    \begin{macrocode}
+%</core>
+%<*loader>
 \NewDocumentCommand { \meaningsc } { o m }
+  { \@@_meaningsc_internal:nn {#1} {#2} }
+%</loader>
+%<*core>
+\cs_new_protected:Npn \@@_meaningsc_internal:nn #1 #2
   {
     \group_begin:
       \int_set:Nn \l_@@_seq_item_int { 1 }
-      \IfValueT {#1} { \keys_set:nn {  scontents / typemeaning } {#1} }
+      \tl_if_novalue:nF {#1} { \keys_set:nn { scontents / typemeaning } {#1} }
       \@@_meaningsc:n {#2}
     \group_end:
   }
@@ -2580,9 +3186,7 @@ No tab
   \cs_new_protected:Npn \@@_meaningsc:n #1
     {
       \tl_set:Nx \l_@@_temp_tl
-        {
-          \exp_args:NV \@@_getfrom_seq:nn \l_@@_seq_item_int {#1}
-        }
+        { \exp_args:NV \@@_getfrom_seq:nn \l_@@_seq_item_int {#1} }
       \tl_replace_all:Nxn \l_@@_temp_tl { \iow_char:N \^^J } { ~ }
       \tl_remove_once:NV  \l_@@_temp_tl \c_@@_hidden_space_str
       \tl_log:N \l_@@_temp_tl
@@ -2601,8 +3205,12 @@ No tab
 %   User command §\countsc§ to count number of contents stored in |seq|.
 %
 %    \begin{macrocode}
+%</core>
+%<*loader>
 \NewExpandableDocumentCommand { \countsc } { m }
   { \seq_count:c { g_@@_name_#1_seq } }
+%</loader>
+%<*core>
 %    \end{macrocode}
 % \end{macro}
 %
@@ -2613,8 +3221,12 @@ No tab
 %   A user command §\cleanseqsc§ to clear (remove) a defined |seq|.
 %
 %    \begin{macrocode}
+%</core>
+%<*loader>
 \NewDocumentCommand { \cleanseqsc } { m }
   { \seq_clear_new:c { g_@@_name_#1_seq } }
+%</loader>
+%<*core>
 %    \end{macrocode}
 % \end{macro}
 %
@@ -2677,6 +3289,18 @@ No tab
     The~command~'\c_backslash_str Scontents'~does~not~have~a~key~called~'#1'.\\
     Check~that~you~have~spelled~the~key~name~correctly.
   }
+\msg_new:nnnn { scontents } { for-key-unknown }
+  { The~key~'#1'~is~unknown~by~'\c_backslash_str foreachsc'~and~is~being~ignored.}
+  {
+    The~command~'\c_backslash_str foreachsc'~does~not~have~a~key~called~'#1'.\\
+    Check~that~you~have~spelled~the~key~name~correctly.
+  }
+\msg_new:nnnn { scontents } { for-key-value-unknown }
+  { The~key~'#1=#2'~is~unknown~by~'\c_backslash_str foreachsc'~and~is~being~ignored. }
+  {
+    The~command~'\c_backslash_str foreachsc'~does~not~have~a~key~called~'#1'.\\
+    Check~that~you~have~spelled~the~key~name~correctly.
+  }
 \msg_new:nnnn { scontents } { type-key-unknown }
   { The~key~'#1'~is~unknown~and~is~being~ignored. }
   {
@@ -2689,6 +3313,27 @@ No tab
     This~command~does~not~have~a~key~called~'#1'.\\
     This~command~only~accepts~the~key~'width-tab'.
   }
+\msg_new:nnn { scontents } { empty-environment }
+  { scontents~environment~empty~\msg_line_context:. }
+\msg_new:nnnn { scontents } { verbatim-newline }
+  { Verbatim~argument~of~#1~ended~by~end~of~line. }
+  {
+    The~verbatim~argument~of~the~#1~cannot~contain~more~than~one~line,~
+    but~the~end~
+    of~the~current~line~has~been~reached.~You~may~have~forgotten~the~
+    closing~delimiter.
+    \\ \\
+    LaTeX~will~ignore~'#2'.
+  }
+\msg_new:nnnn { scontents } { verbatim-tokenized }
+  { The~verbatim~#1~cannot~be~used~inside~an~argument. }
+  {
+    The~#1~takes~a~verbatim~argument.~
+    It~may~not~appear~within~the~argument~of~another~function.~
+    It~received~an~illegal~token \tl_if_empty:nF {#3} { ~'#3' } .
+    \\ \\
+    LaTeX~will~ignore~'#2'.
+  }
 %    \end{macrocode}
 %
 % \subsection{Finish package}
@@ -2696,9 +3341,7 @@ No tab
 % Finish package implementation.
 %
 %    \begin{macrocode}
-\file_input_stop:
+%</core>
+%<plain|context>\ExplSyntaxOff
 %    \end{macrocode}
-% \iffalse
-%</package>
-% \fi
 % \Finale
-- 
cgit v1.2.3

